final remaining wells groundwater investigation …

FINAL REMAINING WELLS GROUNDWATER INVESTIGATION

WORK PLAN PHOENIX–GOODYEAR AIRPORT–NORTH

SUPERFUND SITE Goodyear, Arizona

Submitted to:

United States Environmental Protection Agency

Submitted by:

AMEC Geomatrix, Inc., Scottsdale, Arizona

April 11, 2011

Project No. 0146821030

SDMS DOCID#1142192

AMEC Geomatrix, Inc.

FINAL REMAINING WELLS GROUNDWATER INVESTIGATION WORK PLAN Phoenix–Goodyear Airport–North Superfund Site Goodyear, Arizona

April 11, 2011 Project No. 0146821030

This Work Plan was prepared by the staff of AMEC Geomatrix, Inc., under the supervision of the Engineers and/or Geologists whose seals and signatures appear hereon.

The findings, recommendations, specifications, or professional opinions are presented within the limits described by the client, in accordance with generally accepted professional engineering and geologic practice. No warranty is expressed or implied.

Paul Jeffers, PG Senior Hydrogeologist

Stephanie L. Koehne, MBA Project Manager/Project Geologist

AMEC Geomatrix, Inc. i

TABLE OF CONTENTS

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

2.0 PURPOSE AND OBJECTIVES ......................................................................................... 2 2.1 OBJECTIVES ....................................................................................................... 2

3.0 SCHEDULE AND PROJECT TEAM ................................................................................. 3 3.1 PROJECT TEAM .................................................................................................. 4

4.0 INVESTIGATION PRIORITIES ......................................................................................... 4 4.1 Plume Extent/Migration and Hydraulic Characterization ........................... 5 4.1.1 Northeast Subunit A Plume Boundary – North of Interstate 10 (I-10) ....... 5 4.1.2 North and Northwest Subunit A Plume Boundary – North of I-10 ............. 6 4.1.3 Western Subunit A Plume Boundary – North of I-10 ................................. 6 4.1.4 Central Subunit A Plume – North of I-10 ................................................... 6 4.1.5 East and West Subunit A Plume Boundary – South of I-10 ...................... 6 4.1.6 North, Northeast and Northwest Subunit C Plume Boundary – South of I-10 .......................................................................................................... 7 4.1.7 Western Subunit C Plume Boundary – West of UPI Property ................... 7 4.1.8 Central Subunit C – North of I-10 .............................................................. 7 4.1.9 Former Potential Conduit Wells ................................................................. 7 4.1.10 Subunit A and Subunit C - COG-03 Area .................................................. 7

5.0 TECHNICAL APPROACH ................................................................................................. 8 5.1 PRE-FIELD ACTIVITIES ......................................................................................... 8 5.2 DRILLING ............................................................................................................ 8

5.2.1 Subunit A Wells ......................................................................................... 9 5.2.2 Subunit C Wells ....................................................................................... 10

5.3 FORMATION LOGGING AND DOCUMENTATION ...................................................... 10 5.3.1 Photoionization Detector (PID) Measurements ....................................... 11

5.4 GROUNDWATER SAMPLING ................................................................................ 11 5.4.1 Quality Assurance/Quality Control (QA/QC) Samples ............................. 11 5.4.2 Preservation ............................................................................................ 11 5.4.3 Sample Handling, Labeling, and Custody Requirement .......................... 12 5.4.4 Decontamination...................................................................................... 12

5.5 WELL INSTALLATION .......................................................................................... 13 5.5.1 Subunit A Monitor Wells .......................................................................... 13 5.5.2 Subunit C Monitor Wells .......................................................................... 13

5.6 WELL DEVELOPMENT ........................................................................................ 14 5.7 AQUIFER TESTING ............................................................................................. 14 5.8 SURVEYING ...................................................................................................... 15 5.9 INITIAL MONITOR WELL SAMPLING ..................................................................... 15 5.10 INVESTIGATIVE DERIVED WASTE ........................................................................ 15

6.0 REFERENCES ................................................................................................................ 17

TABLES

Table 1 Proposed Remaining Groundwater Investigation Monitor Wells

AMEC Geomatrix, Inc. ii

FIGURES

Figure 1 Site Location Map Figure 2 Proposed Remaining Monitor Wells for Groundwater Investigation –

Subunit A Figure 3 Proposed Remaining Monitor Wells for Groundwater Investigation –

Subunit C Figure 4 Proposed Subunit A Well Construction Diagram Figure 5 Proposed Subunit C Well Construction Diagram

AMEC Geomatrix, Inc. 1

FINAL REMAINING WELLS GROUNDWATER INVESTIGATION WORK PLAN

Phoenix-Goodyear Airport-North Superfund Site Goodyear, Arizona

1.0 INTRODUCTION

AMEC Geomatrix, Inc. (AMEC Geomatrix), on behalf of Crane Co., has prepared this Final Remaining Wells Groundwater Investigation Work Plan (Work Plan) to provide the objectives, rationale, and procedures to be followed for the continuing groundwater investigation at the Phoenix-Goodyear Airport-North Superfund Site (PGA-North [Site]), Goodyear, Arizona. This Work Plan is considered an amendment and references and updates the Revised Final 2005 Groundwater Investigation Work Plan, dated December 29, 2005, (ARCADIS G&M, Inc. 2005a) that was approved by the United States Environmental Protection Agency (EPA) on January 23, 2006 and the EPA approved Final

Year 2 and Final Year 3 Groundwater Investigation Work Plans, (ARCADIS G&M, Inc., 2007; AMEC Geomatrix, Inc. 2009a). The Remaining Wells Groundwater Investigation (Groundwater Investigation) will be conducted in accordance with Task 2.0 of the Scope of Work (SOW) which is part of a Consent Decree (CD) between the EPA, the United States Department of Justice, and Crane Co. that was entered into the Federal Register on April 26, 2006.

PGA-North is the northern portion of the Phoenix-Goodyear Airport (PGA) Superfund Site, which also includes a southern portion, PGA-South. This document specifically refers to the activities conducted at the PGA-North Site associated with the former Unidynamics-Phoenix, Inc. (UPI) facility, located in the City of Goodyear, Maricopa County, Arizona. The Site is approximately 17 miles west of central Phoenix, in the western portion of the Salt River Valley (Figure 1).

