Final_J-1_Range_South_RRA_SPM_Plan_2007.pdf

Impact Area Groundwater Study Program

FINAL

J-1 South Rapid Response Action System Performance Monitoring Plan

Camp Edwards Massachusetts Military Reservation

Cape Cod, Massachusetts

October 25, 2007

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-1 South Rapid Response Action 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.

Final J-1 South Rapid Response Action System Performance Monitoring Plan October 25, 2007

TABLE OF CONTENTS

ACRONYMS AND ABBREVIATIONS...............................................................................iii 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 J-1 SOUTH CONTAMINANT DISTRIBUTION.................................................2-3

3.0 J-1 SOUTH 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............................................................3-2

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

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

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

4.1.1 Baseline Monitoring ...............................................................................4-1

4.1.2 Start-Up Monitoring and Testing ............................................................4-2

4.1.3 Long-Term Hydraulic Monitoring............................................................4-5

4.2 CONTAMINANT MONITORING ......................................................................4-6

4.3 PLANT PERFORMANCE ................................................................................4-9

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 MONITORING AND REPORTING SUMMARY ......................................................6-1

7.0 REFERENCES........................................................................................................7-1 i

ECC-J23-35AY5302-M10-0036

October 25, 2007

FIGURES

Figure 1-1 Location of J-1 Range

Figure 2-1 Regional Surficial Geology Map of Upper Cape Cod

Figure 2-2 J-1 Range South RDX Distribution and Lines of Cross Section

Figure 2-3 J-1 South Cross Section A-A’ RDX Distribution

Figure 2-4 J-1 South Cross Section B-B’ RDX Distribution

Figure 2-5 J-1 South Cross Section C-C’ RDX Distribution

Figure 2-6 J-1 South Cross Section D-D’ RDX Distribution

Figure 2-7 J-1 South Cross Section E-E’ RDX Distribution

Figure 2-8 2003 Synoptic Groundwater Elevations and Model-Predicted Elevations

Figure 3-1 J-1 South RRA GAC-GAC Process Flow Diagram

Figure 4-1 J-1 Range South SPM Baseline and Startup Hydraulic Monitoring Locations and Setup

Figure 4-2 J-1 Range South Long-Term Hydraulic Monitoring Locations

Figure 4-3 J-1 Range South Chemical Monitoring Locations

Figure 4-4 Reverse Tracks from J-1 South Extraction Well (with 1-year time markers) Under Operational Conditions

Figure 4-5 J-1 South Plant Sampling Locations

TABLES

Table 4-1 Start-Up, Baseline, and Long-Term Hydraulic Monitoring Wells for the J-1 South RRA ETI System

Table 4-2 Start-Up Test Procedures for the J-1 South RRA ETI System

Table 4-3 J-1 South Groundwater Chemical Monitoring Network

Table 4-4 J-1 South RRA ETI System Sampling Locations and Parameters for Operational Monitoring ii

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ACRONYMS AND ABBREVIATIONS

3-D three-dimensional

AO Administrative Order

BBM Buzzards Bay Moraine

CMR Commonwealth of Massachusetts Regulation

COC contaminant of concern

DO dissolved oxygen

EDB ethylene dibromide

EPA U.S. Environmental Protection Agency

ETI extraction, treatment, and infiltration

FS-12 Fuel Spill-12 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

IRP Installation Restoration Program

K hydraulic conductivity

MassDEP Massachusetts Department of Environmental Protection

MCL maximum contaminant level

MDL method detection limit

MMR Massachusetts Military Reservation

MPP Mashpee Pitted Plain msl mean sea level

ORP oxidation-reduction potential

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

RL reporting limit

RRA rapid response action

SDWA Safe Drinking Water Act of 1974

SM Sandwich Moraine

SPM system performance monitoring

SPEIM system performance and ecological impact monitoring iii

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TERC Total Environmental Restoration Contract

USACE U.S. Army Corps of Engineers

ZOC zone of contribution µg/L micrograms per liter iv

October 25, 2007

EXECUTIVE SUMMARY

This System Performance Monitoring (SPM) Plan outlines the approach for monitoring the effectiveness of the Rapid Response Action (RRA) for the J-1 South Range contaminant plume. The RRA for the J-1 South Groundwater Operable Unit 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-1 Range at Camp

Edwards.

