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07 - euro -rtL4 HAMPTON WATER WORKS CO 1_ 1 ) A
AUG 0 6 99
HAND DELIVERED Department of Environmental Service
August 5 1991
dvard J Schaidt PE PhD Director Dapartbullant of Environmental Sarvicaa 6 Hazan Dr 1 va concord NH 03302-0095
RE BALISTRO REPORT - HAMPTON WATER WORKS CO HOBBS WELL tl5
Dear Doctor Schaidt
0 Attached ia a raviav or tha June 27 1991 Thoaaa p Ballaataro Aaaaaaaant Rapo-t Thia review waa partoraad by the hydroqaoloqiat ataff of o L Mahar company for tha Coapany Aa indicatad in thia raviav tha Ballaataro MODFLOW bullodal and aubaaquant concluaiona dravn baaed on tha aodal ara aarioualy tlavad and randar tha antira report to ba auapact in tarabull of ita credibility
The coapany and D L Mahar are available to you and tha o s Staff tor quaationa or further aaaiatanca that we can otter with regard to any and all data andjor apprabala o the data on Habullpton bull Well fl~l
Sincerely
~~~~Manager ~unq (
I bull Attachment
~21+9 Su bull PO Boo 11bull1 bull Hbull mi)IIOn NH036lt2 t6031iHmiddot lllt
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DL MAHER CO ~~~~t=AUG0699t
Department of Auquot s lUI[nvlronmental Strvicll
Mr Keith Boaeung Hampton Water Works 52 High Street Hampton NH 03842
REI Review of Balleatero Report
Dear Mr Boaaung1
We have completed a review o f the report titled Aaaeantent of the Potential Interaction Between the Aquifer Contamination Prom the Coakley Landfill and the Hampton Water Works Propoaed Hobba Well by Thomabull P Balleatero June 27 1991 The Balle1tero report h r e ferenced in t hh letter by the inltlah TB D L MAHER Report a D LH and the Remedial Inveatiqation Coakley Landfill report u RICL The following conta pertain to the aforementioned reporta1
1 Page 1 - T B report aaya inorganic and organic paruatera
indicative of landfill leachate have been detected abull tar
bullouth and webullt aa North Road However on paqe 7-30
(RLC L ) bulltatea However bullbulltimatea of qroundwater bull- shy
~9bull velocitiebull within the Little River Wetlandbull of only
003 to 0 3 teetday indicate that advective tranaport of
VOC contaminantbull from the Coakley Landfill aoutherly toward
monitorinq vella GZ-127 and GZ-129 may not have occurred in
the approximate ly lS yean aince the landfill dhpoaal
activitiebull beqan Therefore an additional undefined 10urce
h conaidered a pouibilitymiddot
2 Page 7- Eucutive Summary (R IC L ) - Although water
quality data suggest c ontaminant migration aa far aa North
Road within the Li ttle Ri ver wate r s hed hydrogeo l ogic da t a
71 CONCORD Sl REET NORlH READING MASSACHUSETlS 01864 6171933middot3210 FAX 508166 middot3299
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indicate that thh 1a improbable bull The T B report doea not
qualify ita statement through recognition of the RICL
raporta uncerta inty on contamination migration to North Road
or ita aourca
3 Paqa J - (TB ) - The Litt e River as preaented in the TB
report did not and could not have depoaited the bullavathbull of
low permeability material which holatea the Hobba Site from
Coakley The Little River h of recent origin reaultinq
from runoff on top of the underlying low permeable marine
depoe ita The low permeable material ia a product of aanda
aUt and claya depodtad in a glacioeatuarine marine
enviroNMnt during deglaciation approximately 8000-11000
B P The Little River ie too IMell of dynampJIIic erosional
-chanhbull to have reworked the aandgravel depoeitbull A
caplata undantandinq of the bulltudy are qeoloqic
depobullitional processes h a very important part in
conbulltructinq an accurate model
4 Paqa 3 (TB) - 0 L MAHER Te8t Well loq 9-90 bullhowbull
pradoinantly dlt and clay are found throuqhout the
bulltratabullbull indicative of marine deposita of vary low
hydraulic c onductivity The T B report states - there h
atronq evidence that t he sand and qravel deposits o f the
Hobba Site ia connec ted to t he sand and gravel of the
Coakley Site - Howe ver TB does not preaent any evidenc e
other than speculation
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5 Page S (T B) etatee ~ bedrock fracturebull to the weet of
Coakley exte nd towarde t he Hobba Site The TB report
doea not eubetantiate tha statement with d11ta in thie
portion of tha report
6 Paqe 6 (TB) - middot 60 o f the average annual rainfall
recharqea the aanda and gravele bull the OLM report utilized
50 not 60 of the average annual rainfall On page 11 of
T B report 21 inchesyearbull h used which equah 50
Apparent lack of cone latency in data uee
7 Paqe 8 (TBJ- a apecific yield of 005 falh within
publbhed water table valuea particularly for ailty eand _
aedimenta auch aa thoae edatinq within the Hobba aquifer
8 Pa9a 8-9 (T B ) - The logic of a direct ratio chanqa ~tween
groundwater level and change in total precipitation ia
incorrect Thle logic anwnee the aquifer ia a cloaed
ayater11 without horhontal dhcharge The Hobba aquifer h
reactinq in reality aa a mound with horhontal diacharqe
continually occurring through the fine qrain aedJnenta
aurroundinq the aquifer Aa precipitation entera the
aquifer qroundwater dilchar9t1 11 o ngo in9 draining the
aquifer A direc t rat io relationehip between precipitation
and groundwa ter levale h flawed
A rain induc ed rea ponee o f t he water tabla in a fi neshy
grained (allty) unc onfined aquHar 11 related to the eoil
moiature c o nt e nt air e ntrainmen t and the tillable porosi ty
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in the uneaturated zona Dry material can ftbaorb
eubltantially more water than can wet material because in
the latter c aae part o f t he atoraqe apace ie alre ady
occupied Therefore in reality the TB value o f bull 16 of
precipitation 18 e hown t o result in r echar9e bull la not a
reliable nor accurate number Alec the Hobba aquifer doea
not have uniform aquifer characterletice Run off on the
marine aUtclay cap overlying parte of the aquifer affect
the rate of recharge often imparting a delayed reaponae to
water lavale The recharqe area a actually quite amorphous
in ahape not suitable to the application of a circulac
andylie utilhinq linear radiua logic Derivinq an area of
radiua of 3210 feet and any concluliona from thh area are
not valid
t Pa~ 9 (T B ) - An 80 ratio of water level chanqe to total
precipitation ill u11ad in the T B report to indicate water
leveh at the end of the pWIIpinq test should be 0 1 feat
hiqher In contra lit a 16 ratio 111 used on paqe 9 (T B)
to e11tiJiate the recharqe area to the well The T B report
loqic 18 contradictory and euqqe11ts t hat the valubullbull selected
for a particular analyais are baBed on whichever value will
produce the most severe r e 11ult not on ac tual field
conditionbull The 11tre n9 th o f the conclusions r e ac hed by this
analyllill ill wea k
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10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such
aa lov permeable sediments and a ehallow depth to bedrock in
the vicinity of Well 6-90 Wood Knoll Drive serving aa a
hydrogeologic boundary between U SGS 69 waa not mentioned
in the T B report Test Well H- 2 is located in low
permeable sediments with shallow depth to bedrock The
pumping effects would take a much longer period of time to
be felt withJn the low permeable eedimente surrounding M-2
than in higher permeable sandbull and gravel
11 Page 10 (TB) - It appeare that a 3420 foot radius of
influence after 20 days of pumpinq at 260 GPM ia calculated
by the Theis equation The Theis equation assumes the
J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of
infinite areal extent horizontal piezometric surface the
vell 1bull fully ~netratinq and tranerniuivity ie conbulltant
The ubulle of the Theie equation in thia report qrobullbullly
violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull
(qreater than 700 feet) from the well The Hobbbull aquifer h
hiqhly heterocrenaoua of variable thicknenhydraulic
conductivity and areal extent A eloping water table
exbtbull Bedrock barrier boundaries axht within 700 feet of
the pwnped well near Wood rnoll and 1200 feet to the north
near North Road The depth to bedrock shallows to 30 feet
at M-2 Co nc luding t hat uniform radius o f 3420 feet h111
achieved after 20 days pumping h er r oneoue
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12 Paqe 10 (TB) - There 18 little evidence that Mtainted
river waterbull exists at RIC L aampling location S-2 along
the North River which contains cherllical parameters capable
of migrating through the marine aedimentll to the Hobbe Well
Site
13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad
on the use of the Thaie equation To reach a aubatantial
concluaion and precision of 58 GPM utilizing the Theia
equation h incorrect
14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate
the apecUic yield value of 0 05 yet on page 8 the T B
report states middoto2 is moat likely a very reasonable value
for sand and gravel bull There does not appear to be
condatency in the T B reporU logic
lS Paqe 12 (TB) - The DL M report flow path model equations
do not utilize storage coefficient valuebull in bullteady bulltate
analybullh Porosity is only utilized in the reverbullbull particle
tracking portion of the model for time of travel capture
ampone delineation not hydraulic head calculationa It would
be ubulleful for the TB author to read the flow path manual
to better understand the model
16 (DL M ) report flow path wae utilized o nly in a conceptual
format (DLM paqe 30) abull a precunor to r unning MODFLOW
Thie procedure is utlhe quite o ften i n many states to
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efficiently and economically determine where additionall field data needs to be collected in order to increase the
predicative accuracy of the HODFLOW model
17 Page 13 (TB)- a porosity of 02 not specific yield of
0 2 wae utilized in the 180-day particle tracking zoe of
the DLM report
18 Page 13 (TB) report states there was an annual rainfall
rate of 78 inchesyear during the seven days of pumping
Thh statement ia confusing and should be clarified Ie the
equivalent amount of rainfall experienced during the pump
teat extrapolated out an annual baaia
0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M
report h derived from reverse particle tracking which
deterwinea how lonq it would take a conaervative aolute euch
aa chloride to reach the wbullll The time of travbulll to
TOT-ZOC dbulllineation method haa been an accepted method by
the EPA The particle tracking zoe method ia D2t intended
to mimic the area of influence of the well It is incorrect
tor the TB report to auume the particle tr~ckinq zoe of
thbull vall is the aame as its area of influence
20 Page 17 (TB ) report states Corneliua Brook has an
elevation of 59 feet HSL However Cor nelius Brook when it
haa water in it has a signific ant gradient and not just one
elevation of 59 feet Cornellua Brook is not a po nd but
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rather hu multiple elevations depending on where i t l8
lftllaaured (Henry Fuller property or near I-95) Teet Nella
3middot84 and 4-84 which are located in c loae proximity to
Cornelius Brook have groundwater elevationa of 6724 and
65 75 feet reapectlvely The Little River has variable
elevations betwee n 6744 and 652 feet at RIC L staff
qauga SN-9 The TB report aqain eeema to aelect values
for a particular analyah baaed upon whichever value will
produce the desired outcome Therefore it la lncorract for
the TB report to aaaume ~that the Little River would be
aarving aa aOIMI portion of the recharge to the Hobbs Well~
baaed upon thh logic
21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta
aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull
Site b anhotropic hiqhly etratified with variable
hydraulic conductivitlee and traneminivltlee thereby
viohtinq the majority of the Theia auumptionbull and
conclubullione derived thereof
22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the
y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct
a atraiqht line encompaebullinq small dhtancee and drawing
bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect
Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat
ie covered yet the T B report extrapolatebull t he line out to
10 000 feet
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The T B Figure 1 plot clearly shows the drawdown ie
variable and not uniform in all directions thereby
violating a major aaaumption of Thela theory Teat Well
5-84 ahowa greater drawdown than Teet Well 11-90 in TB
Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from
the pumping well than 11-90 ( 97) It is reasonable to
conclude that low permeable boundarlea muet e xist in the
directio n of 5-84 If a radial line la constructed
connec ting 2-84 to 11-90 leas drawdown la s hown towards
11-90 indicative of more permeable material existing in
thia directio n The aquifer permeability variations are
clearly ahovn on DLH report Figure P4
A conparison of OLM teat well logs 5-84 and 11-90
ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84
Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while
11-90 pumped 20 GPM DL H cro section 8-8 shows leu
permeable eilty eand and gravel (not highly permeability
zones as stated in the TB report) surrounds the highly
permeable und and gravel in which the e ight inch pumped
well h located As an example on Tab l e J o f the RICL
report low hydraulic conductivity (lq values a r e shown for
six out of seven overburden wel ls even though t he strata
descriptions would imply a high~ value TB Figure 1 and
D L H P- 4 confirm the exhtence of l ow permeable barrier
boundaries to the north and northeast o f the pumped well
eite It ia incorrect t o c alc ulate and apply a radius o f
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l influence projecting (10000 feat in TB report) in the
direction of and beyond the barrier boundarlee
I 23 Page 18 - TB Figure 1 plot doea not include all t he
observation well data points thereby biasing the
conclusions
24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the
principal recharge direction to the well is from the
northwat and weat Thil recharge direction interpretation
bullbullkbullbull aenae aa it is in the direction of the center of the
aquifer
25 Page 18 (TB) - The last aentence in paragraph one
beginning with Both wells ~ and the first sentence in
paragraph two beginning with ~Another interpretation bull
contradict one another
2 Paqe 18 - T B atatee One curious point but does not aay
what that point is
27 Paqbull 18 - TB report doea not aubatanthte what data in the
drawdown level ill revealing vertical flow from the
underlying bedrock
28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J
fracture tracea underlying the aite The O LM report
