april 7, 2015 mr. henry t. willems new york state department of

Site Investigation and Remediation, 175 East Old Country Road, Hicksville, New York 11801 T: (516) [email protected]

April 7, 2015 Mr. Henry T. Willems New York State Department of Environmental Conservation Division of Environmental Remediation Remedial Bureau C 625 Broadway, 11th Floor Albany, New York 12233-7014 Re: Supplemental Design Investigation Work Plan

Citizens Former Manufactured Gas Plant Site Carroll Gardens/Public Place Borough of Brooklyn, Kings County, New York Site No. C224012

Dear Mr. Willems:

Attached is the Supplemental Design Investigation Work Plan for the Citizens Former Manufactured Gas Plant Site. This letter is also provided as a follow up to our recent conversations and our meeting on January 7, 2015. During the January 7th meeting we discussed the progress and status of the Citizens remedial design (RD) and National Grid’s plans for modifying the design in order to facilitate more timely installation of the bulkhead barrier wall by avoiding relocation of the New York City Department of Environmental Protection (NYC DEP) 72-inch diameter Bond-Lorraine Street sewer. The decision to modify the bulkhead barrier wall design was made as a result of a peer review of GEI’s June 2011 50% RD by ARCADIS of New York, Inc. (ARCADIS). During the peer review, ARCADIS identified two bulkhead barrier wall design alternatives that should allow the installation of the barrier wall without the need to relocate the sewer. National Grid then had GZA GeoEnvironmental, Inc. (GZA) perform an independent review of the ARCADIS barrier wall design alternatives, and this confirmed the viability of both alternatives.

As we discussed, modification of the bulkhead barrier wall design to avoid relocation of the Bond-Lorraine Street sewer offers a number of benefits to the project including:

1. Reducing the Construction Schedule: Under the current design, relocation of the sewer would be prerequisite to allow the installation of the bulkhead barrier wall. Relocation of the sewer has numerous technical, permitting, and schedule implications that the design changes are intended to address, and the additional efforts associated with excavation and handling of soils, dewatering the excavation, by-pass pumping the sewer to maintain service,

Patrick J. Van Rossem Project Manager Site Investigation and Remediation

Mr. Henry T. Willems April 7, 2015

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constructing a continuous pile support system for the sewer (as depicted in the 50% RD), and installing over 900 lineal feet of 72-inch diameter precast concrete sewer pipe would add at least an additional construction season to the bulkhead barrier wall construction schedule and this is in addition to establishing agreements and obtaining any permits for the sewer related work.

2. Reducing Project Complexity: Relocation of the sewer creates significant additional project complexities and requires lengthy technical review of the relocation details by NYSDEC and NYC DEP. Removing the sewer relocation component will simplify the review process and expedite the process for all parties. In addition, permits and additional coordination required to support the relocation of the sewer will not be necessary, further simplifying the project and reducing the overall schedule for completing the bulkhead barrier wall.

The modified bulkhead barrier wall design identified by ARCADIS will maintain a similar design to the current barrier wall (as depicted in the 50% RD) for the portion of the wall where the tie-back system design does not interfere with the Bond-Lorraine sewer (primarily in Parcel III) and it will supplement that system with one or both of the following barrier wall design alternatives:

1. Design Alternative No. 1 – Reaction Pile Tieback System (Preferred Alternative): This system utilizes steel H-piles as tiebacks for the bulkhead barrier wall. This alternative allows shorter tiebacks to be used where the Bond-Lorraine Street sewer is closer to the bulkhead barrier wall. The existing tieback system design depicted in the 50% RD will be used where the bulkhead barrier wall is not as close to the sewer (e.g., Parcel III).

2. Design Alternative No. 2 – Cantilevered Combination Wall System: This system utilizes a standard steel H-pile integrated into a sheet pile section. This alternative provides additional stiffness to mitigate the need for tiebacks by allowing the bulkhead barrier wall to act in a cantilevered manner, and requires deeper installation. Because this alternative does not require lateral support (no tiebacks), this alternative could be used where the proximity of Bond-Lorraine Street sewer to the bulkhead barrier wall restricts the ability to utilize a tieback system (if this condition exists).

As part of the modification to the RD, we will also be designing the bulkhead barrier wall termination to coincide with the property line separating Parcel II and the 98 4th Street property, as discussed with NYSDEC at the January 7, 2015 meeting. In addition, National Grid plans to update the Site groundwater model (presented in GEI’s Groundwater Model for Hydraulic Effect of Proposed Remedial Alternatives, dated September 2011) to account for the latest understanding of Site conditions and to confirm the design basis for the hydraulic liner system identified in the 50% RD. If the updated Site groundwater model confirms that groundwater mounding upgradient of the new bulkhead barrier wall could be an issue, then the model will be used to support the evaluation of options to address the mounding (possibly instead of the hydraulic liner system currently identified in the 50% RD). As you are aware, the liner system requires long-term maintenance and results in the need for post-construction storm water management. By evaluating alternate options to address groundwater mounding (if necessary),


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we want to be sure that a liner system is the best approach to support future Site use and that there are not other methods that could effectively achieve the objectives with fewer long-term maintenance requirements.

As discussed during our January 7, 2015 meeting, several supplemental design investigation (SDI) activities have been identified to collect the additional data needed for the evaluation and design of the potential alternate bulkhead barrier wall configurations and other components of the RD, including the following:

• Test pit excavation, to verify the alignment of the Bond-Lorraine Street sewer on Parcels I and II and the locations of the former holder foundations on Parcel I relative to Smith and 5th Streets;

• Geotechnical drilling and subsurface soil sampling, to collect additional geotechnical data necessary for the evaluation and design of 1) potential alternate bulkhead barrier wall configurations along Parcels I and II and 2) temporary excavation support systems for the deep excavation areas on Parcels I and III;

• Test pile program, to approximate the effects of pile driving in close proximity to the existing Bond-Lorraine Street sewer, and evaluate bending stresses and lateral deflections for the alternative reaction pile system design;

• Dense non-aqueous phase liquid (DNAPL) transmissivity evaluation, to collect additional DNAPL transmissivity and fluid property data necessary to 1) assess current DNAPL recovery rates at the Site and 2) design the long-term DNAPL recovery program; and

• Hydraulic conductivity evaluation, to collect additional hydraulic conductivity data necessary to refine and update the existing groundwater flow model for the Site in order to more fully evaluate 1) the effect of the bulkhead barrier wall on groundwater and NAPL movement and 2) the need for the hydraulic liner system currently identified in the 50% RD.

Subsequent to our January 7, 2015 meeting, the following additional SDI activities were identified to support the completion of the RD:

• Preliminary waste characterization program for the deep excavation areas in Parcels I and III, to collect additional soil quality data necessary to 1) provide a preliminary basis for the material handling and disposal requirements to be included in the RD and 2) help determine the suitability of Site-related excavation wastes to be treated/disposed of at regional treatment/disposal facilities;

• In-situ solidification (ISS) bench-scale treatability study, to evaluate the applicability of ISS, as an option instead of excavation/removal, to remediate soils in the Holder No. 1/5 area in Parcel I; and


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• Topographic and property boundary survey, to collect supplemental survey data necessary to 1) update Site base mapping to reflect current (pre-construction) conditions and 2) calculate estimated material quantities (including excavation volumes) for construction.

The proposed scope of the above SDI activities is more fully described in the Supplemental Design Investigation Work Plan, which is attached for your review.