The J-1 Range, which is one of the four former training ranges that comprise the Southeast

Ranges near the eastern border of the Massachusetts Military Reservation (MMR), was used by both military contractors for testing and development of various weapons and systems, and by the military for training purposes. The J-1 South plume consists primarily of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetrinitro-1,3,5,7-tetrazocine (HMX), and is believed to have originated upgradient of monitoring well location

MW-360 and west of monitoring well location MW-131 in the southeast portion of the J-1

Range. The plume migrates in a southeasterly direction away from the southern end of the

J-1 Range.

The on-base portion of the RDX plume, as currently conceptualized, extends approximately

1,300 feet (ft) southeast from the presumed source area (upgradient of location MW-360 and west of location MW-131), to the base boundary, and is currently conceptualized to extend approximately 1,300 ft southeast of the base boundary. The plume is approximately

650 ft wide at its widest point, along the base boundary. At the base boundary, the plume is approximately 65 ft thick, with the deepest extent being constrained by a 60 ft thick low hydraulic conductivity (K) unit.

The J-1 South RRA system, as presented in the Draft J-1 Southeast Groundwater Rapid

Response Action Plan (ECC 2007) includes one extraction well, an in-plume well

(J1SEW0001) located southeast of Greenway Road along the base boundary, co-located with drive point DP-384, and an infiltration trench located southwest of the extraction well along the base boundary adjacent to drive point DP-387. The wellfield design has a total

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October 25, 2007 flow rate of 75 gallons per minute (gpm). All water treated from the J-1 South RRA system will be returned to the aquifer using the infiltration trench.

The J-1 South RRA treatment process consists of granular activated carbon (GAC) to address RDX. This treatment train is comprised of a leading GAC vessel array used to remove RDX followed by a final GAC vessel array as a polishing step. The water will be treated in a new plant located between Greenway Road and the base boundary in proximity to the new extraction well. This new plant is a mobile treatment unit that was previously used as part of the Demolition Area 1 remedial action.

The purpose of this groundwater RRA SPM plan is to outline procedures to monitor the effectiveness of the J-1 South RRA extraction, treatment, and infiltration (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 and changes in plume characteristics with time. 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 trench is below the reporting limit of 0.25 micrograms per liter (µg/L) for RDX.

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1.0 INTRODUCTION

This System Performance Monitoring (SPM) Plan for the Rapid Response Action (RRA) for the J-1 Range South plume presents a program for monitoring the effectiveness of the remedial Extraction, Treatment, and Infiltration (ETI) system. The ETI system comprises one extraction well situated in an area of high plume concentrations southeast of Greenway

Road along the Massachusetts Military Reservation (MMR) base boundary. Monitoring activities will be conducted to determine the extent of capture of the hexahydro-1,3,5-trinitro-

1,3,5-triazine (RDX) plume 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 an infiltration trench.

The J-1 Range is located adjacent to and southeast of the Impact Area, and is situated between the L- and J-2 Ranges of the four former training ranges that comprise the

Southeast Ranges (Figure 1-1). The Southeast Ranges are former military training and defense contractor test ranges that operated from the mid 1930s through the early 1990s;

the past activities have resulted in explosives and perchlorate contamination in the groundwater.

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

Total Environmental Restoration Contract (TERC) DACW33-02-D-0003, contract task order

CTO-002 in support of the Impact Area Groundwater Study Program (IAGWSP). This work is 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 cleanup standards in the Massachusetts

Contingency Plan 310 CMR 40.

1.1 PURPOSE

The installation of the J-1 South RRA ETI system will facilitate contaminant mass removal and reduce plume migration. By reducing the spread of the plume, the RRA ETI system will limit the ultimate size of the comprehensive remedy and associated effects on natural resources.

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

• evaluate hydraulic conditions to assess the effectiveness of the J-1 South RRA ETI system on the contaminant plume;

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

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

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

The J-1 South RRA ETI system is expected to begin operation in the summer of 2007. The final comprehensive remedy for the J-1 South plume will be assessed in 2008 following completion of the groundwater characterization report and feasibility study.

