REMEDIATION SYSTEM EVALUATION
DELPHI CORPORATION
VANDALIA, OHIO
Report of the Remediation System Evaluation,
Site Visit Conducted at the Delphi Corporation, Vandalia, Ohio Facility
March 6, 2003
,
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Office of Solid Waste EPA 542-F-04-023
and Emergency Response June 2003
(5102G) www.epa.gov/tio
clu-in.org/optimization
Remediation System Evaluation
Delphi Corporation
Vandalia, Ohio
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NOTICE AND DISCLAIMER
Work described herein was performed by GeoTrans, Inc. (GeoTrans) for the U.S. Environmental
Protection Agency (U.S. EPA). Work conducted by GeoTrans, including preparation of this report, was
performed under S&K Technologies Prime Contract No. GS06T02BND0723. Mention of trade names or
commercial products does not constitute endorsement or recommendation for use
This report has undergone review by the EPA site managers and EPA headquarters staff. For more
infomation about this project, contact: Mike Fitzpatrick (703-308-8411 or fitzpatrick.mike@epa.gov) or
Kathy Yager (617-918-8362 or yager.kathleen@epa.gov).
Delphi RSE Report, June 10, 2003
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EXECUTIVE SUMMARY
A Remediation System Evaluation (RSE) involves a team of expert hydrogeologists and engineers,
independent of the site, conducting a third-party evaluation of site operations. It is a broad evaluation that
considers the goals of the remedy, site conceptual model, above-ground and subsurface performance, and
site exit strategy. The evaluation includes reviewing site documents, visiting the site for up to 1.5 days, and
compiling a report that includes recommendations to improve the system. Recommendations with cost and
cost savings estimates are provided in the following four categories:
improvements in remedy effectiveness
reductions in operation and maintenance costs
technical improvements
gaining site closeout
The recommendations are intended to help the site team (the responsible party and the regulators) identify
opportunities for improvements. In many cases, further analysis of a recommendation, beyond that
provided in this report, may be needed prior to implementation of the recommendation. Note that the
recommendations are based on an independent evaluation by the RSE team, and represent the opinions of
the RSE team. These recommendations do not constitute requirements for future action, but rather are
provided for the consideration of all site stakeholders.
This RSE pertains to aspects of the corrective action underway at two neighboring plants, the Delphi
Energy and Chassis Systems Plant and Delphi Safety and Interior Systems Plant, collectively referred to as
the "facility" in this report. The facility occupies approximately 136 acres on two tracts of land, with
industrial activities occurring on the 82-acre southern tract. The 54-acre northern tract is partially
developed for railways but is otherwise undeveloped. The facility is located adjacent to the Dayton
International Airport in a mixed industrial, residential, commercial, and agricultural area.
Dense non-aqueous phase liquids (DNAPL) and volatile organic compound (VOC) contamination of soil
and ground water have resulted in three primary interim measures:
ground water migration control with a pump and treat system
DNAPL recovery
survey of ground water use in the area and connections to public water supplies
The RCRA Facility Investigation is currently underway. Completion is expected by the end of 2003, and
final measures will be taken accordingly.
The RSE team observed an extremely well-managed remedy. Based on the RSE document review and site
visit, the RSE team concludes that Delphi, their contractors, and EPA all have an excellent understanding
of the complex site conditions, interim measures, ongoing investigation, and potential risks. Continuing
efforts have been made by the site team as a whole to improve interim measures and conduct a
comprehensive investigation. The observations and recommendations contained in this report are not
intended to imply a deficiency in the work of either the system designers or operators but are offered as
constructive suggestions in the best interest of the EPA, the public, and the facility.
Delphi RSE Report, June 10, 2003
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Recommendations are provided with respect to effectiveness, cost reduction, and technical improvement.
The recommendations to improve effectiveness include the following:
More fully evaluate the potential for public contact with water at the seeps, and based on those
results consider posting signs near impacted ground water seeps to inform the public that the water
is not suitable for drinking
Consider providing and maintaining a point-of-entry treatment system for a nearby residence with
an impacted supply well
Proceed with the planned corrective measures to address the seeping of impacted ground water in
the overburden at the facility
Proceed with lowering the pump in the extraction well to increase the extraction rate
Avoid altering the site hydrogeology - do not seal old borings that may connect the Top of Rock
and Sugar Rock aquifers
One recommendation is made to reduce cost, which is to modify the monitoring program and consider
reducing the number of sampled wells and the sampling frequency. Estimated annual cost savings of
$67,000 per year might result from implementing example reductions suggested by the RSE team. One
recommendation is made for technical improvement, which is to consider replacing the corroding pipe in the
treatment plant with PVC when replacement is necessary.
No specific recommendations are provided for gaining site closeout; however, the RSE team provides
considerations for cost-effectively addressing this long-term remedy while maintaining protectiveness.
A table summarizing the recommendations, including estimated costs and/or savings associated with those
recommendations, is presented in Section 7.0 of this report.
Delphi RSE Report, June 10, 2003
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PREFACE
This report was prepared as part of a pilot project conducted by the United States Environmental
Protection Agency (USEPA) Office of Solid Waste (OSW) and Technology Innovation Office (TIO). The
objective of this project is to conduct Remediation System Evaluations (RSEs) of pump and treat systems
under the Resource Conservation and Recovery Act. The following organizations are implementing this
project.
Organization
Key Contact
Contact Information
USEPA Office of Solid Waste
(OSW)
Mike Fitzpatrick
5303W
USEPA Headquarters
Ariel Rios Building 1200 Pennsylvania
Avenue, N. W. Washington, DC 20460
phone: 703-308-8411
fitzpatrick.mike@epa.gov
USEPA Technology Innovation
Office
(USEPA TIO)
Kathy Yager
11 Technology Drive (ECA/OEME)
North Chelmsford, MA 01863
phone: 617-918-8362
fax: 617-918-8427
yager.kathleen@epa.gov
GeoTrans, Inc.
(Contractor to USEPA)
Doug Sutton
GeoTrans, Inc.
2 Paragon Way
Freehold, NJ 07728
(732) 409-0344
Fax: (732) 409-3020
dsutton@geotransinc.com
Delphi RSE Report, June 10, 2003
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TABLE OF CONTENTS
EXECUTIVE SUMMARY i
PREFACE iii
TABLE OF CONTENTS iv
1.0 INTRODUCTION 1
1.1 PURPOSE 1
1.2 TEAM COMPOSITION 1
1.3 DOCUMENTS REVIEWED 2
1.4 PERSONS CONTACTED 3
1.5 SITE LOCATION, HISTORY, AND CHARACTERISTICS 3
1.5.1 LOCATION 3
1.5.2 POTENTIAL SOURCES 5
1.5.3 HYDROGEOLOGIC SETTING 5
1.5.4 POTENTIAL RECEPTORS 6
1.5.5 DESCRIPTION OF GROUND WATER PLUME 6
2.0 SYSTEM DESCRIPTION 8
2.1 DNAPL RECOVERY SYSTEM 8
2.2 GROUND WATER MIGRATION CONTROL SYSTEM 8
2.3 MONITORING PROGRAM 9
3.0 SYSTEM OBJECTIVES, PERFORMANCE AND CLOSURE CRITERIA 10
3.1 CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA 10
3.2 TREATMENT PLANT OPERATION STANDARDS 10
4.0 FINDINGS AND OBSERVATIONS FROM THE RSE SITE VISIT 12
4.1 FINDINGS 12
4.2 SUBSURFACE PERFORMANCE AND RESPONSE 12
4.2.1 WATER LEVELS 12
4.2.2 CAPTURE ZONES 13
4.2.3 CONTAMINANT LEVELS 13
4.3 COMPONENT PERFORMANCE 14
4.3.1 DNAPL RECOVERY SYSTEM 14
4.3.2 GROUND WATER MIGRATION CONTROL SYSTEM 14
4.4 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF ANNUAL COSTS 15
4.4.1 UTILITIES 16
4.4.2 NON-UTILITY CONSUMABLES AND DISPOSAL COSTS 16
4.4.3 LABOR 16
4.4.4 CHEMICAL ANALYSIS 16
4.5 RECURRING PROBLEMS OR ISSUES 17
4.6 REGULATORY COMPLIANCE 17
4.7 SAFETY RECORD 17
5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN HEALTH AND THE ENVIRONMENT
18
5.1 GROUND WATER 18
5.2 SURFACE WATER 18
5.3 AIR 18
Delphi RSE Report, June 10, 2003 iv
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5.4 SOILS 19
5.5 WETLANDS AND SEDIMENTS 19
6.0 RECOMMENDATIONS 20
6.1 RECOMMENDATIONS TO IMPROVE EFFECTIVENESS 20
6.1.1 EVALUATE POTENTIAL PUBLIC CONTACT WITH SEEPS AND CONSIDER POSTING SIGNS AT SEEPS
DISCHARGING IMPACTED WATER 20
6.1.2 CONSIDER PROVIDING A POINT-OF-ENTRY TREATMENT SYSTEM FO 10591 ENGLE ROAD .... 20
6.1.3 PROCEED WITH PLANNED CONNECTION OF OVERBURDEN GROUND WATER EXTRACTION TO THE
EXISTING TREATMENT SYSTEM 20
6.1.4 PROCEED WITH PLANNED LOWERING OF THE EXTRACTION PUMP IN P-301 21
6.1.5 AVOID ALTERING SITE HYDROGEOLOGY - Do NOT SEAL BORINGS FROM OLD PRODUCTION
WELLS 21
6.2 RECOMMENDATIONS TO REDUCE COSTS 21
6.2.1 CONSIDER MODIFICATIONS TO GROUND WATER MONITORING PROGRAM 21
6.3 MODIFICATIONS INTENDED FOR TECHNICAL IMPROVEMENT 24
6.3.1 CONSIDER REPLACEMENT OF TREATMENT SYSTEMPIPE 24
6.4 CONSIDERATIONS FOR GAINING SITE CLOSE OUT 24
6.5 SUGGESTED APPROACH TO IMPLEMENTATION 25
7.0 SUMMARY 26
List of Tables
Table 7-1. Cost summary table
List of Figures
Figure 1-1. The Delphi Facility and the Surrounding Area
Figure 1-2. Extent of DNAPL and Locations of DNAPL Recovery Wells in First Sand Unit of Overburden
Figure 1-3. TCE Distribution in the Top of Rock
Figure 1-4. TCE Distribution in the Sugar Rock, First Quarter 2003
Figure 4-1. Potentiometric surface map for the Top of Rock, July 2002
Figure 4-2. Potentiometric surface map for the Sugar Rock, July 2002
Figure 4-3. Potentiometric surface map for the Sugar Rock, February 2003
Delphi RSE Report, June 10, 2003
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1.0 INTRODUCTION
1.1 PURPOSE
During fiscal years 2000, 2001, and 2002 Remediation System Evaluations (RSEs) were conducted at 24
Fund-lead pump and treat (P&T) sites (i.e., those sites with pump and treat systems funded and managed
by Superfund and the States). Due to the opportunities for system optimization that arose from those
RSEs, EPA TIO and OSW are performing a pilot study of conducting RSEs at RCRA sites. During fiscal
year 2003, RSEs at up to 5 RCRA sites are planned in an effort to evaluate the effectiveness of this
optimization tool for this class of sites. GeoTrans, Inc., an EPA contractor, is conducting these
evaluations, and representatives from EPA OSW and TIO are attending the RSEs as observers.