atatea bulla potential north - northeaat trending fault atructure
may underlie the we ll sitebull The D L M r epo r t sta t ement
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l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
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be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
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a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
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11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
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high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
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U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
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these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
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area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
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unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
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n Q = = Ul
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the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
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conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
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habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
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C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
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bull EltCltllWIDl I
DL MAHER CO ~~~~t=AUG0699t
Department of Auquot s lUI[nvlronmental Strvicll
Mr Keith Boaeung Hampton Water Works 52 High Street Hampton NH 03842
REI Review of Balleatero Report
Dear Mr Boaaung1
We have completed a review o f the report titled Aaaeantent of the Potential Interaction Between the Aquifer Contamination Prom the Coakley Landfill and the Hampton Water Works Propoaed Hobba Well by Thomabull P Balleatero June 27 1991 The Balle1tero report h r e ferenced in t hh letter by the inltlah TB D L MAHER Report a D LH and the Remedial Inveatiqation Coakley Landfill report u RICL The following conta pertain to the aforementioned reporta1
1 Page 1 - T B report aaya inorganic and organic paruatera
indicative of landfill leachate have been detected abull tar
bullouth and webullt aa North Road However on paqe 7-30
(RLC L ) bulltatea However bullbulltimatea of qroundwater bull- shy
~9bull velocitiebull within the Little River Wetlandbull of only
003 to 0 3 teetday indicate that advective tranaport of
VOC contaminantbull from the Coakley Landfill aoutherly toward
monitorinq vella GZ-127 and GZ-129 may not have occurred in
the approximate ly lS yean aince the landfill dhpoaal
activitiebull beqan Therefore an additional undefined 10urce
h conaidered a pouibilitymiddot
2 Page 7- Eucutive Summary (R IC L ) - Although water
quality data suggest c ontaminant migration aa far aa North
Road within the Li ttle Ri ver wate r s hed hydrogeo l ogic da t a
71 CONCORD Sl REET NORlH READING MASSACHUSETlS 01864 6171933middot3210 FAX 508166 middot3299
co
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indicate that thh 1a improbable bull The T B report doea not
qualify ita statement through recognition of the RICL
raporta uncerta inty on contamination migration to North Road
or ita aourca
3 Paqa J - (TB ) - The Litt e River as preaented in the TB
report did not and could not have depoaited the bullavathbull of
low permeability material which holatea the Hobba Site from
Coakley The Little River h of recent origin reaultinq
from runoff on top of the underlying low permeable marine
depoe ita The low permeable material ia a product of aanda
aUt and claya depodtad in a glacioeatuarine marine
enviroNMnt during deglaciation approximately 8000-11000
B P The Little River ie too IMell of dynampJIIic erosional
-chanhbull to have reworked the aandgravel depoeitbull A
caplata undantandinq of the bulltudy are qeoloqic
depobullitional processes h a very important part in
conbulltructinq an accurate model
4 Paqa 3 (TB) - 0 L MAHER Te8t Well loq 9-90 bullhowbull
pradoinantly dlt and clay are found throuqhout the
bulltratabullbull indicative of marine deposita of vary low
hydraulic c onductivity The T B report states - there h
atronq evidence that t he sand and qravel deposits o f the
Hobba Site ia connec ted to t he sand and gravel of the
Coakley Site - Howe ver TB does not preaent any evidenc e
other than speculation
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5 Page S (T B) etatee ~ bedrock fracturebull to the weet of
Coakley exte nd towarde t he Hobba Site The TB report
doea not eubetantiate tha statement with d11ta in thie
portion of tha report
6 Paqe 6 (TB) - middot 60 o f the average annual rainfall
recharqea the aanda and gravele bull the OLM report utilized
50 not 60 of the average annual rainfall On page 11 of
T B report 21 inchesyearbull h used which equah 50
Apparent lack of cone latency in data uee
7 Paqe 8 (TBJ- a apecific yield of 005 falh within
publbhed water table valuea particularly for ailty eand _
aedimenta auch aa thoae edatinq within the Hobba aquifer
8 Pa9a 8-9 (T B ) - The logic of a direct ratio chanqa ~tween
groundwater level and change in total precipitation ia
incorrect Thle logic anwnee the aquifer ia a cloaed
ayater11 without horhontal dhcharge The Hobba aquifer h
reactinq in reality aa a mound with horhontal diacharqe
continually occurring through the fine qrain aedJnenta
aurroundinq the aquifer Aa precipitation entera the
aquifer qroundwater dilchar9t1 11 o ngo in9 draining the
aquifer A direc t rat io relationehip between precipitation
and groundwa ter levale h flawed
A rain induc ed rea ponee o f t he water tabla in a fi neshy
grained (allty) unc onfined aquHar 11 related to the eoil
moiature c o nt e nt air e ntrainmen t and the tillable porosi ty
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in the uneaturated zona Dry material can ftbaorb
eubltantially more water than can wet material because in
the latter c aae part o f t he atoraqe apace ie alre ady
occupied Therefore in reality the TB value o f bull 16 of
precipitation 18 e hown t o result in r echar9e bull la not a
reliable nor accurate number Alec the Hobba aquifer doea
not have uniform aquifer characterletice Run off on the
marine aUtclay cap overlying parte of the aquifer affect
the rate of recharge often imparting a delayed reaponae to
water lavale The recharqe area a actually quite amorphous
in ahape not suitable to the application of a circulac
andylie utilhinq linear radiua logic Derivinq an area of
radiua of 3210 feet and any concluliona from thh area are
not valid
t Pa~ 9 (T B ) - An 80 ratio of water level chanqe to total
precipitation ill u11ad in the T B report to indicate water
leveh at the end of the pWIIpinq test should be 0 1 feat
hiqher In contra lit a 16 ratio 111 used on paqe 9 (T B)
to e11tiJiate the recharqe area to the well The T B report
loqic 18 contradictory and euqqe11ts t hat the valubullbull selected
for a particular analyais are baBed on whichever value will
produce the most severe r e 11ult not on ac tual field
conditionbull The 11tre n9 th o f the conclusions r e ac hed by this
analyllill ill wea k
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10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such
aa lov permeable sediments and a ehallow depth to bedrock in
the vicinity of Well 6-90 Wood Knoll Drive serving aa a
hydrogeologic boundary between U SGS 69 waa not mentioned
in the T B report Test Well H- 2 is located in low
permeable sediments with shallow depth to bedrock The
pumping effects would take a much longer period of time to
be felt withJn the low permeable eedimente surrounding M-2
than in higher permeable sandbull and gravel
11 Page 10 (TB) - It appeare that a 3420 foot radius of
influence after 20 days of pumpinq at 260 GPM ia calculated
by the Theis equation The Theis equation assumes the
J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of
infinite areal extent horizontal piezometric surface the
vell 1bull fully ~netratinq and tranerniuivity ie conbulltant
The ubulle of the Theie equation in thia report qrobullbullly
violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull
(qreater than 700 feet) from the well The Hobbbull aquifer h
hiqhly heterocrenaoua of variable thicknenhydraulic
conductivity and areal extent A eloping water table
exbtbull Bedrock barrier boundaries axht within 700 feet of
the pwnped well near Wood rnoll and 1200 feet to the north
near North Road The depth to bedrock shallows to 30 feet
at M-2 Co nc luding t hat uniform radius o f 3420 feet h111
achieved after 20 days pumping h er r oneoue
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12 Paqe 10 (TB) - There 18 little evidence that Mtainted
river waterbull exists at RIC L aampling location S-2 along
the North River which contains cherllical parameters capable
of migrating through the marine aedimentll to the Hobbe Well
Site
13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad
on the use of the Thaie equation To reach a aubatantial
concluaion and precision of 58 GPM utilizing the Theia
equation h incorrect
14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate
the apecUic yield value of 0 05 yet on page 8 the T B
report states middoto2 is moat likely a very reasonable value
for sand and gravel bull There does not appear to be
condatency in the T B reporU logic
lS Paqe 12 (TB) - The DL M report flow path model equations
do not utilize storage coefficient valuebull in bullteady bulltate
analybullh Porosity is only utilized in the reverbullbull particle
tracking portion of the model for time of travel capture
ampone delineation not hydraulic head calculationa It would
be ubulleful for the TB author to read the flow path manual
to better understand the model
16 (DL M ) report flow path wae utilized o nly in a conceptual
format (DLM paqe 30) abull a precunor to r unning MODFLOW
Thie procedure is utlhe quite o ften i n many states to
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efficiently and economically determine where additionall field data needs to be collected in order to increase the
predicative accuracy of the HODFLOW model
17 Page 13 (TB)- a porosity of 02 not specific yield of
0 2 wae utilized in the 180-day particle tracking zoe of
the DLM report
18 Page 13 (TB) report states there was an annual rainfall
rate of 78 inchesyear during the seven days of pumping
Thh statement ia confusing and should be clarified Ie the
equivalent amount of rainfall experienced during the pump
teat extrapolated out an annual baaia
0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M
report h derived from reverse particle tracking which
deterwinea how lonq it would take a conaervative aolute euch
aa chloride to reach the wbullll The time of travbulll to
TOT-ZOC dbulllineation method haa been an accepted method by
the EPA The particle tracking zoe method ia D2t intended
to mimic the area of influence of the well It is incorrect
tor the TB report to auume the particle tr~ckinq zoe of
thbull vall is the aame as its area of influence
20 Page 17 (TB ) report states Corneliua Brook has an
elevation of 59 feet HSL However Cor nelius Brook when it
haa water in it has a signific ant gradient and not just one
elevation of 59 feet Cornellua Brook is not a po nd but
_ -7 shy
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rather hu multiple elevations depending on where i t l8
lftllaaured (Henry Fuller property or near I-95) Teet Nella
3middot84 and 4-84 which are located in c loae proximity to
Cornelius Brook have groundwater elevationa of 6724 and
65 75 feet reapectlvely The Little River has variable
elevations betwee n 6744 and 652 feet at RIC L staff
qauga SN-9 The TB report aqain eeema to aelect values
for a particular analyah baaed upon whichever value will
produce the desired outcome Therefore it la lncorract for
the TB report to aaaume ~that the Little River would be
aarving aa aOIMI portion of the recharge to the Hobbs Well~
baaed upon thh logic
21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta
aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull
Site b anhotropic hiqhly etratified with variable
hydraulic conductivitlee and traneminivltlee thereby
viohtinq the majority of the Theia auumptionbull and
conclubullione derived thereof
22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the
y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct
a atraiqht line encompaebullinq small dhtancee and drawing
bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect
Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat
ie covered yet the T B report extrapolatebull t he line out to
10 000 feet
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The T B Figure 1 plot clearly shows the drawdown ie
variable and not uniform in all directions thereby
violating a major aaaumption of Thela theory Teat Well
5-84 ahowa greater drawdown than Teet Well 11-90 in TB
Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from
the pumping well than 11-90 ( 97) It is reasonable to
conclude that low permeable boundarlea muet e xist in the
directio n of 5-84 If a radial line la constructed
connec ting 2-84 to 11-90 leas drawdown la s hown towards
11-90 indicative of more permeable material existing in
thia directio n The aquifer permeability variations are
clearly ahovn on DLH report Figure P4
A conparison of OLM teat well logs 5-84 and 11-90
ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84
Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while
11-90 pumped 20 GPM DL H cro section 8-8 shows leu
permeable eilty eand and gravel (not highly permeability
zones as stated in the TB report) surrounds the highly
permeable und and gravel in which the e ight inch pumped
well h located As an example on Tab l e J o f the RICL
report low hydraulic conductivity (lq values a r e shown for
six out of seven overburden wel ls even though t he strata
descriptions would imply a high~ value TB Figure 1 and
D L H P- 4 confirm the exhtence of l ow permeable barrier
boundaries to the north and northeast o f the pumped well
eite It ia incorrect t o c alc ulate and apply a radius o f
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l influence projecting (10000 feat in TB report) in the
direction of and beyond the barrier boundarlee
I 23 Page 18 - TB Figure 1 plot doea not include all t he
observation well data points thereby biasing the
conclusions
24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the
principal recharge direction to the well is from the
northwat and weat Thil recharge direction interpretation
bullbullkbullbull aenae aa it is in the direction of the center of the
