1_-_ARS_Volume_1_Supplemental_RD.pdf

Solicitation Number – P16PS00832

VAFO Remediation

Remediation for the Asbestos Release Site Remedial Action at Valley Forge National Historical Park, Upper Merion Township, Montgomery County, PA

Attachment 1:

Valley Forge ARS Volume 1

Supplemental RD March 2016

SUPPLEMENTAL

REMEDIAL DESIGN REPORT

VOLUME 1

VALLEY FORGE NATIONAL HISTORICAL PARK

ASBESTOS RELEASE SITE

VALLEY FORGE, PENNSYLVANIA

MARCH 2016

Prepared by:

Supplemental Remedial Design Report Volume 1 i The Johnson Company, Inc.

Asbestos Release Site - Valley Forge National Historical Park March 2016

TABLE OF CONTENTS

1.0 INTRODUCTION AND OVERVIEW

1.1 REPORT ORGANIZATION

1.2 SITE DESCRIPTION

1.3 HISTORIC LAND USE

1.4 PREVIOUS SITE ACTIVITIES

1.5 DESIGN OBJECTIVE

1.6 REMEDIAL ACTION SCHEDULE

2.0 DESCRIPTION OF THE SELECTED REMEDY

2.1 DISPOSAL OF EXCAVATED SOILS

2.2 PLACEMENT OF CLEAN FILL OVER CONTAMINATED SOILS

2.3 PERFORMANCE VERIFICATION

2.4 SITE RESTORATION

2.5 INSTITUTIONAL CONTROLS

2.6 PERFORMANCE STANDARDS

2.6.1 Remedy Overall

2.6.2 Contaminated Soil Remediation

2.6.3 Clean Fill and Backfill

2.6.4 Site Restoration/Revegetation

3.0 DESIGN METHODS

3.1 ADDITIONAL REMEDIATION AREA BOUNDARIES

3.2 DESIGN OF EXCAVATION DEPTHS

3.3 INSTITUTIONAL CONTROLS

3.4 REMEDIATION AREAS ACCESS

3.5 EROSION CONTROL AND STORM WATER MANAGEMENT

3.6 WETLANDS MANAGEMENT

3.7 THREATENED AND ENDANGERED SPECIES

4.0 BASIS OF DESIGN

4.1 MAINTENANCE AREA RUINS

4.1.1 MAR-A-NB-01

4.1.2 MAR-A-NB-02

4.2 FORMER KEENE PLANT

4.2.1 FKP-A-NB-01

4.2.2 FKP-B2/M-NB-01

4.2.3 FKP-C2-NB-01

4.2.4 FKP-E-NB-01

4.2.5 FKP-F/G/J-NB-01

4.2.6 FKP-K/L-NB-01

4.2.7 FKP-K/L-NB-02

4.3 HISTORIC BRIDGE AREA

4.4 SMALL ADDITIONAL QUARRY

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4.5 WASTE CHANNEL AND RAIL BED SOUTH

