P197_1620400 SIGN RFP_Parts 6 (5 of 11).pdf

Land Disturbance Work Plan

P199 Aircraft Maintenance Hangar

MCAS Cherry Point

Havelock, North Carolina

Revised January 22, 2022

NAVY Contract No. N40085-20-C-8051

Prepared For:

OICC Florence – ROICC Cherry Point

P199 Aircraft Maintenance Hangar MCAS Cherry Point

Havelock, North Carolina

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Figure 2 P-199 Construction Footprint and 2018

OU14 Lower Surficial Aquifer Plumes Marine Corps Air Station Cherry Point

Cherry Point, North Carolina

0 500250 Feet

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Legend +U Lower Surficial Aquifer Monitoring Well

TCE (>3 µg/L to 3.7 µg/L) VC (>0.03 µg/L to 5.8 µg/L) 1,2-DCA (>0.4 µg/L to 2.2 µg/L) cis 1,2-DCE (>70 µg/L to 83 µg/L) Plume Boundary (dashed where inferred)

Underground Culvert Stream IRP Site 90 OU14 Study Area Boundary P-199 Construction Footprint NOTES:

No exceedances for 1,1-DCA.

Plume extents are based on the 2018 OU14 LTM results.

MCAS, Cherry Point, NC i

Table of Contents

1.0 PROJECT INFORMATION ............................................................................... 1-1

1.1 Project Authorization ............................................................................... 1-1

1.2 Site Location and Project Description ..................................................... 1-1

1.3 Purpose and Scope of Services .............................................................. 1-2

2.0 CONSTRUCTION ACTIVITIES ......................................................................... 2-1

2.1 SCOPE OF WORK ................................................................................. 2-1

2.1.1 Aircraft Maintenance Hangar: .................................................... 2-1

2.1.2 Paraloft Facility: ......................................................................... 2-2

2.1.3 DEMOLITION AND DECONSTRUCTION ................................. 2-2

2.2 Concrete Slabs-On-Grade and Airfield Concrete Pavement ................... 2-3

2.3 Aircraft Maintenance Hangar Foundation Support – Driven Piles ........... 2-4

2.3.1 Driven Pile Spacing ................................................................... 2-6

2.3.2 Construction/Installation Considerations ................................... 2-6

2.4 Utility Locates .............................................................................................. 2-8

2.5 Preliminary Data Review ............................................................................. 2-9

2.6 Excavation ................................................................................................... 2-9

2.7 Backfill ......................................................................................................... 2-9

3.0 MANAGEMENT OF EXCAVATED SOILS AND MATERIALS ......................... 3-1

3.1 Management and Characterization of Excavated Materials .................... 3-1

3.2 Soil Screening ......................................................................................... 3-2

3.3 Soil Stockpiling ....................................................................................... 3-2

3.4 Soil Testing ............................................................................................. 3-3

3.5 Soil Disposal ........................................................................................... 3-5

3.6 Backfilling ................................................................................................ 3-5

3.7 Management and Characterization of Liquids ......................................... 3-6

4.0 HEALTH AND SAFETY .................................................................................... 4-1

5.0 REPORTING ..................................................................................................... 5-1

6.0 REFERENCES .................................................................................................. 6-1

7.0 APPENDICES………………………………………………………………………..7-1

ii

APPENDICES

APPENDIX A – CIVIL DRAWINGS

APPENDIX B – GEOTECHNICAL REPORT

APPENDIX C - WELL DATA

APPENDIX D - VAPOR BARRIER SPECIFICATIONS

APPENDIX E – PROJECT LOCATION WITHIN OU14

APPENDIX G - SUBMITTAL REGISTER

APPENDIX H - SCHEDULE

APPENDIX I - DESKTOP VI EVALUATION

APPENDIX J - 1ST REVIEW REGULATORY COMMENTS (WITH RTCS)

