Final_J-2_Range_East_SPM_Plan_2008.pdf

Impact Area Groundwater Study Program

Final

J-2 Range East System Performance Monitoring Plan

Camp Edwards Massachusetts Military Reservation

Cape Cod, Massachusetts

February 13, 2008

Prepared for:

U.S. Army Corps of Engineers New England District

Concord, Massachusetts for

U.S. Army / National Guard Bureau

Camp Edwards, Massachusetts

Prepared by:

ECC

Contract No. DACW33-02-D-0003, CTO 002

IMPACT AREA GROUNDWATER STUDY PROGRAM

Final

J-2 Range East System Performance Monitoring

Plan

Camp Edwards Massachusetts Military Reservation

Cape Cod, Massachusetts

Prepared for:

U.S. Army Corps of Engineers New England District Concord, Massachusetts

Camp Edwards, Massachusetts

Prepared by:

ECC

DISCLAIMER

This document has been prepared pursuant to government administrative orders (U.S. EPA Region 1 SDWA Docket No. I-97-1019 and 1-2000-0014) and is subject to approval by the U.S. Environmental Protection Agency. The opinions, findings, and conclusions expressed are those of the authors and not necessarily those of the Environmental Protection Agency.

NOTICE

The United States Department of Defense, Department of the Army, funded wholly or in part the preparation of this document and work described herein under Contract DACW33-02-D-0003. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

2/11/08

Shouvik Gangopadhyay

2008.02.11 15:54:34 -05'00'

2/11/08

Final J-2 Range East System Performance Monitoring Plan

TABLE OF CONTENTS

ACRONYMS AND ABBREVIATIONS...............................................................................iv EXECUTIVE SUMMARY ............................................................................................ ES-1

1.0 INTRODUCTION.....................................................................................................1-1

1.1 PURPOSE .........................................................................................................1-1

1.2 ORGANIZATION OF SPM PLAN ......................................................................1-2

2.0 BACKGROUND ......................................................................................................2-1

2.1 SITE SETTING ..................................................................................................2-1

2.2 GEOLOGY.........................................................................................................2-2

2.3 HYDROLOGY....................................................................................................2-3

2.4 CONTAMINANT DISTRIBUTION ......................................................................2-4

3.0 J-2 RANGE EAST TREATMENT SYSTEM ............................................................3-1

3.1 J-2 RANGE EAST WELLFIELD.........................................................................3-1

3.2 TREATMENT SYSTEM .....................................................................................3-3

3.2.1 Treatment System Overview........................................................................3-3

3.2.2 Modeled Influent Characteristics..................................................................3-3

3.2.3 Effluent Criteria ............................................................................................3-4

4.0 PERFORMANCE MONITORING............................................................................4-1

4.1 J-2 RANGE EAST DRILLING ............................................................................4-1

4.2 HYDRAULIC MONITORING..............................................................................4-3

4.2.1 Baseline Monitoring .....................................................................................4-4

4.2.2 Start-Up Monitoring and Testing ..................................................................4-5

4.2.3 Long-Term Hydraulic Monitoring................................................................4-10

4.3 CONTAMINANT MONITORING ......................................................................4-11

4.4 PLANT PERFORMANCE MONITORING ........................................................4-14

5.0 DATA EVALUATION...............................................................................................5-1

5.1 HYDRAULIC DATA............................................................................................5-1

5.1.1 Baseline Hydraulic Data...............................................................................5-1

5.1.2 Start-Up Hydraulic Data...............................................................................5-1

5.1.3 Long-Term Hydraulic Data...........................................................................5-3

5.2 CHEMICAL DATA..............................................................................................5-3

5.3 PLANT PERFORMANCE ..................................................................................5-5

6.0 ECOLOGICAL IMPACT MONITORING..................................................................6-1 i

ECC-J23-35AY5302-M10-0041

7.0 REPORTING SUMMARY .......................................................................................7-1

8.0 REFERENCES........................................................................................................8-1

FIGURES

Figure 1-1 Location of J-2 Range

Figure 2-1 J-2 Range Features

Figure 2-2 Regional Surficial Geology Map of Upper Cape Cod

Figure 2-3 2000 Synoptic Groundwater Elevations

Figure 2-4 J-2 Range Plume Perchlorate Distribution and Lines of Cross Section Locations

Figure 2-5 J-2 Range Plume RDX Distribution and Lines of Cross Section Locations

Figure 2-6 J-2 Range East Plume Cross Section B-B′ Illustrating Perchlorate Distributions

Figure 2-7 J-2 Range Plume Cross Section C-C′ Illustrating Perchlorate Distributions

Figure 2-8 J-2 Range Plume Cross Section D-D′ Illustrating Perchlorate Distributions

Figure 2-9 J-2 Range East Plume Cross Section E-E′ Illustrating Perchlorate Distributions

Figure 2-10 J-2 Range East Plume Cross Section B-B′ Illustrating RDX Distributions

Figure 2-11 J-2 Range Plume Cross Section C-C′ Illustrating RDX Distributions

Figure 2-12 J-2 Range Plume Cross Section D-D′ Illustrating RDX Distributions

Figure 2-13 J-2 Range East Plume Cross Section E-E′ Illustrating RDX Distributions

Figure 3-1 2007 J-2 East Wellfield Design Plume Shells with J-2 East Wellfield Design Capture Zones