4.5.1 WCRS-B North

4.5.2 WCRS-C1

4.5.3 WCRS-D

4.5.4 WCRS-G-South

4.6 REMOVAL OF TREES AND STUMPS

4.7 REMOVAL OF WARNING FENCING/SIGNAGE

4.8 CLOSURE OF SITE MONITORING WELLS

4.9 STORMWATER CONTROLS

4.9.1 Erosion Control Methods

4.9.2 Administrative Controls

5.0 PERFORMANCE VERIFICATION

5.1 VERIFICATION OF REMEDIATION AREA DIMENSIONS

5.2 PERFORMANCE VERIFICATION TESTS FOR RESTORATION ACTIVITIES

6.0 DECONTAMINATION

7.0 WASTE CHARACTERIZATION AND DISPOSAL

7.1 CONTAMINATED SOILS

7.2 DECONTAMINATION WASTES

8.0 TRANSPORTATION PLAN

9.0 INSTITUTIONAL CONTROLS

9.1 TYPES OF INSTITUTIONAL CONTROL AREAS

9.1.1 Type 1 Institutional Controls

9.1.2 Type 2 Institutional Controls

9.1.3 Other Areas of the Site

9.2 FUTURE LAND USE RESTRICTIONS

9.3 INSTITUTIONAL CONTROL AREAS AT THE SITE

9.3.1 Institutional Control Areas from the 2012 RD Report

9.3.2 Institutional Control Areas Identified From Verification Sample Data

9.3.3 Institutional Control Areas Identified For Additional Remediation Areas

10.0 ARCHEOLOGICALLY SENSITIVE AREAS

11.0 COMPLIANCE WITH ARARS

12.0 REFERENCES

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LIST OF TABLES

Table 2-1 Contaminants of Concern and Remediation Goals Table 4-1 Design Remediation Dimensions and Contaminants of Concern Table 4-2 Verification Sample Data for MAR-A Table 4-3 Verification Sample Data for MAR-A-NB-01 Table 4-4 New Boundary Sample Data for MAR-A Table 4-5 Verification Sample Data for FKP-A Southwest Table 4-6 New Boundary Sample Data for FKP-A Table 4-7 Verification Sample Data for FKP-B2 Table 4-8 Verification Sample Data for FKP-M Table 4-9 New Boundary Sample Data for FKP-B2 Table 4-10 New Boundary Sample Data for FKP-M Table 4-11 Verification Sample Data for FKP-C2 East Table 4-12 Verification Sample Data for FKP-C2 West Table 4-13 New Boundary Sample Data for FKP-C2 Table 4-14 Verification Sample Data for FKP-E Table 4-15 New Boundary Sample Data for FKP-E Table 4-16 Verification Sample Data for FKP-F Table 4-17 Verification Sample Data for FKP-G Table 4-18 Verification Sample Data for FKP-J South Table 4-19 Verification Sample Data for FKP-J North Table 4-20 New Boundary Sample Data for FKP-F, G, and J Table 4-21 Verification Sample Data for FKP-K Table 4-22 Verification Sample Data for FKP-L Table 4-23 New Boundary Sample Data for FKP-K Table 4-24 New Boundary Sample Data for FKP-L Table 4-25 Verification Sample Data for HIB-C3 Table 4-26 New Boundary Sample Data for HIB-C3 Table 4-27 Verification Sample Data for SAQ-A Table 4-28 New Boundary Sample Data for SAQ-A Table 4-29 Verification Sample Data for WCRS-B North Table 4-30 New Boundary Sample Data for WCRS-B North Table 4-31 Verification Sample Data for WCRS-C1 Table 4-32 New Boundary Sample Data for WCRS-C1 Table 4-33 Verification Sample Data for WCRS-D Table 4-34 New Boundary Sample Data for WCRS-D Table 4-35 Verification Sample Data for WCRS-G South Table 4-36 New Boundary Sample Data for WCRS-G South Table 7-1 Waste Characterization Sampling Requirements

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LIST OF TABLES continued

Table 9-1 Summary of Institutional Control Areas from the 2012 RD Report Table 9-2 Summary of Institutional Control Areas Identified by Verification Sample Data

Obtained During 2013/2014 RA Table 9-3 Summary of Institutional Control Areas for Additional Excavation Area Table 11-1 Compliance with Applicable or Relevant and Appropriate Requirements

LIST OF FIGURES

Figure 1-1 Site Location Map Figure 1-2 Areas of Concern Figure 1-3 Preliminary Remedial Action Schedule Figure 4-1 Index of Figures Showing Additional Excavation Areas Figure 4-2 Recommended Additional Excavation Area MAR-A Figure 4-3 Recommended Additional Excavation Area FKP-A Figure 4-4 Recommended Additional Remediation Areas FKP-B2 and M Figure 4-5 Recommended Additional Remediation Area FKP-C2 Figure 4-6 Recommended Additional Remediation Area FKP-E Figure 4-7 Recommended Additional Excavation Areas FKP-F, G and J Figure 4-8 Recommended Additional Excavation Areas FKP-K and L Figure 4-9 Recommended Additional Excavation Areas HIB-C3, WCRS-B North, and

WCRS-C1

Figure 4-10 Recommended Additional Excavation Areas SAQ-A and WCRS-D Figure 4-11 Recommended Additional Excavation Area WCRS-G South Figure 4-12 Locations of Flex Fence and Posts to be Removed During the RA Figure 9-1 Type 1 and Type 2 Institutional Control Areas

LIST OF APPENDICES

Appendix A Background Information About Separation Fabric Barrier Appendix B Information Regarding Site Monitoring Wells Appendix C NPS Clean Fill Policy and PADEP Management of Fill Policy Appendix D Warning Layer Information Appendix E Description and Sketch of Structural Ruins Located in FKP-B/M-NB-01

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LIST OF ACRONYMS AND ABBREVIATIONS

AASHTO = American Association of State Highway and Transportation Officials AMQ = Amphitheater Quarry Area of Concern AOC = Area of Concern ARARs = Applicable or Relevant and Appropriate Requirements ARS = Asbestos Release Site ASTM = American Society for Testing of Materials bgs = below ground surface BZB = Betzwood Bridge Area of Concern CERCLA = Comprehensive Environmental Response, Compensation and Liability Act CFR = Code of Federal Regulations cfs = cubic feet per second COC = Contaminant of Concern COPC = Contaminant of Potential Concern COPEC = Contaminant of Potential Ecological Concern CQA = Construction Quality Assurance CQAP = Construction Quality Assurance Plan CVQ = Cave Quarry Area of Concern DOT = U.S. Department of Transportation ECB = Erosion Control Blanket EPA = United States Environmental Protection Agency f/cc = fibers per cubic centimeter FKP = Former Keene Plant Area of Concern FSP = Field Sampling Plan FS = Feasibility Study feet bgs = feet below the ground surface HASP = Health and Safety Plan GPS = Global Positioning System HIB = Historic Bridge Area of Concern IC = Institutional Control IDW = Investigation Derived Waste JCO = The Johnson Company, Inc.

lf = linear feet MAR = Maintenance Area Ruins Area of Concern mg/kg = milligrams per kilogram MSDS = Material Safety Data Sheet NB = New Boundary ND = Not Detected NIOSH = National Institute for Occupational Safety and Health

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LIST OF ACRONYMS AND ABBREVIATIONS continued

NPS = National Park Service O & M = Operation and Maintenance OSHA = Occupational Safety & Health Administration PADEP = Pennsylvania Department of Environmental Protection PA = Pennsylvania PAH = Polycyclic Aromatic Hydrocarbons PDI = Pre Design Investigation PDQ = Pennsylvania Department of Transportation Quarry Area of Concern PEL = Permissible Exposure Limit PLM = Polarized Light Microscopy PPE = Personal Protective Equipment QA/QC = Quality Assurance/Quality Control QAPP = Quality Assurance Project Plan RA = Remedial Action RAO = Remedial Action Objective RAWP = Remedial Action Work Plan RCRA = Resource Conservation and Recovery Act RD = Remedial Design RECP = Rolled Erosion Control Product RG = Remediation Goal ROD = Record of Decision SAP = Sampling and Analysis Plan SAQ = Small Additional Quarry Area of Concern SIB = Silicate Bank Area of Concern SMP = Site Management Plan TCLP = Toxicity Characteristic Leachate Procedure TEM = Transmission Electron Microscopy TRM = Turf Reinforcement Mat TSDF = Treatment, Storage or Disposal Facility TtFW = Tetra Tech Foster Wheeler USGS = United States Geological Survey VFNHP = Valley Forge National Historical Park WCRN = Waste Channel Rail Bed North Area of Concern WCRS = Waste Channel Rail Bed South Area of Concern

Supplemental Remedial Design Report Volume 1 1 The Johnson Company, Inc.

