final task report geophysical survey

/. CORPORATION

1S CP1OSSV DRIVE 3EDFOHD MASSACHUSETTS O1 73O

C-583-1-9-124 January 27,1989

Final Task Report TDD No. F1-8701-32 Geophysical Survey Reference No. S375RI10EI11 Rose Hill Regional Landfill CERCLISNo. RID980521025 South Kingstown, Rhode Island

1.0 INTRODUCTION

The NUS Corporation Field Investigation Team (NUS/FIT) was directed by the Waste Management Division of the Region I U.S. Environmental Protection Agency (EPA) to conduct an Expanded Site Inspection (ESI) of the Rose Hill Regional Landfill (RHRL) in South Kingstown, Rhode Island. A Task Work Plan (TWP No. D-583-11-7-4) to conduct geophysical surveying at the RHRL was prepared under Technical Directive Document (TDD) No. F1-8707-06. Geophysical work at the RHRL was to be conducted in two phases. Phase I included Very Low Frequency (VLF) electromagnetic resistivity (EMR) surveying in order to assess the extent of on- and offsite contaminant generation/migration in groundwater. During phase II, seismic refraction surveying would be performed to characterize overburden and bedrock stratigraphy and structure beneath and surrounding the landfill. At EPA's request, geophysical tasks were discontinued in early January 1988. This report discusses the results of geophysical data (VLF EM-16R) gathered prior to the discontinuation of the geophysical tasks. Other tasks completed for this ESI are detailed in the following reports:

Final Task Report for Surface Water and Sediment Sampling Final Task Report for Soil Sampling Final Task Report for Stream Gauging Final Task Report for Leachate Sampling Final Summary Report

2.0 METHODS

NUS/FIT utilized a Geonics Limited VLF electromagnetic unit in the 16R (resistivity) mode to collect apparent electrical resistivity and phase angle measurements. Apparent electrical resistivity is the total resistivity of the earth down to the depth of penetration; i.e., it is an average rather than absolute measurement. Measurements of the apparent electrical resistivity of the earth will decrease in an area underlainrby a conductive target. Conductive targets, such as a plume of contaminated groundwater, are identified by anomalously low resistivity measurements made relative to a more resistive, uncontaminated background.

The depth of VLF EM-16R signal penetration is primarily dependent on the earth's resistivity and to a lesser extent on signal frequency. The depth of penetration can be approximated from the "skin depth" equation for electromagnetic field attenuation with depth. The skin depth, 2, is defined as the depth at which the field has been attenuated to e-1 of it's value at the surface,

Z = 503 (p/f) 1« (meters) where, p = uniform resistivity in ohm-meters

f = signal frequency in hertz (Stewart & BretnalI, 1986).

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souowAsrr LANOfNJ.

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LEGEND

WETLANDS

VIFEM-16R LINES

COMPLETED

- .x DISCONTINUED (ATTEMKD DATA REJECTED DUE TO SIGNAL DtSTOKTIOM)

5 NOT TO SCALE

VLF EM-R SURVEY LINES LOCATIONS

ROSE HILL REGIONAL LANDFILL SOUTH KINGSTOWN, Rl

C-583-1-9-124 January 27, 1989

As the resistivity of a material increases, so does the effective depth of signal penetration. Groundwater contamination is generally a conductive target, and as such, is observed as a low resistivity measurement (an anomaly). Measurements indicative of groundwater contamination are generally less than 100 ohm-meters. According to the above equation, apparent resistivity values characteristic of groundwater contamination will generally be associated with penetration depths of less than 100 feet.

Phase angle measurements refer to measuring the lag or lead in phase between the electrical and magnetic components of the electromagnetic field. These measurements provide information on the vertical variation of the earth's resistivity. If the earth is electrically homogeneous down to the depth of signal penetration (as with a single layer earth model) the phase angle will be 45 degrees. In a two layer case, with a conductive layer over a resistive layer (as with saturated overburden over bedrock) the phase angle will be less than 45 degrees. Conversely, a more resistive surface layer over a conductive layer will produce a phase angle greater than 45 degrees. Therefore, if groundwater contamination (a conductive target) exists at relatively shallow depths in an overburden/bedrock system, we would expect phase angles of less than 45 degrees.