This Work Plan focuses on the investigation of water quality impacts within Subunit A, Subunit B, and Subunit C of the Upper Alluvial Unit (UAU). No Middle Alluvial Unit (MAU) wells are currently planned. The information obtained during this Groundwater Investigation will also help identify other areas of concern that may require the installation of additional monitor and/or extraction wells in order to protect domestic and irrigation supply wells in the area. Based on discussions with the EPA and the Arizona Department of Environmental Quality (ADEQ) during the 2009 and 2010 PGA-North Technical and Focused Hydro Meetings, a total of 30 monitor wells will be installed as part of this Groundwater Investigation. As of the preparation of this Work Plan, Crane Co. has completed installation of 14 of the 30 remaining monitor wells.


2.0 PURPOSE AND OBJECTIVES

This Work Plan identifies the groundwater investigation objectives, investigation rationale, technical approach, decision-making tools, and activities necessary to continue the characterization of the vertical and lateral extent of groundwater quality impacts at PGA-North in accordance with the SOW and CD during this Groundwater Investigation.

The most widespread compounds of concern (COCs) in groundwater at PGA-North are trichloroethene (TCE) and perchlorate. The full list of COCs in groundwater including TCE and perchlorate, along with their action levels and reporting limits, is presented in Tables 1 and 2 of the Quality Assurance Project Plan, Groundwater Investigation, Phoenix-

Goodyear Airport-North-Superfund Site, (QAPP) dated December 29, 2005 (ARCADIS G&M, Inc., 2005b) which was approved by EPA on January 23, 2006.

EPA, Region IX, is conducting oversight of investigation and remedial activities at PGA-North. Remedial actions include the installation and operation of groundwater extraction/injection and above-ground treatment systems, operation of a soil vapor extraction (SVE) system, groundwater monitoring, and in-situ nano-scale zero valent iron studies. These activities are not considered a part of the Groundwater Investigation and are not covered under this Work Plan.

2.1 OBJECTIVES

The objectives of this Work Plan are:

Continue to evaluate the extent and concentrations of site COCs in groundwater and more specifically the vertical and lateral extent of TCE and perchlorate in the UAU (Subunit A, Subunit B, and Subunit C).

Further characterize the hydrogeologic properties of the UAU by a program of drilling, lithologic logging, well installation, and aquifer testing to evaluate, where possible, any hydraulic connection between Subunits A, B, and C in areas of known impacts.

Provide additional data to refine the existing three-dimensional groundwater flow model and continue to update the site fate and transport model.

To fulfill these objectives, the following activities will be conducted:

Installation of exploratory boreholes to: 1) further characterize the vertical and lateral extent of impacts in the UAU; 2) characterize hydrogeologic properties; and 3) characterize potential contaminant pathways, including pathways in or near potential conduit wells.


Completion of exploratory boreholes as groundwater monitor wells to further the understanding of contaminant distribution and to monitor the effectiveness of remedial systems.

Aquifer testing to characterize the hydraulic properties in the vicinity of the planned monitor well locations and, where possible, assess potential hydraulic communication between the UAU subunits.

3.0 SCHEDULE AND PROJECT TEAM

Based on discussions with the EPA, ADEQ, and other stakeholders during the 2009 and 2010 PGA-North Technical and Focused Hydro Meetings, Crane Co. has proposed new monitor well locations to meet the objectives of this Work Plan. A total of 30 monitor wells have been identified and prioritized for installation during this Groundwater Investigation, which is scheduled to be completed by the end of 2011 or soon thereafter. As of the preparation of this Work Plan, 14 of the 30 remaining monitor wells have already been installed. The rationale and purpose for the locations of the proposed Groundwater Investigation monitor wells is presented in Table 1. Determination of the final locations for the Groundwater Investigation monitor wells will be an iterative process, based on data collected as the Groundwater Investigation progresses.

Any data-driven proposed additional monitor wells will be submitted in the form of an updated monitor wells priority table and associated figures on a semi-annual basis. These updated tables and figures will be considered an addendum to this Work Plan and the locations will be presented to the agencies and stakeholders in advance of the scheduled well installation date and would only be implemented with the final approval from the EPA.

The primary activity described in this Work Plan is the installation of the remaining Groundwater Investigation monitor wells; for scheduling purposes, the activities associated with this task are further divided into the following sequence of work:

1. Identify land owner 2. Acquire permits and access 3. Public notifications 4. Stake boring location 5. Screen for public and private utilities 6. Conduct drilling and depth-specific sampling 7. Construct well 8. Develop well 9. Conduct 8-hr aquifer test 10. Sample well 11. Survey well


It is anticipated that Subunit A monitor wells will take approximately 10 days to drill, sample and install. Subunit C monitor wells are anticipated to take approximately 20 days to drill, sample, and install.

A Remaining Monitor Well Groundwater Investigation Report will be prepared within 90 days of completion of field work associated with this Work Plan. Additionally, weekly reports will be prepared and submitted to the agencies and stakeholders during the implementation of field activities. The weekly report will be an electronic-mail update of field activities conducted during the previous week. This report will be in conjunction with other weekly reporting conducted for other portions of the project (e.g., SVE, groundwater monitoring, etc.).

3.1 PROJECT TEAM

The following is the Project Team that will implement this Work Plan:

Stephanie Koehne, MBA – Stephanie Koehne is the project manager for the PGA-North Project and is responsible for the overall direction of the project.

Paul Jeffers, P.G. – Paul Jeffers is the senior hydrogeologist on the project and is responsible for the overall hydrogeological/technical direction of this Work Plan. In addition, Mr. Jeffers will be responsible for supervising the day to day drilling and sampling activities.

Robert Fifield and Gwen Minnier - Robert Fifield and Gwen Minnier are the field geologists on the project and are responsible for the implementation of the field activities.

4.0 INVESTIGATION PRIORITIES

This Work Plan is the final plan for the multi-year effort to characterize the lateral and vertical extent of impacted groundwater associated with the PGA-North Site. The monitor wells were prioritized based on input from agencies (EPA and ADEQ) and stakeholders [including City of Goodyear (COG), City of Avondale (COA), City of Litchfield Park, and Liberty Water Company] and Crane Co. during the November 2, 2009 Remaining Wells meeting. The well installation priorities are summarized below and reflected in Table 1, which lists the designation, general location, and the purpose/objective for each proposed monitor well.