Finally, we would like to note that NYC’s relocation of their tenant Ferrara is a critical factor in completing the RD, procurement, and remedial construction at the Site. We are looking forward to the future meeting that NYSDEC is arranging with the other agencies to better understand the timing for the Ferrara relocation.

If you have any questions, please call me at (516) 545-2578, or contact me by e-mail at [email protected].

Sincerely, Patrick J. Van Rossem Project Manager Site Investigation & Remediation Attachment cc: Gardiner Cross, NYSDEC

Justin Deming, NYSDOH Chris Doroski, NYSDOH Ted Leissing, National Grid Andrew Prophete, National Grid Katherine Vater, PE, National Grid Chris Young, de maximis Terry Young, PE, ARCADIS Michael Benoit, PE, ARCADIS

Imagine the result

Mr. Patrick Van Rossem Project Manager National Grid 175 East Old Country Road Hicksville, New York 11801

Subject:

Supplemental Design Investigation Work Plan Former Citizens Gas Works Manufactured Gas Plant Site Carroll Gardens/Public Place Borough of Brooklyn, Kings County, New York Site No. C224012 Dear Mr. Van Rossem:

This letter presents the scope of supplemental design investigation (SDI) activities to

support the completion of the Remedial Design (RD) for the former Citizens Gas

Works manufactured gas plant (MGP) site located in the Carroll Gardens/Public

Place section of the Borough of Brooklyn, Kings County, New York (the “Site”). The

SDI scope includes several field activities to support further evaluation of two

bulkhead barrier wall design alternatives that do not require relocation of the New

York City Department of Environmental Protection (NYC DEP) Bond-Lorraine Street

sewer (a 72-inch diameter combined sewer that traverses the Site from northeast to

southwest; see Figure 1).

The bulkhead barrier wall configuration presented in the 50% RD encroaches on the

existing NYC DEP Bond-Lorraine Street sewer easement, mainly on Parcel II

(Drawing 23 from the 50% RD shows the barrier wall overview plan; a copy is

provided in Attachment A). The Bond-Lorraine Street sewer modification and

relocation plans detailed in the 50% RD would result in an extended bulkhead barrier

wall construction schedule, increased project complexities, potential project delays,

and unnecessary project costs. Accordingly, at National Grid’s request, ARCADIS of

New York, Inc. (ARCADIS) has identified bulkhead barrier wall design alternatives

that will not require relocation of, or otherwise directly interfere with, the NYC DEP

Bond-Lorraine Street sewer. The modified bulkhead barrier wall design identified by

ARCADIS will maintain a similar design to the system currently depicted in the 50%

RD for the portion of the wall where the tie-back system design does not interfere

with the Bond-Lorraine Street sewer (primarily in Parcel III), and supplements that

system with one or both of the following barrier wall design alternatives:

ARCADIS of New York, Inc.

6723 Towpath Road

PO Box 66

Syracuse

New York 13214-0066

Tel 315 446 9120

Fax 315 449 0017

www.arcadis-us.com

ENVIRONMENT

Date:

April 7, 2015

Contact:

Terry W. Young, PE

Phone:

315.671.9478

Email:

terry.young2@ arcadis-us.com Our ref:

B0036728

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Mr. Patrick Van Rossem

April 7, 2015

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1. Design Alternative No. 1 – Reaction Pile Tieback System (Preferred Alternative):

This system utilizes steel H-piles as tiebacks for the bulkhead barrier wall (see

Figure 2). This design alternative allows shorter tiebacks to be used where the

Bond-Lorraine sewer is closer to the bulkhead barrier wall. The existing tieback

system design depicted in the 50% RD will be used where the bulkhead barrier

wall is not as close to the sewer (e.g., Parcel III).

2. Design Alternative No. 2 – Cantilevered Combination Wall System: This system

utilizes a standard steel H-pile integrated into a sheet pile section (see Figure 3).

This design alternative provides additional stiffness to mitigate the need for

tiebacks by allowing the bulkhead barrier wall to act in a cantilevered manner,

and requires deeper installation. Because this alternative does not require lateral

support (no tiebacks), this alternative could be used where proximity of the Bond-

Lorraine Street sewer to the bulkhead barrier wall restricts the ability to utilize a

tieback system (if this condition exists).

The SDI scope also includes the collection of supplemental data necessary to further

evaluate other elements of the 50% RD. Collectively, the SDI scope and objectives

are as follows:

• Excavation of test pits to verify the extent, location, or alignment of certain

underground facilities at the Site (e.g., foundations, utilities, etc.), including the

alignment of the existing NYC DEP Bond-Lorraine Street sewer on Parcels I and II

and the locations of the former holder foundations on Parcel I relative to Smith and

5th Streets;

• Drilling of land- and canal-side borings and collection of additional geotechnical

data necessary to evaluate and design potential alternate bulkhead barrier wall

configurations along Parcels I and II;

• Drilling of borings and collection of additional geotechnical data necessary to

evaluate and design temporary excavation support systems for the deep

excavation areas on Parcels I and III;

• Drilling of borings and collection of additional chemical data necessary to 1)

provide a preliminary basis for the material handling and disposal requirements to

be included in the RD and 2) help determine the suitability of Site-related

excavation wastes to be treated/disposed of at regional treatment/disposal

facilities;



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• Drilling of borings and collection of additional chemical and geotechnical data

necessary to evaluate the applicability of in-situ solidification (ISS), as an option

instead of excavation and removal, to remediate soils in the Holder No. 1/5 area of

Parcel I;

• Installation of test H-piles to approximate the effects of pile driving in close

proximity to the existing NYC DEP Bond-Lorraine Street sewer and evaluate

bending stresses and lateral deflections for a reaction pile bulkhead barrier wall

system;

• Collection of additional dense non-aqueous phase liquid (DNAPL) transmissivity

and fluid property data necessary to 1) assess current DNAPL recovery rates at

the Site and 2) design the long-term DNAPL recovery program;

• Collection of additional hydraulic conductivity data necessary to refine the existing

groundwater flow model for the Site (presented in GEI’s Groundwater Model for

Hydraulic Effect of Proposed Remedial Alternatives, dated September 2011) in

order to more fully evaluate 1) the effect of the bulkhead barrier wall on

groundwater and NAPL movement and 2) the need for the hydraulic liner system

currently identified in the 50% RD, which was submitted to the New York State

Department of Environmental Conservation (NYSDEC) in June 2011; and

• Collection of additional survey data necessary to 1) update Site base mapping to

reflect current (pre-construction) conditions and 2) calculate estimated material

quantities (including excavation volumes) for construction.

The proposed detailed scope of SDI activities to achieve these objectives is

presented in Section I below. Section II of this letter identifies the anticipated

contents of the SDI Summary Report, and Section III identifies the proposed

schedule for the implementation of the SDI activities.

The SDI activities will be conducted (as appropriate) in accordance with the

NYSDEC-approved Quality Assurance Project Plan and Field Sampling Plan (FSP)

for the Site. Additionally, permits/approvals from stakeholder agencies will be

obtained as necessary and appropriate.



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I. PROPOSED SCOPE OF SDI ACTIVITIES

Test Pit Excavation

A series of test pits, identified as CGTPA-207 through CGTPA-219 on Figure 1, will

be excavated to verify the alignment of the Bond-Lorraine Street sewer between

manholes MH-13 and MH-16. The location of the existing sewer (especially in Parcel

II) is critical to the bulkhead barrier wall design modification. Each test pit will be

excavated to the top of sewer, which is located between approximately two feet and

10 feet below ground surface (bgs) in Parcels I and II.