The Remediation System Evaluation (RSE) process was developed by the US Army Corps of Engineers
(USAGE) and is documented on the following website:
http://www.cnvironmcntal.usacc.arMv .mMibrary/guidc/rscchk/rscchk.httnl
A RSE involves a team of expert hydrogeologists and engineers, independent of the site, conducting a third-
party evaluation of site operations. It is a broad evaluation that considers the goals of the remedy, site
conceptual model, above-ground and subsurface performance, and site exit strategy. The evaluation
includes reviewing site documents, visiting the site for 1 to 1.5 days, and compiling a report that includes
recommendations to improve the system. Recommendations with cost and cost savings estimates are
provided in the following four categories:
improvements in remedy effectiveness
reductions in operation and maintenance costs
technical improvements
gaining site closeout
The recommendations are intended to help the site team (the responsible party and the regulators) identify
opportunities for improvements. In many cases, further analysis of a recommendation, beyond that
provided in this report, might be needed prior to implementation of the recommendation. Note that the
recommendations are based on an independent evaluation by the RSE team, and represent the opinions of
the RSE team. These recommendations do not constitute requirements for future action, but rather are
provided for the consideration of all site stakeholders.
The Delphi facility was selected by EPA OSW based on progress made toward Environmental Indicators
and comments from the EPA project manager for the site. This report provides a brief background on the
site and current operations, a summary of the observations made during a site visit, and recommendations
for changes and additional studies. The cost impacts of the recommendations are also discussed.
1.2 TEAM COMPOSITION
The team conducting the RSE consisted of the following individuals:
Delphi RSE Report, June 10, 2003 1
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Rob Greenwald, Hydrogeologist, GeoTrans, Inc.
Erik Petrovskis, Engineer, GeoTrans, Inc.
Peter Rich, Civil and Environmental Engineer, GeoTrans, Inc.
Doug Sutton, Water Resources Engineer, GeoTrans, Inc.
The RSE team was also accompanied by the following observers:
Kathy Yager from EPA TIO
Mike Fitzpatrick from EPA OSW
EPA-TIO and EPA-OSW are jointly conducting this RSE Pilot Study for RCRA sites.
1.3
DOCUMENTS REVIEWED
Author
Delphi
Haley and Aldrich
Ohio EPA
US EPA
NOVA Consultants, Inc.
NOVA Consultants, Inc.
US EPA
US EPA
Haley and Aldrich
Haley and Aldrich
US EPA
Haley and Aldrich
Haley and Aldrich
Haley and Aldrich
Date
3/1999
5/1999
10/1999
12/1999
3/2000
4/2000
1/2002
2/2002
4/2002
4/2002
5/2002
7/2002
10/2002
1/2003
Title
Modification of NPDES Permit
Description of Current Conditions
Modification of NPDES Permit
Documentation of Environmental Indicator
Determination
Equipment Specifications, Vacuum Enhanced
Groundwater/DNAPL Recovery and Treatment
System
Air Emission Calculation, Vacuum Enhanced
Groundwater/DNAPL Recovery and Treatment
System
Administrative Order on Consent
EPA Comments on the Description of Current
Conditions Report
Interim Measures and Implementation Report
Progress Report, 1st Quarter 2002
EPA Comments on the Interim Measures and
Implementation Report
Progress Report, 2nd Quarter 2002
Progress Report, 3rd Quarter 2002
Progress Report, 4th Quarter 2002
Delphi RSE Report, June 10, 2003
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1.4 PERSONS CONTACTED
The following individuals associated with the site were present for the visit:
Kenneth Bardo, Project Manager, EPA Region 5
Tom Byrne, Operator, Delphi Corporation
John Ridd, Project Manager, Delphi Corporation
Steve Weflen, Manager, Environmental Services, Delphi Corporation
Dave Bean, Operator, Haley & Aldrich
David Hagen, Vice President, Haley & Aldrich
Dennis Kreitzburg, Staff Environmental Geologist, Haley & Aldrich
James Little, Vice President, Haley & Aldrich
1.5 SITE LOCATION, HISTORY, AND CHARACTERISTICS
1.5.1 LOCATION
This RSE pertains to aspects of the corrective action underway at two neighboring plants, the Delphi
Energy and Chassis Systems Plant and Delphi Safety and Interior Systems Plant, collectively referred to as
the "facility" in this report. The Energy and Chassis Systems plant is located at 480 North Dixie Highway,
and the Safety and Interior Systems Plant is located at 250 Northwoods Boulevard in Vandalia, Ohio. The
facility occupies approximately 136 acres on two tracts of land, with industrial activities occurring on the
82-acre southern tract. The 54-acre northern tract is partially developed for railways but is otherwise
undeveloped. The facility is located in a mixed industrial, residential, commercial, and agricultural area.
The Dayton International airport is located to the west, on the other side of North Dixie Highway. The
airport and light industrial facilities occupy land to northwest of the facility. Fields, wooded land, railways,
and residential/commercial properties and railways are located to north and northeast. Interstate 75 is east
of the facility. Fields, wooded, commercial, and agricultural lands are east of Interstate 75. Further east is
Cassel Road with residences, and beyond Cassel Road is the Great Miami River. Land to the southeast
and south of the facility is primarily residential. Figure 1-1 depicts the facility and the surrounding area.
Dense non-aqueous phase liquids (DNAPL) and volatile organic compound (VOC) contamination of soil
and ground water have resulted in three primary interim measures:
ground water migration control with a pump and treat system
DNAPL recovery
survey of ground water use in the area and connections to public water supplies
The RCRA Facility Investigation is currently underway. Completion is expected by the end of 2003, and
final measures will be taken accordingly. A brief outline of the site history and future corrective action
milestones are summarized below:
1941 - Facility was first industrially developed by the Aeroproducts Division of General
Motors.
1941-1958 - Facility manufactured and tested airplane and helicopter blades and parts.
Delphi RSE Report, June 10, 2003 3
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1958-1961
1960s-1970s
1960s-present
1980s
1991-1993
1992
1995-1996
1997-1998
5/1999
4/2000
11/2000
2/2001
7-8/2001
1/2002
4/2002
6/2002
10/2002
Facility was idle while manufacturing operations were restored.
Facility expanded operations.
Manufactured items include brake hoses, brake hose couplings, asbestos brake
linings, foam set pads, coated vinyl sheeting, ball joints, steering wheels, steering
wheel covers, air bags, instrument panels, and rubber bumpers.
Multiple spills, facility-wide closures of underground storage tanks (UST), and
other activities occurred and are discussed. They are discussed in the Description
of Current Conditions Report (May 1999).
Multiple monitoring wells and soil borings were installed to delineate
contamination in soils and ground water found during UST closures in Tank Areas
A through F and particularly in the area surrounding Tank Area C.
Source of TCE identified at the NPDES outfall was investigated. In addition, a
regional ground water investigation was undertaken by the Ohio EPA and CSX
including the installation of bedrock monitoring wells. The installation of bedrock
monitoring wells, including those installed offsite, has continued through 2002.
DNAPL was identified. An investigation was conducted to characterize and
delineate the contamination, and a pilot program was initiated to test the feasibility
of vacuum-enhanced DNAPL recovery.
Phase I and Phase II Environmental Site Assessments were conducted on the
northern and southern tract in accordance with the Ohio Voluntary Action
Program.
Delphi submitted a Description of Current Conditions Report.
Ground water migration control system began operation.
DNAPL recovery system began operation. The system operated for 11 days in
2000 and 32 days in 2001.
Delphi installed a new storm sewer to replace major sections of the existing system
to prevent impacted ground water from infiltrating in to the storm sewers and
discharging to surface water. The new sewer was constructed with impermeable
HOPE and installed in a HDPE-lined trench that was backfilled with impermeable
material. Other work included slip-lining another sewer with HOPE, replacing a
manhole, and rerouting roof collectors. The abandoned sewers were blocked and
sealed at both ends.
A door-to-door survey water use survey was conducted. Approximately 800
locations were visited. Where active wells were identified, requests were made to
sample the water. With permission, connections to public water are being
provided and wells are being abandoned.
