Final_J-2_North_RRA_PME_Plan.pdf

Impact Area Groundwater Study Program

FINAL

J-2 North Rapid Response Action Performance Monitoring and Evaluation Plan

Camp Edwards Massachusetts Military Reservation

Cape Cod, Massachusetts

April 20, 2006

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

Performance Monitoring and Evaluation 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.

Performance Monitoring and Evaluation Plan

Camp Edwards Massachusetts Military Reservation

Cape Cod, Massachusetts

April 20, 2006

CERTIFICATION:

I hereby certify that the enclosed Final J-2 North Rapid Response Action Performance Monitoring and Evaluation Plan, shown and marked in this submittal, is that proposed to be incorporated with Contract Number DACW33-02-D-0003, Contract Task Order 002. This Plan has been prepared in accordance with USACE Scope of Work and is hereby submitted for Government approval.

Reviewed by:

Contractor Quality System Manager Date

ECC Project Manager Date

ECC Program Manager Date

Received By:

USACE Project Manager Date

Digitally signed by Paul Hunt DN: CN = Paul Hunt, C = US, O = ECC, OU = Environmental Reason: I have reviewed this document.

Date: 2006.04.18 14:41:30 -04'00'

Brenton Taylor Digitally signed by Brenton Taylor DN: CN = Brenton Taylor, C = US, O = Environmental Chemical Corporation, OU = Massachusetts Military Reservation Date: 2006.04.18 14:56:37 -04'00'

04/18/06

Final J-2 North Rapid Response Action Performance Monitoring and Evaluation Plan April 20, 2006

TABLE OF CONTENTS

PAGE

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

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

1.1 PURPOSE .......................................................................................................1-2

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

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

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

2.2 GEOLOGY .......................................................................................................2-3

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

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

3.0 J-2 NORTH SYSTEM DESIGN...............................................................................3-1

3.1 WELLFIELD DESIGN ......................................................................................3-1

3.2 TREATMENT SYSTEM DESIGN.....................................................................3-2

3.2.1 Treatment System Overview..................................................................3-2

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

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

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

4.1 HYDRAULIC MONITORING............................................................................4-1

4.1.1 Baseline Monitoring ...............................................................................4-2

4.1.2 Start-Up Monitoring and Testing ............................................................4-3

4.1.3 Long-Term Hydraulic Monitoring............................................................4-7

4.2 CONTAMINANT MONITORING ......................................................................4-8

4.2.1 Periodic Monitoring ................................................................................4-8

4.2.2 Long-Term Plume Monitoring ..............................................................4-11

4.3 PLANT PERFORMANCE MONITORING ......................................................4-12

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 i Final J-2 North RRA PME Text

ECC-J23-35AY5302-M22-0007

April 20, 2006

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

5.3 PLANT PERFORMANCE ................................................................................5-4

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

7.0 MONITORING AND REPORTING SUMMARY ......................................................7-1

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

FIGURES

Figure 1-1 Location of J-2 Range Study Area

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 North Plume Perchlorate Distribution, Line of Cross Section Location, and RRA Treatment System Location

Figure 2-5 J-2 North Cross Section A-A’ Perchlorate Distribution

Figure 2-6 J-2 North Plume RDX Distribution, Line of Cross Section Location, and RRA Treatment System Location

Figure 2-7 J-2 North Cross Section A-A’ RDX Distribution

Figure 3-1 J-2 North RRA IX-GAC-GAC Process Flow Diagrams

Figure 4-1 Baseline Hydraulic Monitoring Locations for J-2 North PME

Figure 4-2 Start-Up Hydraulic Monitoring Locations for J-2 North PME

Figure 4-3 Long-Term Hydraulic Monitoring Locations for J-2 North PME

Figure 4-4 Chemical Monitoring Locations for J-2 North PME

Figure 4-5 Forward Particle Tracks from the J-2 North Source Area, with 1-Year Time Markers, under Ambient Conditions

Figure 4-6 Reverse Particle Tracks from J-2 North Extraction Wells Under Pumping Conditions