Test pits CGTPA-215 through CGTPA-219 (Figure 1) will be excavated on Parcel I to

verify the locations of the former holder foundations relative to Smith and 5th Streets.

The holder foundations, if located closer to the roadways than currently depicted,

may affect the anticipated alignment and/or the ability to drive temporary steel sheet

piling along Smith and 5th Streets in this area. Each test pit will be excavated to the

top of the holder foundation wall, which is located between approximately one and

four feet bgs based on previous test pits excavated in this area.

Test pits will be excavated using an appropriate method or combination of methods

based on field conditions, the depth to the top of the sewer (test pits CGTPA-207

through CGTPA-214), and the depth to the top of the holder foundation walls (test

pits CGTPA-215 through CGTPA-219). These methods will include, but may not be

limited to, using air-knife-type vacuum excavation and a rubber-tired backhoe or

small excavator. At each location, excavated materials will be visually examined and

logged, and will be temporarily staged on polyethylene sheeting adjacent to the test

pit. Once complete, test pits will be sketched and photographed, as appropriate, to

record significant subsurface features. Excavated materials will then be placed back

into the test pits at approximately the same depth and location from which they were

removed, with visually clean soils used to cover impacted materials. As necessary

and appropriate, the test pitting work for CGTPA-207 through CGTPA-214 will be

coordinated with the NYC DEP. The completed test pits, centerline of the sewer, and

holder foundation walls (if encountered) will be marked in the field, surveyed by a

New York State-licensed land surveyor, and incorporated into the Site-wide survey

database.

Test pits may be relocated in the field, and additional test pits may be excavated,

based on accessibility, conditions observed, and related factors.



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Geotechnical Drilling and Subsurface Soil Sampling

Upland soil borings CGSBA-302 through CGSBA-320 (Figure 1) will be drilled to

collect additional geotechnical data necessary for the evaluation and design of 1)

potential alternate bulkhead barrier wall configurations along Parcels I and II and 2)

temporary excavation support systems for the deep excavation areas on Parcels I

and III. In-water borings CGSBA-331 through CGSBA-338 (Figure 1) will be drilled

to collect additional geotechnical data necessary to refine the design modification for

the portion of the bulkhead barrier wall to be installed near the existing Bond-Lorraine

Street sewer. The in-water borings are not necessary to determine the design

modifications, only to refine the design prior to finalization. Accordingly, the in-water

borings will be drilled at a later date than the upland borings. This will allow the

collective SDI results and the design modifications to be used to determine specific

details (including total drilling depth) for the in-water borings. Previous in-water

borings were drilled to a maximum elevation of −29 feet NAVD88.

Before initiating drilling activities, mark-outs will be called, and each upland soil

boring location will be hand-cleared to a depth of approximately seven feet bgs to

facilitate the identification of potential near-surface utilities and shallow obstructions.

Upland soil borings will be drilled using sonic drilling methods to the approximate

depths identified below:

• Soil borings CGSBA-302, CGSBA-304, and CGSBA-306 will be drilled to a total

depth of approximately 100 feet bgs and soil borings CGSBA-303 and CGSBA-305

will be drilled to a total depth of approximately 60 feet bgs, based on the

anticipated depths of the reaction pile tieback system (Figure 2);

• Soil borings CGSBA-307 through CGSBA-314 (Parcel I) will be drilled to a total

depth of approximately 80 feet bgs; and

• Soil borings CGSBA-315 through CGSBA-320 (Parcel III) will be drilled to a total

depth of approximately 70 feet bgs.

In-water borings will be drilled using mud-rotary drilling methods and may be drilled

to bedrock, which is anticipated to be encountered at an elevation of approximately

−110 feet NAVD88. As noted above, the collective SDI results and bulkhead barrier

wall design modifications will be considered in determining the total drilling depth for

the in-water borings. Upland/in-water soil borings may be relocated in the field, and

additional soil borings may be drilled, based on accessibility, obstructions (refusal),

conditions observed, and related factors.



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At each soil boring location, standard penetration testing will be performed in

accordance with ASTM D1586 to assess the relative density of in-place soils. Soil

samples will be collected and logged continuously from approximately seven feet bgs

(upland borings), or existing sediment surface (in-water borings), to a depth of 20

feet bgs/below sediment surface (bss), and in five foot intervals thereafter (e.g., 20 to

22 feet bgs/bss, 25 to 27 feet bgs/bss, 30 to 32 feet bgs/bss, etc.) to the bottom of

the boring. If encountered, fine-grained cohesive soils will be sampled using a thin-

walled sampler. Consistent with the NYSDEC-approved FSP, each sample will be

screened for volatile organic compound (VOC) vapors with a photoionization detector

(PID) and will be visually characterized for soil type and the presence of coal tar

DNAPL. Each borehole will be tremie-grouted to existing grade/sediment surface

upon completion of drilling. The soil boring locations will be marked in the field (as

appropriate), surveyed by a New York State-licensed land surveyor, and

incorporated into the Site-wide survey database.

Select soil samples collected from the soil borings will be submitted to a geotechnical

testing laboratory for one or more of the following geotechnical analyses:

• Moisture content in accordance with ASTM D2216;

• Atterberg limits in accordance with ASTM D4318;

• Grain-size analysis in accordance with ASTM D422;

• Specific gravity in accordance with ASTM D854;

• Unconsolidated-undrained (UU) triaxial compression with pore pressure in

accordance with ASTM D2850;

• Consolidated-undrained (CU) triaxial compression with pore pressure in

accordance with ASTM D4767; and

• One-dimensional consolidation properties in accordance with ASTM

D2435/D2435M.

The number of samples to be submitted and specific geotechnical analyses to be

performed will be determined based on the conditions observed in the field.



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Preliminary Waste Characterization Program

Soil borings CGSBA-321 through CGSBA-326 (Figure 1) will be drilled within the

limits of the deep excavation areas on Parcels I and III in order to collect

representative soil samples for preliminary waste characterization purposes. The

resulting soil data will 1) provide a preliminary basis for the material handling and

disposal requirements to be included in the RD and 2) help determine the suitability

of Site-related excavation wastes to be treated/disposed of at the following

treatment/disposal facilities:

• ESMI of New York, Inc. (Fort Edward, New York);

• Bayshore Soil Management, Inc. (Keasbey, New Jersey);

• Clean Earth of North Jersey, Inc. (Kearny, New Jersey);

• Clean Earth of Southeast Pennsylvania, LLC (Morrisville, Pennsylvania);

• Clean Earth of Philadelphia, LLC; and

• Clean Earth of New Castle, LLC (New Castle, Delaware).

Before initiating drilling activities, mark-outs will be called, and each soil boring

location will be hand-cleared to a depth of approximately seven feet bgs to facilitate

the identification of potential near-surface utilities and shallow obstructions. Drilling

will be performed using sonic drilling methods from approximately seven feet bgs to

the approximate depth of each excavation area (between approximately 25 feet and

30 feet bgs in Parcel I and approximately 20 feet bgs in Parcel III). Soil borings may

be relocated in the field, and additional soil borings may be drilled, based on

accessibility, obstructions (refusal), conditions observed, and related factors.