The remaining monitor wells that comprise the Groundwater Investigation have been categorized based on perceived environmental risks and data gaps identified using First Quarter 2010 groundwater monitoring data and continuing review of the data. Based on discussions with the EPA, ADEQ, and other stakeholders the proposed remaining Groundwater Investigation monitor wells are located to: 1) further define the vertical and


lateral extent of the contaminant plumes in Subunit A and Subunit C in the northern, northeastern, eastern, central, and southern PGA-North areas; 2) provide hydraulic characterization; and 3) provide sentinel wells for potential conduit wells. A total of 21 Subunit A groundwater monitor wells (EPA MW-12A, EPA MW-21A, EPA MW-33A, EPA MW-38A, EPA MW-42A, EPA MW-44A, EPA MW-46A, EPA MW-47A, EPA MW-48A, EPA MW-50A, EPA MW-51A, EPA MW-52A, EPA MW-53A, EPA MW-54A, EPA MW-55A, EPA MW-56A, EPA MW-57A, EPA MW-58A, EPA MW-59A, EPA MW-60A, and EPA MW-61A) and 9 Subunit C groundwater monitor wells (EPA MW-2C, EPA MW-3C, EPA MW-5C, EPA MW-12C, EPA MW-21C, EPA MW-22C, EPA MW-26C, EPA MW-47C, and EPA MW-48C) have been prioritized for the remaining monitor wells Groundwater Investigation.

The scope and priority of the Groundwater Investigation monitor wells are subject to changes in order of installation, location, or methods of investigation, depending on data acquired during the scope of work as it progresses. Changes in order include the sequence in which areas are investigated or wells are installed. Changes in methods include the use of different drilling methods, sampling methods, development methods, and aquifer test methods. Proposed changes in location (e.g., access issues) would be discussed at Focused Hydro Meetings, routine Quarterly Technical Meetings, and/or conference calls as they become known. Any proposed change in order, location, or drilling and sampling methods will be communicated to the EPA for comments at least seven days prior to implementing the change.

4.1 Plume Extent/Migration and Hydraulic Characterization

This section describes the proposed locations and rationale of each monitor well as it relates to plume extent/migration and/or hydraulic characterization in the northern, northeastern, eastern, central and southern areas of PGA-North Site.

4.1.1 Northeast Subunit A Plume Boundary – North of Interstate 10 (I-10)

Based on discussions with the EPA, ADEQ, and other stakeholders during recent PGA-North Quarterly Technical Meetings, there was a general concern over the migration of the Subunit A plume near the northeastern plume boundary north of I-10. Monitor wells EPA MW-54A, EPA MW-55A, EPA MW-60A, and EPA MW-61A are proposed for this area (monitor wells EPA MW-54A and EPA MW-55A have already been installed). Pursuant to a request from COA, additional monitor wells are needed to monitor the performance of injection wells IA-11 through IA-15 on the east side of Dysart Road. Monitor wells EPA MW-52A, EPA MW-53A, and EPA MW-59A are proposed for this area (Figure 2).


4.1.2 North and Northwest Subunit A Plume Boundary – North of I-10

EPA MW-38A was installed to refine the 100 microgram per liter (µg/L) TCE concentration contour west of extraction well EA-06. Due to the concentrations of TCE in excess of 100 µg/L detected in this well, an additional Subunit A monitor well was installed (EPA MW-50A) to further delineate the northern boundary of the Subunit A TCE plume in this area. EPA MW-51A is proposed northwest of extraction well 33A and EPA MW-21A is proposed southwest of extraction well 33A to help determine if there is a loss of plume control when extraction well 33A is inactive (Figure 2).

4.1.3 Western Subunit A Plume Boundary – North of I-10

Further delineation of the Subunit A TCE western plume boundary was needed north of 1-10. EPA MW-44A was installed during first quarter 2011 west of monitor well MW-15, just north of 1-10, in an area where there was minimal data (Figure 2).

4.1.4 Central Subunit A Plume – North of I-10

EPA MW-33A and EPA MW-42A are both proposed to be located in the central portion of the plume, north of I-10 (Figure 2). EPA MW-33A is proposed in the center of the plume south of extraction well EA-06 and is intended to confirm and refine the extent of the groundwater divide in this portion of the Subunit A TCE plume. EPA MW-42A is proposed between monitor wells MW-16 and EPA MW-25A and will aid in defining the western extent of the 100 µg/L TCE concentration contour. In addition, this well can be used for hydraulic characterization of the groundwater divide in the area of MW-16.

4.1.5 East and West Subunit A Plume Boundary – South of I-10

Further delineation of the Subunit A TCE eastern and western plume boundaries is needed south of I-10. EPA MW-48A was installed northeast of MW-12 to help define the 100 µg/L TCE concentration contour. EPA MW-48A serves as a replacement well for MW-22, because MW-22 was determined to be too deep to intercept the eastern plume boundary. EPA MW-56A was installed to help delineate the lateral extent of the Subunit A eastern plume boundary. Chevron Wells MW-08 and MW-09 have not been used for groundwater contouring or chemical sampling because of their shallow depths, and have been abandoned. As a result, EPA MW-46A was installed as a replacement well. EPA MW-57A was installed to help delineate the lateral extent of the Subunit A TCE eastern plume boundary and provide a sentinel for the COG water supply wells. EPA MW-47A was installed to help delineate the lateral extent of the Subunit A TCE western plume boundary. In addition, EPA MW-47A will be paired with proposed Subunit C well EPA MW-47C to determine hydraulic connection between Subunit A and Subunit C in this area. EPA MW-12A is proposed to be located in the western portion of the plume, south


of I-10, and is intended to confirm and refine the extent of the western plume boundary in this portion of the site (Figure 2).

4.1.6 North, Northeast and Northwest Subunit C Plume Boundary – South of I-10

As with the Subunit A plume, the Subunit C plume boundary is in need of further delineation south of I-10. EPA MW-48C was installed northeast of MW-29 to delineate the Subunit C plume boundary (Figure 3). EPA MW-47C was installed to help delineate the lateral extent of the northwestern Subunit C plume boundary. EPA MW-12C will be installed to help delineate the lateral extent of the Subunit C plume boundary (the location for EPA MW-12C will be dependent upon results obtained from EPA MW-47C).

4.1.7 Western Subunit C Plume Boundary – West of UPI Property

Further delineation of the Subunit C TCE plume boundary in the area west of the Site was needed. EPA MW-3C and EPA MW-5C were installed in this area. EPA MW-3C was installed in the area downgradient of former conduit well COG-04 and was intended to define the extent of impacts associated with this well. EPA MW-3C was paired with Subunit A well MW-07. EPA MW-5C was installed to define the western boundary of the Subunit C plume on-Site. EPA MW-5C was paired with Subunit A well MW-08. EPA MW-26C will be installed to help delineate the lateral extent of the Subunit C TCE plume boundary west of the former UPI property (Figure 3).