3.0 FIELD ACTIVITIES

Phase I field work was conducted on November 30 and December 1 and 2, 1987. Significant site observations included high levels of volatile organic compounds (VOCs) in the breathing zone, areas of stained soil, and equipment disturbances and failures. These observations and procedural deviations from TWP No. D-583-11-7-4 are discussed in a Trip Report (No. C-583-1-8-36) to EPA RSPO Don Smith dated January 11, 1987 (Attachment A). Unsatisfactory weather conditions, equipment failure and eventual discontinuation of the project by EPA resulted in the partial completion of only the phase I field work, VLF EM-16R surveying. However, since all survey lines were prioritized in the TWP, those lines regarded as most critical to the survey (source areas and downgradient of source areas) were completed.

A total of five lines of VLF EM-16R data covering approximately 3,800 linear feet were collected at a station interval of 50 feet on November 30 and December 1, 1987 (Figure 1). Two of these lines, VLF5 and VLF-6, covering approximately 1,200.linear feet, were run onsite. The remaining three lines, VLF-2, VLF-7, and VLF-8, covering approximately 2,600 linear feet, were run offsite. A line rational and prioritization(from TWP No. D-583-11-7-4) is included in Table 1, Attachment A.

VLF transmitters utilized for this survey included NSS from Cutler, Maine (operating at a frequency of 24 kHz) on November 30 for lines VLF-6 and VLF-8 and NAA from Annapolis, Maryland (operating at a frequency of 21.4 kHz) on December 1 for lines VLF-2, VLF-5, and VLF-7. Different transmitters were utilized due to the superior strength of one signal over the other on different days.

4.0 VLF SURVEY RESULTS *

Observed field data is listed in Table II and displayed graphically in Attachment B. Graphs are presented in semi-logarithmic form to.enhance identification of apparent resistivity anomalies (resistivity lows) which may be indicative of groundwater contamination. In general, onsite VLF EM16R survey lines exhibit apparent resistivity anomalies which may be indicative of groundwater contamination; however, none of the anomalies identified in data collected offsite are believed to be a result of groundwater contamination. Apparent resistivities observed in this investigation varied from 30 to 10,000 ohm-meters, corresponding to skin depths between 18 and 344 meters (59 and 1,129 feet). Phase angles in this investigation were almost always less than 45 degrees, suggesting increasing resistivity with depth. A line by line interpretation of VLF data (referring to Table 1 and graphs in Attachment B) is presented below:

C-583-1-9-124 January 27,1989

VLF-2 - Exhibits two apparent resistivity lows at line intervals of 500 and 650-700 feet, obtaining a minimum value of 800 ohm-meters. These anomalies are attributed to the presence of two unnamed surface water bodies, a small pond and brook. They are not believed to be a result of groundwater contamination for the following reasons:

1) Apparent resistivity values indicative of groundwater contamination are typically much lower (less than 100 ohm-meters) than the observed minimum (800 ohmmeters).

2) The locations of these anomalies correlate spatially with the locations of the surface water bodies. Measurements made close to both the brook and the pond were both low.

3) The response of the VLF unit is at a maximum at the surface and decreases with depth. Therefore it is reasonable that conductive surface features, such as brooks and ponds, could drop the relative response 200 ohm-meters in a background of 1,000 to 3,000 ohm-meters.

VLF-5- Exhibits a sharp decrease in apparent resistivity which is believed to be a result of traversing Mitchell Brook, which flows through the landfill. The bottom of this brook was observed to have an orange appearance, possibly due to the oxidation of ferrous constituents, which could account for the low resistivities observed. If contamination were present here, it could certainly be electromagnetically masked by the potential ferrous constituents in the brook. Therefore, attribution of the anomaly to constituents in surface water or groundwater cannot be conclusively determined. Signal distortion due to cultural interferences (power lines and chain link fence) required discontinuation of VLF-5 along the southern border of the solid waste landfill.