Figure 4-7 J-2 North RRA Plant Sampling Locations

TABLES

Table 4-1 J-2 North ETI System Baseline Hydraulic Monitoring Wells

Table 4-2 J-2 North System Hydraulic Start-Up Test Procedures

Table 4-3 J-2 North Hydraulic Start-Up Monitoring Wells

Table 4-4 J-2 North Long-Term Hydraulic Monitoring Wells

Table 4-5 J-2 North Groundwater Chemical Monitoring Network ii

April 20, 2006

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

APPENDIX

Appendix A Cross Sections and Sampling Locations for J-2 North PME iii

ACRONYMS AND ABBREVIATIONS

2A-DNT 2-amino-4,6-dinitrotoluene

3D three-dimensional

4A-DNT 4-amino-2,6-dinitrotoluene

AO Administrative Order

BBM Buzzards Bay Moraine

CERCLA Comprehensive Environmental Response, Compensation and Liability Act of 1980 (Superfund)

CMR Commonwealth of Massachusetts Regulation

COC contaminant of concern

DO dissolved oxygen

EPA U.S. Environmental Protection Agency

ETI extraction, treatment, and infiltration ft feet

GAC granular activated carbon gpm gallons per minute

HA health advisory

HMX octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine

IAGWSP Impact Area Groundwater Study Program

IX ion exchange

K hydraulic conductivity

LAW light antitank weapon

LTTD low temperature thermal desorption

MassDEP Massachusetts Department of Environmental Protection

MCL maximum contaminant level

MMR Massachusetts Military Reservation

MPP Mashpee Pitted Plain msl mean sea level

ORP oxidation-reduction potential

PEP pyrotechnic, explosives and propellant

PME performance monitoring and evaluation

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

RRA rapid response action iv

April 20, 2006

SDWA Safe Drinking Water Act of 1974

SE Southeast

SM Sandwich Moraine

SPEIM system performance and ecological impact monitoring

TERC Total Environmental Restoration Contract

TOC total organic carbon

TSS total suspended solids

USACE U.S. Army Corps of Engineers

UXO unexploded ordnance

ZOC zone of contribution µg/L micrograms per liter v

(intentionally blank) vi

April 20, 2006

EXECUTIVE SUMMARY

This Performance Monitoring and Evaluation (PME) Plan is targeted at monitoring the effectiveness of the Rapid Response Action (RRA) for the J-2 Range North (J-2 North) contaminant plume. The RRA for the J-2 North Groundwater Operable Unit (OU) includes interim actions by the U.S. Army/National Guard Bureau’s Impact Area Groundwater Study

Program (IAGWSP) to remediate groundwater contamination emanating from the J-2 Range at Camp Edwards.

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 area covered by this investigation has been used historically as a musketry range (1935-1940s), transition range (1940s-1950s), rifle range (1960’s-1980’s), and a contractor test range (1953-1980). Based on the presence of pyrotechnic, explosives and propellant (PEP) compounds in soils, and particle backtracking of downgradient groundwater contamination, Disposal Area 2 is the most likely potential source area for the J-2 North plume. Analytical results indicate that the plume which emanates from the J-2 Range Disposal Area 2 is composed principally of perchlorate and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), with lesser amounts of 2-amino-4,6-dinitrotoluene (2A-DNT) and 4-amino-2,6-dinitrotoluene (4A-DNT).

The current conceptualized downgradient extent of the main body of perchlorate contamination is approximately 7,800 feet (ft) north-northeast from the source area. The plume, from the source area, widens to approximately 2,300 ft at its widest point, near Wood

Road (approximately 2,900 ft downgradient of the source area), and then tapers to approximately 300 ft at the projected toe of the plume. The RDX plume, as currently conceptualized, extends approximately 4,200 ft north-northeast downgradient from the source area, and is approximately 700 ft wide at its widest point, along Wood Road. The

RDX plume and all other contaminant of concern (COC) plumes are within the perchlorate plume.

ES-1

April 20, 2006

Since a public water supply well is situated approximately 3,400 feet downgradient from the toe of the J-2 North plume, the response objective for the J-2 North groundwater RRA extraction, treatment and infiltration (ETI) system is to provide accelerated protection of

WS-2 and aquifer restoration by capturing and treating contaminated groundwater until an expedited long-term remedy can be selected for the plume via the RI/FS process.