Soil samples will be collected and logged continuously at each location from

approximately seven feet bgs to the bottom of the boring. Consistent with the

NYSDEC-approved FSP, each sample will be screened for VOC vapors with a PID

and will be visually characterized for soil type and the presence of coal tar DNAPL.

Each borehole will be tremie-grouted to existing grade upon completion of drilling.

The soil boring locations will be marked in the field, surveyed by a New York State-

licensed land surveyor, and incorporated into the Site-wide survey database.



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Representative soil samples collected from soil borings CGSBA-321 through

CGSBA-326 will be homogenized (as appropriate) and submitted to a chemical

testing laboratory for the following waste characterization analyses:

• VOCs in accordance with United States Environmental Protection Agency

(USEPA) SW-846 Method 8260;

• Semi-volatile organic compounds (SVOCs) in accordance with USEPA SW-846

Method 8270;

• Pesticides in accordance with USEPA SW-846 Method 8081;

• Polychlorinated biphenyls in accordance with USEPA SW-846 Method 8082;

• Metals in accordance with USEPA SW-846 Methods 6010/7471;

• Hexavalent chromium in accordance with USEPA SW-846 Methods 3060/7196;

• Total cyanide in accordance with USEPA SW-846 Method 9010;

• Percent sulfur in accordance with ASTM D129;

• Total petroleum hydrocarbons (diesel-range organics and gasoline-range organics)

in accordance with USEPA SW-846 Method 8015;

• Extractable petroleum hydrocarbons (EPH) in accordance with New Jersey

Department of Environmental Protection EPH Method;

• Total extractable organic halides in accordance with USEPA SW-846 Method

9023;

• Heat of combustion in accordance with ASTM D240;

• TCLP VOCs in accordance with USEPA SW-846 Methods 1311/8260;

• TCLP SVOCs in accordance with USEPA SW-846 Methods 1311/8270;

• TCLP metals in accordance with USEPA SW-846 Methods 1311/6010/7470;



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• TCLP pesticides in accordance with USEPA SW-846 Methods 1311/8081;

• TCLP herbicides in accordance with USEPA SW-846 Methods 1311/8151;

• Ignitability in accordance with USEPA SW-846 Method 1010;

• Corrosivity (as pH) in accordance with USEPA SW-846 Methods 9040/9045; and

• Reactive cyanide and sulfide in accordance with USEPA SW-846 Sections

7.3.2/7.3.3.

These waste characterization analyses satisfy the combined analytical (but not

volumetric-/mass-based) acceptance criteria of the treatment/disposal facilities

identified above.

A total of 16 soil samples – three samples each from soil borings CGSBA-321

through CGSBA-324 (Parcel I), and two samples each from soil borings CGSBA-325

and CGSBA-326 (Parcel III) – are anticipated to be collected and analyzed during the

preliminary waste characterization program. The number of samples to be submitted

for chemical testing may be modified based on the conditions observed in the field.

ISS Bench-Scale Treatability Study

The current remediation approach for the Holder No. 1/5 area in Parcel I involves the

excavation and removal of existing materials to the top of the holder foundation slab,

which is generally located at elevation 14 feet NAVD88 (roughly 12 feet bgs to 14

feet bgs, depending on location). To achieve this, the 50% RD contemplates

excavation protection systems (to be designed by the selected contractor) consisting

of sloping/benching to the south and east and shoring/bracing to north and west

along 5th and Smith Streets, respectively. Drawings 13 and 14 from the 50% RD

(copies provided in Attachment A) show the anticipated limits of excavation and

approximate extent of sloping/benching and shoring/bracing in Parcel I.

The excavation/removal of materials in the Holder No. 1/5 area presents a number of

challenges due to the close proximity of the former holder foundation (and required

shoring/bracing system) to Smith and 5th Streets, the elevated Metropolitan

Transportation Authority (MTA) subway lines (Culver Viaduct), and the 12-inch

diameter natural gas mains located beneath Smith and 5th Streets. Further, the

erection of a temporary fabric structure (for odor, vapor, and dust control) over the

Holder No. 1/5 area will impede vehicular and pedestrian traffic along Smith and 5th

Streets due to the acute angle of the property line in this corner of the Site. In



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consideration of these challenges and the relatively small quantity of materials

containing visible coal tar DNAPL1, ARCADIS will conduct an ISS bench-scale

treatability study as part of the SDI to evaluate the applicability of ISS (as an option

instead of excavation and removal) to remediate soils in the Holder No. 1/5 area.

The objective of the ISS bench-scale treatability study is to identify a technically

appropriate and cost-effective mix design that will 1) reduce hydraulic conductivity

and 2) achieve a target cured strength. Specific ISS performance requirements and

design considerations include, but are not limited to, the following:

• Reduction in the average hydraulic conductivity of the soil matrix resulting from

treatment. The target hydraulic conductivity for the treated soil matrix following

addition of mixing reagents will be approximately 1 x 10-6 centimeters per second

(cm/sec) or less.

• The treated soil matrix will need to have suitable physical properties to withstand

anticipated future Site activities and surface/subsurface loads without settling or

deterioration, as well as be able to allow future development at the Site, which may

include the installation of piling through the ISS monolith. The target 28-day

unconfined compressive strength (UCS) of the treated soil matrix will be greater

than 30 pounds per square inch (psi) and compatible with native soils and future

use. Minimum and maximum UCS requirements may be updated pending further

evaluation of future Site use.

Potential mix designs will be subject to geotechnical testing to evaluate their

effectiveness in meeting these criteria.

Drilling and Subsurface Soil Sampling

Soil borings CGSBA-327 through CGSBA-330 (Figure 1) will be drilled within the

limits of the foundation of former Holder No. 1/5 in order to 1) gain additional

information regarding the extent of soils containing visible coal tar and 2) collect

representative soil samples for the ISS bench-scale treatability study. Before

initiating drilling activities, mark-outs will be called, and each soil boring location will

be hand-cleared to a depth of approximately seven feet bgs to facilitate the

1 Visible coal tar DNAPL was only identified at depths between 10 and 13.7 feet bgs in soil borings CGSB-01 (taffy-like viscous tar from 11 to 12 feet bgs), CGSB-101 (tar-coated grains/viscous tar from 10 to 11 feet bgs), and CGSB-115 (tar-coated grains from 11 to 13 feet bgs and tar-saturated grains from 13.4 to 13.7 feet bgs).



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identification of potential near-surface utilities and shallow obstructions. Drilling will

be performed using sonic drilling methods from approximately seven feet bgs to the

top of the holder foundation slab, which is generally located at elevation 14 feet

NAVD88 (roughly 12 feet bgs to 14 feet bgs, depending on location). Representative

soil samples from CGSBA-327 through CGSBA-330 will be collected, homogenized,

and placed into five-gallon buckets for shipment to the ARCADIS Treatability

Laboratory in Durham, North Carolina. As part of this effort, homogenized samples

will also be submitted to a geotechnical testing laboratory for the following baseline

geotechnical analyses:

• Grain-size analysis (sieve and hydrometer) in accordance with ASTM D422;

• Specific gravity in accordance with ASTM D854;


• USCS classification in accordance with ASTM D2487;

• Organic matter and ash content in accordance with ASTM D2974; and

• Atterberg limits in accordance with ASTM D4318.

Approximately three gallons of potable (municipal) water will also be collected while

on-site and shipped to the ARCADIS Treatability Laboratory for use in preparing the

mix designs.