Asbestos Release Site - Valley Forge National Historical Park February 2015

1.0 INTRODUCTION AND OVERVIEW

On behalf of the National Park Service (NPS), The Johnson Company Inc. (JCO) has developed this supplemental remedial design report (Supplemental RD Report) for the Valley

Forge National Historical Park Asbestos Release Site (the Site). This report describes 12 additional excavation areas to address residual shallow soil contamination identified by horizontal verification samples collected following remedial excavations completed in 2013 and

2014. This report also describes requirements for removing vinyl split rail warning fence, signage and posts previously installed around portions of the Site, and for closing monitoring wells installed at the Site during the remedial investigation.

The 12 additional excavation areas described in this report are located within the previously identified Areas of Concern (AOCs) known as the Maintenance Area Ruins (MAR), the Former Keene plant (FKP), the Historic Bridge (HIB), the Small Additional Quarry (SAQ), and the Waste Channel Rail Bed South (WCRS). This report supplements the 2012 remedial design report prepared for the Site (2012 RD Report - JCO, 2012), which described the design of the original 65 different remedial excavations in 11 AOCs at the Site.

In 2013 and 2014 Frontier Services Inc. (FSI), under contract to NPS, excavated approximately 45,000 cubic yards of contaminated soil from the Site as part of a remedial action

(RA) to implement the design in the 2012 RD Report. All excavated soils were transported to either Waste Managements’ Tulleytown or GROWS East landfill facilities for disposal. In accordance with the requirements in Section 5 of Volume 1 of the 2012 RD Report, FSI collected soil samples from the sidewalls of excavations completed in 2013/2014 for laboratory analysis. Some of these horizontal (sidewall) verification samples contained concentrations of the contaminants of concern (COCs) that exceed the remediation goals (RGs) established in the

Record of Decision (ROD) for the Site (NPS, 2007).

In response to the RG exceedances identified by these horizontal verification samples

(HV samples), JCO and NPS collected samples of undisturbed soils (new boundary (NB) samples) located near the HV sample collection locations that exceeded the RGs. Data obtained

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from these new boundary samples provide the basis for design of additional remediation areas described in this document.

1.1 REPORT ORGANIZATION

This Supplemental RD report includes a description of areas of the Site requiring additional remediation, the design methodology, the activities required to implement the

Supplemental RA, and required actions to confirm compliance with the applicable, or relevant and appropriate requirements (ARARs) during implementation of the remedy.

This Volume 1 is a companion document to three other volumes, all of which make up the Supplemental RD Report. A description of the topics covered by each of the Supplemental

RD Report volumes is provided below.

• Volume 1 provides abbreviated background information for the Site (detailed background information is provided in the 2012 RD Report (JCO, 2012); the basis of design; performance standards and verification methods for evaluating success of the remedy; decontamination and waste characterization and disposal requirements; soil transportation requirements; an institutional controls plan; a description of archeologically sensitive areas and associated protections; and a summary of ARAR compliance.

• Volume 2 describes the following implementation plans: site management plan;

planting and restoration plan; sampling and analysis plan; construction quality assurance plan; and operation and maintenance plan.

• Volume 3 presents the Design Drawings, which along with the implementation plans (Volume 2) and construction specifications (Volume 4), describe the requirements of the Supplemental RA.

• Volume 4 includes the construction specifications which will be used in conjunction with the design drawings and implementation plans to perform the Supplemental RA.

All of the documents listed above will be incorporated into a construction contract with a remediation contractor to implement the Supplemental RA. Throughout these volumes, responsibilities and obligations of the NPS and RA Contractor are identified. Where NPS is

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identified as the responsible entity, NPS may elect to delegate the responsibility to another contractor.

1.2 SITE DESCRIPTION

The Site is located in the Valley Forge National Historical Park (the Park) in southeastern

Pennsylvania, 18 miles northwest of center city Philadelphia (Figure 1-1). The Site includes a mixture of forests, meadows, wetlands, surface water bodies, developed areas, and altered landscapes resulting from historic anthropogenic activities. Developed areas of the Site include three currently unoccupied residential buildings located along Cinder Lane, the Lower Visitor

Center parking lot located south of County Line Road, several inactive quarries located throughout the Site, a paved recreation path near County Line Road, unpaved recreation trails located near the Unnamed Tributary and Historic Bridge areas, and five public roads

(Pennsylvania [PA] Route 23, Cinder Lane, County Line Road, Station Road, and Trooper

Road).

Two surface water bodies are located on the Site. The southern bank of the Schuylkill

River forms the northern boundary of the Site. An Unnamed Tributary to the Schuylkill River originates near the intersection of Cinder Lane and Trooper Road, and flows approximately

1,200 feet before its confluence with the Schuylkill River. A waste channel formerly utilized by the former Keene plant (a pipe insulation manufacturing facility that is no longer present at the

Site) discharges into the Unnamed Tributary from a culvert located along County Line Road that directs flow underneath PA Route 23. The Unnamed Tributary is a riverine, upper perennial system with an unconsolidated bottom dominated by cobbles and gravel (TtFW, 2005a).