An Administrative Consent Order was signed by Delphi and EPA.
Delphi submitted an Interim Measures and Implementation Report.
Delphi submitted a RCRA Facility Investigation (RFI) Work Plan.
The DNAPL recovery system operation for 2002 was limited to October and 12
gallons of DNAPL was recovered. Operation is planned for the summer of 2003.
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12/2003 - The end of 2003 is the established deadline for the Environmental Indicator (El)
Report for Current Human Exposures Under Control and implementation of onsite
work plan.
6/2004 - This is the projected completion date for the offsite ground water investigation.
12/2004 - The end of 2004 is the established deadline for the Environmental Indicator (El)
Report for Ground Water Stabilization.
8/2005 - This is the projected completion date for the final investigation report.
12/2005 - This is the established deadline for the Final Corrective Measure Proposal to be
submitted.
1.5.2 POTENTIAL SOURCES
In February 1995, DNAPL was identified in Tank Area C. Although the release is no longer occurring (the
tanks were excavated in the early 1990s), the DNAPL provides a potential ongoing source of dissolved
ground water contamination. The extent of DNAPL in Tank Area C has been delineated and characterized.
The plume is depicted in Figure 1-2. It is approximately 64% trichloroethylene and 22% 1,1,1-
trichloroethane. The remaining constituents include carbon tetrachloride, methylene chloride, acetone,
tetrachloroethane, and xylenes. The DNAPL appears to be limited to the upper layers of the overburden,
but is a potential the source of dissolved contamination found in the underlying bedrock. An alternate
possibility for the deeper dissolved contamination that persists in the bedrock is that historical DNAPL
releases could have introduced DNAPL directly into the bedrock.
1.5.3 HYDROGEOLOGIC SETTING
The RFI Work Plan and other site documents state that the geologic strata in this area are typified by
interbedded layers of glacial till and glacial outwash sand and gravel that lack horizontal continuity and
overlie limestone and shale bedrock. Investigations at the facility have found that glacial deposits,
consisting of till with silty and sandy lenses, extend to approximately 40-60 feet below ground surface.
These glacial deposits overlie approximately 40 to 70 feet of dolomite from the Dayton Dolomite and
Brassfield formations, which overlies approximately 75 feet of the Elkhorn Shale. The lowest few feet of
the Brassfield is very porous and is commonly referred to as the "Sugar Rock".
At the facility, ground water is typically found within 3 to 8 feet of the ground surface, but on occasion has
discharged to the surface through seeps. Such discharges are generally due to mounding of ground water
caused by preferential flow through storm sewers. Horizontal ground water flow in the overburden is
typically to the northeast and primarily flows through the sand and silt lenses. The hydraulic conductivity
within the overburden ranges from 6.9 x 10"7 to 3.5 x 10"3 cm/sec. Three hydrostratigraphic units have
been identified in the overburden: the Shallow, First, and Second Sands. The First Sand, where the
DNAPL has been found, is approximately 10 to 15 feet below ground surface (bgs) and is approximately 1
to 3 feet thick where present. DNAPL has not been identified in the Second Sand unit, which is
approximately 20 to 30 feet bgs.
The Top of Rock zone is fractured and weathered, and the ground water in this unit is confined by the
overburden and the underlying bedrock. The hydraulic conductivity of this unit ranges from 6.2 x 10"5 to
1.6 x 10"3 cm/sec.
Delphi RSE Report, June 10, 2003
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The Sugar Rock, which is separated from the Top of Rock by the less conductive dolomite of the upper
Brassfield, forms a third hydrostratigraphic unit with a hydraulic conductivity ranging from 10~4 to 10~2
cm/sec. The piezometric surface in this unit is generally 25 to 40 feet lower than the water level in the Top
of Rock unit, providing a substantial driving force for downward flow from the Top of Rock to the Sugar
Rock through either natural or artificial passage ways. Previous efforts had been made to drill production
wells for manufacturing purposes and resulting borings may provide a conduit for such flow. Horizontal
flow in the Sugar Rock is to the east toward the Great Miami River. The Sugar Rock is exposed at the
surface along the river valley where ground water discharges in multiple seeps. Intermittent pumping at an
average rate of 80 gpm from another industrial facility to the southeast of the Delphi facility influences
ground water flow and appears to cause a component of flow to the south/southeast. That facility has
historically been called Leland Electric Systems, but the name was recently changed to Smith Aerospace.
1.5.4 POTENTIAL RECEPTORS
Potential receptors include private supply wells at residences, an Unnamed Tributary to North Creek,
surface water at seep locations, the Great Miami River, and potential areas for vapor intrusion.
The private supply wells within one mile of the site are being addressed in an interim
measure water use survey. Wells with detectable concentrations of TCE are located on
Engle Road to the north (one well that has always been below the MCL) and Cassel Road
to the east. The well on Engle Road has an open intake that extends from the Top of Rock
to the Sugar Rock, and the wells along Cassel Road are screened in the Sugar Rock.
TCE impacted ground water has discharged to the Unnamed Tributary to the north of the
facility by seeping into storm sewers that discharge to this unnamed tributary or by
mounding of ground water that resulted in surface seeps that drain into the creek.
Replacement of the storm sewer and other work reduced the discharge, but additional
efforts have been required, including the use of a sump pump to assist with dewatering of
the abandoned storm sewers. Additional efforts will likely include removing drain tiles that
allow infiltration, converting an unused storm sewer into a collection trench, and extracting
and treating the collected water.
Ground water from the Sugar Rock aquifer discharges to seeps along Great Miami River
valley. The discharged water travels a few hundred feet before reaching the river. TCE
concentrations of over 300 ug/L have been detected in some of the seeps.
The east tunnel inside the Delphi facility has been identified as a potential area for vapor
intrusion due to its proximity to Tank Area C. Other areas with potential for vapor
intrusion may be identified during the remainder of the RFI.
1.5.5 DESCRIPTION OF GROUND WATER PLUME
Dissolved ground water contamination consists primarily of TCE and cis-l,2-dichloroethylene (cis-1,2-
DCE). Contamination in the overburden is heavily influenced by the presence of DNAPL in the First Sand
unit. Although TCE concentrations greater than 500 ug/L are present in the overburden in other areas of
the facility, the majority of the dissolved TCE contamination is in the vicinity of the DNAPL plume.
Additional investigation within this unit is ongoing and was not available for review at the time of the RSE.
Delphi RSE Report, June 10, 2003
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Dissolved ground water contamination in the Top of Rock zone (see Figure 1-3) appears to be controlled
by a piezometric low near MW-424S (see Section 4.2.1 and 4.2.2 of this report) where water in the Top of
Rock appears to discharge to the underlying Sugar Rock. Wells upgradient of this area historically have
elevated TCE concentrations. For example, in the fourth quarter of 2002, MW-422S had a TCE
concentration of 200,000 ug/L. Wells downgradient of this area (MW-423S, MW-445S, MW-446S, and
others) have undetectable TCE concentrations. Although this piezometric low appears to capture site-
related contamination within the Top of Rock aquifer, one supply well at a property located on Engle Road,
located just north of the facility, has detectable concentrations of TCE that are below the MCLs. However,
that well on Engle Road has an open intake that extends from the Top of Rock to the Sugar Rock, so the
contamination at that well is likely drawn from the Sugar Rock.
Ground water contamination in the Sugar Rock extends over a mile from the site to the east. The highest
concentration in this unit is repeatedly detected at MW-424D (see Figure 1-4 for location), which is located
in the area where TCE impacted water from the Top of Rock zone is suspected to enter the Sugar Rock
through an old production well boring. During the fourth quarter of 2002, MW-424D had a TCE
concentration of 30,000 ug/L. Elevated concentrations of cis-l,2-DCE and 1,1 DCA were also detected
(5,000 ug/L cis-l,2-DCE and 290 ug/L 1,1 DCA). Concentrations offsite to the east decrease near P-301,
which is the extraction well for the ground water migration control system, and then increase again
approximately 3,000 feet from the facility. In the first quarter of 2003, the TCE concentrations along
Cassel Road were over 1,000 ug/L (1,200 ug/L in MW-41 ID and 1,400 ug/L in MW-412D). Beyond
these points ground water discharge through seeps to surface water that eventually empties into the Great
Miami River.
TCE contamination in the Sugar Rock is also present to the southeast of the facility but at significantly
lower concentrations than those found elsewhere in the vicinity. For example, south of MW-433D, the
TCE concentrations were below 50 ug/L during the first quarter of 2003, with the exception of MW-453D,
which had a concentration of 52 ug/L. This area would likely be side-gradient to the facility under regional
ground water flow, but pumping from the Leland/Smith facility may establish a component of ground water
flow in this direction.
Delphi RSE Report, June 10, 2003
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2.0 SYSTEM DESCRIPTION
Two active remediation systems are currently in place at the facility: the DNAPL recovery system and the
ground water migration control system. These systems are described separately.
2.1 DNAPL RECOVERY SYSTEM
Thirteen 6-inch diameter stainless steel recovery wells are installed into the First Sand unit for DNAPL
recovery (see Figure 1-2 for locations). A mobile extraction and treatment system operates seasonally from
April to October and is typically employed at a well for 3 to 5 days then moved to one of the other 13
recovery wells. The DNAPL recovery system includes a QED Hammerhead pneumatic submersible pump,
a Busch vacuum pump to vacuum enhance recovery, a phase separator, bag filter and 2 polymeric resin
vessels in series. After treatment coproduced water is stored prior to discharge to the POTW. The system
operates 40 hours per week with full time operator attention to visually inspect the system influent and
make adjustments to the vacuum level and pumping rate.