aquifer
25 Page 18 (TB) - The last aentence in paragraph one
beginning with Both wells ~ and the first sentence in
paragraph two beginning with ~Another interpretation bull
contradict one another
2 Paqe 18 - T B atatee One curious point but does not aay
what that point is
27 Paqbull 18 - TB report doea not aubatanthte what data in the
drawdown level ill revealing vertical flow from the
underlying bedrock
28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J
fracture tracea underlying the aite The O LM report
atatea bulla potential north - northeaat trending fault atructure
may underlie the we ll sitebull The D L M r epo r t sta t ement
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l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
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be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
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a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
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11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
r -r -
high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
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area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
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the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
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conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
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habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
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C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
r -r -
indicate that thh 1a improbable bull The T B report doea not
qualify ita statement through recognition of the RICL
raporta uncerta inty on contamination migration to North Road
or ita aourca
3 Paqa J - (TB ) - The Litt e River as preaented in the TB
report did not and could not have depoaited the bullavathbull of
low permeability material which holatea the Hobba Site from
Coakley The Little River h of recent origin reaultinq
from runoff on top of the underlying low permeable marine
depoe ita The low permeable material ia a product of aanda
aUt and claya depodtad in a glacioeatuarine marine
enviroNMnt during deglaciation approximately 8000-11000
B P The Little River ie too IMell of dynampJIIic erosional
-chanhbull to have reworked the aandgravel depoeitbull A
caplata undantandinq of the bulltudy are qeoloqic
depobullitional processes h a very important part in
conbulltructinq an accurate model
4 Paqa 3 (TB) - 0 L MAHER Te8t Well loq 9-90 bullhowbull
pradoinantly dlt and clay are found throuqhout the
bulltratabullbull indicative of marine deposita of vary low
hydraulic c onductivity The T B report states - there h
atronq evidence that t he sand and qravel deposits o f the
Hobba Site ia connec ted to t he sand and gravel of the
Coakley Site - Howe ver TB does not preaent any evidenc e
other than speculation
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5 Page S (T B) etatee ~ bedrock fracturebull to the weet of
Coakley exte nd towarde t he Hobba Site The TB report
doea not eubetantiate tha statement with d11ta in thie
portion of tha report
6 Paqe 6 (TB) - middot 60 o f the average annual rainfall
recharqea the aanda and gravele bull the OLM report utilized
50 not 60 of the average annual rainfall On page 11 of
T B report 21 inchesyearbull h used which equah 50
Apparent lack of cone latency in data uee
7 Paqe 8 (TBJ- a apecific yield of 005 falh within
publbhed water table valuea particularly for ailty eand _
aedimenta auch aa thoae edatinq within the Hobba aquifer
8 Pa9a 8-9 (T B ) - The logic of a direct ratio chanqa ~tween
groundwater level and change in total precipitation ia
incorrect Thle logic anwnee the aquifer ia a cloaed
ayater11 without horhontal dhcharge The Hobba aquifer h
reactinq in reality aa a mound with horhontal diacharqe
continually occurring through the fine qrain aedJnenta
aurroundinq the aquifer Aa precipitation entera the
aquifer qroundwater dilchar9t1 11 o ngo in9 draining the
aquifer A direc t rat io relationehip between precipitation
and groundwa ter levale h flawed
A rain induc ed rea ponee o f t he water tabla in a fi neshy
grained (allty) unc onfined aquHar 11 related to the eoil
moiature c o nt e nt air e ntrainmen t and the tillable porosi ty
-3shy
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in the uneaturated zona Dry material can ftbaorb
eubltantially more water than can wet material because in
the latter c aae part o f t he atoraqe apace ie alre ady
occupied Therefore in reality the TB value o f bull 16 of
precipitation 18 e hown t o result in r echar9e bull la not a
reliable nor accurate number Alec the Hobba aquifer doea
not have uniform aquifer characterletice Run off on the
marine aUtclay cap overlying parte of the aquifer affect
the rate of recharge often imparting a delayed reaponae to
water lavale The recharqe area a actually quite amorphous
in ahape not suitable to the application of a circulac
andylie utilhinq linear radiua logic Derivinq an area of
radiua of 3210 feet and any concluliona from thh area are
not valid
t Pa~ 9 (T B ) - An 80 ratio of water level chanqe to total
precipitation ill u11ad in the T B report to indicate water
leveh at the end of the pWIIpinq test should be 0 1 feat
hiqher In contra lit a 16 ratio 111 used on paqe 9 (T B)
to e11tiJiate the recharqe area to the well The T B report
loqic 18 contradictory and euqqe11ts t hat the valubullbull selected
for a particular analyais are baBed on whichever value will
produce the most severe r e 11ult not on ac tual field
conditionbull The 11tre n9 th o f the conclusions r e ac hed by this
analyllill ill wea k
-middotshy
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10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such
aa lov permeable sediments and a ehallow depth to bedrock in
the vicinity of Well 6-90 Wood Knoll Drive serving aa a
hydrogeologic boundary between U SGS 69 waa not mentioned
in the T B report Test Well H- 2 is located in low
permeable sediments with shallow depth to bedrock The
pumping effects would take a much longer period of time to
be felt withJn the low permeable eedimente surrounding M-2
than in higher permeable sandbull and gravel
11 Page 10 (TB) - It appeare that a 3420 foot radius of
influence after 20 days of pumpinq at 260 GPM ia calculated
by the Theis equation The Theis equation assumes the
J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of
infinite areal extent horizontal piezometric surface the
vell 1bull fully ~netratinq and tranerniuivity ie conbulltant
The ubulle of the Theie equation in thia report qrobullbullly
violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull
(qreater than 700 feet) from the well The Hobbbull aquifer h
hiqhly heterocrenaoua of variable thicknenhydraulic
conductivity and areal extent A eloping water table
exbtbull Bedrock barrier boundaries axht within 700 feet of
the pwnped well near Wood rnoll and 1200 feet to the north
near North Road The depth to bedrock shallows to 30 feet
at M-2 Co nc luding t hat uniform radius o f 3420 feet h111
achieved after 20 days pumping h er r oneoue
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12 Paqe 10 (TB) - There 18 little evidence that Mtainted
river waterbull exists at RIC L aampling location S-2 along
the North River which contains cherllical parameters capable
of migrating through the marine aedimentll to the Hobbe Well
Site
13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad
on the use of the Thaie equation To reach a aubatantial
concluaion and precision of 58 GPM utilizing the Theia
equation h incorrect
14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate
the apecUic yield value of 0 05 yet on page 8 the T B
report states middoto2 is moat likely a very reasonable value
for sand and gravel bull There does not appear to be
condatency in the T B reporU logic
lS Paqe 12 (TB) - The DL M report flow path model equations
do not utilize storage coefficient valuebull in bullteady bulltate
analybullh Porosity is only utilized in the reverbullbull particle
tracking portion of the model for time of travel capture
ampone delineation not hydraulic head calculationa It would
be ubulleful for the TB author to read the flow path manual
to better understand the model
16 (DL M ) report flow path wae utilized o nly in a conceptual
format (DLM paqe 30) abull a precunor to r unning MODFLOW
Thie procedure is utlhe quite o ften i n many states to
- 6shy
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efficiently and economically determine where additionall field data needs to be collected in order to increase the
predicative accuracy of the HODFLOW model
17 Page 13 (TB)- a porosity of 02 not specific yield of
0 2 wae utilized in the 180-day particle tracking zoe of
the DLM report
18 Page 13 (TB) report states there was an annual rainfall
rate of 78 inchesyear during the seven days of pumping
Thh statement ia confusing and should be clarified Ie the
equivalent amount of rainfall experienced during the pump
teat extrapolated out an annual baaia
0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M
report h derived from reverse particle tracking which
deterwinea how lonq it would take a conaervative aolute euch
aa chloride to reach the wbullll The time of travbulll to
TOT-ZOC dbulllineation method haa been an accepted method by
the EPA The particle tracking zoe method ia D2t intended
to mimic the area of influence of the well It is incorrect
tor the TB report to auume the particle tr~ckinq zoe of
thbull vall is the aame as its area of influence
20 Page 17 (TB ) report states Corneliua Brook has an
elevation of 59 feet HSL However Cor nelius Brook when it
haa water in it has a signific ant gradient and not just one
elevation of 59 feet Cornellua Brook is not a po nd but
_ -7 shy
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rather hu multiple elevations depending on where i t l8
lftllaaured (Henry Fuller property or near I-95) Teet Nella
3middot84 and 4-84 which are located in c loae proximity to
Cornelius Brook have groundwater elevationa of 6724 and
65 75 feet reapectlvely The Little River has variable
elevations betwee n 6744 and 652 feet at RIC L staff
qauga SN-9 The TB report aqain eeema to aelect values
for a particular analyah baaed upon whichever value will
produce the desired outcome Therefore it la lncorract for
the TB report to aaaume ~that the Little River would be
aarving aa aOIMI portion of the recharge to the Hobbs Well~
baaed upon thh logic
21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta
aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull
Site b anhotropic hiqhly etratified with variable
hydraulic conductivitlee and traneminivltlee thereby
viohtinq the majority of the Theia auumptionbull and
conclubullione derived thereof
22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the
y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct
a atraiqht line encompaebullinq small dhtancee and drawing
bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect
Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat
ie covered yet the T B report extrapolatebull t he line out to
10 000 feet
-middotshy
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The T B Figure 1 plot clearly shows the drawdown ie
variable and not uniform in all directions thereby
violating a major aaaumption of Thela theory Teat Well
5-84 ahowa greater drawdown than Teet Well 11-90 in TB
Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from
the pumping well than 11-90 ( 97) It is reasonable to
conclude that low permeable boundarlea muet e xist in the
directio n of 5-84 If a radial line la constructed
connec ting 2-84 to 11-90 leas drawdown la s hown towards
11-90 indicative of more permeable material existing in
thia directio n The aquifer permeability variations are
clearly ahovn on DLH report Figure P4
A conparison of OLM teat well logs 5-84 and 11-90
ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84
Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while
11-90 pumped 20 GPM DL H cro section 8-8 shows leu
permeable eilty eand and gravel (not highly permeability
zones as stated in the TB report) surrounds the highly
permeable und and gravel in which the e ight inch pumped
well h located As an example on Tab l e J o f the RICL
report low hydraulic conductivity (lq values a r e shown for
six out of seven overburden wel ls even though t he strata
descriptions would imply a high~ value TB Figure 1 and
D L H P- 4 confirm the exhtence of l ow permeable barrier
boundaries to the north and northeast o f the pumped well
eite It ia incorrect t o c alc ulate and apply a radius o f
- 9 shy
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l influence projecting (10000 feat in TB report) in the
direction of and beyond the barrier boundarlee
I 23 Page 18 - TB Figure 1 plot doea not include all t he
observation well data points thereby biasing the
conclusions
24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the
principal recharge direction to the well is from the
northwat and weat Thil recharge direction interpretation
bullbullkbullbull aenae aa it is in the direction of the center of the
aquifer
25 Page 18 (TB) - The last aentence in paragraph one
beginning with Both wells ~ and the first sentence in
paragraph two beginning with ~Another interpretation bull
contradict one another
2 Paqe 18 - T B atatee One curious point but does not aay
what that point is
27 Paqbull 18 - TB report doea not aubatanthte what data in the
drawdown level ill revealing vertical flow from the
underlying bedrock
28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J
fracture tracea underlying the aite The O LM report
atatea bulla potential north - northeaat trending fault atructure
may underlie the we ll sitebull The D L M r epo r t sta t ement
- 10shy
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I r -r -
l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
-11shy
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be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
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a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
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11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
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high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
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U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
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n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
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n Q = = Ul