Initial Site investigations identified numerous AOCs that may have been impacted by

COCs due to historical activities. Further investigation indicated that 11of these AOCs contained soil concentrations of COCs that are greater than RGs established for the Site. The locations of these 11 AOCs are shown on Figure 1-2. Remediation in some of the AOCs has been completed, including the Amphitheater Quarry (AMQ), Silicate Bank (SIB), PADOT

Quarry (PDQ), Cave Quarry (CVQ), Betzwood Bridge (BZB) and Waste Channel and Rail Bed

North (WCRN). The individual AOCs and specific areas within those AOCs that require

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additional (supplemental) remediation are shown on Figures 4-1 through 4-11. Brief descriptions of each AOC requiring additional remediation are presented below.

Maintenance Area Ruins (MAR) – The MAR AOC is east of the Park maintenance area access road and north of County Line Road, southwest of the location of the former Keene plant. Investigations completed at this AOC characterized the area as containing metal debris, including an empty metal storage tank, and a metal pipe that was suspected to be a former waste slurry pipe (TtFW, 2005a). This area may have been used to dispose of unwanted equipment and materials while the former Keene plant was operational. The COCs identified for this area are lead, mercury, and benzo(a)pyrene.

Former Keene Plant (FKP) – The FKP AOC includes the building footprint of the former Keene plant. This area is located north of County Line Road, in a landscape dominated by meadows with pockets of trees. The COCs identified for this area are asbestos, lead, mercury, benzo(a)anthracene, benzo(a)pyrene, and dibenzo(a,h)anthracene.

Historic Bridge (HIB) – The HIB AOC is located south of County Line Road and north of the AMQ AOC, near a historic arched stone bridge. The COC identified for this AOC is asbestos.

Small Additional Quarry (SAQ) – The SAQ AOC is located just north of County Line Road, on the floor of an abandoned quarry. The COCs identified for this AOC are arsenic and lead.

Waste Channel and Rail Bed South (WCRS) - The WCRS AOC includes a waste channel used by the former Keene plant to transport waste slurry material to the Schuylkill River (see Section 1.3). This area also includes a former rail bed where a railroad siding was constructed to connect the quarries and the former Keene plant to the railroad line located in the northern portion of the Site. The discharge of slurry waste from the former Keene plant to the Schuylkill River resulted in deposits of waste slurry material throughout the waste channel area. The COCs identified for this AOC are asbestos, arsenic, lead, mercury, and benzo(a)pyrene.

1.3 HISTORIC LAND USE

The 2012 RD Report provides a detailed description of historic land uses at the Site.

Briefly, before the Park was established in 1976, it was a combination of private property and a

Pennsylvania State Park, which was established in 1893 (NPS, 2006). Prior to 1893, the Site experienced mixed land use, which included development of limestone quarries and construction of lime kilns, a railroad siding, the Ehret and Keene pipe insulation manufacturing facility – the

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former Keene plant, and a tow path along the southern bank of the Schuylkill River (see

Appendix A of the 2012 RD report: Phase 1A Archaeological Assessment Report). The former

Keene produced asbestos containing pipe insulation, and operated from the late 1800s to the

1970s. The pipe insulation was manufactured by pouring a slurry mix of asbestos fibers and magnesium carbonate into molds. Asbestos slurry waste was disposed of by either pumping it through pipelines into nearby limestone quarries or by directing it into a natural drainage swale, used as a waste channel ultimately discharging to the Schuylkill River. The slurry waste placed in the limestone quarries was subsequently covered with soil and (in some locations) asphalt.

On October 13, 1976, NPS purchased the former Keene plant property. The former

Keene plant manufacturing building was demolished in September 1980. Following the official transfer of title for the adjacent Pennsylvania state park land to NPS, the Secretary of the Interior issued official notice establishing the Valley Forge National Historical Park (VFNHP) as a unit of the NPS on November 24, 1982. Currently, the area where the former Keene plant manufacturing building was located is characterized as an open meadow/grassland with isolated pockets of trees (TtFW, 2005a).

1.4 PREVIOUS SITE ACTIVITIES

The 2012 RD Report summarizes Site investigation and remediation activities conducted from 1976 through 2012, including an initial site visit by the US Department of Interior (1976);

NPS’s discovery of highly contaminated (by asbestos) soils at the Site (January 1997); an emergency action performed by EPA to address this soil contamination (PMC, 1998);

completion of a Remedial Investigation (TtFW, 2005a), Baseline Human Health and Ecological

Risk Assessments (TtFW, 2005b and TtFW, 2005c), and a Feasibility Study Report (NPS, 2006);

publication of a Record of Decision (NPS, 2007); and completion of a pre-design investigation report (JCO, 2010a).

In June 2012, JCO completed a Remedial Design Report which was the basis of the initial remedial action implemented in 2013-2014. During the 2013-2014 remedial action, FSI collected verification samples from the sidewalls and floors of excavations as required by the

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2012 RD Report. When verification samples contained reported concentrations of COCs that exceeded RGs, JCO collected additional samples (new boundary, or NB samples) to define the spatial extent of remaining shallow soil contamination. Data obtained from these NB samples were used as the basis for the design of the 12 additional remediation areas described in this

Supplemental RD report.

1.5 DESIGN OBJECTIVE

The objective of this Supplemental RD is to provide the basis for additional remediation of contaminated soils identified by verification samples collected from the sidewalls of the 2013-

2014 remedial excavations and as further defined by subsequently collected NB samples. This report uses the same design methodology and performance criteria as in the 2012 RD, which was developed based on the requirements of the ROD. As such, the 2012 RD Report (JCO, 2012) is referenced frequently throughout this document.