2.2 GROUND WATER MIGRATION CONTROL SYSTEM
This system consists of a single recovery well (P-301) screened in the Sugar Rock with a variable speed
drive 1.5 HP electric submersible pump. Due to discharge permit requirements, the pumping rate is limited
to a 50 gpm maximum, but the pump runs continuously at approximately 45 gpm to maintain a set level in
the well. Water is routed from the well head to the treatment building through 2-inch diameter HOPE pipe
(which replaced originally installed carbon steel pipe) contained in 4-inch diameter PVC.
The treatment building is a 24-foot by 24-foot Parkline pre-engineered building with a curbed concrete
floor and containment sump. Water enters the plant, and the sequestering agent Drewsperse is injected
prior to the 2,000 gallon HOPE feed tank. From the feed tank, water is pumped by a 1.5 HP pump on a
batch basis to a CarbonAir 4 tray model Stat 180 air stripper (200 gpm capacity). The air stripper has a
7.5HP blower, and during the winter a 15 kW heater warms the air that enters the building due to the
suction of the blower. The air stripper effluent is pumped by a 1.5 HP pump through a 4-inch diameter
HOPE discharge line to the NPDES discharge point at a catch basin east of the facility that connects to the
East Channel. A Rosedale Products duplex bag filter and two liquid GAC units, each with a capacity of
900 pounds, were previously used for effluent polishing but are currently bypassed because the air stripper
effectively treats the water to discharge standards.
The current system influent has 2.2 to 4.3 mg/1 total VOCs with about 70% TCE (3rd Quarter 2002). This
concentration and flow rate results in a total VOC mass removal of up to 2.3 Ibs/day as shown below,
which is well below the reported 10 Ib/day de minimus limit for direct discharge from the air stripper and
tank vent to the atmosphere. The system has appropriate failsafes and alarm communication functions and
is checked on a weekly basis.
45 gal. 3.785 L 4,300 ug 1440 min. 2.2 Ibs. 2.32 Ibs.
x x x x =
mm. gal. L day Ix 10 ug day
Delphi RSE Report, June 10, 2003 8
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2.3 MONITORING PROGRAM
The ground water monitoring program utilizes a total of 67 bedrock monitoring wells. Regular monitoring
is not conducted in the overburden, though storm sewers have been sampled to determine the cause of seeps
and impacts to the Unnamed Tributary. Additional investigation in the overburden is underway as part of
the RFI, but this information was not available at the time of the RSE.
Of the 67 wells, 23 are screened in the Top of Rock, 41 are screened in the Sugar Rock, and 3 other wells
are screened intermediate to these two units. Ground water elevations are measured in each Sugar Rock
well on a monthly basis and in each Top of Rock well on a quarterly basis. Potentiometric surfaces for
each unit are developed for each round of measurements to assist in interpreting plume control. Water
quality sampling and analysis for VOCs is conducted at approximately 47 wells (assuming access is
available) on a quarterly basis and the remaining 20 wells on an annual basis. Sampling and analysis for
VOCs is conducted at 7 surface water locations on a quarterly basis. Samples are collected and analyzed
and flow rates are measured at 11 seeps annually. This sampling totals approximately 247 samples per
year, and each sample is analyzed using EPA Method 8260b.
For process monitoring, the influent concentration from the recovery well and the effluent concentration are
sampled monthly and analyzed for VOCs with EPA Method 624. For the DNAPL recovery system,
chemical analysis is performed on treated effluent that is stored in holding tanks before that effluent is
discharged to the POTW.
Collected data are presented in quarterly progress reports. The reports include work performed during the
quarter, data collected, problems encountered, and an update on the project schedule. Although tables and
figures are made to present the data, interpretations of the data are not provided in the progress reports.
Delphi RSE Report, June 10, 2003
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3.0 SYSTEM OBJECTIVES, PERFORMANCE AND CLOSURE
CRITERIA
3.1 CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA
Currently, the site is in the investigation phase; however, due to ground water contamination and the
presence of DNAPL, interim measures have been implemented. The goals for the interim measures, as
described in the Interim Measures and Implementation Report, are as follows:
Ground water migration control system - control the migration of site contaminants at the
eastern (downgradient) property boundary in the Sugar Rock aquifer. Control of plume migration
in the Top of Rock is not a goal of this system.
DNAPL recovery system - remove, to the extent practical, free DNAPL from the area identified
as containing this material, using a vacuum enhanced system designed specifically for such
purpose. It is not the intent of the system to remediate contaminated media in the form ground
water, soil, or soil vapor. Operation of the system will be discontinued when measurable free
product can no longer be recovered from each of the existing recovery wells.
Water Use Survey - sample private wells within the study area and replace water systems along
Cassel Road.
The overall remedial objective for the facility is to achieve an EPA-approved determination of Completion
of Corrective Action Activities and terminate interim status as a RCRA storage facility. The path to
completion involves the typical phases of investigation and remediation under the RCRA Corrective Action
Program, which include, investigating the site, assessing risk, developing media protection standards and
objectives, performing a Corrective Measures Study, implementing the selected Corrective Measure, and
final site closure/completion. In addition to the overall objective, the facility also has the short-term
objective of achieving site stabilization through the demonstration of achievement of Environmental
Indicators CA725 - Current Human Exposures Under Control and CA750 - Migration of Contaminated
Groundwater Under Control. A report detailing the achievement of CA725 is due by the end of 2003, and
a report detailing the achievement of CA750 is due by the end of 2004.
A proposal for a final Corrective Measure is due by the end of 2005 and will depend on the results of the
ongoing RFI. This RSE report focuses primarily on the interim measures, but some of the
recommendations in Section 6.0 of this report may pertain to the final remedy, if the final remedy resembles
the currently implemented interim measures.
3.2 TREATMENT PLANT OPERATION STANDARDS
The groundwater migration control system discharges to surface water in accordance with a NPDES
permit. The permitted discharge requirements are summarized in the following table. The maximum
permitted flow is 50 gpm, and the permitted mass loading rates are calculated based on this maximum
permitted flow.
Delphi RSE Report, June 10, 2003 10
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NPDES Discharge Requirements
Parameter
1 , 1 -Dichloroethane
1 , 1 -Dichloroethy lene
1,1,1 -Trichloroethane
1 ,2-Dichloroethane
cis- 1 ,2-Dichloroethylene
trans- 1 , 1 -Dichloroethy lene
Vinyl Chloride
Trichloroethylene
30 Day Average
Concentration
(mg/L)
0.005
0.005
0.005
0.005
0.005
0.005
0.005
0.005
Load
(kg/day)
0.0013
0.0013
0.0013
0.0013
0.0013
0.0013
0.0013
0.0013
Daily Maximum
Concentration
(mg/L)
0.010
0.010
0.010
0.010
0.010
0.010
0.010
0.010
Load
(kg/day)
0.0027
0.0027
0.0027
0.0027
0.0027
0.0027
0.0027
0.0027
The treated water from the DNAPL recovery system is discharged to the POTW. The Permit to Install
(PTI) indicates a maximum design flow rate is 5 gpm as well as effluent concentration limits of 2.13 mg/1
total toxic organics.
Delphi RSE Report, June 10, 2003
11
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4.0 FINDINGS AND OBSERVATIONS FROM THE RSE SITE VISIT
4.1 FINDINGS
The RSE team observed an extremely well-managed remedy. Based on the RSE document review and site
visit, the RSE team concludes that Delphi, their contractors, and EPA all have an excellent understanding
of the complex site conditions, interim measures, ongoing RFI, and potential risks. Continuing efforts have
been made by the site team as a whole to improve interim measures and conduct a comprehensive RFI.
The observations provided below are not intended to imply a deficiency in the work of the system designers,
system operators, or site managers but are offered as constructive suggestions in the best interest of the
EPA and the public. These observations obviously have the benefit of being formulated based upon
operational data unavailable to the original designers. Furthermore, it is likely that site conditions and
general knowledge of ground water remediation have changed overtime.
4.2 SUBSURFACE PERFORMANCE AND RESPONSE
4.2.1 WATER LEVELS
Water levels from the Top of Rock are collected quarterly and corresponding potentiometric maps are
generated. Figures 4-1 depicts atypical potentiometric surface map for the Top of Rock unit. The
regional water elevation ranges from approximately 980 feet above mean sea level (MSL) at the western
property boundary to approximately 960 feet MSL at the eastern property boundary. A localized low in
the water table is present at MW-424S where the water level is approximately 956 feet MSL. This low
likely represents an area where water from the Top of Rock discharges to the Sugar Rock.
Water levels in the Sugar Rock are collected monthly and corresponding potentiometric surface maps are
generated. The results are generally consistent from month to month with some variations due to local
pumping. Figures 4-2 and 4-3 depict typical potentiometric surface maps for the Sugar Rock. The
primary difference between the two maps is presumably the affect of variable pumping at the Leland/Smith
facility. The water elevation across the property typically ranges from 945 feet MSL at the western
boundary to approximately 915 feet MSL at the eastern boundary. No mounding is obvious near MW-
424D to correspond with the cone of depression near MW-424S in the Top of Rock. Influence from
pumping at P-301 at the northeastern corner of the property is evident in both figures. Although the
capture zone boundary is not completely outlined, there is sufficient resolution to draw streamlines and
outline the estimated horizontal capture zone. The hydraulic gradient to the east of the pumping is relatively
flat for approximately 2,000 to 3,000 feet but then steepens again as it turns to the north east. The
relatively flat gradient is perhaps in part due to the reduced amount of water flowing through that portion
of the aquifer due to pumping from P-301 and from the Leland/Smith well to the south, which pumps an
estimated 80 gpm on average. There is a relatively small component of flow from the facility to the
southeast in July 2002, but it appears that a more pronounced component is present in February 2003
(Figure 4-3) in which an inward gradient for the Leland/Smith well is apparent.