4.1.8 Central Subunit C – North of I-10

EPA MW-22C is proposed as an additional Subunit C data point in this area to confirm water levels observed at MW-26 (which appear anomalous).

4.1.9 Former Potential Conduit Wells

Based on the Third Quarter 2009 Conduit Well Investigation Report, there is a need to assess the potential impacts from the former conduit wells that are listed as high/unknown, also referred to as 28 section wells, in the area northeast of extraction well 33A. EPA MW-21C is proposed to evaluate the potential impacts from the 28 section wells (Figure 3).

4.1.10 Subunit A and Subunit C - COG-03 Area

EPA MW-2C is proposed as a possible step-out well for EPA MW-10C to define the eastern extent of the Subunit C TCE plume expansion and provide a sentinel well for COG-03 in the event that EPA MW-10C exceeds the maximum contaminant level of 5 µg/L for TCE for three consecutive quarterly sampling events (Figure 3). EPA MW-58A is proposed as a step-out well for EPA MW-10A to define the extent of the Subunit A TCE plume boundary in this area (Figure 2).


5.0 TECHNICAL APPROACH

The following sections describe the technical approach for drilling, lithologic logging, groundwater sampling, well installation, and aquifer testing. All characterization activities outlined below will be conducted in general accordance with the data quality objectives outlined in ARCADIS’s approved QAPP (ARCADIS G&M, Inc., 2005b) and the AMEC Geomatrix Quality Management Plan, Groundwater Investigation, Phoenix-Goodyear Airport-North Superfund Site (AMEC Geomatrix, Inc., 2009c).

5.1 PRE-FIELD ACTIVITIES

The following pre-field activities will be conducted prior to drilling:

Select qualified driller; Contact subcontractors; Acquire permits and access; Locate underground utilities; and Notify EPA fifteen days in advance of fieldwork.

Each selected driller will be licensed in Arizona and will be capable of demonstrating experience in West Salt River Valley stratigraphy and SimulProbe™ and HydroPunch® sampling techniques.

Prior to the initiation of fieldwork, Crane Co. will acquire drilling permits from the Arizona Department of Water Resources and right-of-way access agreements from either private property owners, COG, COA, or Litchfield Park. If necessary, Crane Co. will provide traffic control plans in city right-of-ways. Drilling within the right-of-ways is preferable in terms of minimizing access issues. The EPA will be notified in the event any significant difficulties with access are encountered.

Public utilities will be marked using Arizona BlueStake. A private utility locator will independently locate and physically mark private underground utilities that may be present at the selected drilling locations. The markings will be made with colored spray paint or colored flagging which corresponds to the types of utilities encountered.

5.2 DRILLING

It is anticipated that all wells will be drilled and installed using pneumatic hammer, air rotary casing hammer (ARCH), or SonicTM drilling methodologies. These drilling methods were chosen to provide accurate lithologic information within the Subunits and to seal off the upper and lower units to prevent cross contamination.


The pneumatic hammer method advances a dual-walled, 9-inch diameter drill pipe into the subsurface by means of a diesel-powered pile hammer. Drill cuttings are removed by air supplied by an onboard and auxiliary compressor which is pumped down the space between the inner and outer walls of the drill pipe to the bit. The high velocity air stream carries the cuttings back to the surface through the center of the drill pipe. Cuttings are separated from the discharging air by a cyclone. The pneumatic hammer drilling methodology is a proven method that has been used on State and Federal sites throughout Arizona that have VOC contamination in soil and groundwater. This drilling method is also well suited for conventional soil sampling and SimulProbe™ and HydroPunch® sampling for groundwater. The combined capabilities of this method are well suited to the objectives of this Work Plan.

The ARCH system consists of a non-rotating flush-threaded casing driven in conjunction with a conventional air rotary drill string. Cuttings are cleared from the hole by the bit rotation and air circulation. The material is discharged through a hose into a cyclone, which separates the air from the formation cuttings to facilitate sampling and drill cuttings containment. The advanced drive casing is a heavy wall flush-threaded pipe. The casing is driven with a pneumatic or hydraulic drill through casing hammer.

The Sonic™ drilling method utilizes high-speed counter-balances on the top of the drill stem to produce resonant energy waves which minimize borehole friction on the drill pipe, resulting in faster drilling. The Sonic™ method also creates a continuous core of material drilled, which minimizes investigative-derived wastes (IDW) and allows for an accurate description of the subsurface stratigraphy. In addition to continuous sample recovery, Sonic™ techniques are suitable for conventional soil sampling, and SimulProbe™ and HydroPunch® sampling for groundwater. The combined capabilities of this method are well suited to the objectives of this Work Plan.

5.2.1 Subunit A Wells

Based on previous investigations, the depth to the base of Subunit A ranges from approximately 150 feet below ground surface (bgs) at the UPI property to 200 feet bgs near the northern Subunit A TCE plume boundary. Proposed Subunit A monitor wells (EPA MW-12A, EPA MW-21A, EPA MW-33A, EPA MW-38A, EPA MW-42A, EPA MW-44A, EPA MW-46A, EPA MW-47A, EPA MW-48A, EPA MW-50A, EPA MW-51A, EPA MW-52A, EPA MW-53A, EPA MW-54A, EPA MW-55A, EPA MW-56A, EPA MW-57A, EPA MW-58A, EPA MW-59A, EPA MW-60A, and EPA MW-61A) designated in this Work Plan are anticipated to be drilled using either pneumatic hammer or ARCH drilling methods. All Subunit A monitor wells will be drilled to a total depth based on geologic information gathered from each boring, adjacent borings, and depth-discrete groundwater sample results. All wells are proposed outside the UPI property and source area related


soil contamination is not expected, therefore, soil samples will be collected for lithologic logging only. Borehole and casing size specifications and proposed well construction details are presented in Figure 4.