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-1 South 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. The monitoring and reporting schedule is presented in Section 6.0. References used in this plan are presented in Section 7.0.

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2.0 BACKGROUND

The site setting, geological and hydrogeological setting, and contaminant distribution for the

J-1 Range South plume are summarized in this section.

2.1 SITE SETTING

The MMR is located in the western portion of Cape Cod and occupies approximately 22,000 acres (34 square miles) within the towns of Bourne, Sandwich, Mashpee, and Falmouth in

Barnstable County, Massachusetts. Military use of portions of the MMR began as early as

1911. Most of the activity, however, has been conducted since 1935 and has included operations by the U.S. Army, U.S. Coast Guard, U.S. Air Force, Massachusetts Army

National Guard, U.S. Air National Guard, and Veterans Administration. The level of activity at MMR has varied over its operational history. Some specific activities have resulted in a number of contaminants being released into the environment, including the groundwater.

The Southeast Ranges are former training and defense contractor test ranges that operated from the late 1940s through the early 1990s (AMEC 2004). Activities at the J-1 Range

(Figure 1-1) have occurred under several designations: the former I Range, the J-1

Transition Range, the J-1 Department of Defense Contractor Test Range, and the current M

Range. Defense contractor waste-management practices included open burning and detonation of explosives, disposal of wastewater, and disposal of munitions in burial pits.

Military activities conducted in the area of the J-1 Range primarily involved small arms, mortar and grenade training. The IAGWSP is conducting ongoing investigations to determine the extent of soil and groundwater contamination within and emanating from the

Southeast Ranges.

The area occupied by the current J-1 Range was established between 1935 and 1941, with the construction of the former I Range. Between 1935 and 1941 the former I Range was utilized as an estimation range. In 1941, the former I Range was expanded for use as an anti-tank range and was used in this capacity until the 1950s. In 1967, the I Range was re-established in the J-1 Range area as a rifle technique range and used until the early 1970s.

The J-1 Range was originally established in the late-1940s as a transition range for small arms fire and was used until the 1950s. The J-1 Department of Defense Contractor Test

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Range was used as a tank and artillery firing range by various contractors from 1957 to

1980s. The current configuration of the area is designated as the M Range, which was established in the 1980s and incorporates the former J-1 and I Ranges (AMEC 2004).

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 2-1). 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 (Masterson et al. 1997).

The J-1 Range and downgradient areas are located within the MPP. The sandy nature of the surface soils promotes rapid infiltration with little run-off. The J-1 South plume is migrating through very transmissive unconfined sandy glacial outwash deposits.

Discontinuous silty sand or clayey sand units occur sporadically within the saturated zone.

The continuity of these fine-grained deposits increases with depth and results in localized areas of lower hydraulic conductivities (K) and reduced groundwater velocities that serve to restrain plume contaminants. In the vicinity of the southeast portion of the J-1 range, it appears the silt units are interbedded with sands; however, the silts do not directly overlie bedrock, which is at approximately -145 feet (ft) mean sea level (msl) to -160 ft msl under the J-1 South plume. At the base boundary, low-conductivity silts are located from approximately -20 ft msl to -85 ft msl and constrain plume depth by inhibiting the downward migration of the plume in this area (Figure 2-2 through Figure 2-7).

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October 25, 2007

2.3 HYDROLOGY

A single groundwater flow system underlies western Cape Cod, including 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 north of the J-1

South plume source area (Figure 2-8). 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.

The J-1 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. Based on water table measurements and contaminant data, a distinct vertical gradient is distinguishable at wells in or near the J-1 South plume source area. This indicates notable downward flow near the top of the groundwater mound.