The major components of the J-2 North RRA ETI system include:

• three extraction wells pumping at a combined total flow rate of approximately 375 gallons per minute (gpm);

• an ex-situ treatment process consisting of granular activated carbon (GAC) media and ion exchange (IX) resin to treat perchlorate and explosives with the option of using other treatment media in the future; and,

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

The purpose of this RRA Groundwater PME plan is to outline procedures to monitor the effectiveness of the J-2 North RRA 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. 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

April 20, 2006

1.0 INTRODUCTION

This Performance Monitoring and Evaluation (PME) Plan for the Rapid Response Action

(RRA) for the J-2 Range North plume presents a program for monitoring the effectiveness of the remedial Extraction, Treatment, and Infiltration (ETI) system. The ETI system comprises three extraction wells situated on the longitudinal axis of the J-2 North 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 RRA ETI system’s effectiveness in treating the extracted groundwater prior to recharge back to the aquifer through four infiltration trenches.

A detailed description of the J-2 North RRA system design is contained in the Draft J-2

Range North Groundwater Rapid Response Action (RRA) Plan (ECC 2005b). A brief description of the ETI system is presented in Section 3.0 of this plan.

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 (ECC

2005a). The J-2 Range was used from 1935 through the 1980s (AMEC 2003).

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 CMR 40.

1-1

April 20, 2006

1.1 PURPOSE

The installation of the RRA ETI system will facilitate contaminant mass removal, control plume migration, and provide protection for public water supply well WS-2 situated downgradient of the J-2 North plume. By controlling the spread of the plume, the RRA ETI system will limit the ultimate size of the comprehensive remedy and associated effects on natural resources.

The purpose of this PME plan is to specify monitoring activities to meet the following objectives:

• evaluate hydraulic conditions to assess the effectiveness of the RRA ETI system on the contaminant plume;

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

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

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

The RRA ETI system is expected to begin operation in the fall of 2006. The final comprehensive remedy for the J-2 North plume will be assessed in 2008 following completion of the groundwater characterization report and feasibility study.

1.2 ORGANIZATION OF PME PLAN

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

2.0. A general description of the J-2 North RRA 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

April 20, 2006

2.0 BACKGROUND

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

North 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 (1960’s-1980’s), and a contractor test range (1953-1980) (AMEC 2003).

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 (LAW) rockets. Based on various witness interviews, the J-2 Range was also reportedly utilized as an open burn/open detonation area (AMEC 2003).

The J-2 Range and areas immediately downgradient are located within the Mashpee Pitted

Plain (MPP), which consists of high-permeability sand and gravel. The Impact Area is proximal to the apparent glacier terminus, and therefore, contains the coarsest sand and gravel deposits in the MPP (Masterson et al. 1997). The J-2 Range lies near the top of the

Sagamore Lens of the aquifer underlying the upper Cape, and as a result, the water table beneath the range is very flat. This results in low horizontal gradients and relatively steep vertical gradients.

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 PME plan. The objective of this continuing work is to better

2-1

April 20, 2006 characterize known J-2 Range source areas and identify (and delineate) additional potential source areas not previously identified. Based on the presence of pyrotechnic, explosives and propellant (PEP) compounds in soils, and particle backtracking of downgradient groundwater contamination, Disposal Area 2 is the primary source area for the J-2 North plume.

Under the Munitions Survey Project, numerous locations with the potential for presence of munitions and explosives of concern (MEC), buried caches of MEC or MEC-related material, material potentially presenting an explosive hazard, and other scrap were identified at the J-

2 Range. These areas were identified through air-borne and ground-based geophysical investigations. A total of 35 polygons, comprising certain individual and grouped anomalies, were selected for investigation by inspection and excavation (ECC 2004). These investigation results have identified a wide variety of non-MEC materials as well as MEC-related munitions, grenades, barrage rockets, fuses and other components. To date, approximately 11,100 tons of soil were treated at an on-site low temperature thermal desorption (LTTD) unit, approximately 400 tons were sent off-site for disposal, and another

300 to 400 tons (estimated) are to be excavated and sent off-site for disposal.

The J-2 Range Soil RRA was implemented to excavate soil near these polygons and site features where existing analytical data indicated the highest levels of explosive or PEP compounds are present. These activities commenced in May 2004, and continue through the writing of this work plan. To date, approximately 6,200 cubic yards (cy) of soil have been MEC cleared, excavated, mechanically screened for MEC, and thermally treated.