5.2.2 Subunit C Wells

Based on previous investigations, the base of Subunit C is located at approximately 350 feet bgs. Proposed Subunit C monitor wells (EPA MW-2C, EPA MW-3C, EPA MW-5C, EPA MW-12C, EPA MW-21C, EPA MW-22C, EPA MW-26C, EPA MW-47C, and EPA MW-48C) designated in this Work Plan are anticipated to be drilled using either pneumatic hammer, ARCH, or SonicTM drilling methods. The type of drilling selected will be based on the intended objectives of the boring and whether or not continuous coring is warranted. All Subunit C monitor wells will be drilled to a total depth based on geologic information gathered from each boring, adjacent borings, and depth-discrete groundwater sample results. Soil samples will be collected for lithologic logging only. Borehole and casing size specifications and proposed well construction details are presented in Figure 5.

During drilling, once the base of Subunit A is determined, temporary casing will be set into the finer grained deposits associated with upper portion of Subunit B to prevent the vertical migration of contaminants from Subunit A to the lower subunits. Once the depth of the temporary casing is determined, two to three feet of bentonite will be placed at the bottom of the boring for added protection.

5.3 FORMATION LOGGING AND DOCUMENTATION

Documentation and lithologic logging will be compiled for each borehole/monitor well and will include the following:

Monitor well completion and development report form. Boring log of drill cutting samples in the field logs; lithologic descriptions will be in

general accordance with the Unified Soil Classification System (USCS). Field notes compiled by the on-site geologist during drilling operations. Photographs, if available.

A log of conditions encountered during drilling will be maintained by the site geologist. Lithologic logs compiled during drilling activities will be evaluated along with analytical data to enhance site characterization. The log will include lithologic and hydrogeologic descriptions as well as notations on drill rig behavior and any anomalous conditions encountered during drilling. Field lithologic descriptions will be based on examination of drill cuttings with consideration of impacts of the drilling process on cuttings. Lithology will be classified using the USCS for guidance as described in ASTM International (ASTM)


Standard D 2488-09a (ASTM, 2009). Visual grain-size distribution, color, moisture content, and other pertinent characteristics will also be included on the lithologic logs.

5.3.1 Photoionization Detector (PID) Measurements

Field measurements will be collected from the soil samples. Soil obtained for the purpose of lithologic logging will be placed in a Ziploc™-type bag, allowing for any VOCs present to volatilize. Each sample will be stored for 15 to 30 minutes before being subjected to headspace measurement. The headspace in the bag will then be monitored for VOCs using the PID. The PIDs will be calibrated before the start of the sampling day. Calibration will be in accordance with procedures and schedules outlined in the particular instrument’s operation manual. The results of calibrations and records of repairs will be recorded in a field form.

5.4 GROUNDWATER SAMPLING

To define the vertical extent of groundwater impacts, depth-discrete groundwater sampling will be conducted at approximately 20-foot intervals beginning at the water table to the total depth of each boring and will be analyzed for VOCs and perchlorate. Depth-discrete groundwater samples collected during the implementation of this Work Plan will be collected using a SimulProbe™ or HydroPunch® sampling device. Groundwater samples will be collected in accordance with the EPA approved Final Year 3 Groundwater

Investigation Work Plan (AMEC Geomatrix, 2009a).

5.4.1 Quality Assurance/Quality Control (QA/QC) Samples

One equipment rinsate sample will be collected from the SimulProbe™ or HydroPunch® upon the completion of sampling from each boring to verify the decontamination procedures are adequate. Equipment rinsate samples will only be collected from the lead drill bit prior to entering the saturated zone if field measurements indicate contamination is present in the vadose zone. One field duplicate per boring will be collected during depth-discrete groundwater sampling. Additional information regarding the collection of QA/QC samples is presented in Section 3.4 of the QAPP (ARCADIS G&M, Inc., 2005b).

5.4.2 Preservation

Samples will be preserved in accordance with appropriate procedures for specific analytical methods, as outlined in “Test Methods for Evaluating Solid Waste SW-846” and as presented in Table 1 of the QAPP (ARCADIS G&M, Inc., 2005b). All samples will be maintained in a cooler with ice to ensure that sample preservation is appropriate.


5.4.3 Sample Handling, Labeling, and Custody Requirement

Appropriate sample custody is one of several factors which determine the defensibility of environmental data. Samples are deemed to be in custody if they are in the actual physical possession of or are in a secured area restricted to authorized personnel only.

Proper custody procedures will ensure that samples are collected, transferred, stored and analyzed properly, and that sample integrity is maintained during all phases of collection and analysis.

All sample information will be entered onto chain-of-custody forms as they are collected and included in the sample cooler. The sample containers will be placed on ice prior to transport to the laboratory. Prior to shipping, custody seals will be placed on the samples and on the cooler. The use of custody seals will minimize potential for tampering and provide assurance of sample integrity upon receipt by the laboratories.

Sample custody procedures used by the laboratories are presented in the QA manuals presented in Appendix A of the QAPP (ARCADIS G&M, Inc., 2005b).

Sample labels will be filled out with indelible ink and will be affixed to each sample container. Each sample container will be labeled with, at the minimum, the following information:

Sample identification number; Sample collection date (month/day/year); Time of collection (military time); Sampler’s initials; and Sample preservation (if any).

5.4.4 Decontamination

The SimulProbe™ and HydroPunch® devices and associated drilling equipment will be decontaminated between each aquifer unit and after each sample collection interval. The consumables kit associated with the SimulProbeTM and HydroPunch® devices will be replaced after each sample is collected in accordance with manufacturers’ recommendations. SimulProbe™ canister tubing will also be replaced after each sample collection. The device will be completely disassembled prior to decontamination. The non-consumable portions of the SimulProbeTM and HydroPunch® samplers will be washed in Alconox™ or similar non-phosphate soap solution, followed by a tap water rinse, followed in turn by a distilled water rinse. Decontamination water will be disposed of at the PGA-North Main Groundwater Treatment System (MTS), in accordance with the QAPP (ARCADIS G&M, Inc., 2005b).


5.5 WELL INSTALLATION

Prior to well construction activities, screen lengths and depths will be selected based on analytical results from the depth-discrete groundwater samples and lithologic logs. All screen lengths and depths will be discussed with and approved by the EPA, ADEQ, and stakeholders and/or its representatives prior to placement.

5.5.1 Subunit A Monitor Wells

Subunit A monitor wells will be installed in a 10-inch diameter borehole. It is anticipated that the exact screened interval will be dependent on depth-discrete groundwater sample results and the lithologic logs as described above. The majority of current monitor wells have screened lengths of 40 to 50 feet. The rationale for long screen lengths is the necessity of capturing multiple coarse-grained layers and multiple zones of contamination within the Subunit. The wells will be constructed of 4-inch, Schedule 40 polyvinylchloride (PVC). The monitor well screen will have a 0.020-inch slot opening. Final construction of Subunit A monitor wells will be similar to the depiction in Figure 4.