Delphi RSE Report, June 10, 2003 12
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4.2.2 CAPTURE ZONES
In the Top of Rock, there is no intended target capture zone and no implemented remedy because
contaminated water appears to be naturally contained by the discharge of water to the underlying Sugar
Rock. As shown in Figure 1-3, ground water sampling and analysis in the Top of Rock suggests that VOC
contamination above MCLs is limited to four wells in the north central portion of the property (MW-422S,
MW-424S, MW-425S, and MW-428S). The sampling results from other monitoring wells in the Top of
Rock and interpretation of capture from the potentiometric surface map suggest that the contamination in
these wells is contained horizontally. The only indications of potential TCE or cis-l,2-DCE contamination
in the Top of Rock that is likely outside of the capture zone are the sampling results from 10591 Engle
Road, which is approximately 500 feet to the northeast of the facility and near the Unnamed Tributary.
The concentrations at this location are below MCLs and all other wells in the area (both monitoring and
supply wells) have no detectable concentrations of these constituents. This well is constructed with an open
interval that extends from the Top of Rock to the Sugar Rock and it is likely that TCE in this well is related
to the Sugar Rock.
In the Sugar Rock, the target capture zone is the eastern property boundary. The potentiometric surface
maps suggest that capture is provided for ground water leaving the northern portion of the eastern property
boundary but that capture is not likely provided along the southern portion of the eastern property
boundary. Sugar Rock monitoring wells (MW-401D and MW-405D) in the southern portion of the
property, however, routinely have either no detectable VOC concentrations or concentrations only slightly
above detection limits. The concentration trends in downgradient wells MW-413D, MW-416D, MW-
418D, and MW-420D are analyzed in the progress reports to evaluate capture. Based on the trends and the
potentiometric surface maps, the RSE team believes that MW-413D, MW-416D, and MW-418D are
generally within the capture zone and that MW-420D is likely beyond the capture zone. One possible
interpretation of the concentration trends is that concentrations in MW-413D and MW-416D are remaining
relatively unchanged as impacted water travels past these points to the extraction well, and the
concentrations in MW-418D have decreased as pumping has entrained cleaner water from the southern
portion of the property. If this interpretation is correct, the MW-418D concentrations may stabilize either
above or below the MCLs over time. Concentrations at MW-420D would be expected to continue
declining until background concentrations are reached.
Contamination to the east of the capture zone will likely either naturally degrade or continue to migrate to
the east and northeast until it discharges through the seeps to surface water. Contamination to the south
(MW-432D, MW-441D, and MW-45 ID) might be captured by the Leland/Smith pumping. However, the
RSE team does not have enough information regarding other extraction points to determine this
conclusively.
4.2.3 CONTAMINANT LEVELS
Historical concentration data and trend plots for monitoring wells other than MW-301D, MW-413D, MW-
416D, MW-418D, and MW-420D are not reported in the progress report. A cursory review of monitoring
data from other downgradient monitoring wells suggests that concentrations have not yet shown a
discernible decrease due to the pumping. This is expected, however, because the hydraulic gradient
downgradient of P-301 is relatively flat and the ground water velocity is relatively slow. Using Darcy's
law and dividing by an effective porosity, the seepage velocity in this area is approximately 0.1 feet per day
assuming a hydraulic conductivity of 10"2 cm/sec, a hydraulic gradient of 0.001 (consistent with the
potentiometric surface maps), and an effective porosity of 0.2. At this velocity, ground water may take
decades to travel 1,000 feet, which is the distance to downgradient wells such as MW-419D and MW-
Delphi RSE Report, June 10, 2003 13
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434D. Although this velocity is relatively small compared to the velocity required to result in the current
plume extent, the velocity in this area prior to pumping was likely greater than it is now given that more
ground water was moving through the aquifer rather than being extracted. A number of years may pass
before concentrations in MW-419D, MW-434D, and other downgradient wells decrease as a result of
containing the plume onsite. Natural degradation of TCE will likely contribute to declining concentrations.
Concentrations of cis-l,2-DCE and vinyl chloride suggest that natural dechlorination is occurring or has
occurred, at least in portions of the plume. With respect to risks to receptors at the seeps, TCE and cis-
1,2-DCE have been detected at seeps at concentrations over 100 ug/L, but vinyl chloride has not been
detected.
Contaminant concentrations in ground water beneath the facility have also not decreased. This is expected
given the likely presence of DNAPL that is acting as a continuous source of dissolved phase contamination.
As discussed in Section 1.5.2, DNAPL in Tank Area C appears to be limited to the upper layers of the
overburden, but is a potential the source of dissolved contamination found in the underlying bedrock.
Therefore, tracking DNAPL recovery is appropriate. The facility commented during the RSE site visit that
the most productive DNAPL recovery wells are RW-4, RW-12, RW-5, and RW-3. An alternate
possibility for the deeper dissolved contamination that persists in the bedrock is that historical DNAPL
releases could have introduced DNAPL directly into the bedrock.
4.3 COMPONENT PERFORMANCE
4.3.1 DNAPL RECOVERY SYSTEM
This system did not meet operational expectations during 2000, 2001, and 2002, for two primary reasons.
First, the electric submersible pump emulsified recovered product, and second, the methanol used to
regenerate the resin could not be sufficiently purged from the cannister. As a result, the extracted water
could not meet discharge requirements and had to be containerized. These issues have been addressed by
using a pneumatic submersible pump and by relocating the drain on the resin vessels.
Though the DNAPL recovery system functions well unattended, full time supervision is used to monitor
DNAPL recovery and adjust system operating parameters.
4.3.2 GROUND WATER MIGRATION CONTROL SYSTEM
Extraction System Well, Pump, and Piping
The 1.5 FiP pump with a variable speed drive operates continuously at approximately 45 gpm in order to
maintain a set level in the well. The pump and well have performed to expectations. Fouling has not been
a problem, but the specific capacity is not reported regularly to determine if fouling is becoming an issue.
The carbon steel piping outside of the building has been replaced due to corrosion. The piping inside the
building has not yet been replaced.
Delphi RSE Report, June 10, 2003 14
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Drewsperse
The sequestering agent Drewsperse is added to the process water prior to the air stripper feed tank.
addition has been successful at minimizing the fouling of the process pumps, filters, and GAC.
Approximately 55 gallons of Drewsperse are used per month.
This
Air Stripper
The air stripper is capable of reaching discharge requirements without GAC polishing. It has four trays,
and air is provided by a 7.5 HP blower. At sufficiently low ambient temperatures a heater warms the air
that enters the building as a result of the blower operation. The heater operates approximately 7.5% of the
time the system is operating. The capacity is 200 gpm, which is well above the current plant influent of
approximately 45 to 50 gpm. This system operates in batch mode so that the actual flow rate through the
air stripper is closer to the design capacity.
Filters and GAC
The bag filters and GAC have been bypassed because the air stripper alone is capable of meeting discharge
requirements. These units could be brought back on line in the future, if necessary.
4.4
COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF
ANNUAL COSTS
Operations and maintenance (O&M) budgets for the DNAPL recovery and ground water migration control
systems and the associated monitoring are approximately $265,500 per year. These costs do not include
the ongoing investigations, water use survey, or municipal water connections. A breakdown of the O&M
budgets are provided below based on discussions during the RSE site visit. Descriptions of these cost items
and associated assumptions are discussed in the following sections.
Item Description
DNAPL Recovery System
Operator labor and analytical for batch discharges
Waste disposal
Ground Water Migration Control System
Weekly visits, monthly sampling/analysis, Drewsperse, and
annual acid washes
Electricity
Ground Water, Surface Water, and Seep Monitoring
Reporting
Total Estimated Cost
Estimated Cost
up to $80,000
$10,000
$50,000
$9,000
$86,500
$30,000
up to 265,500
Delphi RSE Report, June 10, 2003
15
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4.4.1 UTILITIES
The utility calculations assume an average use of 20 kW for the ground water migration control system.
This usage would be more than sufficient to power the 7.5 HP blower, the 1.5 HP extraction pump, the two
1.5 HP process pumps, and approximately 5 kW for building heat, lighting, controls, and exhaust fans.
4.4.2 NON-UTILITY CONSUMABLES AND DISPOSAL COSTS
Consumables for the DNAPL recovery system are primarily limited to the methanol used to rinse or
regenerate the polymer resin. Disposal is required for the DNAPL, the methanol rinse, and the treated
water that is extracted during DNAPL recovery. The DNAPL and methanol rinse total approximately 15
to 20 drums per year. The treated water is discharged to the POTW.
Consumables for the ground water migration control system are primarily limited to the Drewsperse and
the acid required for the annual air stripper acid washes. Approximately 55 gallons of Drewsperse are
used per month. Discharge is to the surface water in accordance with a NPDES permit; therefore, costs
associated with disposal are primarily for analytical, which is discussed below.
Equipment, supplies, shipping, and miscellaneous items for ground water sampling are also required. The
RSE team estimates that approximately $75 per sampled well might be required. Given that approximately
208 wells are sampled each year (47 quarterly and 20 annually), the estimate consumables cost for ground
water monitoring is approximately $15,600 per year.
4.4.3 LABOR
Budgeted labor includes approximately 40 hours per week for 30 weeks per year to supervise the DNAPL
recovery system, a few hours per week to check the ground water migration control system and take
process samples, approximately 450 to 500 hours per year for ground water sampling of 208 wells (47
quarterly and 20 annually), and an additional 80 hours per year for collecting monthly water levels. Labor
is also the primary component of the reporting. Approximate costs for O&M of the two systems were
provided during the RSE site visit by the site team. To estimate the costs for ground water sampling and
water level measurements, the RSE team estimated approximately 2.5 hours of labor per sample and 0.25
hours per water level measurement (including mobilization and demobilization) and an approximate billing
rate of $60 per hour (including overhead and profit). The estimate of 2.5 hours per sample is consistent
with the site team's estimate that 5 to 8 wells can be sampled per day by one person with a facilitator.