Analytical results indicate that the plume that emanates from the J-2 Range Disposal Area 2 is composed principally of perchlorate and RDX, with lesser amounts of 2-amino-4,6-dinitrotoluene (2A-DNT) and 4-amino-2,6-dinitrotoluene (4A-DNT). As further detailed in

Section 2.4 of this plan, the perchlorate and RDX lobes of the J-2 North plume both have a deeper component. The depth of these contaminants within the aquifer and reverse particle tracking suggest a source further upgradient than the J-2 Range Disposal Area 2. The data suggest this deeper contamination is detached from its source area (i.e. wells upgradient of this deeper contamination do not contain detectable levels of RDX or perchlorate) indicating that its source area has likely stopped contributing to recent groundwater contamination.

2-2

April 20, 2006

The identified 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 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 North plume is migrating through highly transmissive unconfined sandy glacial outwash deposits. The sandy nature of the surface soils promotes rapid infiltration with little run-off. Discontinuous silty sand or 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 (K) and reduced groundwater velocities that serve to restrain some plume contaminants. In the vicinity of the J-2 Range, it appears the silt units are interbedded with sands; however, the silts do not directly overlie bedrock. Further discussion of the silts and fine sands situated beneath the plume is provided in Section 2.4 of this plan.

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

2-3

April 20, 2006 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 North 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.

As documented in the J-2 North RRA, based on water table measurements and contaminant data, a distinct vertical gradient is distinguishable at wells in the J-2 North plume source area. This indicates notable downward flow near the top of the groundwater mound.

Farther downgradient toward the midpoint of the plume, the vertical gradient is reduced.

Additional details of aquifer properties are provided in the draft J-2 North RRA plan (ECC

2005b).

No surface water bodies are located directly over the J-2 North plume. One surface water body, Ox Pond (located northeast of the plume), was evaluated during the RRA design to determine if the operation of the treatment system would adversely affect its 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 (Figure 2-3). Further discussion of Ox

Pond is provided in Section 6.0 Ecological Impact Monitoring.

2.4 CONTAMINANT DISTRIBUTION

Contaminants of concern (COCs) as defined in the Comprehensive Environmental

Response, Compensation, and Liability Act (CERCLA) have not been formally agreed upon for the J-2 North plume. However, as documented in the J-2 North RRA, a risk screening evaluation was conducted to help identify the contaminants to be addressed. The risk screening was conducted using data available at the time that the Draft J-2 North

Groundwater RRA Plan was developed. The results of the risk screening support the need for remedial action and indicate that an RRA to address contaminated groundwater will safeguard beneficial use of the aquifer (e.g. allow continued use of WS-2 as a public water supply well). Based on the risk screening, perchlorate and RDX were used as the primary

2-4

April 20, 2006 constituents for modeling, treatability assessment, and system design considerations. The

RRA itself is being implemented to address RDX, perchlorate, and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). A full characterization of groundwater and determination of associated risk will be provided in a future J-2 North groundwater characterization report and subsequent feasibility study.

The current conceptualized downgradient extent of the main body of perchlorate contamination is approximately 7,800 feet (ft) north-northeast from the source area (Figure

2-4). The plume, from the source area, widens to approximately 2,300 ft at its widest point, near Wood Road (approximately 2,900 ft downgradient of the source area), and then tapers to approximately 300 ft near the projected toe of the plume. The center of the main body of the J-2 North perchlorate plume plunges from approximately 68 ft mean sea level (msl) at the source area to approximately –35 ft msl 2,600 ft downgradient, where the downward trajectory levels off and stays nearly flat for approximately 3,500 ft, then begins to drop in elevation to approximately –40 ft msl at the toe of the plume (Figure 2-5). The plume is projected to be approximately 50 ft thick where the trajectory flattens out (near Wood Road), and approximately 10 ft thick at the toe of the plume. In addition to the main perchlorate plume, there is a deeper, non-contiguous, area of perchlorate contamination detected at monitoring well MW-289M1 that is projected to have migrated as far downgradient as MW-

293M1 (perchlorate was detected in drilling profile samples collected during drilling of MW-

293 but has not been detected in the wells installed at this location). This area of perchlorate is projected to be approximately 2,800 ft long and approximately 35 ft thick. Its depth in the aquifer indicates that the source area is most likely upgradient of the J-2 Range

Disposal Area 2. Because this deep zone of perchlorate is likely to become trapped in low conductivity (K) silts and silty sands (which are frequently present at these depths), it is unlikely to migrate as far downgradient as the shallow perchlorate plume located in higher conductivity sands.