Filter pack sand will be placed from five feet below the bottom of the screen interval to approximately five feet above the screen. The well will be initially surged to settle the filter pack around the well screen. Additional filter pack will be added if settlement occurs during surging. At least five feet of transition sand will be added above the filter pack to prevent the bentonite seal from entering the filter pack. A ten foot bentonite seal will be place above the transition sand. Well casing will be grouted from the top of the bentonite seal to approximately twenty feet bgs using high-solids bentonite grout which will be tremied down the annular space of the borehole to ensure proper placement of the grout. The top twenty feet of the annulus will be filled with neat cement per ADWR guidelines. The monitor wells will be completed with a locking 18-inch diameter traffic rated well box, unless regulatory requirements or site conditions warrant an alternate completion.

5.5.2 Subunit C Monitor Wells

Subunit C monitor wells will be installed in a 12-inch diameter borehole. It is anticipated that the exact screened interval will be dependent on depth-discrete groundwater sample results and the lithologic logs as described above. The majority of current monitor wells have screened intervals of 40 to 50 feet. The rationale for long screen lengths is the necessity of capturing multiple coarse-grained layers and multiple zones of contamination within the Subunit. The wells will be constructed of 4-inch, Schedule 80 PVC. The well screen will have a 0.020-inch slot opening. Final construction of Subunit C monitor wells will be similar to the depiction in Figure 5.


Filter pack sand will be placed from five feet below the bottom of the screen interval to approximately five feet above the screen. The well will be initially surged to settle the filter pack around the well screen. Additional filter pack will be added if settlement occurs during surging. At least five feet of transition sand will be added above the filter pack to prevent the bentonite seal from entering the filter pack. A ten foot bentonite seal will be place above the transition sand. Monitor well casing will be grouted from the top of the bentonite seal to approximately twenty feet bgs using high-solids bentonite grout which will be tremied down the annular space of the borehole to ensure proper placement of the grout. The top twenty feet of the annulus will be filled with neat cement per ADWR guidelines. The monitor wells will be completed with a locking 18-inch diameter traffic rated well box, unless regulatory requirements or site conditions warrant an alternate completion.

5.6 WELL DEVELOPMENT

All monitor wells will be developed using the surge, bail, and pump method. This development method is performed by surging water into the well to agitate fines, bailing to remove the fines, and pumping to remove remaining fines. Monitor well development will take approximately eight hours per well and will be in accordance with the Standard Guide

for Development of Groundwater Monitoring Wells in Granular Aquifers, ASTM Designation: D 5521-05.

Water produced from monitor well development will be stored in a 6,500-gallon tank and subsequently discharged into a sanitary sewer in accordance with the associated sanitary sewer discharge permit or treated at the MTS.

5.7 AQUIFER TESTING

In accordance with the SOW, aquifer testing will be performed within 30 days of monitor well installation and development (of a minimum of eight hour duration) in all Subunit A and Subunit C monitor wells. Aquifer testing will be conducted on each of the monitor wells after well development and before initial sampling to characterize hydraulic conductivity by controlled pumping of the well. If existing monitor wells in the same hydrostratigraphic unit are within 300 feet of the proposed monitor well, the aquifer test will be modified to include drawdown monitoring at the closest adjacent well.

Prior to conducting the aquifer test, the given monitor well will be allowed to stabilize for at least 24 hours after initial well completion and development. Data loggers will be checked to determine that they are working properly prior to beginning the aquifer test. Aquifer tests will consist of a single eight-hour, constant-rate test for each well. A pressure transducer and data logger will be used to monitor drawdown and recovery in the pumped well. Data collected from the transducer and data loggers will be supplemented by


gauging the wells with a water level indicator. A submersible pump will be used to pump the well. The pump will be operated at maximum capacity; it is estimated that this will produce a flow rate of approximately 20 to 30 gallons per minute (gpm). Aquifer testing procedures will be in accordance with the EPA approved Final Year 3 Groundwater

Investigation Work Plan (AMEC Geomatrix, 2009a).

Water produced from the test will be contained in two 6,500-gallon tanks or discharged to the sanitary sewer. Water contained in the 6,500-gallon tanks will be transported via vacuum truck and transferred to the MTS. The contents will be allowed to settle, and then the water will be processed by the MTS. Sludge remaining in the tank will be collected by a licensed waste hauler (e.g., MP Environmental) as deemed necessary. Once testing is complete and the tanks are emptied, they will be removed from the Site.

Water quality will be periodically monitored throughout the test for each well. Electrical conductivity, pH, and temperature will be monitored using the YSI multi-meter. No analytical samples will be collected from the test water.

5.8 SURVEYING

After the installation of each individual monitor well, its location and elevation will be surveyed by an Arizona Registered Land Surveyor to the nearest one-hundredth of a foot.

5.9 INITIAL MONITOR WELL SAMPLING

Initial groundwater samples will be collected from each of the new monitor wells during the next routine groundwater sampling event and after the dedicated pumps have been installed. Samples will be collected from the wells utilizing low-flow technology (Puls and Barcelona, 1996). The well housing will be cleared of any debris before opening the well. Any water found within the monitor well vault will be removed. Groundwater samples will be analyzed for VOCs and perchlorate.

5.10 INVESTIGATIVE DERIVED WASTE

Waste handling shall be dealt with on a location-specific basis. Waste may be classified as non-investigative waste or IDW. Non-investigative waste, such as litter and household garbage, shall be collected on an as-needed basis to maintain the drilling site in a clean and orderly manner. This waste shall be containerized and transported to the designated sanitary landfill or collection bin. Acceptable containers shall be sealed boxes or plastic garbage bags.

During this Groundwater Investigation, cuttings generated during soil boring advancement will be disposed of properly. Mixed solids and water (mud) from the drilling program will be collected in leak-proof containers to settle. Water will then be separated from the solids.


The soils will be containerized in lined roll-off bins with lids. The bins will then be transported to a temporary storage area until the completion of the investigation when all cuttings will be disposed of according to the site COCs in the containerized soils. The containers shall be transported in such a manner to prevent spillage or particulate loss to the atmosphere.


6.0 REFERENCES

AMEC Geomatrix, 2009a. Final Year 3 Groundwater Investigation Work Plan, Phoenix-

Goodyear Airport-North Superfund Site, Goodyear, Arizona, April 17.