VLF-6- Exhibits low apparent resistivity from 200 to 500 feet with a minimum value of 30 ohmmeters. This response suggests the presence of groundwater contamination, most likely in overburden. VLF EM-16R data is in agreement with the high conductivities observed in overburden wells located along.the eastern border of the sewage sludge landfill (York Wastewater, 1984). In addition, sludge deposited in the sewage sludge area was reported to contain high concentrations of metals, such as copper and zinc (Bampton, 1981). It is therefore likely that the VLF EM-16R response observed could be a result of the conductive constituents in groundwater from the disposed sludge.

VLF-7- This data set shows no anomalous response. It is interpreted to represent a subsurface environment absent of conductive constituents indicative of groundwater contamination. Apparent resistivities^,observed along this line are typical of a "clean" uncontaminated shallow overburden/bedrock system.

VLF-8- Exhibits relatively low apparent resistivities (1,100 ohm-meters) over a very narrow zone (50 to 100 feet). The observed apparent resistivities are judged too high to be indicative of groundwater contamination, but rather may suggest the presence of a water bearing fracture in bedrock. A fracture trace analysis of the RHRL and surrounding region also suggests the presenceof north-notheast oriented bedrock fractures in the vicinity of VLF-8 (BCI Geonetics, 1987).

CONCLUSIONS AND RECOMMENDATIONS

Onsite VLF EM-16R surveying has identified anomalously low apparent resistivities beneath the RHRL in the area of the sewage sludge landfill (Line VLF-6). Correlation of VLF EM-16R data with existing conductivity data and information regarding the past disposal history of the landfill suggest the

5.0

C-583-1-9-124 January 27, 1989

anomalously low observed apparent resistivities are a result of contamination in groundwater. The VLF EM-16Rdata does not indicate whether this contamination is located in overburden, bedrock, or both.

Offsite VLF EM-16R surveying has failed to identify regions of anomalously low apparent resistivity which can be conclusively associated with groundwater contamination. Areas potentially free of conductive constituents in groundwater are located directly north of the solid waste landfill and approximately 0.5 miles southeast of the landfill boundaries. In particular, VLF EM-16R surveying on the opposite side of the Saugatucket River from the landfill (Lines VLF-7 and VLF-8) failed to detect conductive constitutents in groundwater. This result could suggest that the Saugatucket River may be acting as a hydrologic barrier to groundwater flow and also to contaminant migration to the southeast (the primary direction of groundwater flow from the landfill) (York Wastewater, 1984). However, the absence of conductive constituents in groundwater does not preclude the presence of non-conductive groundwater contamination or conductive contamination in sufficiently low concentrations to prohibit detection by VLF EM-16R surveying.

While attempting to identify offsite contaminant migration to the south of RHRL, NUS/FIT encountered severe distortion of VLF signals (attributed to power lines, traffic, and fences), which prohibited the collection of useful data along the western portions of lines VLF-5 and VLF-8. Electromagnetic data from these areas could aid in the evaluation of contaminant migration to the area south of the landfill, west of the Saugatucket River. To avoid "noise" problems encountered with the VLF EM-16R unit, future investigation might utilize electromagnetic units with a self-contained source/receiver couple, such as the Geonics Ltd. EM-31/EM-34. These units may prove less vulnerable to surface interferences for the following reasons:

1) The small source/receiver separation provides a stronger more localized electromagnetic field. This can improve reception in high noise areas and may prove less vulnerable to signal attenuation by power lines.

2) Data can be recorded independent of orientation, eliminating local obstructions between the source and receiver.