This Supplemental RD report identifies steps to be taken during the Supplemental RA to ensure goals established in the ROD are achieved. Specifically, this Supplemental RD Report provides a detailed description of how the remedial action objectives (RAOs) and RGs presented in the ROD will be achieved, how compliance with ARARs will be ensured, and how the public and the environment will be protected during implementation of the RA.

1.6 REMEDIAL ACTION SCHEDULE

A preliminary schedule has been developed for implementation of the Supplemental RA

(Figure 1-3). Major components of the schedule leading up to the start of remedial construction include the selection of a contractor, preparation of a remedial action work plan (RAWP), making required logistical arrangements, and mobilizing equipment to the Site.

The selected remedial action contractor will prepare a RAWP. The RAWP will describe the Contractor’s proposed schedule, construction methods, and operational plan for conducting the work. The duration of RAWP preparation and reviews has been estimated as approximately three months. Once the RAWP is finalized and approved by NPS, the Contractor will mobilize

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to the Site and begin on-Site activities. The duration of the remedial construction is estimated to be approximately eight months.

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2.0 DESCRIPTION OF THE SELECTED REMEDY

To prevent direct contact (i.e., incidental ingestion, inhalation, and dermal absorption) by human and ecological receptors with contaminated soil above acceptable risk levels, the supplemental RA involves remediation of contaminated soils located within 2 feet of the ground surface. Specifically, the RA involves excavation and off-site disposal of contaminated soils or placement of 2 feet of clean fill over contaminated soils followed by seeding and tree/bush plantings to restore pre-existing conditions. Institutional controls (ICs) will be implemented to manage certain areas where subsurface contamination (below 2 feet) will remain on the Site.

The ROD defined contaminated soils as soils containing concentrations of COCs that exceed

RGs. RGs are numerical values above which unacceptable human health or ecological risks are present. In general, reported concentrations greater than the RGs indicate the sample and corresponding soil pose unacceptable risks and requires remediation. Concentrations less than or equal to the RGs indicate the corresponding sample and associated soil do not need to be remediated. The COCs and RGs established for the Site are summarized in Table 2-1.

The ROD requires remediation of contaminated soils present at the Site within 2 feet of the ground surface. In areas to be excavated, the ROD requires over-excavation of between 0.5 and 1.0 feet below the deepest sample depth with a COC concentration that exceeds a RG. The design methods used to determine the excavation depth, and an over-excavation allowance

(either 0.5 feet or 1.0 feet), for each additional excavation are described in Section 3.2.

2.1 DISPOSAL OF EXCAVATED SOILS

Section 7.0 describes the management of excavated soils, decontamination wastes, and construction wastes generated during the Supplemental RA. The requirements in Section 7.0 were developed to ensure the RA will be performed in accordance with the ARARs identified in the ROD, several of which apply specifically to the characterization, transportation and disposal of waste materials.

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2.2 PLACEMENT OF CLEAN FILL OVER CONTAMINATED SOILS

The long-term management plan of the Park includes placement of clean fill in depressions created by quarrying activities with the objective of reestablishing topography present when the Continental Army encamped at Valley Forge. This plan was established to achieve the mission of VFNHP to educate and inform present and future generations about the sacrifices and achievements of General George Washington and the Continental Army at Valley

Forge. Implementation of this plan began in 2014 when clean fill was placed in former quarries located outside the boundary of the ARS.

The FKP AOC is located in a portion of the park known as the Grand Parade, which is a historically significant area of the park. The Grand Parade is where the Continental Army paraded to celebrate an alliance with the French and showcased the Army as a unified, fighting force capable of defeating the British Army. Three of the additional remediation areas located within the FKP (FKP-B/M-NB-01, , FKP-C2-NB-01, and FKP-E-NB-01) are within the area where the Park master plan calls for placement of fill to restablish the historic topography.

Restoring historic topography may require as much as 60 feet of clean imported fill over the FKP remediation areas, which will provide a barrier to direct contact with contaminated soil as consistent with the RAOs. Since the timeframe for restoring historic topography is uncertain, the

RA includes placement of two vertical feet of clean imported fill over the existing ground surface in areas designated as FKP-B/M-NB-01, FKP-C2-NB-01, and FKP-E-NB-01. Prior to placing fill, these areas will be cleared of vegetation (tree stumps will be cut flush with the existing grade) and a warning layer will be installed on the existing ground surface.

2.3 PERFORMANCE VERIFICATION

The supplemental RD includes performance verification procedures to ensure that the supplemental RA meets the requirements of the ROD. These verification testing requirements are described in Section 5.0. These procedures include verifying that the AOCs included in this supplemental RA are remediated to the design dimensions and that all materials brought on-site

(including backfill, topsoil, seed mixes, and plants) meet the requirements of the supplemental

RD.

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2.4 SITE RESTORATION

A Planting and Restoration Plan is included in Volume 2 of this supplemental RD; it describes restoration activities that will be performed for portions of the Site impacted by the

RA.

2.5 INSTITUTIONAL CONTROLS

Contaminated soils located at depths greater than 2 feet bgs will remain in place (except when removed by the over excavation allowance – see Section 3.2). The ROD established requirements for ICs to be implemented where subsurface contamination will remain after completion of the RA. Section 3.3 describes the different types of areas that will require ICs.

The specific ICs to be implemented at the completion of the RA are described in Section 9.0.

2.6 PERFORMANCE STANDARDS

The 2012 RD Report provided performance standards as measureable metrics to ensure the RA meets the RAOs presented in the ROD. The performance standards summarized in the following subsections were developed from the Basis for Performance Standards in Appendix C of the ROD.

2.6.1 Remedy Overall

The remedy must be implemented, monitored, and maintained in compliance with the

ARARs identified in Appendix G of the ROD. Section 11.0 of this report describes what is required to ensure that ARARs are complied with during the Supplemental RA.