2.4 J-1 SOUTH CONTAMINANT DISTRIBUTION

Based on investigations to date, the principal environmental concerns associated with the southern end of the J-1 Range include the following: (1) soils contaminated by explosives and propellants; and (2) a contaminant plume, consisting primarily of RDX, which extends a minimum of 1,300 ft from the presumed source area southeast to the base boundary. This

RDX plume is currently conceptualized to extend approximately another 1,300 ft southeast of the base boundary and is approximately 650 ft wide at its widest point (Figure 2-2 through

Figure 2-7). At the base boundary, the plume is approximately 65 ft thick, with the deepest extent being constrained by a 60 ft thick low hydraulic conductivity unit. Further downgradient, the plume thins and is interpreted to terminate approximately 500 ft upgradient of the Little Acorn Road well fence (MW-400, MW-402, and MW-403

[Figure 2-7]). The raw chromatographic data for samples collected at the Little Acorn Road well fence (locations MW-400M1,M2; MW-402M1,M2; and MW-403M1,M2) were reviewed for evidence of low level concentrations [e.g., less than the reporting limit (RL) of 0.25 µg/L] of RDX, which is the primary constituent of the J-1 South plume. There was no evidence of

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October 25, 2007 low-level RDX present in any of the chromatograms, nor any mislabeled peaks in any of the chromatograms. There was no interference in any of the chromatograms that would have blocked or masked the RDX peak. The associated laboratory quality control was complete

(all surrogate spike compounds were recovered within the limits; there was no blank contamination, and blank spike recoveries were all within acceptable limits).

Although the J-1 South plume contains octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine

(HMX), this contaminant is collocated with the RDX plume. Groundwater concentrations of

HMX in the J-1 South plume are much lower than the health advisory (HA) level (400 micrograms per liter [µg/L]) and a full order-of-magnitude less than the RDX concentration

(maximum detected RDX concentration to date is 290 µg/L [DP-384, 6/28/05, 137.5 ft] although the latest maximum concentration from a fixed well is much lower [34 µg/L, MW-

398M2, 2/1/07]; and the maximum detected HMX concentration to date is 29 µg/L [DP-384, 6/28/05, 137.5 ft] with the latest maximum concentration from a fixed well reduced by approximately one-half [13 µg/L, MW-398M2, 2/1/07]). The lifetime HA for RDX is 2 µg/L.

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October 25, 2007

3.0 J-1 SOUTH SYSTEM DESIGN

With input from the EPA and the Massachusetts Department of Environmental Protection

(MassDEP), ETI was selected as the remediation approach for the J-1 South plume RRA because of its effectiveness and compatibilities with likely future comprehensive response actions. The following sections present a synopsis of the J-1 South ETI well field design and treatment system design as presented in the J-1 South RRA; further discussion on the

ETI system is presented in the Draft J-1 Range South RRA (ECC 2007).

3.1 WELLFIELD DESIGN

The Southeast Ranges flow and transport model and a three-dimensional (3-D) plume shell for RDX was developed for the Final J-1 Range South Groundwater Rapid Response Action

Plan (ECC 2007). Transport simulations were conducted to evaluate the model-predicted trajectory of the RDX plume and to determine an appropriate wellfield strategy to capture the

J-1 South plume.

The J-1 South capture scenario testing results and constructability review indicated that the most appropriate wellfield design includes one extraction well: an in-plume well

(J1SEW0001) located southeast of Greenway Road (near monitoring well MW-398) along the MMR base boundary. The extraction well screen is 45 ft in length and spans the interval of 30 to -15 ft msl. This screen setting captures the higher concentrations of RDX in the vicinity of MW-398 above a low hydraulic conductivity unit in the area. The wellfield design has a flow rate of 75 gallons per minute (gpm) that is pumped to a treatment facility and the treated water is discharged to an infiltration trench located approximately 300 ft southwest of the extraction well along the MMR boundary. The predicted hydraulic response in 11 of the start-up hydraulic monitoring wells (see Section 4.0, Table 4-1), excluding J1SEW0001, was greater than 0.03 ft. The hydraulic stresses were noted primarily in the vicinity of the extraction well and the infiltration trench (ECC 2007).

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3.2 TREATMENT SYSTEM DESIGN

The following sections include discussion of the J-1 South ETI treatment system design, including an overview of the treatment system operation, modeled influent concentrations, and effluent criteria.

3.2.1 Treatment System Overview

After reviewing the available information, the optimum treatment option was determined to be granular activated carbon (GAC)-GAC treatment (ECC 2007). The treatment train is comprised of a leading GAC vessel array used to remove RDX, followed by a final GAC vessel array as a polishing step (Figure 3-1). The selected treatment media is consistent with the technology currently employed at the Frank Perkins Road, J-2 North, and J-3 RRA treatment plants to address RDX, but without the ion-exchange resin used for the clean-up of perchlorate. Further details regarding the design of the treatment system are provided in the Final J-1 South Groundwater Rapid Response Action Plan (ECC 2007). The plant is a mobile unit that was previously used as part of the Demolition Area 1 RRA and was a proven and effective treatment unit.