APPENDIX K - CONSTRUCTION START REQUEST, ROICC

APPENDIX L - LETTER OF SUPPORT, NAVFAC

APPENDIX M - CONDITIONAL LETTER OF APPROVAL TO PROCEED

APPENDIX N - PDA TEST RESULTS

APPENDIX O - VIBRATORY TEST DATA

APPENDIX P - CPT TEST RESULTS

APPENDIX Q - PILE STATUS REPORT

APPENDIX R - NCDEQ VI EVAULATION COMMENTS (WITH RTCS)

APPENDIX S - 2ND REVIEW REGULATORY COMMENTS (WITH RTCS)

APPENDIX T - REGULATORY REVIEW TIMELINE

LIST OF ABBREVIATIONS

Abbreviation Term/Phrase/Name

1,1-DCA

1,2-DCA

AMH

BLS

CERCLA

CFR

cis-1,2-DCE

DEHP

DOT

EAD

EM

EPA

Ft2

FFA

GER

HAZWOPER

HEPA

IWTP

1,1-dichloroethane

1,2-dichloroethane

Aircraft Maintenance Hanger

Below Land Surface

Comprehensive Environmental Response, Compensation, and Liability Act Code of Federal Regulations cis-1,2-dichlorethane diethylhexyl phthalate

United States Department of Transportation

Environmental Affairs Department

Engineer Manual

Environmental Protection Agency square feet

Federal Facility Agreement

Geotechnical Engineering Report

Hazardous Waste Operations and Emergency Response high-efficiency particulate air industrial wastewater treatment plant iii

LDWP

LUC

MCAS

NCDEQ

OSHA

OU

PCB

PFAS

PID

Land Disturbance Work Plan land use controls

Marine Corps Air Station

North Carolina Department of Environmental Quality

Occupational Safety and Health Administration

Operable Unit polychlorinated biphenyl per- and polyfluoroalkyl substances photoionization detector

POL

ppm

SOP

SVOC

TCE

TCLP

USACE

VOC

VC

petroleum, oil, and lubricants parts per million standard operating procedure semivolatile organic compound trichloroethene toxicity characteristic leaching procedure

United States Army Corps of Engineers volatile organic compounds vinyl chloride

1-1

1.0 PROJECT INFORMATION

1.1 Project Authorization

The contractor has been authorized to proceed with P199 Aircraft Maintenance Hangar & P235

Flightline Utility Modernization located within the Marine Corps Air Services (MCAS) Cherry

Point, North Carolina. The work will be performed in accordance with Contract No. N40085-20-

C-8051.

1.2 Site Location and Project Description

The project site is located within the MCAS Cherry Point military installation in North Carolina.

The development at the site is planned to consist of Flightline Utility Modernization and Aircraft

Maintenance Hanger. The project will upgrade, renovate and modernize utilities in the core area of the base to serve the future airfield facilities. Utilities to be modernized include water, sanitary sewer, storm sewer electrical, telecommunications, natural gas and steam. Roadway improvements will also take place. More detailed construction activities provided in Section 2.0

Activities.

It is understood that the project sites are within a land use controls (LUC) boundary. Therefore, this work plan has been prepared and submitted to the MCAS Cherry Point Environmental

Affairs Department (EAD) for approval prior to any work beginning at the sites. LUC in the project area includes the prevention of aquifer use, prohibition of intrusive activities with the potential to cause human exposure to groundwater without prior regulatory approval by United

States Environmental Protection Agency (EPA) and North Carolina Department of

Environmental Quality (NCDEQ), and monitoring of potential impacts until remediation goals have been reached. Evaluations for the potential for vapor intrusion impacts from new building construction, major physical modifications, or changes in occupancy/usage of existing structures within the LUC boundaries will be performed through the IR program under direction of the

MCAS Cherry Point Partnering Team. The maintenance of the integrity of any existing or future monitoring or remediation system at the site that is regulated under the Comprehensive

Environmental Response, Compensation, and Liability Act will be evaluated accordingly.(see the Final Remedial Design for Land Use Controls Operable Unit 14, Site 90, dated March 2010).