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the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
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conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
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habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
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C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
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5 Page S (T B) etatee ~ bedrock fracturebull to the weet of
Coakley exte nd towarde t he Hobba Site The TB report
doea not eubetantiate tha statement with d11ta in thie
portion of tha report
6 Paqe 6 (TB) - middot 60 o f the average annual rainfall
recharqea the aanda and gravele bull the OLM report utilized
50 not 60 of the average annual rainfall On page 11 of
T B report 21 inchesyearbull h used which equah 50
Apparent lack of cone latency in data uee
7 Paqe 8 (TBJ- a apecific yield of 005 falh within
publbhed water table valuea particularly for ailty eand _
aedimenta auch aa thoae edatinq within the Hobba aquifer
8 Pa9a 8-9 (T B ) - The logic of a direct ratio chanqa ~tween
groundwater level and change in total precipitation ia
incorrect Thle logic anwnee the aquifer ia a cloaed
ayater11 without horhontal dhcharge The Hobba aquifer h
reactinq in reality aa a mound with horhontal diacharqe
continually occurring through the fine qrain aedJnenta
aurroundinq the aquifer Aa precipitation entera the
aquifer qroundwater dilchar9t1 11 o ngo in9 draining the
aquifer A direc t rat io relationehip between precipitation
and groundwa ter levale h flawed
A rain induc ed rea ponee o f t he water tabla in a fi neshy
grained (allty) unc onfined aquHar 11 related to the eoil
moiature c o nt e nt air e ntrainmen t and the tillable porosi ty
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in the uneaturated zona Dry material can ftbaorb
eubltantially more water than can wet material because in
the latter c aae part o f t he atoraqe apace ie alre ady
occupied Therefore in reality the TB value o f bull 16 of
precipitation 18 e hown t o result in r echar9e bull la not a
reliable nor accurate number Alec the Hobba aquifer doea
not have uniform aquifer characterletice Run off on the
marine aUtclay cap overlying parte of the aquifer affect
the rate of recharge often imparting a delayed reaponae to
water lavale The recharqe area a actually quite amorphous
in ahape not suitable to the application of a circulac
andylie utilhinq linear radiua logic Derivinq an area of
radiua of 3210 feet and any concluliona from thh area are
not valid
t Pa~ 9 (T B ) - An 80 ratio of water level chanqe to total
precipitation ill u11ad in the T B report to indicate water
leveh at the end of the pWIIpinq test should be 0 1 feat
hiqher In contra lit a 16 ratio 111 used on paqe 9 (T B)
to e11tiJiate the recharqe area to the well The T B report
loqic 18 contradictory and euqqe11ts t hat the valubullbull selected
for a particular analyais are baBed on whichever value will
produce the most severe r e 11ult not on ac tual field
conditionbull The 11tre n9 th o f the conclusions r e ac hed by this
analyllill ill wea k
-middotshy
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10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such
aa lov permeable sediments and a ehallow depth to bedrock in
the vicinity of Well 6-90 Wood Knoll Drive serving aa a
hydrogeologic boundary between U SGS 69 waa not mentioned
in the T B report Test Well H- 2 is located in low
permeable sediments with shallow depth to bedrock The
pumping effects would take a much longer period of time to
be felt withJn the low permeable eedimente surrounding M-2
than in higher permeable sandbull and gravel
11 Page 10 (TB) - It appeare that a 3420 foot radius of
influence after 20 days of pumpinq at 260 GPM ia calculated
by the Theis equation The Theis equation assumes the
J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of
infinite areal extent horizontal piezometric surface the
vell 1bull fully ~netratinq and tranerniuivity ie conbulltant
The ubulle of the Theie equation in thia report qrobullbullly
violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull
(qreater than 700 feet) from the well The Hobbbull aquifer h
hiqhly heterocrenaoua of variable thicknenhydraulic
conductivity and areal extent A eloping water table
exbtbull Bedrock barrier boundaries axht within 700 feet of
the pwnped well near Wood rnoll and 1200 feet to the north
near North Road The depth to bedrock shallows to 30 feet
at M-2 Co nc luding t hat uniform radius o f 3420 feet h111
achieved after 20 days pumping h er r oneoue
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12 Paqe 10 (TB) - There 18 little evidence that Mtainted
river waterbull exists at RIC L aampling location S-2 along
the North River which contains cherllical parameters capable
of migrating through the marine aedimentll to the Hobbe Well
Site
13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad
on the use of the Thaie equation To reach a aubatantial
concluaion and precision of 58 GPM utilizing the Theia
equation h incorrect
14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate
the apecUic yield value of 0 05 yet on page 8 the T B
report states middoto2 is moat likely a very reasonable value
for sand and gravel bull There does not appear to be
condatency in the T B reporU logic
lS Paqe 12 (TB) - The DL M report flow path model equations
do not utilize storage coefficient valuebull in bullteady bulltate
analybullh Porosity is only utilized in the reverbullbull particle
tracking portion of the model for time of travel capture
ampone delineation not hydraulic head calculationa It would
be ubulleful for the TB author to read the flow path manual
to better understand the model
16 (DL M ) report flow path wae utilized o nly in a conceptual
format (DLM paqe 30) abull a precunor to r unning MODFLOW
Thie procedure is utlhe quite o ften i n many states to
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efficiently and economically determine where additionall field data needs to be collected in order to increase the
predicative accuracy of the HODFLOW model
17 Page 13 (TB)- a porosity of 02 not specific yield of
0 2 wae utilized in the 180-day particle tracking zoe of
the DLM report
18 Page 13 (TB) report states there was an annual rainfall
rate of 78 inchesyear during the seven days of pumping
Thh statement ia confusing and should be clarified Ie the
equivalent amount of rainfall experienced during the pump
teat extrapolated out an annual baaia
0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M
report h derived from reverse particle tracking which
deterwinea how lonq it would take a conaervative aolute euch
aa chloride to reach the wbullll The time of travbulll to
TOT-ZOC dbulllineation method haa been an accepted method by
the EPA The particle tracking zoe method ia D2t intended
to mimic the area of influence of the well It is incorrect
tor the TB report to auume the particle tr~ckinq zoe of
thbull vall is the aame as its area of influence
20 Page 17 (TB ) report states Corneliua Brook has an
elevation of 59 feet HSL However Cor nelius Brook when it
haa water in it has a signific ant gradient and not just one
elevation of 59 feet Cornellua Brook is not a po nd but
_ -7 shy
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rather hu multiple elevations depending on where i t l8
lftllaaured (Henry Fuller property or near I-95) Teet Nella
3middot84 and 4-84 which are located in c loae proximity to
Cornelius Brook have groundwater elevationa of 6724 and
65 75 feet reapectlvely The Little River has variable
elevations betwee n 6744 and 652 feet at RIC L staff
qauga SN-9 The TB report aqain eeema to aelect values
for a particular analyah baaed upon whichever value will
produce the desired outcome Therefore it la lncorract for
the TB report to aaaume ~that the Little River would be
aarving aa aOIMI portion of the recharge to the Hobbs Well~
baaed upon thh logic
21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta
aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull
Site b anhotropic hiqhly etratified with variable
hydraulic conductivitlee and traneminivltlee thereby
viohtinq the majority of the Theia auumptionbull and
conclubullione derived thereof
22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the
y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct
a atraiqht line encompaebullinq small dhtancee and drawing
bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect
Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat
ie covered yet the T B report extrapolatebull t he line out to
10 000 feet
-middotshy
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The T B Figure 1 plot clearly shows the drawdown ie
variable and not uniform in all directions thereby
violating a major aaaumption of Thela theory Teat Well
5-84 ahowa greater drawdown than Teet Well 11-90 in TB
Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from
the pumping well than 11-90 ( 97) It is reasonable to
conclude that low permeable boundarlea muet e xist in the
directio n of 5-84 If a radial line la constructed
connec ting 2-84 to 11-90 leas drawdown la s hown towards
11-90 indicative of more permeable material existing in
thia directio n The aquifer permeability variations are
clearly ahovn on DLH report Figure P4
A conparison of OLM teat well logs 5-84 and 11-90
ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84
Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while
11-90 pumped 20 GPM DL H cro section 8-8 shows leu
permeable eilty eand and gravel (not highly permeability
zones as stated in the TB report) surrounds the highly
permeable und and gravel in which the e ight inch pumped
well h located As an example on Tab l e J o f the RICL
report low hydraulic conductivity (lq values a r e shown for
six out of seven overburden wel ls even though t he strata
descriptions would imply a high~ value TB Figure 1 and
D L H P- 4 confirm the exhtence of l ow permeable barrier
boundaries to the north and northeast o f the pumped well
eite It ia incorrect t o c alc ulate and apply a radius o f
- 9 shy
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l influence projecting (10000 feat in TB report) in the
direction of and beyond the barrier boundarlee
I 23 Page 18 - TB Figure 1 plot doea not include all t he
observation well data points thereby biasing the
conclusions
24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the
principal recharge direction to the well is from the
northwat and weat Thil recharge direction interpretation
bullbullkbullbull aenae aa it is in the direction of the center of the
aquifer
25 Page 18 (TB) - The last aentence in paragraph one
beginning with Both wells ~ and the first sentence in
paragraph two beginning with ~Another interpretation bull
contradict one another
2 Paqe 18 - T B atatee One curious point but does not aay
what that point is
27 Paqbull 18 - TB report doea not aubatanthte what data in the
drawdown level ill revealing vertical flow from the
underlying bedrock
28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J
fracture tracea underlying the aite The O LM report
atatea bulla potential north - northeaat trending fault atructure
may underlie the we ll sitebull The D L M r epo r t sta t ement
- 10shy
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I r -r -
l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
-11shy
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be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
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a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
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11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
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high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
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U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
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these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
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r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
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conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
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habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
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C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
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in the uneaturated zona Dry material can ftbaorb
eubltantially more water than can wet material because in
the latter c aae part o f t he atoraqe apace ie alre ady
occupied Therefore in reality the TB value o f bull 16 of
precipitation 18 e hown t o result in r echar9e bull la not a
reliable nor accurate number Alec the Hobba aquifer doea
not have uniform aquifer characterletice Run off on the
marine aUtclay cap overlying parte of the aquifer affect
the rate of recharge often imparting a delayed reaponae to
water lavale The recharqe area a actually quite amorphous
in ahape not suitable to the application of a circulac
andylie utilhinq linear radiua logic Derivinq an area of
radiua of 3210 feet and any concluliona from thh area are
not valid
t Pa~ 9 (T B ) - An 80 ratio of water level chanqe to total
precipitation ill u11ad in the T B report to indicate water
leveh at the end of the pWIIpinq test should be 0 1 feat
hiqher In contra lit a 16 ratio 111 used on paqe 9 (T B)
to e11tiJiate the recharqe area to the well The T B report
loqic 18 contradictory and euqqe11ts t hat the valubullbull selected
for a particular analyais are baBed on whichever value will
produce the most severe r e 11ult not on ac tual field
conditionbull The 11tre n9 th o f the conclusions r e ac hed by this
analyllill ill wea k
-middotshy
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10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such
aa lov permeable sediments and a ehallow depth to bedrock in
the vicinity of Well 6-90 Wood Knoll Drive serving aa a
hydrogeologic boundary between U SGS 69 waa not mentioned
in the T B report Test Well H- 2 is located in low
permeable sediments with shallow depth to bedrock The
pumping effects would take a much longer period of time to
be felt withJn the low permeable eedimente surrounding M-2
than in higher permeable sandbull and gravel
11 Page 10 (TB) - It appeare that a 3420 foot radius of
influence after 20 days of pumpinq at 260 GPM ia calculated
by the Theis equation The Theis equation assumes the
J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of
infinite areal extent horizontal piezometric surface the
vell 1bull fully ~netratinq and tranerniuivity ie conbulltant