3.2.2 Modeled Influent Characteristics

As documented in the Final J-1 South Groundwater Rapid Response Action Plan (ECC

2007), based on the preliminary wellfield scenario testing, the maximum influent concentration of RDX is expected to approach 40 µg/L (average of all the model cells for the extraction well and weighted by layer-specific flow rates). This concentration is predicted to drop significantly within the first six months of system operation. Although the maximum detected RDX concentration within the plume is much higher (290 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 they inevitably capture clean water that mixes with higher concentration water from discrete intervals along the extraction screen. Influent concentrations are predicted to range from an initial RDX concentration of 33 µg/L to 0.32 µg/L six years later.

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3.2.3 Effluent Criteria

The treated groundwater (effluent) from the J-1 South treatment system will be returned to the aquifer via infiltration by a trench located southwest of the treatment system. For the J-1

South ETI system, the Massachusetts groundwater discharge regulations under 314

Commonwealth of Massachusetts Regulation (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 to the groundwater. For RDX, the contaminant of concern (COC) for the J-1

South plume, effluent concentrations will be below the method detection limit (MDL) of 0.25 µg/L. Section 4.0 presents additional parameters that will be monitored as part of the J-1

South RRA ETI system performance monitoring.

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(intentionally blank)

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October 25, 2007

4.0 PERFORMANCE MONITORING

This section describes hydraulic, chemical, and plant monitoring intended to support an evaluation of the performance of the J-1 South RRA ETI system. The goals of the SPM are to collect the data required to evaluate the effectiveness, performance, and optimization of the remedial system and assure protection of human health. The hydraulic network was developed based on availability of monitoring wells, groundwater flow modeling of predicted system operating stresses, and past experiences of system startup at MMR.

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 due to external hydraulic stresses; assess potential impacts on adjacent plumes; provide a basis for groundwater flow model refinement and/or recalibration; and to 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 predictive assessment of the rates of mass removal and hydraulic effectiveness.

The hydraulic monitoring of the J-1 South RRA ETI system will include baseline monitoring, start-up monitoring and testing, and long-term periodic monitoring.

4.1.1 Baseline Monitoring

Baseline monitoring refers to an initial monitoring event that is intended to characterize ambient hydraulic conditions prior to the propagation of hydraulic stress from groundwater extraction through the extraction well and discharge to the infiltration trench at the J-1 South area by collecting water levels from monitoring wells. Baseline monitoring is proposed at the

21 wells that will be used for the start-up test (including one extraction well, one piezometer, and two drivepoints), and 9 background locations (monitoring wells, piezometers and drivepoints located away from the areas of extraction). The background locations will determine the hydraulic variability in the aquifer that should not be affected by the drawdown and mounding due to the operation of the treatment system. Table 4-1 provides baseline

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October 25, 2007 monitoring locations. The first baseline round is scheduled to begin on the seventh day after system shut-down occurring after the proof-of-process test, and consists of the initiation of dataloggers and manual measurements for the start-up and background locations

(Table 4-2).

Baseline monitoring will be conducted after remedial system construction is complete and the system initial trial operations are complete. The system initial trial operations are intended to test system operations as compared to design requirements and are generally conducted by the system construction contractor.

Baseline monitoring will be conducted prior to system startup 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 recorded.

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.

4.1.2 Start-Up Monitoring and Testing

Start-up monitoring and testing will be conducted to obtain information that can be used to improve the understanding of aquifer properties and to evaluate the response of the aquifer to hydraulic stresses imposed by the J-1 South RRA ETI system. The water level monitoring methods will include continuous monitoring using a transducer/datalogger and periodic monitoring using tape measurement. Background monitoring will also be conducted. In addition to water levels, flow rates at the extraction well will be recorded.

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

1. Record changes in water levels in monitoring wells and one shallow piezometer during startup of the J-1 South RRA ETI system.