In order to further identify/characterize groundwater contamination beneath, and migration from, the RHRL, NUS/FIT recommends the following:

1) Electromagnetic surveying could be performed along the western, southern, and eastern boundaries of the Solid Waste Landfill. Since this area of the landfill has been built up to the extent where it is topographically higher than the surrounding"land, a more localized, radial flow pattern may exist. Localized contaminant qiigration may be in directions other than the direction of regional flow (to the southeast). Particular attention should be given to the western side of the Solid Waste Landfill as stressed vegetation (dead trees) can be observed offsite along Rose Hill Road.

2) Electromagnetic surveying could be performed offsite to the south of the RHRL on the same side of the Saugatucket River (west side) as the landfill is situated. This information, in conjunction with the VLF EM-16R data from the opposite side of the Saugatucket River (in this report), may aid in the evaluation of contaminant migration across the Saugatucket River.

3) Electromagnetic surveying could be performed for the purpose of defining the boundaries of each disposal area at the RHRL. Conductivity data could be gathered rapidly over the entire site using an EM-31 unit on a variable spaced grid (closer spaced measurements collected in areas exhibiting higher conductivity

C-583-1-9-124 January 27, 1989

gradients). Contoured conductivity data would enhance delineation of disposal area boundaries. This information may prove valuable in planning future site remediation.

4) If possible, electromagnetic surveying should be performed at hydrologically optimal time periods, such as early to mid-spring, when contaminant generation/migration is at a maximum.

Submitted By:

fa John McTigue M Geophysics Task Manager

Approval: Joanne O. Morin FIT Office Manager

JM/kk

REFERENCES

Bampton, N. (Town Engineer/Utility Director, Town of South Kingstown). 1983. Letter to J.W. Fester (Rhode Island Department of Environmental Management), dated August 6, 1981.

BCI, Geonetics, Inc. 1987. "Photolineament and Fracture Fabric Analyses of the Rose Hill Regional Landfill Prepared for NUS Corporation". November 13, 1987.

NUS/FIT. 1987. "Rose Hill Regional Landfill, South Kingstown, Rhode Island. Final Scope of Work". July 20, 1987. TDD No. F1-8701-32.

Stewart, M. and Bretnal, R. 1986. "Interpretation of VLF Resistivity Data for Groundwater Contamination Surveys". Groundwater Monitoring Review. V.6 No. 5 pp. 71-75.

York Wastewater Consultants, Inc. 1984. "Engineering and Hydrogeological Assessment of the Rose Hill Landfill Prepared for the South Kingstown". February 17,1984.

ATTACH ME NT A

F r? — • 1 f .. . • > X; ffl I U t= - ^ B il

CORPORATION

039517

REGION 1 FIT/EPA CORRESPONDENCE C- 583-1-8-36

TO: DON SMITH/EPA DATE: JANUARY 11.1988

FROM: JOHN MCT1GUE/TASK MANAGER COPIES: RLE

SUBJECT: TRIP REPORT ROSE HILL REGIONAL LANDFILL PHASE I GEOPHYSICS/VLF EM-16R TDD No. FI-8707-06 Reference No. S375R110E111

On Monday November 20, 1987, NUS/FIT began Very Low Frequency (VLF) electromagnetic resistivity surveying of the Rose Hill Regional Landfill in South Kingstown, Rhode Island. Field work was conducted on November 30 (cloudy with rain) and December 1 and 2, 1987 (mixed sun and clouds).

NUS/FIT personnel included Shirley Danke (VLF assistant), Steve Miller (VLF assistant and Site Safety Officer), and John McTigue (VLF coordinator). Resistivity surveying was conducted using a Geonics Limited VLF EM unit in 16R mode. Transmitters from Annapolis, Maryland (NSS) and Cutler, Maine (NAA) were utilized on November 30 and December 1 and 2, 1987, respectively. Data was gathered at a 50 foot station spacing on all lines.

Significant site observation included the following:

* On December 2, 1987 an Organic Vapor Analyzer (OVA) detected volatile organic compounds (VOCs) in the breathing zone at concentrations significantly above background (background approximately 1-2 parts per million (ppm)), in two locations (Figure 1):

1) The northwest comer of the Sulky Waste Landfill (BWL) at 7 ppm (above background).