The ubulle of the Theie equation in thia report qrobullbullly
violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull
(qreater than 700 feet) from the well The Hobbbull aquifer h
hiqhly heterocrenaoua of variable thicknenhydraulic
conductivity and areal extent A eloping water table
exbtbull Bedrock barrier boundaries axht within 700 feet of
the pwnped well near Wood rnoll and 1200 feet to the north
near North Road The depth to bedrock shallows to 30 feet
at M-2 Co nc luding t hat uniform radius o f 3420 feet h111
achieved after 20 days pumping h er r oneoue
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12 Paqe 10 (TB) - There 18 little evidence that Mtainted
river waterbull exists at RIC L aampling location S-2 along
the North River which contains cherllical parameters capable
of migrating through the marine aedimentll to the Hobbe Well
Site
13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad
on the use of the Thaie equation To reach a aubatantial
concluaion and precision of 58 GPM utilizing the Theia
equation h incorrect
14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate
the apecUic yield value of 0 05 yet on page 8 the T B
report states middoto2 is moat likely a very reasonable value
for sand and gravel bull There does not appear to be
condatency in the T B reporU logic
lS Paqe 12 (TB) - The DL M report flow path model equations
do not utilize storage coefficient valuebull in bullteady bulltate
analybullh Porosity is only utilized in the reverbullbull particle
tracking portion of the model for time of travel capture
ampone delineation not hydraulic head calculationa It would
be ubulleful for the TB author to read the flow path manual
to better understand the model
16 (DL M ) report flow path wae utilized o nly in a conceptual
format (DLM paqe 30) abull a precunor to r unning MODFLOW
Thie procedure is utlhe quite o ften i n many states to
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efficiently and economically determine where additionall field data needs to be collected in order to increase the
predicative accuracy of the HODFLOW model
17 Page 13 (TB)- a porosity of 02 not specific yield of
0 2 wae utilized in the 180-day particle tracking zoe of
the DLM report
18 Page 13 (TB) report states there was an annual rainfall
rate of 78 inchesyear during the seven days of pumping
Thh statement ia confusing and should be clarified Ie the
equivalent amount of rainfall experienced during the pump
teat extrapolated out an annual baaia
0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M
report h derived from reverse particle tracking which
deterwinea how lonq it would take a conaervative aolute euch
aa chloride to reach the wbullll The time of travbulll to
TOT-ZOC dbulllineation method haa been an accepted method by
the EPA The particle tracking zoe method ia D2t intended
to mimic the area of influence of the well It is incorrect
tor the TB report to auume the particle tr~ckinq zoe of
thbull vall is the aame as its area of influence
20 Page 17 (TB ) report states Corneliua Brook has an
elevation of 59 feet HSL However Cor nelius Brook when it
haa water in it has a signific ant gradient and not just one
elevation of 59 feet Cornellua Brook is not a po nd but
_ -7 shy
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rather hu multiple elevations depending on where i t l8
lftllaaured (Henry Fuller property or near I-95) Teet Nella
3middot84 and 4-84 which are located in c loae proximity to
Cornelius Brook have groundwater elevationa of 6724 and
65 75 feet reapectlvely The Little River has variable
elevations betwee n 6744 and 652 feet at RIC L staff
qauga SN-9 The TB report aqain eeema to aelect values
for a particular analyah baaed upon whichever value will
produce the desired outcome Therefore it la lncorract for
the TB report to aaaume ~that the Little River would be
aarving aa aOIMI portion of the recharge to the Hobbs Well~
baaed upon thh logic
21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta
aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull
Site b anhotropic hiqhly etratified with variable
hydraulic conductivitlee and traneminivltlee thereby
viohtinq the majority of the Theia auumptionbull and
conclubullione derived thereof
22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the
y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct
a atraiqht line encompaebullinq small dhtancee and drawing
bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect
Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat
ie covered yet the T B report extrapolatebull t he line out to
10 000 feet
-middotshy
r r I
The T B Figure 1 plot clearly shows the drawdown ie
variable and not uniform in all directions thereby
violating a major aaaumption of Thela theory Teat Well
5-84 ahowa greater drawdown than Teet Well 11-90 in TB
Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from
the pumping well than 11-90 ( 97) It is reasonable to
conclude that low permeable boundarlea muet e xist in the
directio n of 5-84 If a radial line la constructed
connec ting 2-84 to 11-90 leas drawdown la s hown towards
11-90 indicative of more permeable material existing in
thia directio n The aquifer permeability variations are
clearly ahovn on DLH report Figure P4
A conparison of OLM teat well logs 5-84 and 11-90
ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84
Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while
11-90 pumped 20 GPM DL H cro section 8-8 shows leu
permeable eilty eand and gravel (not highly permeability
zones as stated in the TB report) surrounds the highly
permeable und and gravel in which the e ight inch pumped
well h located As an example on Tab l e J o f the RICL
report low hydraulic conductivity (lq values a r e shown for
six out of seven overburden wel ls even though t he strata
descriptions would imply a high~ value TB Figure 1 and
D L H P- 4 confirm the exhtence of l ow permeable barrier
boundaries to the north and northeast o f the pumped well
eite It ia incorrect t o c alc ulate and apply a radius o f
- 9 shy
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l influence projecting (10000 feat in TB report) in the
direction of and beyond the barrier boundarlee
I 23 Page 18 - TB Figure 1 plot doea not include all t he
observation well data points thereby biasing the
conclusions
24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the
principal recharge direction to the well is from the
northwat and weat Thil recharge direction interpretation
bullbullkbullbull aenae aa it is in the direction of the center of the
aquifer
25 Page 18 (TB) - The last aentence in paragraph one
beginning with Both wells ~ and the first sentence in
paragraph two beginning with ~Another interpretation bull
contradict one another
2 Paqe 18 - T B atatee One curious point but does not aay
what that point is
27 Paqbull 18 - TB report doea not aubatanthte what data in the
drawdown level ill revealing vertical flow from the
underlying bedrock
28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J
fracture tracea underlying the aite The O LM report
atatea bulla potential north - northeaat trending fault atructure
may underlie the we ll sitebull The D L M r epo r t sta t ement
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I r -r -
l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
-11shy
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be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
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a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
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11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
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high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
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these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
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r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
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conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
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habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
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C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
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10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such
aa lov permeable sediments and a ehallow depth to bedrock in
the vicinity of Well 6-90 Wood Knoll Drive serving aa a
hydrogeologic boundary between U SGS 69 waa not mentioned
in the T B report Test Well H- 2 is located in low
permeable sediments with shallow depth to bedrock The
pumping effects would take a much longer period of time to
be felt withJn the low permeable eedimente surrounding M-2
than in higher permeable sandbull and gravel
11 Page 10 (TB) - It appeare that a 3420 foot radius of
influence after 20 days of pumpinq at 260 GPM ia calculated
by the Theis equation The Theis equation assumes the
J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of
infinite areal extent horizontal piezometric surface the
vell 1bull fully ~netratinq and tranerniuivity ie conbulltant
The ubulle of the Theie equation in thia report qrobullbullly
violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull
(qreater than 700 feet) from the well The Hobbbull aquifer h
hiqhly heterocrenaoua of variable thicknenhydraulic
conductivity and areal extent A eloping water table
exbtbull Bedrock barrier boundaries axht within 700 feet of
the pwnped well near Wood rnoll and 1200 feet to the north
near North Road The depth to bedrock shallows to 30 feet
at M-2 Co nc luding t hat uniform radius o f 3420 feet h111
achieved after 20 days pumping h er r oneoue
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12 Paqe 10 (TB) - There 18 little evidence that Mtainted
river waterbull exists at RIC L aampling location S-2 along
the North River which contains cherllical parameters capable
of migrating through the marine aedimentll to the Hobbe Well
Site
13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad
on the use of the Thaie equation To reach a aubatantial
concluaion and precision of 58 GPM utilizing the Theia
equation h incorrect
14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate
the apecUic yield value of 0 05 yet on page 8 the T B
report states middoto2 is moat likely a very reasonable value
for sand and gravel bull There does not appear to be
condatency in the T B reporU logic
lS Paqe 12 (TB) - The DL M report flow path model equations
do not utilize storage coefficient valuebull in bullteady bulltate
analybullh Porosity is only utilized in the reverbullbull particle
tracking portion of the model for time of travel capture
ampone delineation not hydraulic head calculationa It would
be ubulleful for the TB author to read the flow path manual
to better understand the model
16 (DL M ) report flow path wae utilized o nly in a conceptual
format (DLM paqe 30) abull a precunor to r unning MODFLOW
Thie procedure is utlhe quite o ften i n many states to
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efficiently and economically determine where additionall field data needs to be collected in order to increase the
predicative accuracy of the HODFLOW model
17 Page 13 (TB)- a porosity of 02 not specific yield of
0 2 wae utilized in the 180-day particle tracking zoe of
the DLM report
18 Page 13 (TB) report states there was an annual rainfall
rate of 78 inchesyear during the seven days of pumping
Thh statement ia confusing and should be clarified Ie the
equivalent amount of rainfall experienced during the pump
teat extrapolated out an annual baaia
0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M
report h derived from reverse particle tracking which
deterwinea how lonq it would take a conaervative aolute euch
aa chloride to reach the wbullll The time of travbulll to
TOT-ZOC dbulllineation method haa been an accepted method by
the EPA The particle tracking zoe method ia D2t intended
to mimic the area of influence of the well It is incorrect
tor the TB report to auume the particle tr~ckinq zoe of
thbull vall is the aame as its area of influence
20 Page 17 (TB ) report states Corneliua Brook has an
elevation of 59 feet HSL However Cor nelius Brook when it
haa water in it has a signific ant gradient and not just one
elevation of 59 feet Cornellua Brook is not a po nd but
_ -7 shy
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rather hu multiple elevations depending on where i t l8
lftllaaured (Henry Fuller property or near I-95) Teet Nella
3middot84 and 4-84 which are located in c loae proximity to
Cornelius Brook have groundwater elevationa of 6724 and
65 75 feet reapectlvely The Little River has variable
elevations betwee n 6744 and 652 feet at RIC L staff
qauga SN-9 The TB report aqain eeema to aelect values
for a particular analyah baaed upon whichever value will
produce the desired outcome Therefore it la lncorract for
the TB report to aaaume ~that the Little River would be
aarving aa aOIMI portion of the recharge to the Hobbs Well~
baaed upon thh logic
21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta
aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull
Site b anhotropic hiqhly etratified with variable
hydraulic conductivitlee and traneminivltlee thereby
viohtinq the majority of the Theia auumptionbull and
conclubullione derived thereof
22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the
y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct
a atraiqht line encompaebullinq small dhtancee and drawing
bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect
Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat
ie covered yet the T B report extrapolatebull t he line out to
10 000 feet
-middotshy
r r I
The T B Figure 1 plot clearly shows the drawdown ie
variable and not uniform in all directions thereby
violating a major aaaumption of Thela theory Teat Well
5-84 ahowa greater drawdown than Teet Well 11-90 in TB
Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from
the pumping well than 11-90 ( 97) It is reasonable to
conclude that low permeable boundarlea muet e xist in the
directio n of 5-84 If a radial line la constructed
connec ting 2-84 to 11-90 leas drawdown la s hown towards
11-90 indicative of more permeable material existing in
thia directio n The aquifer permeability variations are
clearly ahovn on DLH report Figure P4
A conparison of OLM teat well logs 5-84 and 11-90
ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84
Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while
11-90 pumped 20 GPM DL H cro section 8-8 shows leu
permeable eilty eand and gravel (not highly permeability
zones as stated in the TB report) surrounds the highly