2.6.2 Contaminated Soil Remediation

The supplemental remedial design drawings provided in Volume 3 of this supplemental

RD delineates all soil within 2 feet of the ground surface at the Site known to exceed the RGs that will be remediated during the RA.

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Excavated soils will be managed in accordance with the procedures outlined in Section

7.0. A determination will be made regarding what type of disposal facility is appropriate for the excavated material (e.g., RCRA Subtitle C or Subtitle D waste disposal facilities), based on data from previous investigations and required waste characterization testing performed by the RA

Contractor.

2.6.3 Clean Fill and Backfill

The RA Contractor will be required to demonstrate compliance with the NPS Clean Fill

Criteria and the Commonwealth of Pennsylvania’s Management of Fill Policy for all imported soil material, common backfill, and topsoil, as required in the Construction Specifications (see

Volume 4, Section 02500). The RA Contractor will also be required to demonstrate that imported common fill has the structural and physical characteristics necessary to support the expected overlying land uses or habitats (e.g., grasslands, forested uplands, etc.). Imported topsoil must be fertile, natural soil, typical of the locality; substantially free of stones, roots, sticks greater than 2 inches in diameter or length, clay, peat, weeds and sod; and obtained from upland areas free of exotic plant seeds. Topsoil must contain organic matter content appropriate for the intended and desired vegetation and restoration scenario (e.g., grasslands, forest, etc.).

The Construction Specifications also require the Contractor to completely decontaminate all tools and equipment that come into contact with the contaminated soils during excavation, transport and disposal activities (see Volume 4, Section 02995). Decontamination will be completed prior to handling any imported clean soil.

2.6.4 Site Restoration/Revegetation

Excavation areas will be restored to establish ground surface elevations and topography similar to the conditions that existed prior to the RA. Remediation areas that will not be excavated, will be filled to elevations indicated on the design drawings (2 vertical feet over the designated remediation area and graded at the edges at a slope of no less than 5 horizontal feet to one vertical feet). All areas disturbed by supplemental RA activities will be restored to establish vegetative covers similar to the conditions which existed prior to the RA with the exception of

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areas where trees currently exist; these areas will not be reforested and wetlands will be planted with a meadow seed mix. The Planting and Restoration Plan included in Volume 2 describes the site restoration methods and performance standards associated with restoring disturbed areas.

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3.0 DESIGN METHODS

The supplemental RD establishes remediation boundaries, access routes, storm water management controls, and ICs for subsurface contamination. This section describes the methods to design these elements of the supplemental RA.

3.1 ADDITIONAL REMEDIATION AREA BOUNDARIES

The additional remediation areas described in this report were designed based on sample locations and analytical results, and locations of physical barriers. Sections 4.1 to 4.5 describe the design basis for each additional remedation area. FSI completed the 2013-2014 excavation verification sample collection and analysis in accordance with their sampling and analysis plan

(FSI, 2013). Subsequent NB samples were collected by JCO and NPS in accordance with JCO’s sampling and analysis plan (JCO, 2013). All verification and NB sample locations are shown on

Figures 4-2 to 4-11.

Physical barriers were used to design four of the additional remediation areas (FKP-E-

NB-01, FKP-F/G/J-NB-01, FKP-K/L-NB-01, and SAQ-A-NB-01). The 2012 RD Report identified Site features such as quarry walls, roads, and railroad beds as physical barriers that define the maximum extent of contaminated soil remedation in a specific AOC. Detailed descriptions of physical barriers used to design the four individual additional remediation areas listed above are provided in Section 4.2 (FKP) and 4.4 (SAQ). General characteristics of these physical barriers and rationale for inclusion in the design are discussed below.

Quarry walls and steep slopes were identified as physical barriers based on the probable mechanisms which resulted in contaminated soils in a specific AOC, and the characteristics of the slopes. For example, in the FKP-E-NB-01 area, asbestos was likely deposited as a slurry waste piped from the Keene plant area. The slurry waste was typically placed on the floor of inactive quarries as fill material. Based on this information, the asbestos soil contamination is likely limited to the floor of the inactive quarry. Therefore quarry walls provide a physical barrier which would have prevented migration of the soil contamination beyond the quarry floor.

Paved surfaces were identified as physical barriers in several AOCs. Pavement is an effective barrier which may have prevented deposition of contaminants in those areas if the pavement was present during the time of operations of the Keene plant, but in any

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event will prevent access to subsurface soils in the future. The presence of pavement on the ground surface would prevent exposure of ecological or human health receptors to contaminants if they are present underneath the pavement. During the RD, County Line Road, Station Road, Trooper Road, PA Route 23, the Lower Visitor Center Parking Lot, and the Maintenance Area Access Road were identified as pavement physical barriers.

3.2 DESIGN OF EXCAVATION DEPTHS

For remedation areas where contaminated soil will be excavated and removed off-site for disposal, design excavation depths were based on the requirements of the ROD and available analytical data. The ROD established two requirements for design excavation depths:

• Total excavation depths (including over-excavation – see below) must be less than or equal to 3.0 feet bgs.

• An excavation depth of 2.0 feet bgs and installation of a warning layer will be implemented for excavations where COC concentrations that exceed the RGs are known to exist at depths greater than 2.0 feet bgs.

• The ROD requires an over-excavation of between 0.5 and 1.0 feet below the deepest sample depth with a COC concentration that exceeds an RG.

Five of the additional excavation areas (FKP-A-NB-01, FKP-F/G/J-NB-01, FKP-K/L-

NB-02, WCRS-B-North-NB-01, and WCRS-D-NB-02) include installation of a warning layer on the excavation floor. These excavations are described in Section 4.0. The design depth for these excavations is 2.0 feet bgs, determined based on the ROD and the 2012 RD Report.