2) The eastern (downgradient) side of the Solid Waste Landfill (SWL) at 11 ppm (above background).

These elevated readings may have resulted from the volatile components of leachate which was generated from heavy rain two days prior. It was not determined if these elevated readings resulted from the presence of methane.

* Stained soil (black and orange) was observed in the areas of the SWL where elevated levels of VOCs were detected in the breathing zone.

,,

»

USI MA* I*OU •IMWIIMNC » HVOOOCI0106KAL A1U SSMINT 0* TMI lOU MU. UMOHJ. VOK WASTTWATH COUWlTAim. «C HWUMV. 1*1

VOC's 7ppm

•ULICrWASTI / VOC't 11ppm

coimMo

OI3CONTMUEO

jo BE COMPLETED

NOT TO SCALE

VLF EM-R SURVEY LINES LOCATIONS


C-583-1-8-36 January 11,1988

MEMO TO: DON SMITH

* VLF EM-16R readings can be significantly obscured by signal interference from power lines if:

1) The power lines are less than one road width away.

2) Individual line segments between poles are vertically separated as distinct lines, rather than being wrapped around each other as one line.

VLF EM-16R surveying was performed in accordance with Task Work Plan No. 0-583-11-7-4 and the accompanying Site Safety Plan, with the following exceptions:

1) VLF-1 was not run along the roadside because of space constraints required by the transmitter/receiver orientation. This line will be relocated along the-western border of the SWL

2) The western end of VLF-2 was discontinued due to signal interference resulting ~ from power lines.

3) The eastern half of line VLF-5 was discontinued due to interference from power lines and a chain link fence located along the southern border of the SWL.

4) Data was not gathered along the western end of line VLF-8 (Figure 1) because power line interference did not allow proper instrument orientation. The Task Manager obtained access to a nearby property, allowing the eastern portion of VLF-8 to be relocated and extended to 700 feet

5) Background lines VLF-A and VLF-8 (Figure 2) were not run because it was judged that their remote location would not provide any useful data. Rather, onsite lines would be extended to include background measurements at the beginning and end of each line, allowing anomaly identification in relations to surrounding background measurements.

The following, problems inhibited survey efficiency and prohibited completion of Phase I of the geophj cai tasks.

1) The HNu systems photoionization detector malfunctioned (the air pump for the probe broke), leaving the OVA as the only air monitoring instrument. The OVA malfunctioned, presumably due to moisture from the heavy rain. Therefore, NUS personnel evacuated the site as required by the site safety plan.

• '/ f ! -,*'

SEWAGE SLUDGE LANDf ILL <V .?•*••»••"';'. > I ' .'

BASE MAP IS A POar/-"W THE FOLLOWING U.S.G.S. 7.S* SEMES QUAOKANGLE(S): NARRAGANSETT «EkA: 1W7. PHOTOKEVtSED 1170 AND If 75 KINGSTOWN. M 1M7*»HOTOAEVtSED IfTO AND 1*7S

* 0 1009

LOCATION OF VLF EM-R BACKGROUND LINES


FIGURE 2

C-583-1-8-36 January 11,1988

MEMO TO: DON SMITH

2) The VLF EM-16R unit malfunctioned (circuitry on pre-amplifier boards located in the probes required soldering). Identification of the problem, repair, and testing of the unit after repair greatly decreased efficiency of the planned activities.

3) Elevated levels of VOCs in the breathing zone required site evacuation (in accordance with the Site Safety Plan) and discontinuation of the Phase I work.