Figure 3-2 J-2 East ETI IX-GAC-GAC Process Flow Diagrams

Figure 4-1 Baseline Hydraulic Monitoring Locations for J-2 Range East SPM

Figure 4-2 Start-Up Hydraulic Monitoring Locations for J-2 Range East SPM

Figure 4-3 Long-Term Hydraulic Monitoring Locations for J-2 Range East SPM

Figure 4-4 Chemical Monitoring Locations for J-2 Range East SPM

Figure 4-5 J-2 East ETI Plant Sampling Locations ii

TABLES

Table 3-1 J-2 Range East Wellfield Design Extraction Well Locations, Screen Intervals, and Flow Rates

Table 3-2 J-2 Range East Proposed Drilling Locations

Table 4-1 J-2 Range East Baseline Hydraulic Monitoring Wells

Table 4-2 J-2 Range East System Hydraulic Start-Up Test Procedures

Table 4-3 J-2 Range East Hydraulic Start-Up Monitoring Wells

Table 4-4 J-2 Range East Long-Term Hydraulic Monitoring Wells

Table 4-5 J-2 Range East Groundwater Chemical Monitoring Network

Table 4-6 J-2 Range East ETI System Sampling Locations and Parameters for Operational Monitoring

APPENDIX

Appendix A J-2 Range East 2006.75 Plume Shells iii

ACRONYMS AND ABBREVIATIONS

3-D three-dimensional

AO Administrative Order

BBM Buzzards Bay Moraine

CMR Commonwealth of Massachusetts Regulation

COC contaminant of concern

EPA U.S. Environmental Protection Agency

ETI extraction, treatment, and infiltration

FS feasibility study ft feet

GAC granular activated carbon gpm gallons per minute

IAGWSP Impact Area Groundwater Study Program

IX ion exchange

MassDEP Massachusetts Department of Environmental Protection

MCL maximum contaminant level

MCP Massachusetts Contingency Plan

MMR Massachusetts Military Reservation

MPP Mashpee Pitted Plain msl mean sea level

RDX hexahydro-1,3,5-trinitro-1,3,5-triazine

RI remedial investigation

RRA rapid response action

SDWA Safe Drinking Water Act of 1974

SE Southeast

SM Sandwich Moraine

SPM system performance monitoring

TERC Total Environmental Restoration Contract

USACE U.S. Army Corps of Engineers

ZOC zone of contribution µg/L micrograms per liter iv

EXECUTIVE SUMMARY

This system performance monitoring (SPM) plan outlines the approach for monitoring the J-2 Range East plume and the effectiveness of the J-2 Range East extraction, treatment, and infiltration (ETI) system. The J-2 Range East ETI system is the active remedial component of the J-2 Range East groundwater remedy.

The J-2 Range is located adjacent to and southeast of the Impact Area, and is one of the ranges formerly utilized by military contractors for testing and development of various weapons and systems, and by the military for training purposes. The original J-2 Range was established in the late 1940s along the west side of Greenway Road, in the area currently designated as N Range. The J-2 Range has been used historically as a musketry range (1935-1940s), transition range (1940s-1950s), rifle range (1960s-

1980s), and a contractor test range (1953-1980). Two plumes have been identified emanating from the J-2 Range—the J-2 North plume and the J-2 Range East plume

(ECC 2007b).

As discussed in the draft J-2 Range groundwater remedial investigation (RI)/feasibility study (FS) report, the J-2 Range East groundwater contaminants of concern (COCs) are perchlorate and hexahydro-1,3,5-nitro-1,3,5-triazine (RDX). The J-2 Range East plume was derived from a number of different sources; thus the nature and extent of groundwater contamination is heterogeneous. The J-2 Range East plume is defined by detectable concentrations of perchlorate and consists of a main body and two lobes— western and eastern lobes (Figure 2-4). The main body of the perchlorate plume is approximately 6,300 feet (ft) long and widens to approximately 2,100 ft at its widest point. RDX encompasses approximately the same extent in the main body of the J-2

Range East plume (Figure 2-5). There is a small area where RDX is detected, below 2 micrograms per liter (µg/L), centered at location MW-399M1, which is located downgradient and slightly to the west of the main body of the plume. The J-2 Range

East western perchlorate lobe is approximately 3,000 ft long and approximately 300 ft across at its widest point. RDX in the western lobe, with concentrations below 2 µg/L, encompasses approximately the same extent as the perchlorate concentrations. The

J-2 Range East eastern lobe is defined by perchlorate and is approximately 2,300 ft long

ES-1

and approximately 500 ft across at its widest point. Downgradient and crossgradient of the east side of the main lobe of the plume is an area of isolated detections of perchlorate below 1 µg/L at monitoring well MW-334M1.

The objective of the J-2 Range East ETI system is to minimize downgradient migration of the J-2 Range East plume by capturing and treating contaminated groundwater. The major components of the J-2 Range East ETI system include:

• three extraction wells, in an axial array, pumping at a combined total flow rate of approximately 425 gallons per minute (gpm);

• an ex-situ treatment process consisting of ion exchange (IX) resin and granular activated carbon (GAC) media to treat perchlorate and explosives; and,

• three infiltration trenches located along the lateral boundaries of the plume where treated water will enter the vadose zone and infiltrate into the aquifer.