The total design depth (including over-excavation) of excavations where a warning layer was not included in the design were selected in the 2012 RD Report based on whether the deepest sample collected near an excavation area contained COC concentrations that exceed the applicable RGs. If the deepest samples contained COC concentrations that are less than the RGs, then an over-excavation depth of 0.5 feet was used in the design. If the deepest samples in the area contained COC concentrations that exceed the RGs, then an over-excavation depth of 1.0 feet was used.

This same method was used to determine design depths for the additional excavation areas, using laboratory data obtained from horizontal verification (HV) and NB samples. For all

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of the additional excavation areas where a warning layer is not included in the design, the deepest HV and/or NB samples contained COC concentrations that are less than the RGs. These data are sufficient to include an over-excavation depth of 0.5 feet in the overall excavation design depth. Therefore, the design excavation depth of the additional excavations where warning layers are not included in the design are 0.5 feet deeper than the deepest HV or NB sample that contained a COC concentration that exceeds the RGs.

3.3 INSTITUTIONAL CONTROLS

The ROD requires that contaminated soils located at depths greater than 2 feet bgs be left in place (except if removed by the over-excavation allowance described above) and ICs implemented to prevent future exposure of potential receptors to the remaining subsurface contamination. The 2012 RD Report described two types of IC areas for the Site:

• Type 1 areas include portions of the Site that are known to contain shallow soil (depths equal to or less than 2 feet bgs) contamination for at least one COC (thus requiring remediation) but also contain subsurface soil (depths greater than 2 feet bgs) contamination.

• Type 2 areas include portions of the Site that contain (or are suspected to contain based on historical information) subsurface soil (depths greater than 2 feet bgs) contamination for at least one COC, but do not contain shallow soil contamination (thus not requiring remediation).

As discussed in Section 3.2, Type 1 areas will be excavated to a depth of 2.0 feet bgs or an additional 2 feet of vertical clean fill will be placed over the area as part of the remediation (to eliminate shallow soil RG exceedances within 2 feet of the ground surface). ICs will include installation of a warning layer at the base of the 2-foot excavation or over the existing ground surface prior to placement of clean fill. Type 1 area boundaries were determined using the design methods described in Section 3.1. The dimensions and locations of seven additional Type

1 IC areas are described in Section 4, and shown (along with the previously established areas from the 2013-2014 RA) on Figures 4-2 to 4-11 and Figure 9-1.

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Requirements for Type 2 IC areas are described in Sections 3.3 and 9.0 of the 2012 RD

Report. These requirements remain in effect; no additional Type 2 IC areas are described in this

Supplemental RD.

3.4 REMEDIATION AREAS ACCESS

Access routes to each additional remediation area have been designed to limit impacts to existing trees, areas of soft soils, surface waters, and wetlands. The design access routes are shown on the design drawings in Volume 3. If the RA Contractor believes that a different access route from what is shown on the design drawings would be beneficial to their implementation of the RA, then the Contractor may request permission from NPS to modify the design access routes shown in Volume 3. Written NPS approval must be obtained for any and all modifications to design access routes or staging areas.

3.5 EROSION CONTROL AND STORM WATER MANAGEMENT

Erosion control and stormwater management requirements for the supplemental RA are specified for areas where disturbed soils could be eroded or otherwise impacted by stormwater.

Erosion controls include silt fences; rolled erosion control products (RECPs); aggregate check dams; construction entrances; and administrative controls for scheduling excavation activities, limiting site activities during precipitation events, and managing material stockpiles. Technical requirements for erosion control and stormwater management are outlined in Section 4.8 and described in detail in the Construction Specifications (Volume 4, Section 02805).

3.6 WETLANDS MANAGEMENT

Wetlands at the Site were identified and delineated as part of the 2012 RD (see Appendix

D, Wetland Delineation Report in the 2012 RD Report). Six different wetland areas located in the FKP and WCRN AOCs were identified. One of these wetlands (located west of FKP-B3, see

Figure 4-4) will be impacted by additional excavation area FKP-C2-NB-01. Remediation work in this area will only proceed at a time when there is no audible evidence that the wetlands are being utilized as habitat for frogs (Pseudacris crucifer, commonly known as spring peepers).

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3.7 THREATENED AND ENDANGERED SPECIES

During the 2012 RD, a habitat assessment report for two threatened/endangered species

(the Bog Turtle and the Eastern Redbelly Turtle) was prepared for the Site (see Appendix E of the 2012 RD Report). This assessment report confirmed that suitable habitats for these turtles was not present in the MAR, FKP, SAQ, HIB, or WCRS AOCS. Therefore specific actions to mitigate potential impacts to threatened and endangered species are not necessary for the additional remediation areas described in this report.

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4.0 BASIS OF DESIGN

During the 2013 and 2014 RA, FSI completed the 65 remedial excavations in 11 AOCs described in the 2012 RD Report. FSI completed these excavations to the design dimensions, and then collected horizontal (HV) and vertical (VV) verification samples from the excavation sidewalls and floors, respectively. HV samples collected from 17 excavations in five AOCs

(MAR, FKP, WCRS, SAQ, and HIB) contained concentrations of COCs that exceed the RGs.

Warning layer material was installed vertically as a separation fabric barrier along the portions of these excavation sidewalls with RG exceedances to isolate the remaining contaminated soils from the clean backfill used to complete the 2013-2014 excavations. Background information regarding the use of separation fabric barrier at the Site is provided in Appendix A. After installing the separation fabric barrier, FSI proceeded to backfill and seed these excavations.