AMEC Geomatrix, Inc., 2009b. Quality Management Plan, Groundwater Investigation,

Phoenix-Goodyear Airport-North Superfund Site.

AMEC Geomatrix, 2010. Amended Comprehensive Regional Approach for Northeast

Subunit A Plume Capture Augmentation and Treatment Work Plan, May 20.

ARCADIS G&M, Inc., 2005a. Revised Final 2005 Groundwater Investigation Work Plan, December 29.

ARCADIS G&M, Inc., 2005b. Quality Assurance Project Plan, Groundwater Investigation,

Phoenix-Goodyear Airport-North Superfund Site, December 29.

ARCADIS G&M, Inc., 2007. Final Year 2 Groundwater Investigation Work Plan, May 21.

ASTM International, 2009. Standard Practice for Description and Identification of Soils (Visual-Manual Procedure).

Puls, Robert, and Barcelona, Michael, 1996. Low-Flow (Minimal Drawdown) Ground-

Water Sampling Procedures. Ground Water Issue. United States Environmental Protection Agency. EPA/540/S-95/504.

TABLES

TABLE 1PROPOSED REMAINING GROUNDWATER INVESTIGATION MONITOR WELLS

Phoenix-Goodyear Airport-North Superfund SiteGoodyear, Arizona

Table No.

Well Designation Location1 SubUnit Purpose for Well Installation Status

Plume extent/migration and hydraulic characterization1 EPA MW-48A North of MW-12 A Replacement well for MW-22. Paired with Subunit C well (EPA MW-48C). Completed

2 EPA MW-48C Northeast of MW-29 C Step out well to investigate and delineate Subunit C plume northeast of MW-29. Paired with Subunit A well (EPA MW-48A).

Completed

3 EPA MW-54A Northeast plume boundary

A Well to investigate and delineate Subunit A plume boundary in the northeast portion of the site.

Completed

4 EPA MW-55A Northeast plume boundary

A Well to investigate and delineate Subunit A plume boundary in the northeast portion of the site.

Completed

5 EPA MW-56A Eastern plume boundary south of I-10

A Delineate the lateral extent of the eastern plume boundary northeast of EPA MW-48A.

Completed

6 EPA MW-38A Northern plume boundary A Performance assessment of plume control measures is largely incomplete as evidenced by: 1. individual capture zone evaluations provided have been limited by data gaps. 2. no evaluation of loss-of-plume-control when extraction well 33A is inactive.

Completed

7 EPA MW-50A North of EPA MW-38A and RID canal

A Step out well for EPA MW-38A. Completed

8 EPA MW-5C Southwestern plume boundary

C Define western boundary of Subunit C plume, currently there is no data for this area. Pair with Subunit A well MW-08.

Completed

9 EPA MW-3C Central plume, on-site C Downgradient extent of conduit well impacts from COG-04 are undefined as to vertical and lateral extent.

Completed

10 EPA MW-46A Eatern plume boundary, east of the site,

replacement for Chevron Wells

A Chrevron wells have not been able to be used for groundwater contouring or chemical sampling due to their shallow depth. These wells have been abandoned. This area therefore has not been delineated as to the extent of the Subunit A groundwater plume .

Completed

11 EPA MW-57A Eastern Subunit A plume boundary, south of I-10.

A Well to investigate and delineate Subunit A plume boundary east-northeast of EPA MW-56A.

Completed

12 EPA MW-44A Western plume boundary north of I-10

A Mimimal data exists for this area of the plume. Completed

13 EPA MW-47A Western plume boundary south of I-10

A No data for gradient control or contaminant concentration confirmation for western plume boundary.

Completed

14 EPA MW-47C Northwest of MW-29 C Well to investigate and delineate Subunit C plume northwest of MW-29. Completed

15 EPA MW-51A Northwest of EPA MW-20A

A Evaluation of loss-of-plume-control when extraction well 33A is inactive. TBD

4/11/2011 Page 1 of 3



Table No.


16 EPA MW-60A Northeast of EPA MW-54A/EPA MW-43A

A This well will aid in the evaluation of the northeast injection/extraction system (wish list well).

TBD

17 EPA MW-61A Northeast Subnit A TCE Plume

A This well will aid in the evaluation of the northeast injection/extraction system (wish list well).

TBD

18 EPA MW-52A East of Dysart Rd. A Well is intended to extend water level control beyond the plume boundary wells and evaluate the effect of the nearby injection wells or extraction wells.

TBD

19 EPA MW-53A East of Dysart Rd. A Well is intended to extend water level control beyond the plume boundary wells and evaluate the effect of the nearby injection wells or extraction wells.

TBD

20 EPA MW-59A Sentinel well for COA-18 A No data for gradient control is available for this area. This well will aid in the evaluation of the IA-10/IA-12 area (wish list well).

TBD

21 EPA MW-12A Western plume boundary south of I-10

A Step-out well for EPA MW-47A TBD

22 EPA MW-12C Northwestern plume boundary south of I-10

C Well to investigate and delineate Subunit C plume downgradient (northwest) from MW-29.

TBD

23 EPA MW-26C Western plume boundary south of I-10

C Step-out well for EPA MW-5C TBD

24 EPA MW-21A West-northwestern plume boundary near extraction

well 33A

A Define west-northwestern extent of plume boundary west of 33A. Evaluation of loss-of-plume-control when extraction well 33A is inactive.

TBD

Perfromance monitoring and hydraulic characterization25 EPA MW-42A Central plume between

MW-16 and EPA MW-25A

A Define the western extent of the 100 ug/L TCE contour, and confirm reason for continued high 33A TCE concentrations. Also can be used for hydraulic characterization for the groundwater divide in the vicinity of MW-16.

TBD

26 EPA MW-33A Central plume south of EA-06

A Confirm and refine the extent of groundwater divide in north-central portion of plume, limited data in this area and difficulties with model calibration indicate the need for additional wells to delineate the groundwater divide.

TBD

27 EPA MW-22C Between MW-26 and SunCor 34B

C Confirm water levels seen at MW-26 (currently difficult to reconcile) and provide an additional Subunit C data point.

TBD

4/11/2011 Page 2 of 3



Table No.


Potential Conduit Wells28 EPA MW-21C Northeast of extraction

well 33AC Potential impacts from potential conduit wells listed as high/unknown (28 section

wells). No current monitoring wells exist to address potential contamination from these conduit wells.