Soil samples will be collected and logged continuously at each boring location from

approximately seven feet bgs to the top of the holder foundation slab. Consistent

with the NYSDEC-approved FSP, each sample will be screened for VOC vapors with

a PID and will be visually characterized for soil type and the presence of coal tar

DNAPL. Each borehole will be tremie-grouted to existing grade upon completion of

drilling. The soil boring locations will be marked in the field, surveyed by a New York

State-licensed land surveyor, and incorporated into the Site-wide survey database.

Soil borings may be relocated in the field, and additional soil borings may be drilled,

based on accessibility, obstructions (refusal), conditions observed, and related

factors.



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Mix Design Preparation and Testing

Up to six mix designs will be prepared at the ARCADIS Treatability Laboratory using

the soil homogenate, potable water from the Site, and admixtures containing different

percentages of Portland cement, blast furnace slag (BFS) cement, and bentonite

clay. The reagent list may be modified based on an evaluation of readily-available

local materials and their quality. Other reagents may be considered depending on

further evaluation of the Site COCs. The soil mixes will be constructed using

prepared grouts combining potable water from the Site, the admixtures, and the soil

homogenate at various soil-to-grout ratios. The six prepared mixes will be tested for

the following:

• Slump in accordance with ASTM C143;

• pH and temperature in accordance with American Petroleum Institute

Recommended Practice 13B (API RP 13B);


• Penetration resistance, at one, three, and five days after mixing, in accordance

with ASTM D1558;

• UCS, at seven and 28 days after mixing, in accordance with ASTM D1633; and

• Hydraulic conductivity, at 28 days or greater after mixing, in accordance with

ASTM D5084.

Mix Design Selection and Grout Testing

After evaluating the geotechnical testing results, one or more mix designs will be

selected for possible field implementation. The grout mixture used in the preparation

of each selected mix design will be prepared and analyzed for the following:

• Viscosity, density, pH, and temperature in accordance with API RP 13B;

• Grout bleed in accordance with ASTM C940; and

• Set time in accordance with ASTM C953.



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Test Pile Program

Up to three test H-piles will be installed between the Bond-Lorraine Street sewer and

existing bulkhead on Parcel III to 1) approximate the effects of pile driving in close

proximity to the existing sewer and 2) evaluate bending stresses and lateral

deflections for a reaction pile system. The approximate location of the test pile

installation area is shown on Figure 1, and a typical test pile construction is depicted

on Figure 4. As previously noted, permits/approvals from stakeholder agencies will

be obtained as necessary and appropriate prior to test pile installation.

Test pile locations will be hand-cleared to a depth of approximately five feet bgs to

facilitate the identification of potential near-surface utilities. The initial test pile will be

installed by first augering and advancing a 30-foot long steel outer casing to a depth

of approximately 34 feet bgs. A 42-foot long steel H-pile will then be centered,

lowered into the outer casing, and driven into the underlying soil formation using a

crane-mounted vibratory hammer to a total depth of approximately 44 feet bgs

(roughly 10 feet below the bottom of the outer casing). Subsequent test piles will

vary in length/embedment depth or flange width in order to evaluate and refine

potential reaction pile designs.

During the driving of the H-piles, portable seismographs with triaxial geophones will

be placed along the alignment of the Bond-Lorraine Street sewer, at distances of

approximately seven feet, 10 feet, and 20 feet on both sides of the pile driving

activities, to continuously monitor and log peak vibrations caused by pile driving

operations. Additionally, a geophone will be placed on the pipe invert at manhole

MH-16 and an inclinometer installed between the test pile and sewer to further

evaluate the effects of pile driving operations.

Upon completion of driving, the outer casing will be completely filled with minimum

5,000 psi concrete to approximately four feet bgs (i.e., the top of the outer casing).

The concrete will be allowed to cure for a minimum of 14 days before proceeding

with the static lateral pile load test described below.

A static lateral pile load test will be performed on the installed test piles in

accordance with ASTM D3966 to approximate the subsurface soil coefficient of

horizontal subgrade reaction. The test involves progressively increasing the lateral

load on each test pile from the estimated design load (in this case, 115 kips) up to

200 percent of the design load (230 kips) in accordance with the standard loading

increments and durations set forth in ASTM D3966. The test results will be used to:

1) approximate bending stresses and lateral deflections in the reaction piles;



April 7, 2015

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2) confirm the lateral load capacity of production piles; and 3) determine p-y curves

(curves relating applied force and lateral deflection) for the piles to be used in the

design.

Test piles will remain in place following the completion of testing and may be used as

production piles to the extent practical if a reaction pile system is selected for the

bulkhead barrier wall in this area of the Site. Test pile locations will be marked in the

field, surveyed by a New York State-licensed land surveyor, and incorporated into

the Site-wide survey database.

DNAPL Transmissivity Evaluation

DNAPL transmissivity will be evaluated to 1) assess current DNAPL recovery rates at

the Site and 2) support the design of the long-term DNAPL recovery program.

DNAPL transmissivity represents the volumetric rate of DNAPL flow through a unit

width of porous media per unit time under a unit hydraulic gradient. DNAPL

transmissivity is directly proportional to the rate of DNAPL recovery that can be

achieved for a given well, inherently accounting for the combined effects of aquifer

matrix permeability, DNAPL physical properties, and the relative proportion of pore

space occupied by DNAPL within a specified vertical interval of aquifer material.

These characteristics make DNAPL transmissivity a useful parameter for assessing

DNAPL recoverability. DNAPL transmissivity testing was previously performed

approximately five years ago as part of the DNAPL recovery well pilot test activities

(described in GEI’s DNAPL Recovery Wells Pilot Test Report, dated March 2011).

Since that time, approximately 30,000 gallons of fluid (consisting of DNAPL and a

small percentage of groundwater) have been removed from the subsurface as part of

the on-going interim NAPL recovery program at the Site.

DNAPL transmissivity will be evaluated at up to 13 recovery wells, consisting of

representative shallow, intermediate, and deep recovery wells with low, moderate,

and high DNAPL production, using DNAPL bail-down testing procedures. Consistent

with the DNAPL recovery well pilot test activities, bail-down testing procedures will

generally involve the removal of accumulated DNAPL and subsequent monitoring of

DNAPL thickness as it re-accumulates in a well.

Following the removal of accumulated DNAPL from each well, manual DNAPL

thickness measurements will be collected over an initial period of 10 hours. The

following measurement schedule will be used as a general guide, and may be

adjusted in the field based on observed recovery rates.



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Time After Initial Purging Measurement Frequency

0 to 10 Minutes Every Minute

10 to 20 Minutes Every Two Minutes

20 to 40 Minutes Every Five Minutes

40 to 90 Minutes Every 10 to 15 Minutes

90 Minutes to Four Hours Every 30 Minutes to One Hour

Over Four Hours Every Four to Six Hours

The rate of DNAPL recovery can vary due to a number of factors, including the

physical properties, the geometry of the DNAPL body, and the local hydraulic

gradient. For this reason, the measurement frequency after the initial 10-hour

monitoring period will be variable and based primarily on field observations.

Consistent with the DNAPL recovery well pilot test activities, DNAPL thickness

measurements will continue until the DNAPL thickness has recovered to

approximately 80 percent of the initial (pre-purge) thickness.

As part of the DNAPL transmissivity evaluation, representative samples of DNAPL

will be collected from up to seven Site recovery wells for laboratory testing of the

following fluid properties:

• Density in accordance with ASTM D1481;

• Viscosity in accordance with ASTM D445; and

• Interfacial tension in accordance with ASTM D971.