permeable und and gravel in which the e ight inch pumped
well h located As an example on Tab l e J o f the RICL
report low hydraulic conductivity (lq values a r e shown for
six out of seven overburden wel ls even though t he strata
descriptions would imply a high~ value TB Figure 1 and
D L H P- 4 confirm the exhtence of l ow permeable barrier
boundaries to the north and northeast o f the pumped well
eite It ia incorrect t o c alc ulate and apply a radius o f
- 9 shy
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l influence projecting (10000 feat in TB report) in the
direction of and beyond the barrier boundarlee
I 23 Page 18 - TB Figure 1 plot doea not include all t he
observation well data points thereby biasing the
conclusions
24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the
principal recharge direction to the well is from the
northwat and weat Thil recharge direction interpretation
bullbullkbullbull aenae aa it is in the direction of the center of the
aquifer
25 Page 18 (TB) - The last aentence in paragraph one
beginning with Both wells ~ and the first sentence in
paragraph two beginning with ~Another interpretation bull
contradict one another
2 Paqe 18 - T B atatee One curious point but does not aay
what that point is
27 Paqbull 18 - TB report doea not aubatanthte what data in the
drawdown level ill revealing vertical flow from the
underlying bedrock
28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J
fracture tracea underlying the aite The O LM report
atatea bulla potential north - northeaat trending fault atructure
may underlie the we ll sitebull The D L M r epo r t sta t ement
- 10shy
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I r -r -
l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
-11shy
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be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
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a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
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r -r -
11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
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high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
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conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
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habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
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C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
--
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12 Paqe 10 (TB) - There 18 little evidence that Mtainted
river waterbull exists at RIC L aampling location S-2 along
the North River which contains cherllical parameters capable
of migrating through the marine aedimentll to the Hobbe Well
Site
13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad
on the use of the Thaie equation To reach a aubatantial
concluaion and precision of 58 GPM utilizing the Theia
equation h incorrect
14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate
the apecUic yield value of 0 05 yet on page 8 the T B
report states middoto2 is moat likely a very reasonable value
for sand and gravel bull There does not appear to be
condatency in the T B reporU logic
lS Paqe 12 (TB) - The DL M report flow path model equations
do not utilize storage coefficient valuebull in bullteady bulltate
analybullh Porosity is only utilized in the reverbullbull particle
tracking portion of the model for time of travel capture
ampone delineation not hydraulic head calculationa It would
be ubulleful for the TB author to read the flow path manual
to better understand the model
16 (DL M ) report flow path wae utilized o nly in a conceptual
format (DLM paqe 30) abull a precunor to r unning MODFLOW
Thie procedure is utlhe quite o ften i n many states to
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efficiently and economically determine where additionall field data needs to be collected in order to increase the
predicative accuracy of the HODFLOW model
17 Page 13 (TB)- a porosity of 02 not specific yield of
0 2 wae utilized in the 180-day particle tracking zoe of
the DLM report
18 Page 13 (TB) report states there was an annual rainfall
rate of 78 inchesyear during the seven days of pumping
Thh statement ia confusing and should be clarified Ie the
equivalent amount of rainfall experienced during the pump
teat extrapolated out an annual baaia
0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M
report h derived from reverse particle tracking which
deterwinea how lonq it would take a conaervative aolute euch
aa chloride to reach the wbullll The time of travbulll to
TOT-ZOC dbulllineation method haa been an accepted method by
the EPA The particle tracking zoe method ia D2t intended
to mimic the area of influence of the well It is incorrect
tor the TB report to auume the particle tr~ckinq zoe of
thbull vall is the aame as its area of influence
20 Page 17 (TB ) report states Corneliua Brook has an
elevation of 59 feet HSL However Cor nelius Brook when it
haa water in it has a signific ant gradient and not just one
elevation of 59 feet Cornellua Brook is not a po nd but
_ -7 shy
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rather hu multiple elevations depending on where i t l8
lftllaaured (Henry Fuller property or near I-95) Teet Nella
3middot84 and 4-84 which are located in c loae proximity to
Cornelius Brook have groundwater elevationa of 6724 and
65 75 feet reapectlvely The Little River has variable
elevations betwee n 6744 and 652 feet at RIC L staff
qauga SN-9 The TB report aqain eeema to aelect values
for a particular analyah baaed upon whichever value will
produce the desired outcome Therefore it la lncorract for
the TB report to aaaume ~that the Little River would be
aarving aa aOIMI portion of the recharge to the Hobbs Well~
baaed upon thh logic
21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta
aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull
Site b anhotropic hiqhly etratified with variable
hydraulic conductivitlee and traneminivltlee thereby
viohtinq the majority of the Theia auumptionbull and
conclubullione derived thereof
22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the
y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct
a atraiqht line encompaebullinq small dhtancee and drawing
bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect
Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat
ie covered yet the T B report extrapolatebull t he line out to
10 000 feet
-middotshy
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The T B Figure 1 plot clearly shows the drawdown ie
variable and not uniform in all directions thereby
violating a major aaaumption of Thela theory Teat Well
5-84 ahowa greater drawdown than Teet Well 11-90 in TB
Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from
the pumping well than 11-90 ( 97) It is reasonable to
conclude that low permeable boundarlea muet e xist in the
directio n of 5-84 If a radial line la constructed
connec ting 2-84 to 11-90 leas drawdown la s hown towards
11-90 indicative of more permeable material existing in
thia directio n The aquifer permeability variations are
clearly ahovn on DLH report Figure P4
A conparison of OLM teat well logs 5-84 and 11-90
ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84
Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while
11-90 pumped 20 GPM DL H cro section 8-8 shows leu
permeable eilty eand and gravel (not highly permeability
zones as stated in the TB report) surrounds the highly
permeable und and gravel in which the e ight inch pumped
well h located As an example on Tab l e J o f the RICL
report low hydraulic conductivity (lq values a r e shown for
six out of seven overburden wel ls even though t he strata
descriptions would imply a high~ value TB Figure 1 and
D L H P- 4 confirm the exhtence of l ow permeable barrier
boundaries to the north and northeast o f the pumped well
eite It ia incorrect t o c alc ulate and apply a radius o f
- 9 shy
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l influence projecting (10000 feat in TB report) in the
direction of and beyond the barrier boundarlee
I 23 Page 18 - TB Figure 1 plot doea not include all t he
observation well data points thereby biasing the
conclusions
24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the
principal recharge direction to the well is from the
northwat and weat Thil recharge direction interpretation
bullbullkbullbull aenae aa it is in the direction of the center of the
aquifer
25 Page 18 (TB) - The last aentence in paragraph one
beginning with Both wells ~ and the first sentence in
paragraph two beginning with ~Another interpretation bull
contradict one another
2 Paqe 18 - T B atatee One curious point but does not aay
what that point is
27 Paqbull 18 - TB report doea not aubatanthte what data in the
drawdown level ill revealing vertical flow from the
underlying bedrock
28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J
fracture tracea underlying the aite The O LM report
atatea bulla potential north - northeaat trending fault atructure
may underlie the we ll sitebull The D L M r epo r t sta t ement
- 10shy
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I r -r -
l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
-11shy
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be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
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a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
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11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
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high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
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U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
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r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
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conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
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habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
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C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
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efficiently and economically determine where additionall field data needs to be collected in order to increase the
predicative accuracy of the HODFLOW model
17 Page 13 (TB)- a porosity of 02 not specific yield of
0 2 wae utilized in the 180-day particle tracking zoe of
the DLM report
18 Page 13 (TB) report states there was an annual rainfall
rate of 78 inchesyear during the seven days of pumping
Thh statement ia confusing and should be clarified Ie the
equivalent amount of rainfall experienced during the pump
teat extrapolated out an annual baaia
0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M
report h derived from reverse particle tracking which
deterwinea how lonq it would take a conaervative aolute euch
aa chloride to reach the wbullll The time of travbulll to
TOT-ZOC dbulllineation method haa been an accepted method by
the EPA The particle tracking zoe method ia D2t intended
to mimic the area of influence of the well It is incorrect
tor the TB report to auume the particle tr~ckinq zoe of
thbull vall is the aame as its area of influence
20 Page 17 (TB ) report states Corneliua Brook has an
elevation of 59 feet HSL However Cor nelius Brook when it
haa water in it has a signific ant gradient and not just one
elevation of 59 feet Cornellua Brook is not a po nd but
_ -7 shy
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rather hu multiple elevations depending on where i t l8
lftllaaured (Henry Fuller property or near I-95) Teet Nella
3middot84 and 4-84 which are located in c loae proximity to
Cornelius Brook have groundwater elevationa of 6724 and
65 75 feet reapectlvely The Little River has variable
elevations betwee n 6744 and 652 feet at RIC L staff
qauga SN-9 The TB report aqain eeema to aelect values
for a particular analyah baaed upon whichever value will
produce the desired outcome Therefore it la lncorract for
the TB report to aaaume ~that the Little River would be
aarving aa aOIMI portion of the recharge to the Hobbs Well~
baaed upon thh logic
21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta
aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull
Site b anhotropic hiqhly etratified with variable
hydraulic conductivitlee and traneminivltlee thereby
viohtinq the majority of the Theia auumptionbull and
conclubullione derived thereof
22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the
y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct
a atraiqht line encompaebullinq small dhtancee and drawing
bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect
Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat
ie covered yet the T B report extrapolatebull t he line out to
10 000 feet
-middotshy
r r I
The T B Figure 1 plot clearly shows the drawdown ie
variable and not uniform in all directions thereby
violating a major aaaumption of Thela theory Teat Well
5-84 ahowa greater drawdown than Teet Well 11-90 in TB
Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from
the pumping well than 11-90 ( 97) It is reasonable to
conclude that low permeable boundarlea muet e xist in the
directio n of 5-84 If a radial line la constructed
connec ting 2-84 to 11-90 leas drawdown la s hown towards
11-90 indicative of more permeable material existing in
thia directio n The aquifer permeability variations are
clearly ahovn on DLH report Figure P4
A conparison of OLM teat well logs 5-84 and 11-90
ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84
Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while
11-90 pumped 20 GPM DL H cro section 8-8 shows leu
permeable eilty eand and gravel (not highly permeability
zones as stated in the TB report) surrounds the highly
permeable und and gravel in which the e ight inch pumped
well h located As an example on Tab l e J o f the RICL
report low hydraulic conductivity (lq values a r e shown for
six out of seven overburden wel ls even though t he strata
descriptions would imply a high~ value TB Figure 1 and
D L H P- 4 confirm the exhtence of l ow permeable barrier
boundaries to the north and northeast o f the pumped well
eite It ia incorrect t o c alc ulate and apply a radius o f
- 9 shy
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l influence projecting (10000 feat in TB report) in the
direction of and beyond the barrier boundarlee
I 23 Page 18 - TB Figure 1 plot doea not include all t he
observation well data points thereby biasing the
conclusions
24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the