The J-2 North RDX plume, as currently conceptualized, extends approximately 4,200 ft north-northeast downgradient from the source area, and is approximately 700 ft wide at its widest point, along Wood Road (Figure 2-6). As with the perchlorate plume, there is also

RDX detected deeper in the aquifer at monitoring well MW-289M1, suggesting a source further upgradient than J-2 Range Disposal Area 2 (Figure 2-7). The concentration of RDX

2-5

April 20, 2006 has remained relatively consistent over three sampling events, and has not been detected down gradient at monitoring well MW-300M1 or MW-293M1, suggesting that either the RDX is being bound in the silt/clay (low K) units as it migrates downgradient, or that the source for this contamination is more recent than the perchlorate source. The main J-2 North RDX plume plunges in a similar fashion to the perchlorate, described above, and begins to flatten out at approximately the same distance downgradient from the source area as the perchlorate; however, because the RDX plume has not migrated as far downgradient, the

RDX does not begin to drop in elevation as the perchlorate plume does. The differential solubilities of RDX (38.4-60 mg/L) and perchlorate (~100,000 mg/L) in water may also explain why the perchlorate plume has migrated farther downgradient even though both contaminants appear to originate from the same source. The maximum concentrations of

RDX, HMX and perchlorate in the main body of the J-2 North plume are 11 µg/L, 3.8 µg/L and 140 µg/L, respectively. The RDX and HMX plumes are contained within the perchlorate plume.

Additionally, there is another lobe of non-contiguous RDX contamination located approximately 800 ft east-southeast of the main J-2 North RDX plume, centered around monitoring well MW-322 (Figure 2-6). This lobe of RDX is estimated to be approximately

600 ft long and 270 ft wide, flowing in the same general direction as the main J-2 North RDX plume. The geometry of this lobe is estimated based on the length-to-width-to-thickness ratios of the main body of the J-2 North RDX plume. This lobe of RDX centered around

MW-322M1 is approximately 40 ft deeper than the J-2 North RDX plume in the aquifer indicating a more upgradient source. This RDX lobe is not within the zone of contribution

(ZOC) of water supply well WS-2.

Although the J-2 North plume contains HMX, the plume extent is largely defined by the distribution of RDX and perchlorate contamination. Also, groundwater concentrations of

HMX in the J-2 North plume are much lower than the health advisory (HA) level [400 micrograms per liter (µg/L)]. Thus, the J-2 North plume conceptual model focuses on the nature and extent of RDX and perchlorate contamination.

2-6

April 20, 2006

3.0 J-2 NORTH SYSTEM DESIGN

Extraction, treatment and infiltration (ETI) was selected, with input from the EPA and the

Massachusetts Department of Environmental Protection (MassDEP), as the remediation approach because of its effectiveness and compatibilities with likely future comprehensive response actions. The following sections present the J-2 North ETI well field design and treatment system design.

3.1 WELLFIELD DESIGN

As documented in the J-2 North RRA plan, the SE Ranges flow and transport model and three-dimensional (3D) plume shells for RDX and perchlorate were updated based on recent groundwater investigation data. Transport simulations were conducted to evaluate the model-predicted trajectory of the RDX and perchlorate plumes and to determine an appropriate wellfield strategy to remediate the J-2 North plume.

The J-2 North wellfield scenario testing results and constructability review indicate that the most efficient wellfield design includes: three extraction wells (J2EW0001, J2EW0002, and

J2EW0003) oriented along the plume axis and operating at 75, 175, and 125 gallons per minute (gpm) respectively, four identical modular treatment units capable of handling 100 gpm of water each, and four infiltration trenches to return treated water through the vadose zone to the aquifer (Figure 2-4 and Figure 2-6). Extraction well J2EW0001 will be located approximately 550 feet (ft) south of the intersection of Wood Road and Barlow Road, J2EW0002 will be located along Barlow Road approximately 900 ft north of the intersection of Wood Road and Jefferson Road, and J2EW0003 will be located approximately 600 ft north of the intersection of Barlow Road and Jefferson Road. The treatment units will be located at the intersection of Wood Road and Barlow Road. The system was designed for mass removal and protection of water supply well WS-2. A small portion of the J-2 North plume downgradient of J2EW0003 will escape capture and attenuate naturally. The fate of this portion of the plume is addressed in the Draft J-2 Range North Groundwater RRA Plan

(ECC 2005b).