TBD

Potential Step Out Wells29 EPA MW-2C Possible step out well for

EPA MW-10CC Define the extent of the eastern plume expansion and provide a sentinel well for

COG-03 in the event that EPA MW-10C exceeds MCL for 3 sampling rounds. TBD

30 EPA MW-58A Possible step out well for EPA MW-10A

A Define the extent of the southeastern Subunit A plume expansion and provide a sentinel well for COG-03. EPA MW-10A has exceeded MCL for at least 3 sampling rounds.

TBD

Notes:1. Locations of wells depicted on Figures 2 and 3 are in the general vicinity; the actual well location will be determined in coordination with agencies and stakeholders.

4/11/2011 Page 3 of 3

FIGURES

Explanation

Site

City limits

REFERENCE: Aerial phalo pnwided by Marieapa Cllullly, R, M8ldl2010.

SITE LOCATION MAP

Phoenix Goodyear Airport North Superfund Site Goodyear, Arizona

Pro'ect No. 0146821030

AMEC Geomatrix Figure 1

eEPAMW-37A

YwnaRoad

McOawell Rd.

Van &Inn St.

I J

eEPAMW-32A

l EPAMw-sA

I EPAMW-20A •

Yu.ma Road

eMW-19 I l J!

EPAMW· 26Ae

EPAMW-39Ae

IR,·34Bm (JhBt:tJVf!J) &!I

Iii McDoMII Rd. !R·3B

(Active)

EPA MW-41A 8 ~ • EPA MW· 40A

0~ z PZ-tOa:fEA-05 e

EPA MW-36A. IA-10 ~

1!1 I!ICOG-188 EPA MW-57A (kHW)

• (Ac;J:ive} COG-06-

1!1

COA·01 1!1 (Active)

COA-19 I!J (ActSve}

.... ..... ~

COA-15 I!J (Active)

EMW-17

eCOAMW4

COG-0~ s<Tc~MWl

r 1!1

TankCOG-11

COG-11 I!J (Active}

'eNEW-04

Explanation

EPA MW-61A e Proposed remaining Subunit A monitor well

EPA MW·57A 8 Subunit A monitor well

EA·07 cf Subunit A extraction well

PZ-14 0 Piezometer

IA·15 d Injection well (treated water)

IRZ IW·Ol d Injection well (IRZ)

• NE-04

EMW-29A8 Subunit A monitor well- PGA South site

coA MWl • Subunit A monitor well Weetem Ave. Plume site

• COAMWS

COG-18A 1!1 City of Goodyear well

PSowlil Park Shadows production well

IR-34B Iii Palm Valley irrigation well

33A EB UPI treatment system well

LPSC0-34C l!l litchfield Park Services Co. production well

coA-D2 m City of Avondale supply wen

AEIW S Avondale Elementary irrigation well

TW-1 m Algonquin water services well

liJ COA-05

Maricopa County _j

lF i

PROPOSED REMAINING MONITOR WELLS FOR GROUNDWATER INVESTIGATION

SUBUNIT A Phoenix Goodyear Airport North Superfund Site

Goodyear, Arizona


Yuma Road

I McDDWIII Rd.

J

-vanBurMSL

1!1 Tank: COG-11

COG-11 1!1 (Active)

SB-9LC e

Explanation

GMW-16UC e

GMW-lSUC e

'fEPA MW·lSC :7

I

.GMW-17UC COG-oslil (Inactive)

IL eGMW-14uc a.

GMW-13UC e j!

EPA MW-26C e Proposed remaining Subunit C monitor well

COG-lBA Iii City of Goodyear well

EPA MW-49C • Subunit C monitor well

EPA MW-28M e MAU monitor well

EB-o1d' Subunit B extraction well

EC-01d' Subunit C extraction well

ow-so Observation well

coG-MW3 • Subunit C monitoring well -PGA Soulh site

PSow Iii Park Shadows production well

IR-34B Iii Palm Valley irrigation well

33A m UPI treatment system well

L..PSC0-34C Iii Litchfield Park Services Co. production well

coA-o2 Iii City of Avondale supply well

AEIW $ Avondale Elementary irrigation wall

TW-1 Iii Algonquin water services well

8~ • ~~m EPA MW -40C ~ I'"

COG-lBA (Ad:M!} 1!1

Iii OOA.-05

COA-15 1!1 (Active}

PROPOSED REMAINING MONITOR WELLS FOR GROUNDWATER INVESTIGATION

SUBUNITC Phoenix Goodyear Airport North Superfund Site

Goodyear, Arizona

DatB: 4/5/11 Pro" ct No. 014682

AM EC Geomatrix Figure 3

Top of Screen

40'

Bottom of Screen

~~~§1--- 9-1 o• Diameter Drilled Hole

~~~§1-- Bentonite Grout: ~ 20'-115'

.l~~~r- 4" Diameter schedule 40 PVC Blank Casing

=-==~~~~...,._- 4• Diameter 0.020• Slotted Schedule 40 PVC Well Screen

Proposed Well Construction

Notes: --1. Depths In feet below ground surface (bga).

2. Final well construction details to be determined based on data collected during drilling.

DRAWING NOT TO SCALE

PROPOSED SUBUNIT A WELL CONSTRUCTION DIAGRAM


By: jrw Date: 1/15110 Pro ct No. 14682.003


Notes:

Estimated Water Table

12.25• Diameter Drilled Hole

Bentonite Grout: 20'-215'

- 110' ~~~~>2S<i .lilit-4~ Diameter schedule eo

50'

PVC Blank Casing

~RS(,.. ....... --10" Diameter Drilled Hole

~o;+----Bentonlte Seal: 215'-225'

~~~------Transition Sand: 225'-230'

~,;t------1 0-20 Filter Pack Sand: 230'-290'

::JE-3.:"'=*~---4~ Diameter 0.020" Slotted Schedule 80 PVC Well Screen

Bottom of Screen 285'----t~.,.~ 29~--~~~~~Tr.~

~~--~~~~~~~~

Proposed Well Construction DRAWING NOT TO SCALE

PROPOSED SUBUNIT C WELL CONSTRUCTION DIAGRAM

1. Depths in feat below ground surface (bgs).


2. Final well construction details to be determined based on data collected durtng drtlllng.

By: jrw Date: 1/15110

AMEC Geomatrix Pro'ect No. 14682.003

Figu.. 5

final remaining wells groundwater investigation …

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