DNAPL generated during the transmissivity evaluation will be managed in

accordance with the DNAPL Management Plan for the Site.

Hydraulic Conductivity Evaluation

A hydraulic conductivity evaluation will be performed to refine and update the existing

groundwater flow model for the Site (presented in GEI’s Groundwater Model for

Hydraulic Effect of Proposed Remedial Alternatives, dated September 2011). As

referenced in that document, previous hydraulic conductivity testing was limited to

slug tests performed in 2003 at three wells on Parcel I and slug tests performed in

2010 at off-site properties in conjunction with the Gowanus Canal Superfund Site.

The updated groundwater flow model will be used to more fully evaluate the



April 7, 2015

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1) effect of the bulkhead barrier wall on groundwater and NAPL movement and 2)

need for the hydraulic liner system currently identified in the 50% RD.

Hydraulic conductivity will be evaluated by conducting a series of pneumatic slug

tests in select (existing) wells at the Site. Pneumatic slug tests are conducted by

sealing the well head and applying air pressure to depress the water level. As air

pressure is increased in the well, the water level falls until the water pressure and the

air pressure return to equilibrium. After the water level is stable, air is released from

the sealed well head by opening an air release valve. The water level recovery is a

rising head slug test and produces high-quality data with little interference. A

pressure transducer is used to monitor and record the change of the water level in

the well during the pneumatic slug test. In instances where a well screen is not fully

submerged, slug testing is performed using the bail-down method. The test

equipment and procedures are more fully described in the standard operating

procedure provided in Attachment B.

Slug testing will be performed at representative wells without significant NAPL

accumulation and with screen zones within the upper aquifer unit:

• Shallow zone wells CGRW-05S and CGRW-07S;

• Intermediate zone wells CGRW-01, CGRW-02, CGRW-03, CGRW-05I, and

CGRW-07I; and

• Deep zone well CGMW-01D.

In addition, CGRW-06S will be used as a “background” well to monitor external (tidal)

influences on groundwater levels before, during, and after slug testing. Recovery

wells screened within the deep zone at the Site contain significant accumulations of

DNAPL and, as a result, are not considered suitable candidates for pneumatic slug

testing. The wells to be tested may be modified in the field based on the presence

and thickness of NAPL in candidate wells at the time of testing, condition of the well,

and other related factors.

Topographic and Property Boundary Survey

An updated topographic and property boundary survey of the Site will be performed

as part of the SDI program to collect supplemental survey data necessary to 1)

update Site base mapping to reflect current (pre-construction) conditions and 2)

calculate estimated material quantities (including excavation volumes) for

construction. The survey work will be performed by a New York State-licensed land



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surveyor, and will include a field survey of existing surface improvements/features

and supplemental spot elevations as necessary to generate one-foot topographic

contours. Existing utilities will also be located based on visible surface features. The

surveyor will enlist the services of a title company to have a title report prepared, and

supplemental research will be performed by the surveyor at the Brooklyn Borough

President’s office. Following analysis of the research, the surveyor will re-establish

property boundary lines and existing easements in accordance with standard

surveying practices. The results of the topographic and property boundary survey

will be used to update the existing Site base mapping and will be incorporated into

the subsequent RD submittal.

In consideration of the on-going operations of Ferrara Brothers Building Materials

(Ferrara) on Parcel II and portions of Parcel I, the topographic and property boundary

survey will be conducted in two separate field mobilizations. The initial survey effort

will be conducted in spring/summer 2015 and will include the available/accessible

portions of Parcels I and III. The second survey effort will be conducted in 2016 after

Ferrara demobilizes its concrete operations from the Site and before the RD is

finalized, and will include Parcel II and any previously-inaccessible portions of

Parcels I and III that were not surveyed in 2015. By phasing the survey work in this

manner, the updated survey will more-closely reflect Site conditions to be

encountered at the time of construction, including any materials/structures Ferrara

leaves behind.

Community Air Monitoring

Community air monitoring will be performed on a daily basis during ground-intrusive

or dust-generating activities to provide real-time measurements of total VOCs and

particulate matter less than 10 micrometers in diameter (PM10) at the upwind and

downwind perimeter of the work area. The general community air monitoring

procedures and action levels for total VOCs and PM10 are identified in Appendix 1A

of NYSDEC’s Technical Guidance for Site Investigation and Remediation (DER-10).

Community air monitoring stations (one upwind and one downwind location) will be

established at the start of each work day based on the predominant wind direction

and general location of work activities at the Site. Each monitoring station will

include a portable, data-logging PID and a portable, data-logging aerosol

photometer.

Odor, vapor, and dust controls will be maintained on-site and employed as necessary

during the ground-intrusive or dust-generating SDI activities.



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Handling and Management of Investigation-Derived Waste

Soil cuttings, DNAPL, and other investigation-derived waste generated during the

SDI activities will be managed in accordance with the DNAPL Management Plan and

FSP for the Site. This includes storing in properly-labeled 55-gallon drums within the

limits of the Site and transporting off-site for treatment/disposal in accordance with

applicable laws and regulations.

II. REPORTING

The results of the SDI activities described in Section I of this letter will be presented

in a SDI Summary Report. The report is anticipated to include, at a minimum, the

following:

• Brief narrative describing the field activities, observations, and results;

• Test pit and soil boring logs;

• Geotechnical testing results;

• Chemical testing results for waste characterization samples;

• ISS bench-scale treatability study results;

• Vibration monitoring and static lateral pile load test results for the test pile

installation activities;

• Estimated DNAPL recovery rates and comparison to recovery rates previously

presented in GEI’s DNAPL Recovery Wells Pilot Test Report;

• Slug test data;

• Updated topographic and boundary survey plan (reflecting the spring/summer

2015 survey work); and

• Conclusions/next steps.

The results of the SDI activities will also be incorporated, as appropriate, in the

subsequent design deliverable, which is anticipated to be a 90% RD.



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III. SDI SCHEDULE

ARCADIS is prepared to initiate the SDI activities described herein within 15 working

days of NYSDEC’s approval of this work plan. The SDI field activities are anticipated

to begin with the topographic and boundary survey activities (in the accessible

portions of Parcels I and III), DNAPL transmissivity evaluation, and the hydraulic

conductivity evaluations, while ARCADIS and National Grid secure contractors and

permits/approvals for the remaining (ground-intrusive) SDI activities. The in-water

geotechnical drilling/subsurface soil sampling activities, as noted in Section I, are not

necessary to determine the bulkhead barrier wall design modifications, only to refine

the design prior to finalization. Accordingly, the in-water borings will be drilled at a

later date than the upland borings.

Please do not hesitate to contact me if you have any questions or require additional

information.