The purpose of this SPM plan is to outline procedures to monitor the effectiveness of the

J-2 Range East ETI system. This plan outlines specific activities proposed to measure the extent of plume capture. Additional monitoring activities are focused on plume concentration monitoring to assess contaminant distribution. The data collection is also aimed at addressing wellfield design uncertainties to optimize performance. In addition, monitoring at the treatment system will include influent and effluent sampling to confirm that the treated water being discharged back into the aquifer through the infiltration trenches is below the method detection limit of 0.35 µg/L for perchlorate and the reporting limit of 0.25 µg/L for RDX.

ES-2

1.0 INTRODUCTION

This system performance monitoring (SPM) Plan for the J-2 Range East remedial system presents a program for monitoring the effectiveness of the proposed remedial extraction, treatment, and infiltration (ETI) system. The ETI system comprises three extraction wells situated on the longitudinal axis of the J-2 Range East plume.

Monitoring activities will be conducted to determine the extent of capture of the hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and perchlorate plumes, and to assess progress towards restoration of the aquifer. Additional monitoring activities will assess the ETI system’s effectiveness in treating the extracted groundwater prior to recharge back to the aquifer through three infiltration trenches.

The J-2 Range is located adjacent to and southeast of the Massachusetts Military

Reservation (MMR) Impact Area, and is the northernmost of the four former training ranges that comprise the Southeast (SE) Ranges (Figure 1-1). The SE Ranges are former military training ranges and defense contractor test ranges that operated from

1935 to 1997. The J-2 Range was used from 1935 through the 1980s (ECC 2007b).

This work has been conducted by the U.S. Army Corps of Engineers (USACE) under the

Total Environmental Restoration Contract (TERC) DACW33-02-D-003, contract task order CTO-02, in support of the Impact Area Groundwater Study Program (IAGWSP), pursuant to the U.S. Environmental Protection Agency (EPA) Administrative Orders

1-97-1019 (AO1) and 1-2000-0014 (AO3) under the Safe Drinking Water Act of 1974

(SDWA), including consideration of the substantive clean up standards in the

Massachusetts Contingency Plan (MCP) 310 Code of Massachusetts Regulations

(CMR) 40.

1.1 PURPOSE

The installation of the J-2 Range East ETI system will facilitate contaminant mass removal and control plume migration. The purpose of this SPM plan is to specify monitoring activities to meet the following objectives:

1-1

• evaluate hydraulic conditions to assess the effectiveness of the J-2 Range East ETI system;

• evaluate the nature and extent of perchlorate and RDX concentrations in groundwater and monitor these trends over time;

• assess the treatment system’s performance at removing perchlorate and RDX from groundwater prior to recharge back to the aquifer through infiltration trenches;

• evaluate uncertainties in local hydrostratigraphy, which will allow for potential optimization; and,

• assess changes in general groundwater chemistry in the treatment process.

The J-2 Range East ETI system is expected to begin operation in September 2008.

1.2 ORGANIZATION OF SPM PLAN

The site setting, geology, hydrology, and contaminant distribution are presented in

Section 2.0. A general description of the J-2 Range East ETI system is presented in

Section 3.0. The approach for hydraulic and chemical monitoring of the treatment system is presented in Section 4.0. The methods of data evaluation for the hydraulic and chemical data collected from the well network and treatment plant are presented in

Section 5.0. An assessment of potential impacts to ecological receptors is presented in

Section 6.0. The monitoring and reporting schedule is presented in Section 7.0.

References used in this plan are presented in Section 8.0.

1-2

2.0 BACKGROUND

The site setting, geology, hydrogeology, and contaminant distribution for the J-2 Range

East plume are summarized in this section.

2.1 SITE SETTING

The J-2 Range (Figure 2-1) is located adjacent to and southeast of the Impact Area, and is one of the ranges formerly utilized by military contractors for testing and development of various weapons and systems, and by the military for training purposes. The original

J-2 Range was established in the late 1940s along the west side of Greenway Road, in the area currently designated as N Range. The J-2 Range area covered by this investigation has been used historically as a musketry range (1935-1940s), transition range (1940s-1950s), rifle range (1960s-1980s), and a contractor test range (1953-1980)

(ECC 2007b). Examples of activities conducted by various contractors include:

propellant and fuze testing, penetration testing for various munitions, fragmentation testing, obscuration testing, infrared testing of tank heat signatures, propellant and waste burning, munitions disposal, loading of munitions with explosives, and development and testing of light antitank weapon rockets. Based on various witness interviews, the J-2

Range was also reportedly utilized as an open burn/open detonation area (ECC 2007b).

Various areas within the J-2 Range boundaries have been investigated as potential sources of the observed groundwater contamination. The Final Revised J-2 Range

Supplemental Soil Workplan (AMEC 2004) summarizes source area characterization that is ongoing at the time of publication of this SPM plan. The objective of this continuing work is to better characterize known J-2 Range source areas and identify

(and delineate) additional potential source areas not previously identified.

The IAGWSP voluntarily performed a Soil Rapid Response Action (RRA) at the J-2

Range (AMEC 2003). The focus of the RRA was to excavate soil from fourteen areas where existing analytical data indicated the presence of the highest concentrations of propellant, explosive, and pyrotechnic compounds. The history of the source J-2 Range, and past and present soil and source characterization of the J-2 Range, will be presented in the forthcoming Draft J-2 soil remedial investigation (RI).

2-1

Analytical results presented in the draft J-2 groundwater RI/feasibility (FS) report (ECC

2007b) indicate that there are multiple sources of the J-2 Range East plume. The plume has numerous lobes composed of perchlorate and RDX. The J-2 Range East plume is further described in Section 2.4. The source areas are undergoing investigation to determine the nature and extent of soil contamination and their existing or potential contribution to groundwater contamination.