principal recharge direction to the well is from the
northwat and weat Thil recharge direction interpretation
bullbullkbullbull aenae aa it is in the direction of the center of the
aquifer
25 Page 18 (TB) - The last aentence in paragraph one
beginning with Both wells ~ and the first sentence in
paragraph two beginning with ~Another interpretation bull
contradict one another
2 Paqe 18 - T B atatee One curious point but does not aay
what that point is
27 Paqbull 18 - TB report doea not aubatanthte what data in the
drawdown level ill revealing vertical flow from the
underlying bedrock
28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J
fracture tracea underlying the aite The O LM report
atatea bulla potential north - northeaat trending fault atructure
may underlie the we ll sitebull The D L M r epo r t sta t ement
- 10shy
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l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
-11shy
--
r -r -
be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
- r -r -
a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
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r -r -
11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
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high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
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conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
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habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
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C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
--
r r
rather hu multiple elevations depending on where i t l8
lftllaaured (Henry Fuller property or near I-95) Teet Nella
3middot84 and 4-84 which are located in c loae proximity to
Cornelius Brook have groundwater elevationa of 6724 and
65 75 feet reapectlvely The Little River has variable
elevations betwee n 6744 and 652 feet at RIC L staff
qauga SN-9 The TB report aqain eeema to aelect values
for a particular analyah baaed upon whichever value will
produce the desired outcome Therefore it la lncorract for
the TB report to aaaume ~that the Little River would be
aarving aa aOIMI portion of the recharge to the Hobbs Well~
baaed upon thh logic
21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta
aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull
Site b anhotropic hiqhly etratified with variable
hydraulic conductivitlee and traneminivltlee thereby
viohtinq the majority of the Theia auumptionbull and
conclubullione derived thereof
22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the
y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct
a atraiqht line encompaebullinq small dhtancee and drawing
bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect
Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat
ie covered yet the T B report extrapolatebull t he line out to
10 000 feet
-middotshy
r r I
The T B Figure 1 plot clearly shows the drawdown ie
variable and not uniform in all directions thereby
violating a major aaaumption of Thela theory Teat Well
5-84 ahowa greater drawdown than Teet Well 11-90 in TB
Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from
the pumping well than 11-90 ( 97) It is reasonable to
conclude that low permeable boundarlea muet e xist in the
directio n of 5-84 If a radial line la constructed
connec ting 2-84 to 11-90 leas drawdown la s hown towards
11-90 indicative of more permeable material existing in
thia directio n The aquifer permeability variations are
clearly ahovn on DLH report Figure P4
A conparison of OLM teat well logs 5-84 and 11-90
ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84
Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while
11-90 pumped 20 GPM DL H cro section 8-8 shows leu
permeable eilty eand and gravel (not highly permeability
zones as stated in the TB report) surrounds the highly
permeable und and gravel in which the e ight inch pumped
well h located As an example on Tab l e J o f the RICL
report low hydraulic conductivity (lq values a r e shown for
six out of seven overburden wel ls even though t he strata
descriptions would imply a high~ value TB Figure 1 and
D L H P- 4 confirm the exhtence of l ow permeable barrier
boundaries to the north and northeast o f the pumped well
eite It ia incorrect t o c alc ulate and apply a radius o f
- 9 shy
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- r -r I
l influence projecting (10000 feat in TB report) in the
direction of and beyond the barrier boundarlee
I 23 Page 18 - TB Figure 1 plot doea not include all t he
observation well data points thereby biasing the
conclusions
24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the
principal recharge direction to the well is from the
northwat and weat Thil recharge direction interpretation
bullbullkbullbull aenae aa it is in the direction of the center of the
aquifer
25 Page 18 (TB) - The last aentence in paragraph one
beginning with Both wells ~ and the first sentence in
paragraph two beginning with ~Another interpretation bull
contradict one another
2 Paqe 18 - T B atatee One curious point but does not aay
what that point is
27 Paqbull 18 - TB report doea not aubatanthte what data in the
drawdown level ill revealing vertical flow from the
underlying bedrock
28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J
fracture tracea underlying the aite The O LM report
atatea bulla potential north - northeaat trending fault atructure
may underlie the we ll sitebull The D L M r epo r t sta t ement
- 10shy
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I r -r -
l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
-11shy
--
r -r -
be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
- r -r -
a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
--
r -r -
11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
r -r -
high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
r r I
The T B Figure 1 plot clearly shows the drawdown ie
variable and not uniform in all directions thereby
violating a major aaaumption of Thela theory Teat Well
5-84 ahowa greater drawdown than Teet Well 11-90 in TB
Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from
the pumping well than 11-90 ( 97) It is reasonable to
conclude that low permeable boundarlea muet e xist in the
directio n of 5-84 If a radial line la constructed
connec ting 2-84 to 11-90 leas drawdown la s hown towards
11-90 indicative of more permeable material existing in
thia directio n The aquifer permeability variations are
clearly ahovn on DLH report Figure P4
A conparison of OLM teat well logs 5-84 and 11-90
ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84
Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while
11-90 pumped 20 GPM DL H cro section 8-8 shows leu
permeable eilty eand and gravel (not highly permeability
zones as stated in the TB report) surrounds the highly
permeable und and gravel in which the e ight inch pumped
well h located As an example on Tab l e J o f the RICL
report low hydraulic conductivity (lq values a r e shown for
six out of seven overburden wel ls even though t he strata
descriptions would imply a high~ value TB Figure 1 and
D L H P- 4 confirm the exhtence of l ow permeable barrier
boundaries to the north and northeast o f the pumped well
eite It ia incorrect t o c alc ulate and apply a radius o f
- 9 shy
-shy
--
- r -r I
l influence projecting (10000 feat in TB report) in the
direction of and beyond the barrier boundarlee
I 23 Page 18 - TB Figure 1 plot doea not include all t he
observation well data points thereby biasing the
conclusions
24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the
principal recharge direction to the well is from the
northwat and weat Thil recharge direction interpretation
bullbullkbullbull aenae aa it is in the direction of the center of the
aquifer
25 Page 18 (TB) - The last aentence in paragraph one
beginning with Both wells ~ and the first sentence in
paragraph two beginning with ~Another interpretation bull
contradict one another
2 Paqe 18 - T B atatee One curious point but does not aay
what that point is
27 Paqbull 18 - TB report doea not aubatanthte what data in the
drawdown level ill revealing vertical flow from the
underlying bedrock
28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J
fracture tracea underlying the aite The O LM report
atatea bulla potential north - northeaat trending fault atructure
may underlie the we ll sitebull The D L M r epo r t sta t ement
- 10shy
--
I r -r -
l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
-11shy
--
r -r -
be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
- r -r -
a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
--
r -r -
11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
r -r -
high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
--
- r -r I
l influence projecting (10000 feat in TB report) in the
direction of and beyond the barrier boundarlee
I 23 Page 18 - TB Figure 1 plot doea not include all t he
observation well data points thereby biasing the
conclusions
24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the
principal recharge direction to the well is from the
northwat and weat Thil recharge direction interpretation
bullbullkbullbull aenae aa it is in the direction of the center of the
aquifer
25 Page 18 (TB) - The last aentence in paragraph one
beginning with Both wells ~ and the first sentence in
paragraph two beginning with ~Another interpretation bull
contradict one another
2 Paqe 18 - T B atatee One curious point but does not aay
what that point is
27 Paqbull 18 - TB report doea not aubatanthte what data in the
drawdown level ill revealing vertical flow from the
underlying bedrock
28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J
fracture tracea underlying the aite The O LM report
atatea bulla potential north - northeaat trending fault atructure
may underlie the we ll sitebull The D L M r epo r t sta t ement
- 10shy
--
I r -r -
l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
-11shy
--
r -r -
be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
- r -r -
a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
--
r -r -
11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
r -r -
high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
--
I r -r -
l vabull baaed upon cron-section interpretation ll2t from remote
1enaln9 and geophysical methods Frecture tracea are
obtained from rerre eeneing imagery analysis not croae
I aactlon i nterpretation The TB r epor t impllea that the
D L H report is s aying the structure 1a fact where the
DLM words poten t ioll and may are ignored
29 Page 20 - T B report Theae fractures presumably continue
directly towards the Ho bbs Site The major frequency
concentration of lineamentamp i dentified in the R IC L study
rlqure 5 doea rurt ehow the prominent lineaments 1111
continuing towards the Hobbs Site The TB report and
IIOdal have incorrectly extrapolated the photolineament swarm
0 aa ahown in the RICL report RI CL bedrock
110nltorin9 well GZ-128 wu drille d in the prominent
UneiUMtnt ewarm waet of the Coakley Landfill to a depth of
184 feet and produced only 0 25 GPH Tabla 4 (R IC L)
ehowe packer pressure taetad hydraulic conduc tivities
ranqinq frobull 014 to 682 feetday GZ-128 was not packer
teetad because o f the nonfractured and l ow water bearing
characterhtics o f the bedrock GZ-105 (bedrock corehola)
only had a hydraulic conductivity o f 2 0 fee tday Basad
upon the field technic al drill dat4 presented in the
R I cL report i t can Jl2t be concluded tha t the prominent
lineament s warm ae identified o n Figure 5 has a high
hydraulic conductivity Remote sensing analy8111 only
identlfie11 linear photo feature11 These f e a t ures may also
-11shy
--
r -r -
be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
- r -r -
a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
--
r -r -
11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
r -r -
high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
--
r -r -
be attributed to nonhydraulically significant geologic
1tructure1 Remote aenaing is an ~art- and drawing far
reachim~ concluaiona without drilling data ill incorrec t
However thh letter recognizee that due to the limitations
of remota saneincJ other signi ficant water bearing fracturea
may exbt in the bedrock not identified in the R ICL
JO Page 20 - TB states ~ bedrock groundwater generally flowa
in the direction of the Little River - However the T B
report oaita that bedrock groundwater aho generally flowbull
aoutheabullt to North Brook as ahovn on Fiqure 13 of the
R ICL report Bedrock groundwater flowbull radially in bullany
directionbull from the Coakley Landfill and the TB report
should not uae the word bullqenerally bull as it impli one major
direction only when in fact there are many flow pathe
R IC L total volatile organic compounds in
Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127
128 129 and 130 were either nondetected or leu than 5 ppb
Theee leveh are very low concentrations Only GZ-105
ehowed eignificant volatile organic compounds weet of the
Coakley Landfill The VOC levels at GZ-129 and GZ-130 may
b attributed t o additional small transient lind undefined
bullourcea in this area The R I C L r epo r t conc ludes o n paqe
8 - Exec utive Summary bullAt t his t lme however five years
of qrou ndwater contam i na t i o n e x ist away from the l andfill
per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill
- 12shy
- r -r -
a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
--
r -r -
11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
r -r -
high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
- r -r -
a likely consequence of the diepereive radial flow and
reaultant contaminant dilution ae well abull othe r operative
attenuation mechaniems diacueaed herein Beaed on the
available data it is anticipated that these olttenuatlon
mechanismbull would be a significant llrniting factor in the
diatance contaminants are able to migrate from the landfill
in detectable conc entrations
31 Pa9e 20 (TB) -The OLM and RICL reporta do not
auqqeat that the bedrock and overburden groundwater are
atrictly aeparated from each other
32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa
the Hobbs Site will create flow of groundwater fro11 beneath
and po ibly east of the Little River durinq amplltended low
rainfall recharge periods bull h very weak and baaed upon
faulty auwnptiona and data No creditable field data or
analyaia were brought forth to support the conclusionbull
JJ Fax Page J (TB) - Placing much emphasis upon the
conclusions derived from the application of Theis theory to
large distances beyond the pumping well is not valid due to
the qaologic conditione grouly violate Theta uawnptione
34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods
It is unclear aa to which time period conclus i o ns are
derived for It i s hiqhly unlikely pumpinq effects c an
deleteriously propaqate in 20 days thro uqh t he l ow permeable
- 13 shy
~ n = = =Ul
--
r -r -
11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
r -r -
high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
--
r -r -
11atariale located east of the Hobbs Site
35 Paqe llA (T B ) concludes that the safe yield from the
Hobbs Site is in the ranqe of 14 to 58 GPW If this yield
h true than the combined pumpage o f all the residential
wellbull in the study area will exceed the safe yie ld and
potentially impact the Coakley Landfill
36 Paqa 22 - TB reports etatea (1) a nything th11t wu not
sand and gravel laterally or vertically) was impermeable
and (2) streams to the northwest (Cornelius Brook) was
repreaented aa havinq a constant water level (basically an
infinite supply of water) bull In the D L MAHER report Paqe
Jl only the bedrock waa treated aa impermeable The llarine
aedlaentbull vera treated aa a constant head boundary allovinq
for flow into the aquifer Cornelius Brook waa not modeled
bullbull havinq a constant water level in the D L MAHER report
37 Paqe 22 (TB) -Some of the streams modeled as drains are
actually perched above the aquifer11 groundwater table upon
very low permeable marine sedmenta The drainbull are not
JnOdeled correctly Cornelius Brook dries up naturally from
June throuqh September and a significant portion h perched
above the aquifers water table Cornelius Brook receives
ita intermittent recharqe from runoff o n top o f the marine
aediment c ap overlying the northern portion of the Hobba
aquife r Some of t he Little River drain c ella are not
located properly Drain file conductance values appear very
-1 4 shy
r -r -
high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
r -r -
high for etreama flowing upon silts and claye
38 Page 27 (T B) model wa11 run b) atar tng at ateady state
conditione 2 of nonnal rechnrge for 180 day a and pumping
250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead
Protection area delineation requires the contributing area
to ~ delineated for a period of 180 daye pumpin with no
net rainfall recharge upon the ~~ regional
piezometric surface map This method of Wellhead
delineation wae stated by Paul Currier Administrator
Groundwater Protection Bureau during the July 25 1991
bullbullUnq at D E S offices in Concord The TB report
apparently did not model the zoe under thie criteria
39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling
effort it h etated that the model should uee hydraulic
coefficients which were measured in the field~ but fails to
follow through with this premise in the model The
tranbullmhbulllvity values selected for both fractured and
unfractured bedrock are neither explained nor supported by
field data If the va lues were taken from publlahed ranges
they are at t he upper ende of t heee rangee and not
reflective of typical conditio ne in New Enqland Based on
Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of
4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x
10middot1 to 1 2 x 10 feet day for unfractured roc k are more
realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy
- 15shy
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
r -r I
U S GS Water Supply Paper 2220 page 13 ehowa hydraulic
conductivity rangee for igneoua lind metamorphic rocks of
10middot7 feat day unfractured to 15 feet day fracture d
40 Page 218 (T B) - The r e port no tee t hat a ~three-layer
ayetam waa modeled however the model used wae a twt middotmiddot layer
110del It appears that the VCONT variable wae ueed to
repreaent the eiltclayfine eand layer with layer
thickneea eat to o ne foot Thera h no eupportive data of
the one foot thic knen value other than being arbitrarily
aeaiqnad Thia ie not an accurate rapraaantation of actual
conditiona nor ie it the beat way to fully and accurately
-adal thh ayatem
41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy
layer RIOdal and the eimpUfying aWDption of horhontal
layerl re1ult in a model which doee not reflect the actual
qeoloqy at thia alta The variable bedrock topography and
aquifer hydraulic conductivitiebull muet be accounte d for in
the lftOdal if an accurate delineation of the rona of
contribution 1a to be made
42 (T B ) - Thera h no me ntion in the text of either a
aanaitiv ity anal yeh being made or o f a water budget being
c alc ula t ed The s e efforts are both important compone nts of
a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the
acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d
they ehould ha ve been no t ed i n t he report I f e ither o f
- 16 shy
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
I r -r I
these was omitted the model results should be viewed as
potentially inacc urate
43 (TB ) - The use of porous media approximation to model flow
in fractured bedrock c an be accomplished ulling HOOFLOW
However reeet~rch done by the Waconein Geologic Survey has
shown that for thie approximation to be valid the model
scale should be two ardara of magnitude greater than the
magnitude of the fracture eyatem This 18 clearly not the
case in the Ballestero model caating doubt on the validity
of the model and accuracy of the model output A larger
JIOdel must be used to model the fracture zone if a porous
dia approdmatlon il to be used
The model area is too small and fails to include
aquifer area extending northwest and southwest of the
proposed well Ae a result model boundary conditionbull
interfere with the model aolution The T B report
recognizebull this need on Page 12 ~ the modeler hopes that the
boundaries are far enough away from the area o f intereat in
order not to influence the aolution at the area of
interest ~ but falls to follow it in the model
On Page 22 it ia noted that ~ groundwater elevationbull
could not be ma tc hed in the locatio n of the Coakley
Landfill because of t he contraat between t he actual s ite
conditione and t he eimplUying anumptione used in t he
development o f the mode l Coneiderlnq the slqnlfic ance o f
the Coakley Site a nd t he need to accurately model thh
- 17shy
n 0 gt = =Ul
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
r -r -
area a model more reflective o f actua l co nditione ehould
have been run At the least the model boundary 8hould have
been eKtanded paat t he vicinity of the landfill to ina ure
that an accur ate repre a e ntat ion of gro undwater flow in this
area waa made The T B report recogn izee t his ne ceaaity on
Page 12 however does not adhere to i t i n the T B model
44 Paqe 218- TS hydraulic conductivitiea i n the R IC L
Tabla three s how i n -flitu hydraulic conducti v itlee r anging
from 006 feet day to 25 feetday for the overburden
GJ-101 It values ( 510 feet day) h highly auepect ae the top
two feet of the well acraan h installed above the water
tabla in unsaturated coarse aand and gravel (aea Wall Loq
Gl-101 and eubeurface profile A-A Figure 9 R ICL) The
r-ainder of the screen 1bull lnbulltslled i n t ill The saturated
thicknebullbull of the sand gravel at GZ-101 is at beat three fee t
and not repre aentativa of the average t ransmha ivlty for the
overburden at the Coakley Landfill
Bedrock borehole pac ker pressure t e ats calculated
hydraulic conduc tivity valuaa ranging between 014 to 6 82
feetday GZ-109 and GZ-125 were not teeted due t o the
bedrock being unfrac tured and nonwater bea ring GZ - 105
(bedrock coreho le) had a hydraulic conducti vity o f only two
feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5
and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone
o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty
v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h
-18 shy
i n = = = U
c
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
~middot r -r I
unrealiatically high The unfractured bedrock
tranemiuivity value of 100 foot2day utilhed outaide the
fracture zone ia very high for typical New England bedrock
Table 4 of the RICL report ehowe a hydraulic
conductivity value o f 0018 feet day for bedrock well
Gl-125 Thie well produced three GPH whic h la
rapreeent ative of typical Nev Hampshire metamorphic bedrock
45 (TB ) - report model does not calibrate correctly at the
Coakley Landfill for no pumping normal recharge in the
bedrock or overburden head mapa The model haa severe
problema in the calculated overburden steady state - head
p1 pup 260 GPM in the vicinity of the Coakley Landfill
The elevationbull under 260 GPM pumpinq c onditione are hiqher
(aa lftuch ae 8 9 feet) than the no pumping normal recharge
overburde n head map An a ccurate rnodel over the Coakley
Landfill bullhould a how either no drawdown or drawdown under
pwnping conditions The pumping 260 GPH normal recharge
overburden eteady a tate head map a leo shows 9999 elevatione
in the southeast and southwest corners where the c alculated
overburden headmap1 c alibration - no pump ing normal
recharge ahowa e levationbull in the 69 to 75 feet range in the
aoutheaet and 65 to 70 feet in the aout hweat Figures 12
a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown
e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7
18 19 20 21 2 2 R8 o f the c alc ulated over burden and
bedrock maps pumping 260 GPH show elevatio ns higher t han
- 19shy
n Q = = Ul
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
r -r I
the no pWipinq head mapa Thea a bullbullrioua model flawe
underecore the waakneaa of the model accuracy and the
reportbull concluaiona
46 Page 37 38 - TB report mapa show Coak ley contaminan t
movement in overburden and bedrock ae not edeting in the
reQion around North Road (GZ-127 128 129 130 well a) Yet
T B report (page 1) aaye Inorganic and organic parameters
indicative of landfill leachate have been detected ae far
eouth and west aa North Road and the Little Riven bull Alec
the TB report on page 50 atatee Ae welh 127128 may
already be raceivinq Coakhy Leachate Figure 23 (page 46)
of the TB report ahowe only three cells affected by
contination when c ompared to Figure 14 (page 37) Fiqure
24 (page 47) bedrock ahowe only tvo cella affected by
contaalnation in bedrock when compared to Fiqure 15 (paqe
Jl)
47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock
fracturebull and the eJttent of the ailt c lay layer between
overburden and bedrock are unknown~ Thia atatement
undencorea the queat1on1 If the reliability of the T B
odel input data la questionable how accurate are the
conclubulliona7
-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to
aqree with t he OL M r eport
-2 0 shy
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
r -r I
49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the
monitorlnq wells as ineffective~ yet in the naJtt paragraph
the report statee bullmonitoring wells H2 127 128 9-90 and
10-90 are in good poaitlona for monitoring any long-term
effecta due to Co11kley contaminants bull This section of the
report ia confusing and contradictory
50 Page 51 (T B) - Wetland areas are incorrectly modeled in
the TB report many of the watlanda are naturally parched
aa much as five feet above the aquifer groundwater tabla
0
51 Paqa 53 (TB) - The report auqqeating the town of North
Hopton to tu or lmpoaa a fee schedule on each qallon of
water puped from the well h counter productive towarda the
auccaaa of the New Hampahlre Wellhead Protection Prograa and
would be precedent settinq Also the tu would only be
pbullbullbullbulld on to the coneumer
52 Paqe 55 (T B ) - Movinq the well to a location about 1000
feet to the south would place the well on Stanley Knowles
property Prior to the Hobbs bullbullvan day pump test HampJnpton
Water Works ne gotiationbull with Kr II nowlee to locate a well
on his property were unsucceeeful Aho u sGS 69 well
water quality indicates manganese l evelll at 0 13 mg1 which
il well above the Safe Drinking Water Standard of 005 mg1
A atrong hydrogen sulfide odo r was detec ted in Tebullt
Well 5 - 90 during pump t esting Majo r wetlands exht in
cloee proximity t o t he pro posed l ocatio n which are in
- 21 shy
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
r -r -
conflict to groundwater pumpage according to the log
presented in the TB report
53 Paqe 55 (TB) - The concept of withdrawing surface water to
artificially recharge the Hobbs aquifer eeema contradictory
to the surface water conclueione ie wetlanda atreame
presented in thie report It a surface water existed with a
suitable safe yield and quality a water treatment plant
would btl constructed
54 Page 55 (T B) - The Dalton Well doea not pwnp two million
qallone ~r day aa it hu a aate yield of approd111ately
100-125 GPM
55 The T B report nun concludea that contaJilinanta from
Coakley will reach the Hobbe Well Site under dry weather
periods ThiB h an important concluaion and aupporta the
D L MAHER aeven day pump teat report
56 The T B report never defines the definition of eafe yield
51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11
private land owner without perlftheion from Hampton Water
Workll or the State of New Hampehire
58 (T B) - In the overburden head map at 180 daye with no
recharge only 13 feet o f drawdown oc c urre d at the Ho bbe
Well node C9Rll resulting in 43 feet o f aquife r saturate d
thlcknen rema i ning The T B report conUrme the wall site
- 22 shy
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
r -r I
habull a 180-day eafe yield of 260 GPM starting at steady etate
conditione
RICQMKENDATIONS 1
In order to move forward on the Hobba wall project it
h rec01111nended that Hampton Water Worka conduct the
following1
A Inatall bedrock and overburden observation walla at
bullelected locations between the Hobba Well Site and
Coakley Landfill The purpoee of the walla h to
obtain additional hydrogeoloqic information on the
0 overburden and bedrock Alao the observation vella
ahould be conatructed in a manner to monitor water
lavale over time
B Perfona a fully three-dimensional model utilhing
MODFLOW and MOOPATH computer programs The model
ahould have a variable-aha horizontal grid with
aufficient are a to include the entire aquifer extent
and avoid boundary interference Variable layer
thicknesaebull and elevationbull should ba hued upon field
veoloqic data and hydraulic parameters The model
ahould foll o w the Hay 1990 draft Wellhead Protection
are a delineatio n rules 1991 AugustSeptember ambient
water leve ls shou ld be incorporated i n the model
-2]shy
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672
--
r -r --
C Lonq term actual pWipinq over many yn will provide
the meet accurate repreaentation of the Hobbe Aquifer
~rformance
Very truly youre
O L MAHER Co
jJ-wJkJYI~ C-t J Theodore Ho~fn~
~ vlea Preedent Senior Hydroqeoloqbt
J f~ ~- Saith Project Manaqar
- 24shy
- barcode 571672
- barcodetext SDMS Doc ID 571672