Sincerely,

ARCADIS of New York, Inc. Terry W. Young, PE Principal-in-Charge

Attachments:

Figures: Figure 1, Site Plan Figure 2, Reaction Pile Tieback System Figure 3, Cantilevered Combination Wall System Figure 4, Typical Test Pile

Attachments: Attachment A, Drawings 13, 14, and 23 from the June 2011 50% RD Attachment B, Slug Test Methods – Standard Operating Procedures

Copies:

Michael Benoit, PE, ARCADIS Stephen Montagna, PE, ARCADIS

Figures

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FIGURE

NATIONAL GRID

FORMER CITIZENS GAS WORKS MANUFACTURED GAS PLANT SITE

BOROUGH OF BROOKLYN, KINGS COUNTY, NEW YORK

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NATIONAL GRID




IMAGES:XREFS:

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NOTES:

1. ELEVATIONS ARE IN FEET NAVD88.

2. CLSM = CONTROLLED LOW

STRENGTH MATERIAL

FIGURE

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DRAFT CONCEPT

NOT FOR CONSTRUCTION

TYPICAL TEST PILE

TYPICAL TEST PILE

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NATIONAL GRID




Attachments

Attachment A

Drawings 13, 14, and 23 from the

June 2011 50% RD

Attachment B

Slug Test Methods – Standard

Operating Procedures

of 6 G:\Clients\National Grid\Carroll Gardens\10 Final Reports and Presentations\SDI Work Plan\Attachment B\SOP for Slug Test Methods.docx

Slug Test Methods – Standard Operating Procedures


THIS PAGE INTENTIONALLY LEFT BLANK


STANDARD OPERATING PROCEDURE FOR PNEUMATIC SLUG TESTS I. Scope and Application Pneumatic slug tests are conducted by sealing the well head and applying air pressure to depress the water level, with fully submerged well screens. As detailed below, the well screen must remain below the water level throughout the pneumatic slug test. During the test, as air pressure is increased in the well, the water level falls until the water pressure and the air pressure return to equilibrium. After the water level is stable, air is released from the sealed well head by opening an air release valve. The water level recovery is a rising head slug test and produces very high quality data with little interference. A pressure transducer is used to monitor and record the change of the water level in the well during the pneumatic slug test. II. Equipment List 1. Personal protective equipment, as required by the site Health and Safety Plan. 2. Pneumatic slug test manifold. 3. Pressure transducer and cable. 4. Pressure transducer software. 5. Air pressurization source (compressed or pump) and appropriate hoses. 6. Leak prevention supplies (Teflon pipe sealant, plumbers putty or similar product). 7. Laptop computer. 8. Water level meter. 9. Measuring tape. 10. Decontamination equipment. 11. Slug test field form. 12. Field notebook. 13. Waterproof marker. III. Procedure 1. Decontaminate all down-well equipment: pressure transducer and cable, water level meter. 2. Measure depth to water and well total depth. Determine the water column length. 3. Review the well construction log to determine screened interval and depth to bottom. If the well

screen is not fully submerged, the well cannot be tested with the pneumatic method. 4. Attach the pneumatic slug test manifold onto the top of the well casing. Tighten the rubber connector

to ensure an airtight seal. 5. Place the pressure transducer at the proper depth (deep enough to accommodate initial change in

head but no deeper than six inches above the well bottom) by measuring the location where the transducer cable will be secured to the compression connector. Also ensure to not exceed the transducer pressure range. Tighten the cable seal by hand to seal the connection to the transducer cable.

6. Program the pressure transducer to record water levels at the following suggested frequencies. Note that the lithologic descriptions and datalogger memory should be used to select the highest measurement frequency possible. a. In hydrologic settings where high hydraulic conductivity is expected, water levels should be

measured at 0.5 second intervals, or the highest frequency available. This measurement frequency should be selected for gravels and sands.

b. In hydrologic settings where low hydraulic conductivity is expected, water levels should be measured at 1 to 2 second intervals. This measurement frequency should be selected for silts and clays.


7. View the measured water level in real time on the laptop computer. Wait for the water levels to stabilize. Note that temperature fluctuations on the pressure transducer will affect measured water levels (i.e. temperature differences between the above surface and groundwater environments).

8. Close the air release valve. 9. Close the inlet air valve with the pressure regulator closed. 10. Verify incoming pressure is less than safe operating pressure of manifold pressure regulator (<40 psi

is necessary) before attaching air hose (not applicable for hand pump). 11. Attach air hose and open regulator to verify incoming pressure (not applicable for hand pump). 12. Close regulator and open the inlet air valve. 13. Slowly open the pressure regulator to pressurize well head and depress water level a sufficient

distance without lowering the head below the top of the well screen (2.31 feet of water is equal to 1 psi). Keep the rule of thumb of 1 to 3 feet displacement and follow best practices with 2 duplicate tests and a third test with double the displacement. Larger displacements may be appropriate for high conductivity formations. Begin with a low pressure and gradually increase the pressure in order to obtain the desired displacement and do not over pressurize the well (do not exceed ~2 psi). If using a hand pump, pressurize well head with pump with regulator open.

14. Close the regulator and leak check the system with leak detection fluid and fix any leaks. If the leak is very slow, or down the well, the regulator may be used to maintain a constant pressure head.

15. Check the pressure transducer response and air pressure to verify system is stable. This may take a period of time as the pressure transducer is equalizing to both the pressurized atmosphere in the well and the displaced water column (see below figure). Stabilization is reached once the pressure returns to near the original pressure. If it is stable proceed to the next step, if not check the seals.

16. Record a baseline pressure for a minimum three minutes. Record data on the field form. 17. Close inlet valve and quickly open the release valve to initiate the test. 18. Allow sufficient time for water level to recover to static level. If completing one test, then 80%

recovery is sufficient. Duplicate tests are highly recommended and the next test should be completed after the first test has recovered to greater than 95%. A third test at a displacement of twice the initial is recommended.

19. Save all data files to the laptop and backup flash drive. 20. Finalize any field notes. 21. Review the data collected to determine the reasonableness of the preliminary results. The

observation of apparently anomalous results will be discussed with senior project staff prior to proceeding. The water level record for each test should show static conditions, pressurization of the well column, and the recovery response. Make notes on the field form and notebook concerning any irregularities.

22. Decontaminate all down-well equipment.


STANDARD OPERATING PROCEDURE FOR BAILDOWN SLUG TESTS I. Scope and Application The use of a bailer to remove a volume of water (slug) is used to complete rising-head tests. A bailer removes water from a well in a near-instantaneous manner. The water level response is observed using a pressure transducer. II. Equipment List The following materials will be available, as required, during slug testing using a bailer: 1. Personal protective equipment, as required by the site Health and Safety Plan. 2. Bailers of known size/capacity. 3. Pressure transducer and barologger. 4. Pressure transducer software. 5. Laptop computer. 6. Rope. 7. Water level meter. 8. Measuring tape. 9. Spring-loaded clamps. 10. Decontamination equipment. 11. Slug test field form. 12. Field notebook. 13. Waterproof marker. III. Procedure 1. Select a bailer according to a target initial displacement using the table below. A general guideline is

that initial displacements are between 1 and 3 feet, but should depend on the anticipated response (i.e. larger initial displacements should be chosen for formations with high hydraulic conductivity, smaller initial displacements can be used for formations with low hydraulic conductivity).

Bailer Volume Bailer Volume Well Casing Diameter Theoretical Initial

Displacement (gallons) (milliliters) (inches) (feet)

0.25 946 2 1.56 0.5 1,893 2 3.13 1 3,785 2 6.25

0.5 1,893 4 0.77 1 3,785 4 1.54 2 7,570 4 3.08 1 3,785 6 0.68 2 7,570 6 1.36 3 11,355 6 2.04

2. Decontaminate all down-well equipment: pressure transducer and cable, rope or cable, water level

meter. 3. Open well and allow enough time for the water level to equilibrate to atmospheric conditions. 4. Measure depth to water and well total depth. Total depth should be taken using a weighted tag line.