Approval: .Joanne O. Morih FIT Office Manager

JM/rlr

cc: LChu J. Connet B. Felitti T. Plant S. Sokol D. Smith/EPA J. Crawford/RIDEM

LINE No. VLF EM-R

VLF-1 VLF-2 VLF-3 VLF-4 VLF-5

VLF-6

VLF-7

VLF-8

SEISMIC REFRACTION

SR-1 SR-2 SR-3 SR-4 SR-5

SR-6

APPENDIX A

APPROX. PRIORITY LENGTH (FT) RATIONAL

HIGH 1000 ( +) VLF-1 through VLF-5 have been HIGH 1000 ( *) located to identify contaminant HIGH 500(-) plume migration along the HIGH 500( +) western, northern, eastern, HIGH 500(-) and southern borders of the Solid

Waste Landfill, respectively.

HIGH 1000(+) To detect downgradient contaminant migration from the Bulky Waste and Sewage Sludge Landfills.

HIGH 1000 (*) Investigation dependant on onsite results. To determine if plumes are migrating beneath the Saugatucket River along the preferred direction of groundwater flow.

HIGH/MEDIUM 1000( + ) Same as VLF-7.

HIGH 1000(+) SR-1 through SR-5 have been MEDIUM 500 ( + ) located to determine HIGH 500 (-) overburden/bedrock structure HIGH 500 (-) surrounding the SWL. These MEDIUM 500 ( + ) line locations are designed to

delineate bedrock structure surrounding a bedrock high reported exist within the boundaries of the SWL The bedrock high may produce radial flow from the SWL

MEDIUM 1000( + ) To define overburden/bedrock structure on the eastern border of the Bulky Waste/Sewage Sludge Landfill.

FORM 2.2 1-87

ATTACHMENT B

TABLE II

VLF-2

Rose Hill Regional Landfill South Kingstown, Rl

F1-8707-06 $375RI10EI11

Survey Date: 12/01/87 Instrument: EM-16R

Transmitter Code: NAA

COMMENTS

next to NECo 8795

Good null

hard object 2" down?

Tight nulling range. EM-1 6R

6.5 ft to WT. by Pond

By pond

Closer to L.F. by pond by cemetery

Near NET&T*2. T.Pole

Edge of L.F. /near small creek

Losing signal

near L.F.& gravel pile

near NECo *795

EM 16 won't null

LINE

VLF-2

STATION

+ 00

+ 50

+ 100

+ 150

+ 200

+ 250

+ 300

+ 350

+ 400

+ 450

+ 500

+ 550

+ 600

+ 650~

+ 700 *

+ 750

+ 800

+ 850

+ 900

APPARENT RESISTIVITY

2400

2400

1400

1900

2000

1900

1600

1700

1600

1400

900

1000

1000

800

800

1200

1400

2200

2400

PHASE ANGLE

24

20

20

20

20

18

15

19

18

17

14

10

9

14

10

10

10

11

4

•fi V •*•

E o

3000 FEWEST; EASTr

800

1 I

0 » 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 8SO 900

DISTANCE (Fc«t)

ROSEHILL REGIONAL LANDFILL SOUTH KINGSTOWN, Rl

LINEVLF-2

F1-8707-06 SURVEY DATE 11/30 -12/01/87 CXDR=ORATO\I

LINE STATION

VLF-5 + 00

+ 50

+ 100

+ 150

4-200

+ 250

+ 300

+ 350

+ 400

+ 450

+ 500

+ 550

TABLE II

VLF-5


F1-8707-06 $375RI10EI11



APPARENT PHASE ANGLE

RESISTIVITY

700 6

700 19

800 24

200 9

80 14

50 14

70 8

50 6

40 10

no null

no null

COMMENTS

near rock lined pond

clayey upper soil/hard packed.

sandier soil

very wet soil

probe approximately 10ft. from brook (east)

skipped due to brook culvert (nearing fence)

across from NECo pole *9540

near fence

directly centered between NECo 9540 & 9539 across street

900-NORTH4r

I 2

E O

I 60 ' —

I a, 3

SO 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900

DISTANCE (Ft«t)