4.4.4 CHEMICAL ANALYSIS
Approximately 5 to 10 samples per year might be required to test the treated water from the DNAPL
recovery system before discharging it to the POTW. Influent and effluent samples are collected monthly
from ground water migration control system and are analyzed using method 624.1. Also, the samples from
approximately 208 wells (47 quarterly and 20 annually) plus the associated quality assurance samples are
analyzed using method 8260b. Approximate costs for O&M (including process samples) of the two
remediation systems were provided during the RSE site visit by the site team, but to estimate the costs for
analysis of ground water samples, the RSE team estimated approximately $125 per sample. It also
assumes that approximately 40 to 50 additional samples per year require analysis for quality assurance
(i.e., field blanks, trip blanks, and blind duplicates) and an additional 20 samples per year require analysis
for the surface water and seep sampling.
Delphi RSE Report, June 10, 2003 16
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4.5 RECURRING PROBLEMS OR ISSUES
Recurring problems associated with the two active remediation systems have reportedly been addressed.
For the DNAPL recovery system this included using a pneumatic pump and moving the drain for the resin
canisters to the bottom to facilitate draining of the methanol rinse. For the ground water migration control
system this included the addition of the sequestering agent Drewsperse to minimize fouling of process
pumps and other units.
The predominant recurring problem that needs continuing attention is the discharge of contaminated ground
water in the overburden to the storm sewers and the subsequent discharge of that water to either surface
water or to land surface. During precipitation events, the infiltrated water collects in abandoned storm
drains and mounds at the end with a lower elevation. The problem is perhaps augmented by a leak in a
water supply line on the southern portion of the facility. The site team has replaced some storm sewers and
is currently using a sump pump in a storm sewer manhole to extract the collecting water. The extracted
water is stored in frac tanks and is treated by a mobile unit at approximately $0.10 per gallon.
Concentrations at times have been as high as 50,000 ug/L and the extraction rate may be as high as 10
gpm. The current plan is to remove infiltration tiles that facilitate infiltration of precipitation, address the
leak in the water supply line, convert an abandoned storm sewer into a collection trench, and pump
collected water to the ground water migration control treatment system (approximately 1,200 feet away).
Because that system currently treats and discharges 45 to 50 gpm, a modification of the NPDES permit
will be required to increase the current discharge rate from 50 gpm. The air stripper has sufficient capacity
to treat the additional water.
4.6 REGULATORY COMPLIANCE
The DNAPL recovery and ground water migration control system meet the applicable air and water
discharge requirements. Discharge of contaminated ground water to surface water through storm sewers is
currently being addressed as discussed in Section 4.5.
4.7 SAFETY RECORD
The site team did not report any health and safety incidents during the site visit.
Delphi RSE Report, June 10, 2003 17
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5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN
HEALTH AND THE ENVIRONMENT
5.1 GROUND WATER
The water use survey has been conducted to identify supply wells in the area. Information on properties
downgradient of the facility was gathered by a door-to-door survey and other records. Information on the
other properties is being collected via a mailed questionnaire. Where active wells are operated and
permission is granted, samples were collected for analysis of VOCs with method 524.2. As reported in the
Interim Measures and Implementation Report, 73 samples were collected from 42 locations. Of those
samples, 58 had no detectable levels of VOCs. VOCs were detected, however in 15 samples from 11
locations. The site team is working with those properties to provide connections to municipal water. One
property along Engle Road, to the north, has detectable concentrations of TCE and cis-l,2-DCE and is not
located near a municipal water line. The site team is monitoring this well, but does not report any current
plans to supply water or a point-of-entry treatment system.
5.2 SURFACE WATER
Current efforts are underway to address the overburden ground water; however, more permanent efforts
with a greater capacity for extraction and treatment will be required. The use of an abandoned storm sewer
as a collection trench and treating the collected water in the ground water migration control system
treatment plant will likely provide this more permanent solution.
Ground water with TCE concentrations exceeding 100 ug/L is discharging to the surface through seeps
along the Great Miami River valley. Although the ground water migration control system is in place to
contain ground water in the Sugar Rock aquifer beneath the facility, discharge of impacted water through
these seeps a mile downgradient will likely continue for decades. Although the TCE and other VOCs in
this seep water will likely volatilize before reaching the river, these rivulets that are formed by the seeps
may be accessible to the public. The site team indicated during the RSE visit that an ecological risk
assessment will be performed and subsequent consultations with the State are required to determine if any
measures are required to address these seeps.
5.3 AIR
The current interim measures do not address the potential for vapor intrusion; however, the investigation
and further evaluation of vapor intrusion are to be conducted during the RFI that is currently underway.
One area of the facility to be investigated is the east tunnel, which is adjacent to the former Tank Area C
where DNAPL has been observed.
Delphi RSE Report, June 10, 2003 18
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5.4 SOILS
The current interim measures do not address soil contamination; however, the investigation and further
evaluation of vapor intrusion are to be conducted during the RFI that is currently underway. The RFI work
plan identifies 8 areas of interest (AOIs) that require confirmation sampling and 29 AOIs that require
investigation.
5.5 WETLANDS AND SEDIMENTS
The wetlands and sediments that may be affected are associated with the surface water discussed in Section
5.4.
Delphi RSE Report, June 10, 2003 19
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6.0 RECOMMENDATIONS
Cost estimates provided herein have levels of certainty comparable to those done for CERCLA Feasibility
Studies (-307+50%), and these cost estimates have been prepared in a manner consistent with EPA 540-R-
00-002, A Guide to Developing and Documenting Cost Estimates During the Feasibility Study, July
2000.
6.1 RECOMMENDATIONS TO IMPROVE EFFECTIVENESS
6.1.1 EVALUATE POTENTIAL PUBLIC CONTACT WITH SEEPS AND CONSIDER POSTING
SIGNS AT SEEPS DISCHARGING IMPACTED WATER
The ground water seeps at the Sugar Rock outcrops located along the Great Miami River valley form
rivulets that eventually discharge to the Great Miami River. Although the VOCs may volatilize prior to
reaching the river, and the seeps are generally inaccessible to the public, the public may access some of the
impacted seeps. The RSE team suggests that the potential for public contact with water from the seeps be
more fully evaluated. Based on the results, signs to notify the public that the water is not suitable for
drinking could then be considered. Note that the RSE team did not view the seeps from a nearby bike path
during the site visit to assess proximity and accessibility, and the site team should use its best judgment in
interpreting the recommendation's intent of protecting human health and the environment. If implemented,
this recommendation should cost less than $5,000.
6.1.2 CONSIDER PROVIDING A POINT-OF-ENTRY TREATMENT SYSTEM FO 10591 ENGLE
ROAD
The residence at 10591 Engle Road has a potable well impacted by VOCs with concentrations below the
MCLs. Municipal water is not available in the that area, so a municipal water hookup cannot be provided
for that residence. The facility has provided municipal water connections for houses along Cassel Road,
even if concentrations were not above standards. The facility may likewise wish to consider providing and
maintaining a point-of-entry treatment system for 10591 Engle Road to mitigate the impacts and reduce the
liability. The estimated cost for implementing this recommendation is approximately $2,000 in capital
costs and $1,000 per year in annual costs.
6.1.3 PROCEED WITH PLANNED CONNECTION OF OVERBURDEN GROUND WATER
EXTRACTION TO THE EXISTING TREATMENT SYSTEM
The RSE team recommends proceeding with the proposed interim measures to address the impacted
overburden ground water that occasionally discharges to surface water through storm sewers or to the
surface through seeps. The site team's approach of converting abandoned storm sewers to collection
trenches and pumping extracted water to the existing treatment system for the ground water migration
control system appears reasonable. The primary cost involved will likely be laying the pipe and controls to
convey the water to the treatment system. For the approximate 1,200 feet of pipe that will be required, the
facility estimates a cost of $75,000.
Delphi RSE Report, June 10, 2003 20
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The increase in the flow rate and the high concentrations may require adjustments to the treatment system.
The water from the overburden has concentrations as high as 50,000 ug/L. Given the added mass loading,
adjustments to the system may be required. Cost-effective options are add trays to the air stripper and/or
recycle some of the air stripper effluent into the feed tank on a continual basis. Recycling would effectively
dilute air stripper influent and would likely allow it to continue meeting the discharge standards without
requiring the use of the GAC polishing units. The air stripper capacity is 200 gpm, and the current flow
rate is approximately 45 to 50 gpm. Therefore, even if the extraction rate from P-301 is increased by 10
gpm and the flow from the overburden provides an additional 10 gpm, the total influent flow will by
approximately 70 gpm and the capacity is available for this approach.
The modifications would require some repiping at a relatively low cost, perhaps $5,000 to $10,000. The
annual costs would primarily be due to the increase in electricity required to operate the air stripper at a
higher batching frequency. This compares favorably to re-incorporating the filters and GAC units, which
would require regular replacement and might be prone to fouling. Based on the information provided, the
RSE team estimates a capital expenditure of approximately $100,000 for the 1,200 feet of trenching, the
conversion of a sewer into a collection trench, modifications to the air stripper, and modifications to the
NPDES permit. Annual costs might increase by $10,000 (up to $5,000 for additional electricity and up to
$5,000 for additional maintenance).