Determine the water column length. 5. Review the well construction log to determine screened interval and depth to bottom.


6. Program the pressure transducer to record water levels at the following suggested frequencies. Note that the lithologic descriptions and datalogger memory should be used to select the highest measurement frequency possible. a. In hydrologic settings where high hydraulic conductivity is expected, water levels should be

measured at 0.5 second intervals, or the highest frequency available. This measurement frequency should be selected for gravels and sands.

b. In hydrologic settings where low hydraulic conductivity is expected, water levels should be measured at 1 to 2 second intervals. This measurement frequency should be selected for silts and clays.

7. Program the barologger to record barometric pressure at the same interval as the pressure transducers measuring water levels. The barologger should be placed in the headspace of an adjacent well.

8. Install the pressure transducer deep enough within the water column to not interfere with the testing equipment (remember not to exceed the PSI range of the transducer). Do not install closer than 6 inches above the well bottom. Remember to use measurements and not the well bottom as silt can clog the pressure transducer. Clamp the pressure transducer cable to the well casing or other static object.

9. View the measured water level in real time on the laptop computer or use water level meter. Wait for the water levels to stabilize. Note that temperature fluctuations on the pressure transducer will affect measured water levels (i.e. temperature differences between the above surface and groundwater environments).

10. Measure the bailer and rope assembly length and mark the rope at a length as follows: Rope Mark #1 = Depth to Potentiometric Surface from TOC Rope Mark #2 = Depth to Potentiometric Surface from TOC + Length of Slug + Safety Factor

(Safety Factor = 10% of the Length of Slug) When deployed, this will ensure that the bailer is fully submerged. If a sufficient water column is

not available to obtain a full bailer, measure the volume removed upon removal. 11. Slowly insert the bailer into the well and stop just above the potentiometric surface rope mark #1. 12. With slack in the rope and the bailer being suspended above the water column, lower the bailer and

place the rope mark #2 at the top of casing. Clamp the non-bailer end of the rope to a static object to keep in place.

13. Wait for water level to equilibrate using response from the laptop computer or from water level meter. 14. Quickly remove the bailer from the water column and carefully pull it to surface. Pour the removed

water into an empty bucket. 15. Observe the water level response on the laptop computer and/or measure depth to water, being

careful not to interfere with the pressure transducer cable. Several manual depth to water measurements should be made throughout the test.

16. Allow sufficient time for water level to recover to static level. If completing one test, then 80% recovery is sufficient. Duplicate tests are highly recommended and the next test should be completed after the first test has recovered to greater than 95%. A third test at a displacement of twice the initial is recommended.

17. Measure the volume of water removed by the bailer that was poured into the empty bucket using a graduated cylinder.

18. Repeat steps 10 and 15. 19. Repeat rising-head slug tests for data reproducibility. If possible, complete a third test with a bailer or

multiple bailers connected in series that equates to twice the volume as the original. 20. Save all data files to the laptop, backup on flash drive and finalize any field notes. 21. Review the data collected to determine the reasonableness of the preliminary results. The

observation of apparently anomalous results will be discussed with senior project staff prior to additional testing or leaving the field site. The water level record for each test should show static conditions, the insertion or removal of the slug(s), and the water level response. Make notes on the field form and notebook concerning any irregularities.

22. Decontaminate all down-well equipment.

ARCADIS Pneumatic Slug Test Log

Site Name: Page: of

Well No: Prepared By: Date: Time:

Completed By:

Test Type: RisingFalling

Project No:

Confining Unit

TD=

Le=

SWL=

Lw=

Rb= Rs=

TS=

Rc=

rt=

Ls=

h=

Length of Screen

Static water Level

Effective Screen Length

Water column

Total Depth

Casing Radius

Radius of Transducer cable

Depth of Transducer Below SWL

Saturated Thickness

Screen RadiusRadius of Filter Pack

Top of Casing

Ground Surface

G:\Clients\National Grid\Carroll Gardens\10 Final Reports and Presentations\SDI Work Plan\Attachment B\Slug Test Field Logs.xls

Page 1 of 2

ARCADIS Pneumatic Slug Test Log

Site Name: Page: of


TESTS

Data DataNumber of Tests: File Name: File Location:

Input Pressure: Pressure Transducer SN: rt:

Test: TS Baseline: Pressure Reading:

Ho: Test Start Test End





Notes:Ho Initial change in head at instant the slug test is started

rt Radius of transducer cable

TS Depth of transducer below static water level

Theoretical Change in Head - 2.307 feet = 1 psi(Feet) (psi) (Feet) (psi) (Feet) (psi)

0.50 0.22 1.50 0.65 2.50 1.080.75 0.33 1.75 0.76 2.75 1.191.00 0.43 2.00 0.87 3.00 1.301.25 0.54 2.25 0.98 3.25 1.41

Well Parameters Required for Calculating Hydraulic Conductivity

Le Effective screen length, including the sand pack

Ls True screen length

Lw Length of water column in Well (TD-SWL)

Rs Screen radius

Rb Radius of filter Pack or borehole

Rc Casing radius

rt Radius of the transducer cable

Ts Depth the transducer is submerged below the SWL

SWL Static water levelTD Total depth of well/screen from reference pointh Saturated thickness of aquiferHo Initial head change at instant the slug test is started.

Aquifer Type Confined or unconfined

Project No:


Page 2 of 2

ARCADIS Baildown Slug Test Log

Site Name: Page: of


Completed By:

Test Type: RisingFalling

Project No:

Confining Unit

TD=

Le=

SWL=

Lw=

Rb= Rs=

TS=

Rc=

rt=

Ls=

h=

Length of Screen

Static water Level

Effective Screen Length

Water column

Total Depth

Casing Radius

Radius of Transducer cable

Depth of Transducer Below SWL

Saturated Thickness

Screen RadiusRadius of Filter Pack

Top of Casing

Ground Surface


Page 1 of 4

TEST DATA

Data DataNumber of Tests: File Name: File Location:

Pressure Transducer SN:

Test Number:Slug Volume:Rising or Falling Head Test?TS Baseline: Baseline Pressure Reading:Ho: Max. Displacement Pressure Reading:

Test Duration:

Manual Depth to Water Measurements:

NOTES:Ho Initial change in head at instant the slug test is started

rt Radius of transducer cable (can be ignored if less than 1/8 inch)

TS Depth of transducer below static water level

THEORETICAL HEAD CHANGE

Slug Volume (gallon)

Slug Volume

(ml)

0.25 9460.5 18931 3785

0.5 18931 37852 75701 37852 75703 11355

Time Depth to Water

6664442

Well Casing Diameter (inches)

Theoretical Initial Displacement (feet)

1.540.776.253.131.56

2.041.360.683.08

22


Page 2 of 4

WELL PARAMETERS REQUIRED FOR CALCULATING HYDRAULIC CONDUCTIVITY

Le Effective screen length, including the sand pack

Ls True screen length

Lw Length of water column in Well (TD-SWL)

Rs Screen radius

Rb Radius of filter Pack or borehole

Rc Casing radius

rt Radius of the transducer cable

Ts Depth the transducer is submerged below the SWL

SWL Static water levelTD Total depth of well/screen from reference pointh Saturated thickness of aquifer

Ho Initial head change at instant the slug test is started.

Aquifer Type Confined or unconfined


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Page 4 of 4

april 7, 2015 mr. henry t. willems new york state department of

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