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

3. Characterize and refine aquifer properties.

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

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

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October 25, 2007

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 contribution (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 startup (ambient/unstressed condition) and after startup (stressed condition). Interval measurements collected during startup 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, hydraulic conductivity, 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, hydraulic 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, particularly the J-2 North and J-3 systems. Similar designs have been successfully used to quantify capture performance at more than 15 system startup, and shut-down/start-up tests conducted on MMR remedial systems.

A single phased approach is selected for the start-up test and monitoring for the J-1 South

RRA ETI system due to its relative simple one-extraction well design and limited design flow rate (75 gpm + 10%). A step-up test will be conducted for the system to characterize the aquifer response and to determine the development of the zone of influence. This approach offers the best combination of data collection and efficiency while achieving the desirable

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October 25, 2007 objectives for the system start-up test. Table 4-2 presents the details of the start-up test procedures.

To enhance the data collection for the Phase I aquifer test, one well cluster near the in-plume extraction well (MW-488M1,PZ) was installed. This well is located approximately 100 feet northeast of the J1SEW0001 extraction well along the base boundary (Figure 4-1).

MW-488 consists of well MW-488M1, located near the middle of the extraction interval, and a piezometer, MW-488PZ, located above the extraction interval (Table 4-1). This well will also be used to support baseline and long-term monitoring.

A narrative summary of the start-up testing sequence is as follows:

• Trial System Shutdown - After system trial operations (system checking and verification) are completed, the aquifer will be allowed to return to ambient conditions. A period of 7 days is provided to ensure full recovery to an ambient (unstressed) condition (Table 4-2).

Background monitoring at wells outside the influence of the system will be measured on day 4 and day 7 to provide regional groundwater level trending information. The first baseline monitoring event will commence on day 7 after shutdown of trial operations.

The baseline monitoring includes continuous water level monitoring using dataloggers and daily manual water level measurements. Steady state conditions will be confirmed using monitoring wells with dataloggers, and indicated by a water level change of less than 0.02 foot within one hour at wells near the extraction locations.

• System Testing - A stepped rate pumping test will be conducted for the extraction well using rates of 50 and 75 gpm at an 8-hour step-up interval as shown in Table 4-2.

Following the initial 8 hour 50 gpm test, the 75 gpm design rate will be maintained for a rest of the test (total of seven days) to approximate the design rate steady state drawdown. Monitoring using data loggers and transducers will be halted after 7 days when steady state condition is expected to be achieved (steady state will be considered to be achieved when the log-time versus drawdown relationship for the distal observation wells approaches the equilibrium condition considering regional fluctuations in water levels [regional groundwater level trend] measured in background wells, or the water level change in distal observation wells is less than 0.05 foot over a two-hour period). System recovery is not proposed for the complete system test phase as the drawdown data is sufficient for the analysis. Background monitoring at wells outside the influence of the system will be measured on days 2, 4 and 7 of the start-up test phase to provide regional groundwater level trending information.

To provide regional water level variation during the start-up test, 10 well locations will be monitored as background wells. These wells are located far enough from the system and are expected not to be affected by the system operation.

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During system start-up testing, hydraulic heads in a network of wells/piezometers will be monitored to assess aquifer response to pumping stress (Table 4-1, Figure 4-1). The spatial distribution of the recommended well network was determined using available field data and the J-1 South groundwater 3-D flow model (ECC 2007). The wells are distributed to provide sufficient drawdown information to assess capture using analytical methods and more importantly to provide a 3-D distribution of groundwater elevations that will be used to compare with the 3-D flow model. The data will be used to recalibrate the flow model (if warranted) and reestablish operating requirements.

A total of 15 wells will be monitored using data loggers. Data logger recording intervals will be every five minutes for the majority of the testing period. However, the near-field data loggers at the extraction wells will be set at one-minute intervals for the first twelve hours of the start-up testing for the wells near the extraction well. Table 4-1 shows the specified recording intervals for the wells. Most commercially available data loggers provide preprogrammed stepped interval logging, or programmable options to accommodate a variable frequency sampling structure that is consistent with the requirements of pumping test data collection. Precipitation in the area during the test periods will be recorded daily.

The aquifer testing will be conducted in accordance with applicable technical procedures

(AMEC 2005b).