6.1.4 PROCEED WITH PLANNED LOWERING OF THE EXTRACTION PUMP IN P-301
Although potentiometric surface maps appear to indicate that capture is achieved along the northern portion
of the site, an increase in the extraction rate is appropriate. The added cost is minor (only the cost of
electricity associated with increasing the air stripper batch frequency), and the additional extraction will
make capture even easier to interpret from the potentiometric surface maps. The capture zone would also
be wider and would likely include the southern portion of the site.
6.1.5 AVOID ALTERING SITE HYDROGEOLOGY - Do NOT SEAL BORINGS FROM OLD
PRODUCTION WELLS
During the RSE site visit there was discussion about potentially eliminating the hydraulic connection
between the Top of Rock and Sugar Rock in an effort to prevent additional contamination from migrating
to the Sugar Rock. The RSE team believes that the site team has a strong understanding of the
hydrogeology at this relatively complex site and discourages efforts to alter that hydrogeology. The current
conditions and remedy appear to contain contamination on site in both the Top of Rock and the Sugar
Rock. If the connection were to be eliminated, migration control would be required in both the Top of
Rock and Sugar Rock for a number of years. The performance of the current system is known and appears
effective, but the performance of a future scenario is unknown and may not be as effective.
6.2 RECOMMENDATIONS TO REDUCE COSTS
6.2.1 CONSIDER MODIFICATIONS TO GROUND WATER MONITORING PROGRAM
The presence of DNAPL and the large area of the downgradient plume make it likely that the final remedy
will require decades of operation, maintenance, and monitoring. As a result, the monitoring program
should be refined to clearly and cost-effectively provide the data necessary to evaluate remedy performance.
The collection, interpretation, and reporting of unnecessary or redundant data is costly and distracts from
the data required for performance evaluation. Assuming the primary the primary goal of any corrective
Delphi RSE Report, June 10, 2003 21
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measure at the site is to contain contamination on site, stabilize the plume, and monitor aquifer restoration,
the RSE team has the following recommendations for modifying the current ground water monitoring
program into a more appropriate long-term monitoring program.
Water levels
Water levels in the Sugar Rock should continue to be measured. The potentiometric surface maps should
continue to be generated and interpreted for capture on a monthly basis for one year after the pumping rate
in P-301 is increased. After this one-year period, water levels should be conducted on a quarterly basis in
the overburden, Top of Rock, and Sugar Rock.
Ground water sampling and analysis
Overburden - Once the RFI is complete, sufficient information will be available to optimize the long-term
monitoring program for the overburden. Because these data are not yet available, the RSE team cannot
provide specific feedback at this point. However, the general recommendation is that each well and each
sampling event in the monitoring program provides specific information that is needed to evaluate the
remedy performance and is not provided by another well. A limited number of wells within the plume
should be sampled, and they likely should be sampled on an annual basis because the progress toward
restoration will take decades and quarterly measurements will not likely provide any additional value. The
majority of sampling in this unit should be reserved for wells that delineate the plume and can be used as
performance monitoring wells or sentinel wells downgradient of the expected capture zone for evaluating
plume migration or the control of plume migration.
Top of Rock - The currently available ground water quality information for this unit should be used to
establish a target capture zone that would likely encompass MW-422S, MW-424S, MW-425S, and MW-
428 S. If capture as interpreted by the potentiometric surface maps routinely and comfortably encompasses
the target capture zone, then additional sampling in this formation can be limited. Select wells, perhaps one
well within the plume and up to 8 wells delineating the plume can be sampled every five years to confirm
migration control is still achieved. The potable drinking well at 10591 Engle Road (which has detectable
VOC concentrations below MCLs) should likely be sampled quarterly, and the wells at the immediately
surrounding properties (which do not have detectable VOC concentrations) should likely be sampled
annually.
Sugar Rock - The RSE team recommends evaluating the Sugar Rock ground water monitoring. One
potential approach could be to reduce the sampling frequency from quarterly to annual. In addition, a
number wells may be redundant because they are located within a plume that, given the options for
remedial action, is not likely to be restored for decades. The team could discuss which wells provide
necessary data for evaluating remedy performance and which wells are redundant. The RSE team suggests
that the following wells be sampled annually as performance monitoring wells for the P-301 capture zone:
MW-409D, MW-418D, MW-419D, MW-420D, MW-433D, and MW-434D. In addition, MW-444D,
MW-448D, MW-450D, and MW-453D (or perhaps an additional well that delineates the contamination at
MW-453D) could be sampled annually as sentinel wells to determine if contamination continues to migrate
beyond the current plume area. Other wells could also be sampled, depending on site-specific needs the
RSE team has not fully considered. If the current interim remedy (with additional pumping from P-301)
becomes the final remedy, the above sampling program might be appropriate for evaluating the
performance over the long-term. Other remaining site wells could be included in the annual sampling or
monitored every few years to evaluate the progress toward restoration.
Delphi RSE Report, June 10, 2003 22
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Ground water seeps at Sugar Rock outcrop
Sampling and analysis of these seeps should continue on an annual basis.
Reporting
Monitoring reports should be produced annually to accompany the annual sampling event, but
progress/O&M reports should likely continue quarterly. In addition to the information provided in the
current reports, each annual report should present the following:
tables with historical sampling and water level data for all wells
trend plots of the sampling data from wells with detectable concentrations, compared to
expected trends
potentiometric surface maps for each unit that include the target capture zone and the
interpreted capture zone depicted by streamlines
a discussion of how the potentiometric surface map was generated and how the capture
zone was interpreted including the known pumping conditions at the time the water levels
were collected
an evaluation of remedy performance relative to the remedy goals based on the current and
previous sampling and water level data
suggestions for alternative remedial approaches, if the remedy does not appear to be
achieving its goals
The RSE team notes that the above suggestions are based on the data reviewed during the RSE project and
additional data will subsequently become available from the RFI and other investigations. If known
changes in other regional pumping are made (e.g., at the Leland Electrode Systems facility) as observed
from potentiometric surface maps, changes in this suggested monitoring program would likely be required.
In addition, the above recommendations generally assume that the final remedy will closely resemble the
interim measures. If other remedial strategies are considered or required, the monitoring requirements
would likely change.
The cost savings of reducing the frequency for water level measurements from monthly to quarterly may be
partially offset because the recommendation includes collecting water levels in the overburden. Cost
savings could result from reducing the number of monitored wells and the monitoring frequency. The
example monitoring program provided by the RSE team includes sampling of approximately 11 wells once
per year in the Sugar Rock, a limited number of wells in the overburden, and perhaps a few additional
wells. Assuming up to 7 wells are sampled in the overburden once per year, 5 additional wells beyond those
mentioned by the RSE team are sampled in the Sugar Rock, and up to 10 additional wells throughout the
site are measured every two years, this example monitoring program would involve a fraction of the
monitoring associated with the current program (23 samples per year and up to 10 additional wells every
two years versus 208 samples per year). Based on the costs of the current monitoring program, the
proposed monitoring program (excluding reporting) should cost approximately $17,000 per year on
average compared to the current cost of $84,000. The cost for reporting would likely decrease by
approximately $5,000 from $30,000 per year to $25,000 per year.
Delphi RSE Report, June 10, 2003 23
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6.3 MODIFICATIONS INTENDED FOR TECHNICAL IMPROVEMENT
6.3.1 CONSIDER REPLACEMENT OF TREATMENT SYSTEM PIPE
The carbon steel piping on the outside of the treatment building has been replaced due to corrosion. When
replacement of the carbon steel piping on the inside of the building is required, it should be replaced by
schedule 80 PVC, which is corrosion resistant. The costs for using PVC would not be substantially
different than carbon steel piping.
6.4 CONSIDERATIONS FOR GAINING SITE CLOSE OUT
The presence of DNAPL beneath the facility offers a continuing source of dissolved ground water
contamination. The RSE team recognizes that the DNAPL recovery system is an appropriate measure for
removing recoverable free product, especially given the extent of this DNAPL, operations at the overlying
facility, and the potential for mobilizing DNAPL if other technologies are used. The RSE team also
acknowledges that DNAPL will remain in the subsurface for decades even after DNAPL recovery is
discontinued (residual, unrecoverable DNAPL will remain). At this time, the RSE team does not know of
an appropriate technology that could guarantee remediation of the DNAPL at a practicable cost. Some
approaches may not be appropriate for the site. For example, the use of six-phase heating would likely be
inappropriate because the vadose zone is too thin and too tight to effectively recover the resulting VOC
vapors. In addition, the heat generated from six-phase heating (or chemical oxidation) could upset above-
ground facility operations. Injection of nano-scale iron is typically reserved for dissolved contamination
and is generally not effective for DNAPL or residual DNAPL. Some bioremediation approaches may be
appropriate, but should be considered after DNAPL recovery stops. The RSE team believes that an
appropriate approach would be to continue operating the ground water migration control system and
evaluate various DNAPL remediation technologies on regular basis, perhaps every five years.
The area downgradient of the ground water migration control system capture zone will also likely remain
well above standards for decades due to a relatively slow flushing rate of clean water through the
contaminated zone and the large contaminated area. Reinjection of treated water could facilitate this
flushing, but the reinjected water would disperse (not destroy the contaminants) and, due to aeration, might
slow the natural reductive dechlorination that is taking place. The use of alternate technologies for this
downgradient plume would also require substantial expense due to the broad area of impacts (nearly a
square mile) and the cost of distributing reagents over this wide area. Assuming a radius of influence for
an injection well of 50 feet, the area of influence would be approximately 10,000 square feet. Assuming a
plume area of approximately one square mile (approximately 25 million square feet), approximately 250
injection wells would be required. At an estimated cost of $10,000 per injection well, the delivery costs
alone would be approximately $2.5 million. Additional costs would be required for planning, materials,
monitoring, and oversight and the results would not be guaranteed. Once the Els are met, the RSE team
believes that an appropriate approach would be to continue operating the ground water migration control
system and maintain institutional controls through the plume area, potentially reviewing various
remediation technologies on regular basis, perhaps every five years, to determine if a technology is
developed that can practicably achieve aquifer restoration or other site goals.