To address the shallow soil contamination identified by the HV sample RG exceedances, JCO and NPS collected new boundary (NB) samples from undisturbed soils in nearby locations.

NB samples were collected and analyzed in accordance with JCO’s Site-specific sampling and analysis plan (JCO, 2013). JCO completed the design of additional remediation areas using data obtained from these NB samples (and the original HV sample data) and the locations of physical barriers as described in Section 3.1. The designs for these additional remediation areas include removal of the separation fabric barrier installed by FSI during the 2013-2014 RA, except in the remediation areas to receive fill where it can remain. The installed locations of separation fabric barrier are shown on the Design Drawings (Volume 3 of this report). The specific design basis for each additional remediation area is described in Sections 4.1 to 4.5, organized and labeled based on the AOCs and excavations identified in the 2012 RD Report.

Some of the areas excavated by FSI in 2013-2014 were restored with tree plantings and the areas surrounded by deer fence to prevent browsing on the new plants. Portions of the deer fence installed around nine excavations (MAR-A, FKP-E, FKP-F, FKP-J, FKP-K, FKP-M, HIB-

C2, SAQ-A, and WCRS-G) are located within the footprint of additional remediation areas described in this supplemental RD. To remediate these additional areas, the existing deer fence must be removed. The Contractor will be required to sequence remediation activities to limit the

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amount of time that new plantings are not completely surrounded by deer fence. Precautions will be described in the Contractor’s RAWP. Alternatively the Contractor can move the deer fence such that it is completely inside the previous excavation, where possible, (but still protective of all of the plantings) prior to starting the remediation of the new area. The existing fence materials currently in contact with contaminated soils must be decontaminated and approved by

NPS prior to re-use.

The Supplemental RA also includes the removal of the existing split-rail vinyl fence, fence posts, and warning signs that were previously installed to prevent visitor access to portions of the Site known to contain asbestos contamination, and the closure of monitoring wells installed at the Site during the remedial investigation. Requirements for warning fence removal and monitoring well closure are described in Sections 4.6 and 4.7, respectively.

Table 4-1 summarizes the COCs and design dimensions (depth, area, and volume) for each additional remediation area. The names of the additional remediation areas identified in

Table 4-1 are based on the naming convention from the 2012 RD Report.

Figure 4-1 presents an overview of the Site, and an index showing the areas covered by the detailed figures that follow (Figures 4-2 to 4-11). Figures 4-2 through 4-11 present the following: design remediation boundaries for each additional remedial area; NB and HV sample collection locations; locations of physical boundaries; and design excavation depths. The

Construction Drawings (Volume 3, Sheets 3 - 6) present the detailed boundaries of the additional remediation areas that are outlined on Figures 4-1 to 4-11 as well as construction layout details, a final grading plan (for areas of proposed fill, where the final grades will be at least 2 feet higher than the existing grades), erosion controls, access routes, decontamination areas, and implementation details.

Descriptions of each additional remediation area and the process used to delineate the new remediation boundaries are provided in the following sections.

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4.1 MAINTENANCE AREA RUINS

The MAR AOC lies east of the Park maintenance area access road and north of County

Line Road, southwest of the FKP AOC. The MAR AOC is surrounded by forests, meadows and developed roads. The 2012 RD Report included designs for two excavation areas (MAR-A and

MAR-B) in the MAR AOC which were excavated and backfilled in 2014. While the verification samples collected from MAR-B contained COC concentrations that are less than the RGs, one of the 16 VV samples and three of the 16 HV samples collected from MAR-A contained benzo(a)pyrene, lead, and/or mercury concentrations that exceed the RGs. These data are summarized on Table 4-2. Based on these data, JCO collected NB samples from locations generally south of MAR-A. Data from these samples were used to design an additional excavation that was completed and backfilled by FSI in 2014: MAR-A-NB-01; and another additional excavation area this is included in the Supplemental RA: MAR-A-NB-02.

Previously completed MAR-A-NB-01 was designed to address shallow soil contamination identified by the one VV sample from the original MAR-A excavation that contained an unacceptable mercury concentration. A description of the design basis for this excavation area, which was completed in 2014, is provided in Section 4.1.1 to provide a complete record of all additional excavations performed for MAR-A.

MAR-A-NB-02, included in this Supplemental RA, was designed to address shallow soil contamination identified by the three HV samples collected from the MAR-A sidewalls that contained unacceptable concentrations of COCs. This excavation is described in Section 4.1.2.

4.1.1 MAR-A-NB-01

The 2012 RD Report included a design excavation depth of 1.0 feet BGS for MAR-A.

Based on this design depth, the 2012 RD report required sixteen VV samples to be collected from eight locations in MAR-A at depth intervals of 1.0-1.5 and 2.0-2.5 feet bgs (0-0.5 and 1.0-

1.5 feet below the excavation floor). VV sample MAR-A-VV-SS-13, collected from a depth of

1.0-1.5 feet bgs, contained a benzo(a)pyrene concentration that exceeds the RGs; all other

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verification samples contained benzo(a)pyrene concentrations that are less than the RG (see

Table 4-2). The design dimensions for MAR-A-NB-01 were selected based on the locations of

VV samples surrounding MAR-A-VV-13-SS, as shown on Figure 4.2. A design excavation depth of 1.00 feet below the MAR-A excavation floor was selected for MAR-A-NB-01. This design excavation depth included 0.5 feet of over-excavation beyond the depth of sample MAR-

A-VV-13-SS increasing the total excavation depth for MAR-A-NB-01 to 2.0 feet bgs).

MAR-A-NB-01 was excavated by FSI in 2014. After completing MAR-A-NB-01 to the design dimensions recommended by JCO, FSI collected 5 VV samples from the floor of this additional excavation.