Five wells will be measured once daily using a water level meter. These are wells that are located far enough from the extraction well that detailed hydraulic response data is not needed, and therefore, data collection using data loggers is not required. However, hydraulic stress due to extraction/infiltration (drawdown/mounding) and zone of hydraulic influence can be defined from the wells.

4.1.3 Long-Term Hydraulic Monitoring

Monitoring of water levels will be conducted to assess long-term (multi-seasonal) trends in groundwater levels and hydraulic gradients. Observed trends will be examined to determine the need for future system hydraulic testing to assess potential effects of extreme hydrologic conditions (e.g., periods of extended drought or higher than normal precipitation) on system performance. The long-term monitoring network is listed in Table 4-1 and illustrated in

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Figure 4-2. Water levels will be measured manually on a semiannual frequency at these locations. The frequency of monitoring will be reassessed after the first year of system operation and documented in the first annual SPM report. If necessary, the long-term monitoring network will also be revised following evaluation of system start-up data and possible model recalibration.

The near-field long-term hydraulic monitoring data will provide validation of the hydraulic stresses caused by the ETI system. Once a remedial system has reached near steady state operation (within the first few weeks of operation), the hydraulic regime will show relatively little change unless influenced by significant natural water level fluctuations (external stresses) or changes in system operating conditions. Extensive and frequent hydraulic monitoring near the remedial system field is not needed. Plume scale hydraulic monitoring is best achieved through the selection of monitoring wells at key locations. This approach is used to document changes in gradients (ambient and system related) to assess remedial system performance.

4.2 CONTAMINANT MONITORING

Chemical monitoring of the J-1 South wellfield will focus on several areas within and near the plume to achieve the monitoring objectives. The contaminant monitoring prescribed in this section is intended to provide a basis for determining if design goals are being met and to monitor the general fate and transport of the uncaptured portion of the plume.

Specifically, monitoring will focus on assessment of contaminant distribution and plume migration, and determining if uncaptured portions of the J-1 South plume are attenuating at rates consistent with design predictions. Contaminant monitoring for the J-1 South plume will consist of explosives. Perchlorate was detected in only two shallow groundwater screening samples (1.4 µg/L—MW-403—132.5 ft bgs—10 October 2005; 0.49J µg/L—MW-

482—102.5 ft bgs—26 February 2007) and one groundwater well (0.42J µg/L—MW-

482M3—16 March 2007) at low concentrations and will therefore not be monitored in the J-1

South plume. Sample collection, and field monitoring equipment calibration and maintenance will be conducted in accordance with approved procedures (AMEC 2005b).

The resulting data will be examined to verify estimates of restoration time frames and to determine the need for modifying or optimizing system operations.

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Periodic monitoring of the well network will be performed to characterize the J-1 South plume and determine the effectiveness of system performance. The primary sampling interval for chemical monitoring will be annual with semiannual sampling of key indicator wells. This approach is consistent with that devised for the J-3 and J-2 North treatment systems (ECC 2006a, 2006b). Periodic monitoring of plume constituents will be conducted at key locations to:

• assure that contaminant concentrations above action levels downgradient of the extraction well (J1SEW0001) capture zone will attenuate consistent with design predictions;

• assess observed trends in plume migration and attenuation;

• monitor plume boundaries and changes in the spatial distribution of plume COCs;

• assess mass capture; and,

• provide a basis for determining near-term wellfield operation optimization.

The monitoring wells selected for this periodic monitoring are presented in Table 4-3 and shown in Figure 4-3. Cross-sections showing monitoring locations and sample frequencies of select wells are presented in Figures 2-3 through 2-7. These wells were chosen to aid in further characterization and subsequent plume re-mapping and plume shell development.

An annual event is recommended for plume re-mapping and characterization and semiannual sampling is recommended for key indicator wells to track trends and assess plume dynamics. Additionally, these data will be used to update plume shells to use in assessing system performance and support system optimization. These data will provide the understanding of the distribution and magnitude of COCs. These data will, in conjunction with the proposed hydraulic data, also serve as a reference for periodic evaluation of system performance, mass capture, and ultimately, the restoration time frame.

A number of monitoring well optimization studies have been conducted on the MMR to determine the number of wells and frequency of monitoring to characterize a given plume.