Delphi RSE Report, June 10, 2003 24
-------
6.5 SUGGESTED APPROACH TO IMPLEMENTATION
The RSE team is impressed with the work conducted at the site and encourages the site team to move
forward with the RFI and meeting the Els. The recommendations provided above are not necessarily
contingent on each other. The site team likely has a better understanding of how to implement these
recommendations in conjunction with ongoing site activities.
Delphi RSE Report, June 10, 2003 25
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7.0 SUMMARY
The RSE team observed an extremely well-managed remedy. Based on the RSE document review and site
visit, the RSE team concludes that Delphi, their contractors, and EPA all have an excellent understanding
of the complex site conditions, interim measures, ongoing RFI, and potential risks. Continuing efforts have
been made by the site team as a whole to improve interim measures and conduct a comprehensive RFI.
The observations and recommendations contained in this report are not intended to imply a deficiency in the
work of either the system designers or operators but are offered as constructive suggestions in the best
interest of the EPA and the public. These recommendations have the obvious benefit of being formulated
based upon operational data unavailable to the original designers.
To enhance effectiveness, the RSE team provides five recommendations. Two of the recommendations are
for the site team to continue with proposed plans of piping extracted water from the overburden to the
existing treatment system and lowering the pump in the extraction well to allow for an increased extraction
rate. The other recommendations are to consider providing a point-of-entry treatment system for one
property, to more fully evaluate the potential for public contact with seeps and add signs as appropriate,
and to avoid altering the site hydrogeology that could result from sealing the connections between the Top
of Rock and Sugar rock aquifers. To reduce costs and maintain protectiveness, the RSE team recommends
modifying the ground water monitoring plan. General concepts and some specific modifications to the
sampling and reporting are mentioned; however, the current RFI and upcoming final remedy may require a
different monitoring plan. Only one technical improvement recommendation is made, and it involves the
eventual replacement of corroding pipe. For site closure, the RSE team acknowledges that decades of
remediation will be required and that current technologies will not likely restore the aquifer. The RSE team
recommends continuing to control plume migration and to review innovative technologies, particularly for
the source area, and evaluate appropriate technologies every five years.
Table 7-1 summarizes the costs and cost savings associated with each recommendation in Sections 6.1
through 6.3. Both capital and annual costs are presented. Also presented is the expected change in life-
cycle costs over a 30-year period for each recommendation both with discounting (i.e., net present value)
and without it.
Delphi RSE Report, June 10, 2003 26
-------
Table 7-1. Cost Summary Table
Recommendation
6.1.1 Evaluate Potential
Public Contact With Seeps,
Consider Signs
6.1.2 Consider Providing a
Point-of -Entry Treatment
System fo 10591 Engle Road
6.1.3 Proceed with
Planned Connection of
Overburden Ground water
Extraction to the Existing
Treatment System
6.1.4 Proceed with
Planned Lowering of the
Extraction Pump in P-301
6. 1.5 Avoid Altering Site
Hydrogeology - Do Not Seal
Borings from Old Production
Wells
6.2.1 Consider
Modifications to Ground
Water Monitoring Program
6.3.1 Consider
Replacement of Treatment
System Pipe
Reason
Effectiveness
Effectiveness
Effectiveness
Effectiveness
Effectiveness
Cost
Reduction
Technical
Improvement
Additional
Capital
Costs
($)
$5,000
$2,000
$100,000
$0
$0
$0
$0
Estimated
Change in
Annual
Costs
($/yr)
$0
$1,000
$10,000
$0
$0
($67,000)
$0
Estimated
Change
In Life-cycle
Costs
($)*
$5,000
$32,000
$400,000
$0
$0
($2,010,000)
$0
Estimated
Change
In Life-cycle
Costs
($)**
$5,000
$18,100
$261,400
$0
$0
($1,081,400)
$0
Costs in parentheses imply cost reductions.
* assumes 30 years of operation with a discount rate of 0% (i.e., no discounting)
** assumes 30 years of operation with a discount rate of 5% and no discounting in the first year
Delphi RSE Report, June 10, 2003
27
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FIGURES
Delphi RSE Report, June 10, 2003
-------
FIGURE 1-1. THE DELPHI FACILITY AND THE SURROUNDING AREA
4 J*-ŧ .1
'"AN DA LI A
' *.
-N-
OHIO
(Note: This figure is taken from Figure 1 of the RCRA Facility Investigation Work Plan, Haley and Aldrich, 2002.)
-------
FIGURE 1-2. EXTENT OF DNAPL AND LOCATIONS OF DNAPL RECOVERY WELLS IN FIRST SAND UNIT OF OVERBURDEN
FEET
(Note: This figure is a re-creation of Figure 2-2 from the Interim Measures and Implementation Report, Haley and Aldrich, 2002).
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FIGURE 1-3. TCE DISTRIBUTION IN THE TOP OF ROCK
-N-
CSX-19S
7/13/2000
<5
CSX-1
12/17/1991
<5
CSX-3
12/18/1991
<5
\
MW-402S
V "y/9/2001
.-' MW-403S \ \ <5
0 7/9/2001 \ \ iŦi
( ) t-5 \
<5
MW-404S
7/10/2001
MW-427S (
1/23/2002
<5
\ ^ 'i
MW-426S\ \ ]
1/23/2002> i i
I I
ro
i MW-101S
J7/1 0/2001
<5
MW-425S
2/5/2002
-Qlii-.
CSX-2 /
4/25/2000l
<5
1/31/2002"
<5
( )7/10/2001
^ Ŧ r.
U MW-429S
1/24/2002
<5
MW-430S/
1/25/2002
<5
-
Tf
f_
'
TC\A^ I I H=I
U
'. MW-422S x-
2/7/2002
193,000
\ MW-428S
2/7/2002
258,000
v_
./7/2002
87,800
U
7/9/2001
<5
MW-401S I
7/9/2001 ,'
1L.UJ
U
CSX-22
4/28/2000
<5
LEGEND
7/9/2001 TRICHLOROETHENE (TCE)
<5 RESULT IN ug/L WITH
SAMPLE DATE
MW-407S
7/11/2001
<5
CSX-15 O
12/16/1991
<5
(Note: This figure is taken from Figure 1-4 of the Interim Measures and Implementation Report,
Haley and Aldnch, 2002).
SCALE IN FEET
-------
-N-
FIGURE 1-4. TCE DISTRIBUTION IN THE SUGAR ROCK, FIRST QUARTER 2003
MW-450D1
\
\
.^ MW-403D \ \ \ CSX-18D
,--"' 0.37J \ \ ] O 0.78J
**** \ ^ '
,-' MW-424D MW-301D ' MMW-413D
I 3UNDO 680 \_\~y 76
~"^~PQ MW-416D,-,
O
MW-417D
0.30J
1MW-101D
\MW-422D
0.2"
n
J d
MW
L
O \
MW-414D\
0.78J
-401Dr-,i
,MW-418D
19J
O
MW-421D
0.3J
MW-420D
O
MW-434D
140
MW-409D
61
MW-410D
730
QMW-407D
350
0MW-408D
520
MW-435D
280
O
MW-437D
100
O
MW-411D
1200
O
MW-412D
1400
O
MW-442D
<1 ,
QMW-443D
Q
MW-433D
130
MW-432D
21
O
u
MW-44
35
O
MW-436B
66
MWD-438D
MW-439D
15
O
'MW-444D
5.6
LEGEND
MW-451D
28
MW-447D
MW-449D
45
MW-448D
1.9
O
MW-453D
52
(Note: This figure is a re-creation of a draft figure created by Haley and Aldrich, 2002).
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FIGURE 4-1. POTENTIOMETRIC SURFACE MAP FOR THE TOP OF ROCK, JULY 2002
-N-
MW-405S
967.85 \ ^
.^\
\
\
\ \MW-402S
952.38
MW-401S
957.95
LEGEND
ŪMW-401S MONITORING WELL
957.95 WATER ELEVATION
570
MW-405S
975.63
(Note: This figure is a re-creation of Figure 4 from the 3rd Quarter 2002 Progress Report,
Haley and Aldrich, October 2002).
-------
FIGURE 4-2. POTENTIOMETRIC SURFACE MAP FOR THE SUGAR ROCK, JULY 2002
-N-
MW-450D
891.22
'.' B001 873.1
B002 876.7
\\ B003 877.6
--^ B004 875.7
" o
C001
^^ 873.800
D001 O
854.40
E001
854.80
MW-439D
909.49
Ū
\
\
X
Ū
MW-440D
909.03
>
\
''-' Ū \
V'MW-444D
908.72
0
F001
881.60
\
\
MW-448D
910.26
EASTERN LIMITS OF
APPARENT CAPTURE ZONE
(Note: This figure is taken from Figure 5 from the 3rd Quarter 2002 Progress Report,
Haley and Aldrich, 2002).
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FIGURE 4-3. POTENTIOMETRIC SURFACE MAP FOR THE SUGAR ROCK, FEBRUARY 2003
MW-450Di
892.90\
B001 873.1
B002 876.7
B003 877.6
B004 875.7
o
MW-415D
914.08
MW-301D
913.89
D001 O
854.40
E001 O
854.80
O
F001
881.60
MW-448D
913.10
LEGEND
ŪMW-401S MONITORING WELL
957.95 WATER ELEVATION
OF001
912
970
EASTERN LIMITS OF
APPARENT CAPTURE ZONE
MW-447D
913.06
MW-453D
912.85
(Note: This figure is a re-creation of a draft figure created by Haley and Aldrich, 2003).
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