LINEVLF-5

F1-8707-06 NLJS SURVEY DATE 11/30 -12/01/87 CORPORATION

TABLE II

VLF-6


F1-8707-06 $375RI10EI11



LINE STATION APPARENT RESISTIVITY

PHASE ANGLE

VLF-6 + 0 80 43

+ 50 200 50

+ 100 500 42

+ 150 700 38

stake + 200 140 30

+ 250 150 40

+ 300 70 18

+ 350 180 20

+ 400 30 30

stake + 450 60 20

+ 500 300 10

+ 550~ 500 18

+ 600 * 300 18

+ 650 280 22

+ 700 180 20

+ 750 60 28

COMMENTS

Base VLF-6 location rock w/ white ), N35E From

escarpment northern end approximately 500

ft.

VLF-6 line on S6E bearing

Clayey -sand

50 ft. W. of 2nd sludge pit.

60 ft. from corner (w) of Southerly pit.

60 ft. from corner (w) of Southerly pit.

near black tarps.

near black tarps.

near embankment center

near embankment center

very wet soil

very wet soil

crossing dirt road.

+ 800 100 24

1000 900-NORTH :~--. SOUTH -br-n800^ —

E O

j

30

20

100

V s S1

o 40,

30 =

20:

\ / 10 0 » 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 8SO 900

DISTANCE (FMt)


LINEVLF-6

F1-8707-06 NUS SURVEY DATE 11/30-12/01/87 CXDRPORATOM

TABLE

VLF-7


F1-8707-06 $375RI10EI11



LINE STATION APPARENT RESISTIVITY

PHASE ANGLE

VLF-7

+ 00 300 36

+ 50

VLF-7 + 00 4000 12

+ 50 3000 6

+ 100 2000 12

+ 150 3500 6

+ 200 3500 9

+ 250 3000 10

+ 300 4000 11

+ 350 5000 8

+ 400 r 6000 10

+ 450 3000 24

+ 500 6000 6

+ 550

+ 600 10,000 20

+ 650 5000 22

+ 700 8000 20

+ 750 7000 18

COMMENTS

From telephone pole all NECo4128.

NSS weaker today than 1 1/30

Leafy cover

again w/NAA

near bench marker/prop, corner stone

crossing driveway 668 Broad Rock Rd.

Near 680 Broad Rock Rd. driveway

Near 680 Broad Rock Rd. driveway

Power lines bend field parallel skipped due to overhead power line - no null by stop sign

scraggly brush / thorny

across from 707 Broad Rock Rd.

across from NECo #4132 T. pole

+ 800 4000 26

10.000 9000 8000

I 3000 = >

2000 EErr

1000 *=—

41

I

20

^1 s 1

—\.s

11

\ x * t

SO 100 150 200

• —"pv

250 300 350

^

/ \

400 450 500 550 600 650 700 750 800 850

_

900

DISTANCE (FMt)


LINEVLF-7

F1-8707-06 SURVEY DATE 11/30-12/01/87 CXDF^PORATlCDrsj

TABLE II

VLF-8


F1-8707-06 S375RI10EI11



COMMENTS

©Farmer's field

scrubby flora

LINE STATION

VLF-8 + 0

+ 50

+ 100

+ 1SO

+ 200

+ 2SO

+ 300

+ 3SO

+ 400

-. +450

+ 500

+ 550

+ 600

+ 650 r

+ 700

APPARENT RESISTIVITY

UDO

1900

1800

1800

1800

1400

1400

1100

1100

1400

1400

1600

1500

1700

1600

PHASE ANGLE

28

34

28

32

38

30

34

38

36

34

32

30

29

29

32

i o

On

1 40 fc^ri-Lssr; p .T =="f =s=gj

l/t

0 SO]

100 |

150 |

200 I

250 ]

300 .

350 | ; 1

400 450 500

DISTANCE (Fc«t)

1

550 1

600 |

650 |

700 ;

750 |

800 850


LINEVLF-8

F1-8707-06 IMUS J CORPORATION SURVEY DATE 11/30 • 12/01/87

TRANSMITTER : NSS

final task report geophysical survey

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