A number of optimization studies conducted on the Fuel Spill-12 (FS-12) plume to determine the most efficient frequency of monitoring have concluded that annual monitoring is appropriate (AFCEE 2002a; Cameron and Hunter 1999, 2000; Ward et al. 2002). In the

Cameron and Hunter report, and subsequent AFCEE studies, there was agreement that annual monitoring was sufficient to capture the variability of ethylene dibromide (EDB)

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October 25, 2007 concentrations within the FS-12 plume. Other plumes within the Installation Restoration

Program (IRP) program have adopted sampling frequencies between semiannual and annual monitoring and some even as long as 3 years between sampling events (AFCEE

2005a, 2005b). Additionally, a monitoring well optimization was conducted for the J-3

Range RRA system and determined that sampling frequencies of semiannual, annual and biennial were appropriate for monitoring this plume (ECC 2006a). The findings from this investigation were also applied to the development of the monitoring network for the J-2

North RRA system (ECC 2006b).

Monitoring wells will be sampled on an annual and semiannual basis. Annual sampling will used to re-characterize the J-1 South plume and refine or redevelop the plume shells to be used in the fate and transport modeling used to assess performance of the J-1 South RRA

ETI system. Semiannual sampling is proposed to monitor the plume boundaries and determine if significant changes in plume geometry are occurring. Based on groundwater flow rates and the length of time needed to develop the current configuration of the J-1

South plume, more frequent sampling is not necessary. The groundwater model suggests that a time of approximately 21 years are required to develop the J-1 South plume and extend to the conceptualized leading edge southeast of the base boundary. Annual re-mapping of plume geometries will provide the information needed to make decisions regarding the performance of the remedial system. Figure 4-4 shows reverse particle tracks seeded from the extraction wells with various time markers under J-1 South system operational conditions. This figure also shows that travel times between monitoring wells and the extraction well are often years apart. For example particle tracks from the source area to extraction well J1SEW0001 show more than nine years travel time. Therefore, sampling frequencies of semiannual and annual are sufficient to adequately assess any changes in the J-1 South plume that would affect the operating conditions of the J-1 South

RRA ETI system.

Annual monitoring is appropriate for the areas of the plume within, upgradient and downgradient of the plume core where plume changes are not expected to be so large as to implement a change in the operation of the treatment system. This frequency of monitoring is adequate to assess observed fate and transport and observed versus predicted restoration time frame.

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Semiannual monitoring is appropriate for the following areas:

• close to the edges of the plume in the vicinity of the extraction well to verify plume boundaries and document restoration of the aquifer in these areas;

• in parts of the plume core, trailing edge, and leading edge where contaminant concentrations may be changing more rapidly over time; and,

• downgradient of the wellfield to monitor attenuation (decline in concentration) of plume contaminants that will not be captured by the extraction system.

The locations of monitoring wells selected for annual and semiannual monitoring are provided in Figure 4-3. The selected extraction and monitoring wells, associated construction information, the type of monitoring, and the specific rationale for each monitoring location are presented in Table 4-3.

The extraction well will be sampled semiannually and coordinated with the sampling of plant influent. The extraction well will be sampled at sampling ports during normal operating conditions. The extraction well will be sampled for explosives. The first round of groundwater monitoring will be completed 6 months after the scheduled J-1 South RRA ETI system startup. The annual round will be completed one year after system startup. The monitoring wells will be sampled in accordance with technical procedures outlined in the

Final Generic Quality Assurance Project Plan (AMEC 2005b). The analytical technique for analyzing the monitoring well samples is explosives by EPA Method SW846/8330. The sampling frequency for each monitoring well is listed in Table 4-3.

4.3 PLANT PERFORMANCE

Treatment plant performance monitoring will be conducted to measure the ability of the J-1

South RRA ETI system to remove contaminants from the extracted groundwater. The performance monitoring will include flow rate recording and sampling of extracted and treated groundwater at various points in the treatment stream.

All samples will be collected in accordance with approved procedures (AMEC 2005b). All field monitoring equipment will be calibrated and maintained in accordance with approved procedures (AMEC 2005b).

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Sampling will be conducted at select locations within the treatment system process as indicated on Figure 4-5.