2.2 GEOLOGY

The surficial geology of western Cape Cod comprises glacial sediments deposited during the retreat of the Wisconsinan stage of continental glaciation (Figure 2-2). Three extensive sedimentary units characterize the regional geology: the Buzzards Bay

Moraine (BBM), the Sandwich Moraine (SM), and the Mashpee Pitted Plain (MPP). The

BBM and the SM lie along the western and northern edges of western Cape Cod, respectively. The BBM and SM are composed of ablation till, which is poorly sorted material ranging from clay to boulder size that was deposited at the leading and lateral edges of two lobes of the Laurentide ice sheet during a readvance of the ice front.

These moraines form hummocky ridges. The MPP, which consists of fine- to coarse-grained sands forming a broad outwash plain, lies south and east of the two moraines.

Underlying the MPP are fine-grained, glaciolacustrine sediments and basal till. In some areas these units are not evident and the sand of the MPP overlies bedrock.

The J-2 Range East plume is migrating through transmissive unconfined sandy glacial outwash deposits. The sandy nature of the surface soils promotes rapid infiltration with little run-off. Discontinuous silty sand, silts, and clayey sand units occur sporadically within the saturated zone. The continuity of these fine-grained deposits increases deep within the aquifer and results in localized areas of lower hydraulic conductivities and reduced groundwater velocities. These fine-grained deposits are in the vicinity of the J-2

Range East plume and some portions of the plume are restrained by the fine-grained deposits.

2-2

2.3 HYDROLOGY

A single groundwater flow system underlies western Cape Cod, including the MMR. The aquifer system is unconfined (i.e., it is in equilibrium with atmospheric pressure and is recharged by infiltration from precipitation). The high point of the water table occurs as a groundwater mound beneath the southeastern portion of Camp Edwards, immediately south-southwest of the J-2 Range East plume source area (Figure 2-3). Groundwater flow generally radiates outward from this mound. The ocean bounds the aquifer on three sides, with groundwater discharging into Nantucket Sound on the south, Buzzards

Bay on the west, and Cape Cod Bay on the north. The Bass River in Yarmouth forms the eastern lateral aquifer boundary. Precipitation at MMR can range from less than 30 inches per year to greater than 70 inches per year. Therefore, recharge to the aquifer varies significantly, as do groundwater levels. Near the top of the groundwater mound, the water table may fluctuate 8 feet (ft) or more due to varying recharge. Fluctuations of this magnitude have occurred within the last decade at MMR, with record high water levels in summer 1998 and fall 2006, and near record low water levels in fall 2002.

Based on distribution of contaminant data and groundwater head data there is vertical flow near the top of the groundwater mound. Farther downgradient, north-northeast of the top of the groundwater mound, toward the midpoint of the plume, there is less vertical flow. Additional details of aquifer properties are provided in the draft J-2 groundwater RI/FS (ECC 2007b).

No surface water bodies are located directly over the J-2 Range East plume. Two surface water bodies, Ox Pond (located northwest of the plume) and Coast Guard Tower

Pond (located east of the leading edge of the plume), were evaluated during wellfield design modeling to determine if the operation of the treatment system would adversely affect water levels. Ox Pond is less than an acre in size and located approximately

2,500 ft northeast of the intersection of Jefferson Road and Barlow Road (Figures 2-4 and 2-5). The Ox Pond surface elevation is approximately 125 ft msl. Because the groundwater elevation in this area is approximately 64 ft msl, Ox Pond is a perched water body and not connected to the groundwater table. The Coast Guard Tower Pond is less than an acre in size and located approximately 1,400 ft east of the intersection of

2-3 the Coast Guard Transmitter Station Access Road and Greenway Road (Figures 2-4 and 2-5). The Coast Guard Tower Pond surface elevation is approximately 157 ft msl and the groundwater elevation in the area is approximately 66 ft; therefore, the Coast

Guard Tower Pond is a perched water body and not connected to the groundwater table.

2.4 CONTAMINANT DISTRIBUTION

The J-2 Range East contaminants of concern (COCs) are perchlorate and RDX. The

J-2 Range East plume was derived from a number of different sources and thus the nature and extent of groundwater contamination is heterogeneous. The distribution of groundwater contamination is shown in Figures 2-4 through 2-13. The perchlorate concentrations within and just downgradient of the source area are relatively low (below

30 micrograms per liter [µg/L]) and generally decreasing. These trends suggest that the amount of contamination leaching from the source areas has decreased in recent years.

The J-2 Range East plume, as defined by detectable concentrations of perchlorate, consists of a main body and two flanking lobes. However, the amount of uncontaminated groundwater between the lobes is minor and the main body and lobes may be connected. The main body of the perchlorate plume is approximately 6,300 ft long and widens to approximately 2,100 ft at it widest point. The main body of the plume encompasses two areas where concentrations are above 2 µg/L. The principal area defined by perchlorate concentrations of 2 µg/L or greater is approximately 4,800 ft long and approximately 1,200 ft wide at it widest point, with a maximum detected concentration of 69 µg/L. The smaller area of above 2 µg/L associated with the main J-2

Range East plume is approximately 1,300 ft long and 300 ft wide centered around MW-

310, and has a maximum detected concentration of 20 µg/L. RDX encompasses approximately the same extent in the main body of the J-2 Range East perchlorate plume and has a maximum detected concentration of 18 µg/L. The center of the main body of the J-2 Range East perchlorate plume plunges from approximately 68 ft mean sea level (ft msl) at the source area to approximately –160 ft msl (top of bedrock) at MW-

393. The plume is approximately 30 feet thick beneath the source area at MW-307 and thicker as the plume migrates downgradient (80 feet thick at MW-368 and 100 feet thick at MW-393). The leading edge of the RDX plume is slightly shallower and thinner than the perchlorate plume (–50 to –80 ft msl). There is an area of RDX detections, all below

2-4

2 µg/L, centered at location MW-399M1, which is located downgradient and slightly to the west of the main body of the plume.