3-1

April 20, 2006

3.2 TREATMENT SYSTEM DESIGN

The following sections include discussion of the J-2 North 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

The J-2 North treatment system will consist of two identical modular treatment units each capable of handling 125 gpm of water, one stand-alone treatment system contained within a small pre-engineered metal building capable of handling 175 gpm of water, and four infiltration trenches to return treated groundwater to the aquifer (Figure 2-4). The design of the system is similar to what is currently in use at the Demolition Area 1 site which has successfully treated groundwater of similar quality as the J-2 North plume.

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 3-1).

The modular units and pre-engineered building will each house a filtration system, IX-GAC-

GAC units, and backwash system. The backwash system includes a backwash water tank and backwash pump. The electrical connection to the treatment components and all other power-based equipment in the units will be housed in locked steel cabinets. An independent electrical cabinet will contain all the wiring for the connections to the main power supply, as well as the extraction/infiltration equipment and exterior lighting. The modular units and pre-engineered building construction will meet applicable codes and regulations including the Massachusetts Building Code and the National Electrical Code.

Piping and other connections between the modular units will be detachable, such that the modular units can be transported to other locations, if necessary.

3-2

April 20, 2006

3.2.2 Modeled Influent Characteristics

As documented in the draft J-2 North RRA Plan (ECC 2005b), based on the preliminary wellfield scenario testing, the maximum influent concentration of perchlorate from the three extraction wells is expected to approach 33.6 µg/L, with the maximum from any one extraction well approaching 40.1 µg/L. Although the maximum detected perchlorate concentration within the plume is much higher (140 µg/L), influent concentrations in extraction wells are typically much lower because the extraction wells are screened across both low and high concentration areas within plumes and the well captures low concentration areas outside the core of the plume. They inevitably capture some clean water that mixes with higher concentration water from discreet intervals along the extraction screen. These values are comparable to influent concentrations observed for the Frank

Perkins Road Treatment System (AMEC 2005a); the average perchlorate concentration in the influent over a 6-month period from start-up was 28.3 µg/L with a maximum value of

38.2 µg/L.

The maximum influent concentration of RDX from the three extraction wells is expected to approach 0.23 µg/L, with the maximum from any one extraction well approaching 0.42 µg/L.

The maximum detected RDX concentration within the plume is higher (11 µg/L). These projected concentrations are lower than the influent concentrations observed for the Frank

Perkins Road Treatment System (AMEC 2005a). The average RDX concentration for influent over a 6-month period from start-up was 6.5 µg/L with a maximum concentrations of

8.6 µg/L.

3.2.3 Effluent Criteria

The Massachusetts groundwater discharge regulations under 314 Code of Massachusetts

Regulations (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

3-3

April 20, 2006 meet these levels prior to discharge to the ground. Sections 4.0 and 6.0 present additional parameters that will be monitored as part of the J-2 North system performance monitoring.

3-4

April 20, 2006

4.0 PERFORMANCE MONITORING

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

4.1 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 imposed by the remedial system. This event consists of initial water level measurements taken from a series of locations prior to the system operation. Water levels are then measured continuously during 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 model refinement and recalibration. The updated groundwater flow model can then be used to verify the effectiveness of the remedial system in relation to the design goals and predicted performance. The 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, hydraulic monitoring is conducted to monitor water levels at selected monitoring wells, extraction wells, and surface water

4-1

April 20, 2006 locations to provide a basis for comparison to flow model predictions, and evaluate trends due to ambient hydraulic stresses (e.g. recharge, private and municipal extraction).

The hydraulic monitoring of the J-2 Range North ETI system components will include 1) baseline monitoring, 2) start-up monitoring and testing, and 3) long-term periodic monitoring.