The J-2 Range East western lobe, as defined by perchlorate detections, is approximately

3,000 ft long, and approximately 300 ft across at its widest point and has a maximum detected concentration of 4.1 µg/L. RDX encompasses approximately the same extent as the perchlorate with concentrations below 2 µg/L. Based on source area monitoring wells, the western lobe is detached from the source area.

The J-2 Range East eastern lobe is approximately 2,300 ft long and approximately 500 ft across at its widest point and consists of perchlorate with a maximum concentration of

5.2 µg/L. Based on source area monitoring wells, the eastern lobe is detached from the source area. Downgradient and crossgradient of the east side of the main lobe of the plume is an area of isolated detections of perchlorate below 1 µg/L at monitoring well

MW-334M1.

2-5

(intentionally blank)

2-6

3.0 J-2 RANGE EAST TREATMENT SYSTEM

The conceptual design for the J-2 Range East remedial system consists of in-plume and leading edge extraction, and peripheral infiltration. The system was designed to remove mass, to control plume migration, and have minimal impact on the adjacent J-2 Range

North groundwater remedial system. This remedy was selected with concurrence from the EPA and the Massachusetts Department of Environmental Protection (MassDEP).

The following sections present the J-2 Range East ETI wellfield design and treatment system design.

3.1 J-2 RANGE EAST WELLFIELD

The J-2 Range East RI three-dimensional (3-D) perchlorate and RDX plume shells originally developed for the J-2 groundwater RI/FS were updated with groundwater data collected between April and October of 2006 (Appendix A). Based on evaluation of the new plume shells, minor changes were made in the extraction well locations and screen intervals. The capture zone of the revised wellfield is shown in Figure 3-1.

A level of conservatism was added to the design by slightly lengthening the extraction well screen intervals. The longer screens were designed to compensate for the potential presence of low-hydraulic conductivity units, which could potentially affect the performance of the ETI system. The geology in the J-2 Range East area is described in the Draft J-2 Range Groundwater Remedial Investigation and Feasibility Study (ECC

2007b). SPM data collection activities and startup evaluation (Sections 4 and 5) will be used to update the conceptual understanding of the aquifer in the area of the J-2 Range

East plume, which in turn will be used to determine if future optimization of the J-2

Range East ETI system (e.g., shortening the extraction well screen intervals by packering, adjustment of flow rates, etc.) to improve system performance is warranted.

The J-2 Range East wellfield design includes: three extraction wells (J2EW0004, J2EW0005, and J2EW0006) oriented along the plume axis and operating at 90, 210, and 125 gallons per minute (gpm) respectively (Table 3-1), a treatment system, and three infiltration trenches to return treated water through the vadose zone to the aquifer

(Figures 2-4 and 2-5). Extraction well J2EW0004 will be located approximately 1,330 ft

3-1 south of Wood Road, J2EW0005 will be located along Wood Road, and J2EW0006 will be located along the Coast Guard Transmitter Station Access Road.

During drilling of the extraction wells, grain-size samples and groundwater profile samples will be collected and soil cores from the boreholes will be characterized. The proposed elevation of the extraction well screens and the sample intervals for each extraction well are presented in Table 3-2. The locations are approximate and may be adjusted slightly due to access considerations.

Grain size samples will be collected from each pilot boring across the proposed well screen interval including 20 ft above and 20 ft below the proposed well screen interval.

The grain-size samples will be used to determine the appropriate slot size and filter pack for each extraction well screen. The samples that will be collected within, above, and below the proposed screen interval are necessary if low-hydraulic conductivity units are observed, which may result in the shifting or blanking of the proposed screen interval.

Lithologic characterization of soil cores from the pilot borings (using the American

Society for Testing and Materials ASTM Unified Soil Classification System USCS

[ASTM-D2487]) is necessary to characterize the aquifer matrix at the extraction well locations (Table 3-2). The characterization of the soil cores is necessary because previous aquifer matrix data from within the J-2 Range East plume has been from soil cuttings (adequate for RI/FS purposes); however, no lithologic borings have been conducted within the core of the J-2 Range East plume. Appropriate characterization of the aquifer matrix is necessary to assess the performance of the ETI system and to update the hydrostratigraphic model and the groundwater flow model, which will be used to predict aquifer response to the ETI system pumping and to assess potential system optimization opportunities. These include screen length and pumping rate revisions to enhance capture performance. Groundwater profile samples will be collected every 10 feet at J2EW0004 and J2EW0005 to characterize the upgradient and downgradient extent of the core of the plume (Table 3-2). The laboratory analytical methods for analyzing all the groundwater profile samples will be EPA Method SW846/8330 for explosives and EPA Method E314.0 for perchlorate.

3-2

Installation of monitoring wells and piezometers is proposed for each of the extraction well pilot borings and for locations separate from the pilot borings. Proposed monitoring wells are shown on Figures 2-4 and 2-5. The proposed locations, screen intervals, and data collection for each monitoring well is presented in Table 3-2. Discussion of the proposed monitoring wells and piezometers for chemical and hydraulic performance monitoring is presented in Section 4.1.

3.2 TREATMENT SYSTEM

The following sections include discussion of the J-2 Range East ETI treatment system design, including an overview of the treatment system operation, treatment system components, modeled influent concentrations, and effluent criteria.

3.2.1 Treatment System Overview

Treatment of the J-2 Range East plume will consist of filtration through treatment vessels and discharge to three infiltration trenches to return treated groundwater to the aquifer

(Figure 2-4). Each treatment train will use ion exchange (IX) resin followed by granular activated carbon (GAC) media followed by polishing GAC media. The IX and GAC vessels will be used in conjunction with additional system components as summarized in the process flow diagram (Figure 3-2). The backwash system includes a backwash water tank and backwash pump. The treatment facility will meet applicable codes and regulations including the Massachusetts Building Code and the National Electrical Code.

3.2.2 Modeled Influent Characteristics

Based on the wellfield design modeling, the maximum influent concentration of perchlorate from any one extraction well is expected to approach 12.4 µg/L. The maximum influent concentration of RDX from any one extraction well is expected to approach 4.3 µg/L. Although the maximum detected perchlorate and RDX concentrations within the plume are much higher (69 and 18 µg/L, respectively), influent concentrations in extraction wells are typically much lower because they inevitably capture some clean water that mixes with higher concentration water from discreet intervals along the extraction screen.

3-3

3.2.3 Effluent Criteria

The Massachusetts groundwater discharge regulations under 314 CMR 5.00 et seq.

govern the discharge of treated groundwater and require, in 314 CMR 5.10(3), that the concentrations of discharge effluent be adequate to assure the attainment and maintenance of the assigned groundwater quality standards of the receiving waters, as listed in 314 CMR 6.00 et seq. The minimum standards for Class I groundwater

(MassDEP has classified MMR groundwater as Class I), as listed in 314 CMR 6.06(1), are equivalent to the SDWA Maximum Contaminant Levels (MCLs). The treated effluent will meet these levels prior to discharge and will be below the method detection limit of

0.35 µg/L for perchlorate and the reporting limit of 0.25 µg/L for RDX. Sections 4.0 and

6.0 present additional parameters that will be monitored as part of the J-2 Range East system performance monitoring.

3-4

4.0 PERFORMANCE MONITORING

This section describes hydraulic, chemical, and plant monitoring intended to support an evaluation of the performance of the J-2 Range East ETI system. The goals of the SPM are to collect the data required to evaluate the effectiveness, performance, and optimization of the remedial system.

4.1 J-2 RANGE EAST DRILLING

The existing monitoring well network will be expanded to provide more information on the aquifer matrix and the plume nature and extent. Additions to the monitoring well network are necessary to:

• Characterize the localized stratigraphic heterogeneity near the extraction wells and to allow optimization of screen lengths.

• Increase the hydraulic monitoring network in order to measure horizontal and vertical hydraulic stresses posed by the ETI system for evaluation the performance of the extraction wells.

• Increase the chemical monitoring network to evaluate system performance, guide future system operations, and evaluate changes in plume geometry.

The proposed monitoring wells and piezometers are shown in Figures 2-4 and 2-5. The locations are approximate and may be adjusted slightly due to access considerations and objectives for each monitoring location. The approximate coordinates, screen intervals, and data collection intervals are presented in Table 3-2. The proposed monitoring wells will be installed and developed in accordance with technical procedures as outlined in the Draft Quality Assurance Project Plan (ECC 2003).

J2MW-01 will to be installed approximately 30 ft north or south of J2EW0005. The borehole for installation of J2MW-01 may also serve as the pilot boring of J2EW0005. In order to minimize site preparation, the pilot boring can be drilled north or south of Wood

Road and the extraction well installed on the opposite side of the road. The location

J2MW-02 will be drilled approximately 100 ft southeast of J2EW0005 along Wood Road.

The installation and appropriate placement of J2MW-01 and J2MW-02 are critical to accurately assess the hydraulic influence at J2EW0005. At J2MW-01 and J2MW-02 two

4-1 monitoring wells and one piezometer will be installed at each location. The monitoring wells will be installed below and within the elevation of the extraction well and the piezometer above the extraction well screen (Table 3-2). The J2MW-01 and J2MW-02 proposed well screens will be used to assess the hydraulic stress imposed by the operation of J2EW0005 at different depths within the aquifer and the lateral propagation of the hydraulic stress. The monitoring wells at J2MW-01 will also be used to characterize the concentrations and the thickness of the plume near J2EW0005 over time.

J2MW-03 will to be placed approximately 30 feet northwest of J2EW0006 along the

Coast Guard Transmitter Station Access Road. Two monitoring wells, with screens placed within and above the elevation of the extraction well screen, and one piezometer, installed above the extraction well screen, will be constructed at J2MW-03 (Table 3-2).

The monitoring wells and piezometer at J2MW-03 can likely be installed in the pilot boring drilled for J2EW0006. The well cluster needs to be close to the extraction well in order to accurately measure the relatively small drawdown expected from J2EW0006 at different depths within the aquifer.