4.1.1 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 reinjection/infiltration. Baseline monitoring is proposed at 31 locations (54 screens), including 3 extraction wells, and 6 background locations (monitoring wells located away from the areas of extraction and reinjection/infiltration). Six new clusters of monitoring wells are proposed to be installed to support baseline monitoring, start-up monitoring, and long-term monitoring as follows (Figure 4-1 through Figure 4-3, and Table 4-1).

• Two new well clusters and one shallow well are to be installed near J2EW0002. These new wells, along with the MW-348 well cluster, will provide near-field drawdown data to quantify well efficiency and hydraulic conductivity. One of these well clusters will be located along Barlow Road. However, the second well cluster (MW-2) will need to be situated cross-gradient to J2EW0002 and cannot be situated on Barlow Road. One new well with a shallow screen interval (50-60 ft msl) will be installed near MW-348 forming a cluster with the existing MW-348 screens. The two new well clusters will consist of three well screen intervals that are above, within, and below extraction intervals for J2EW0002. The placement of the three new well clusters is approximately 50, 150, and 300 feet from the extraction well. The MW-348 well cluster will be approximately 50 ft from the extraction well. Observation wells are usually placed, in common practice, at a minimum distance equal to 1.5 to 2 times the aquifer thickness from a partially penetrating well. For J-2 North, the new wells are located closer to the extraction well due to the relatively small drawdown expected from the pumping test. These wells will be installed after the completion of the extraction well boring.

• Two well clusters, consisting of three well screen intervals located above, within, and below extraction intervals, are to be installed along Barlow Road north of extraction well J2EW003. The proposed distances from the extraction wells are 100 and 300 ft.

• One well cluster, consisting of three well screen intervals located above, within, and below extraction intervals, is to be installed on Barlow Road 100 ft south of extraction well J2EW0001.

4-2

April 20, 2006

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). Baseline monitoring locations are listed in Table 4-1 and depicted in Figure 4-1. Pumping rates from water supply well WS-2 will be collected from the Upper Cape Water Supply Cooperative to assess potential changes in pumping stress on baseline and start-up conditions.

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).

Precipitation during and for the 72 hours preceding the measurement event will be noted.

The baseline monitoring event is intended to be a synoptic event and measurements will be conducted over the course of one day. Water levels will be measured via a combination of data logging and manual measurement. Data from the hydraulic monitoring will be delivered per MMR protocols.

4.1.2 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 periodic monitoring by hand 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 reinjection trenches will also be recorded.

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

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

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

3. Characterize and refine aquifer properties.

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

4-3

April 20, 2006

5. Provide data to develop a more representative groundwater model to support system optimization.

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 or 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 – 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 some 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 from start-up monitoring and aquifer testing previously conducted at the MMR and Impact area.

Similar designs have been successfully used to quantify capture performance at more than

10 system start-up, and shut-down/start-up tests conducted on AFCEE-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 North extraction system. The

4-4

April 20, 2006 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 hydraulic performance monitoring wells should 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 period of 6 days is provided 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 periodic monitoring via manual water level measurement. Background wells (MW-18M1,M2) outside the influence of the system will be measured once on day 4 and once per day on days 6 through 11 to provide a snapshot of regional groundwater potentiometric conditions and to assess regional trends in background wells during the test.

Near steady state conditions (equilibration of water levels) 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/reinjection locations.

Phase I: Single Well Test - J2EW0002 will be used for the single well test to assess aquifer hydraulic characteristics because of its central location, higher pumping rate, and availability of nearby monitoring wells. A step-up pumping test will be conducted for the well using rates of 100, 150, and 200 gpm at four-hour step-up intervals as shown in Table 4-2. The reinjection rate and distribution to the four infiltration trenches are also shown in the table.

Following the step test, a three-day constant rate test will be conducted. This will allow comprehensive analysis of aquifer characteristics and facilitate a transient calibration to start-up data. After a three-day pumping test, a shutdown period of 3 days is proposed to allow the recovery of the aquifer system to ambient conditions. Because of the small model-predicted drawdown and mounding and potentially large background variation in

4-5

April 20, 2006 groundwater elevation for the test period, a second baseline monitoring event for the new ambient conditions will be performed to reduce uncertainty and potential errors.

Phase II: Complete System Test – All three extraction wells and four infiltration trenches will be operated at design rates for 5 days to approximate the composite steady state drawdown and mounding effects under operational conditions.