The primary objective of J2MW-04 is to characterize the nature and extent of the plume downgradient of J2EW0005. During drilling of J2MW-04, groundwater profile samples will be collected and analyzed for perchlorate and RDX (Table 3-2). The laboratory analytical methods for analyzing all the groundwater profile samples will be EPA Method

SW846/8330 for explosives and EPA Method E314.0 for perchlorate. J2MW-04 will be an important monitoring well cluster to understand changes in the plume downgradient of J2EW0005, which will be used to guide the future operation of J2EW0006. The proposed well screen intervals are at the predicted depth of the core of the RDX plume

(approximately –60 to –70 ft msl) and the perchlorate plume (approximately –95 to –105 ft msl) (Table 3-2). The final vertical placement of the monitoring well screens will be determined after the results from the profile samples have been analyzed. J2MW-04 will also be used to assess the hydraulic stress from J2EW0005 and J2EW0006 at different depths within the aquifer.

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Within the J2EW0004 pilot boring two monitoring wells will be set; one below and one within the elevation of the extraction well screen (J2MW-05) (Table 3-2). The monitoring wells will be used to assess the nearfield hydraulic stress of J2EW0004 at different depths within the aquifer. The monitoring wells at J2MW-05 will also be used to characterize the concentrations and the thickness of the plume near the downgradient extent of the core of the plume over time.

4.2 HYDRAULIC MONITORING

Hydraulic monitoring is conducted to verify the hydraulic performance of the system in regard to capture zone development, gradient manipulation, and plume trajectory;

assess effects due to changes in system operations or external hydraulic stresses;

assess potential impacts on adjacent plumes; determine if drawdown or mounding is impacting local surface water environments; provide a basis for groundwater flow model refinement and/or recalibration; and refine and optimize system operation. System flow rates are also monitored to confirm that design flows are being achieved and to provide a further basis for assessment of mass removal and hydraulic effectiveness.

The strategy for hydraulic monitoring consists of an assessment of the drawdown and mounding stresses and resulting capture zone from the operation of the J-2 Range East

ETI system. This approach consists of initial water level measurements taken from a series of locations prior to the system operation. Water levels are then measured continuously during initial operation of the system under various pumping scenarios to determine the development of the zone of influence, to provide updated information on aquifer properties, and to provide a basis for potential model refinement and recalibration. The groundwater flow model can then be used, in conjunction with mass transport applications as required, to modify or optimize system operations to meet performance expectations.

After the initial hydraulic assessment is completed, long-term hydraulic monitoring is conducted to monitor water levels at selected monitoring wells to evaluate the system operational performance and expected hydraulic stresses. The hydraulic monitoring of

4-3 the J-2 Range East ETI system components will include (1) baseline monitoring, (2) start-up monitoring and testing, and (3) long-term periodic monitoring.

4.2.1 Baseline Monitoring

Baseline monitoring refers to an initial monitoring event that characterizes ambient hydraulic conditions prior to the propagation of hydraulic stress from groundwater extraction and infiltration of treated groundwater. Baseline monitoring is proposed at 28 locations (66 screens), including 3 extraction wells, and 5 background locations (11 screens) (monitoring wells located away from the areas of extraction and infiltration stress) that will be used for the start-up test. As described in Section 4.1, five new clusters of monitoring wells are proposed to be installed to support hydraulic baseline monitoring, start-up monitoring, and long-term monitoring as follows (Figures 4-1 through

Figure 4-3, and Tables 4-1, 4-3, and 4-4).

• As described in Section 4.1, two new well clusters are to be installed near J2EW0005. These new wells will provide near-field drawdown data to quantify aquifer stratigraphy, well efficiency and hydraulic conductivity. One of these well clusters (J2MW-01M1,M2,PZ) will be located approximately 30 ft north or south of J2EW0005. The second well cluster (J2MW-02M1,M2,PZ) will need to be situated approximately 100 ft southeast of J2EW0005 along Wood Road. The two new well clusters will consist of two well screen intervals that are below and within the extraction interval and a piezometer screen above the extraction interval for J2EW0005. Observation wells are usually placed, in common practice, at a minimum distance equal to 1.5 to 2 times the aquifer penetration depth from a partially penetrating well. For J-2 Range East, the new wells are located closer to the extraction well due to the relatively small drawdown expected from the pumping test and full-scale operations.

• One monitoring well cluster (J2MW-03M1,M2,PZ) consisting of two well screens and a piezometer located above and within the extraction interval are to be installed near extraction well J2EW0006. The monitoring well cluster needs to be close to the extraction well in order to accurately measure the relatively small drawdown expected from the pumping test and full-scale operations.

• One monitoring well cluster (J2MW-05M1,M2) will be installed near extraction well J2EW0004. The cluster will consist of two well screen intervals located within and below the extraction interval. The monitoring well cluster needs to be close to the extraction well in order to accurately measure the relatively small drawdown expected from the pumping test.

• One monitoring well cluster (J2MW-04M1,M2), consisting of two well screen intervals will be situated between J2EW0005 and J2EW0006. This well cluster will be used

4-4 primarily for chemical monitoring. These wells will also be used for hydraulic monitoring.

Baseline monitoring locations are listed in Table 4-1 and depicted in Figure 4-1.

Pumping rates from water supply wells WS-1, -2, and -3 will be obtained from the Upper

Cape Water Supply Cooperative to assess potential changes in pumping stress and potential impacts on baseline and start-up conditions. Baseline monitoring will be conducted after remedial system construction and the initial system trial operations are complete. The initial trial operations are intended to test system operations as compared to design requirements and are conducted by the system construction contractor.

Two baseline monitoring events will be conducted. The baseline monitoring event is intended to be a synoptic event and measurements will be conducted over the course of one day. The first baseline monitoring will be conducted prior to system start-up during a period that is not subject to significant precipitation (more than 0.30 inches of rainfall in

24 hours). A second baseline monitoring event will be conducted during the start-up test when the ambient (unstressed) aquifer condition returns after completion of the single well aquifer tests have been completed (Table 4-2). Water levels will be measured via a combination of data logging and manual measurements. Precipitation during and for the

72 hours preceding the measurement event will be noted.

4.2.2 Start-Up Monitoring and Testing

Start-up monitoring is the primary means by which system performance is evaluated.

Start-up monitoring and testing will be conducted to obtain information that can be used to characterize aquifer properties and to evaluate the response of the aquifer to hydraulic stresses imposed by operational pumping and infiltration. The water level monitoring methods will include continuous monitoring using datalogger and manual periodic monitoring using a water level meter. Measurement of water levels from wells within and outside the influence of system operation will be conducted. In addition to collection of water levels, flow rates at the extraction wells and infiltration trenches will also be recorded.

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The primary objectives of the start-up test are to:

• Record changes in water levels in monitoring wells during start-up of the remedial system.

• Quantify aquifer response to the pumping stresses and delineate the 3-D hydraulic zones of influence for the extraction wells.

• Characterize and refine aquifer properties.

• Validate model predicted stress and quantify system capture zone development.

• Provide data to develop a more representative groundwater model to support system optimization, if needed.

The zone of hydraulic influence is the area affected by system stress relative to the ambient (natural/no stress) condition. It is defined as the zone of drawdown at the water table or at depths where change in potentiometric head from ambient conditions occurs.

The zone of influence is not the same as the zone of capture (ZOC) to a well. ZOC is determined by flownet analysis or a particle tracking analysis by subjecting a flow model to a stressed (operational) condition. The ZOC is usually narrower across the natural flow path than the zone of influence in a regional flow regime, but usually extends further in the upgradient direction.

The data needed to define the zone of influence include water level measurements collected before start-up (ambient/unstressed condition) and after start-up (stressed condition). Interval measurements collected during start-up provide useful information to monitor the development of the zone of influence. The development and final shape of the zone of influence provides insights regarding aquifer heterogeneity.

The aquifer characteristics that can be determined with start-up water level monitoring include transmissivity, storativity, and anisotropy. These hydraulic properties (along with the geologic information gathered from well drilling activities during system installation) will be compared to the current site specific geologic and hydrogeologic model in terms of aquifer matrix, sediment properties, and hydrogeologic unit distribution patterns.

The design of the start-up test and monitoring sequence is based on the layout of the wellfield, design goals regarding the propagation of hydraulic stress, and experience

4-6 from start-up monitoring and aquifer testing previously conducted at the MMR. Similar designs have been successfully used to quantify capture performance at more than 15 system start-up, and shut-down/start-up tests conducted on MMR remedial systems.

After consideration of many possible start-up testing scenarios, a two phased approach will be implemented for the start-up test and monitoring for the J-2 Range East ETI system. The start-up test will be conducted after operational shakedown of the treatment system has been completed and trial operations are complete. Trial operations are intended to test the proper system construction, installation, and operation. Installation and development of the proposed new hydraulic performance monitoring wells will also occur before the system start-up test.

Table 4-2 presents the details of the start-up test procedures. The start-up testing sequence is as follows.

Phase 0 - Shutdown of Trial Operation and Baseline Monitoring: Wellfield trial operations (system checking and verification) will be halted allowing the aquifer to return to ambient conditions. A shutdown period of 6 days is required to ensure full recovery to ambient (unstressed) conditions (Table 4-2). The first baseline monitoring will commence on day 6 after shutdown of trial operations. The baseline monitoring includes continuous monitoring using dataloggers and manual water level measurement.

Background wells outside the influence of the system will also be measured. Near steady-state conditions will be confirmed from monitoring wells equipped with dataloggers. For the purposes of this test, near steady-state conditions will be achieved when the water level change is less than 0.02 foot within an hour at wells near the extraction/infiltration locations.

Phase I - Single Well Tests: J2EW0005 and J2EW0006 will be used for the single well tests to assess aquifer hydraulic characteristics. Tests at these locations are necessary because of their locations, significance of their performance relative to total system performance, and lack of quantification of local aquifer properties in these areas.

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• Phase I-1 – First, a step-up pumping test will be conducted at J2EW0005 using rates of 150, 210, and 250 gpm, or the maximum flow from the well, at four-hour step-up intervals as shown in Table 4-2. The design rate for the well is 210 gpm, however, 250 gpm rate is likely the maximum capacity of the extraction well. The infiltration rate to the two infiltration trenches are equally distributed as shown in Table 4-2.

Following the step test, and without turning off the well, a three-day constant rate test will be conducted at 250 gpm flow rate or the maximum capacity of the pump. This will allow comprehensive analysis of aquifer characteristics and facilitate a transient calibration to the start-up data, if warranted. After three days, the pumping test for the J2EW0005 will be terminated.

• Phase I-2 – One day after the completion…