The project sites are located within Operable Unit (OU) 14. In December 1994, MCAS Cherry

Point was placed on the USEPA’s National Priorities List, established under the Comprehensive

Environmental Response, Compensation, and Liability Act (CERCLA). In May 2005, a Federal

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Facility Agreement (FFA) was executed for MCAS Cherry Point that develops a course of action for future work requirements at each site listed in the FFA. OU 14, Site 90 is located in the west-central portion of the MCAS Cherry Point flightline. OU 14 consists of a broad expanse of concrete tarmac, buildings, taxiways, and some grassy areas adjacent to Runway 14L. Site 90 consists of the area included and surrounding Building 130, a large aircraft hangar approximately 5,000 feet north-northwest, terminating near an unnamed stream adjacent to

Runway 14L.

Constituents of concern for OU 14 include the following:

1,1-Dichloroethane (1,1-DCA)

1,2-Dichloroethane (1,2-DCA)

Chloromethane cis-1,2-Dichloroethene (cis-1,2-DCE)

Methylene Chloride

Tetrachloroethene (PCE)

Trichloroethene (TCE)

Vinyl Chloride (VC) per- and polyfluoroalkyl substances (PFAS)

The COCs associated with OU14 are the VOCs listed in the OU14 Record of Decision, and

PFAS are considered to be constituents of potential concern (COPCs) as they are emerging contaminants that are currently being evaluated.

1.3 Purpose and Scope of Services

This Land Disturbance Work Plan (LDWP) presents the management framework to be applied to activities performed during the P199 Aircraft Maintenance Hangar.

The purpose of the LDWP is to fulfill the following objectives:

Present methodology that sets forth standards for the sampling of areas in which land disturbance activities (i.e. – excavation, grading, pouring concrete, etc.) are performed.

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Outline management strategies for soil characterization, waste management, and reporting procedures to be used when sampling, handling, and disposing of materials generated as a result of land disturbance activities.

The management framework presented in this LDWP will be applied to land disturbance activities (i.e.- excavation, grading, pouring concrete, etc.) performed at MCAS that meet all of the following criteria:

Any part of the disturbed area is located within a known or suspected OU.

The activity is not performed in response to routine maintenance.

The activity is not part of an emergency response effort or actions to abate immediate threats to human health or the environment.

Furthermore, the procedures and requirements presented in this plan shall not inhibit the abatement of immediate threats to human health or the environment.

Land disturbance activities will be conducted in accordance with LUCS (NAVY/MCAS LUC guidance), Occupational Safety and Health Administration (OSHA) safety standards, the United

States Army Corp of Engineers (USACE) Engineer Manual (EM) 385-1-1 Safety and Health

Requirements, and the project-specific safety and health plan developed by the contractor(s) performing the field activities detailed in this LDWP.

If the Yorktown confining unit is unintentional/accidentally impacted during any construction activities, regulatory agencies will be notified as soon as possible, but no later than two days.

Final Land Disturbance Work Plan Construction Activities MCAS, Cherry Point, NC

2-1 April 2020

2.0 CONSTRUCTION ACTIVITIES

Activities performed during the demolition of existing structures and installation of the driven foundation piles will result in the excavation of soils. These land disturbance activities are within a known or suspected OUs and are not part of routine maintenance or emergency response activities. The project sites are within a LUC boundary. Soil and groundwater contamination have been identified and may be encountered. Special protocols will be implemented within the

LUC boundary as further defined herein. The field staff will be made aware of the LUC condition and requirements by the Environmental Manager and will include the following:

No intrusive work within the LUC boundary will commence until this Work Plan has been reviewed and approved by MCAS Cherry Point EAD, EPA and North Carolina

Department of Environmental Quality.

Removal of impacted soils/groundwater will be limited to the immediate work areas and handled in accordance with this LDWP and CERCLA guidance.

The location of the groundwater contaminant plumes are depicted on the figures in appendix (E) provided. There are no known areas of vadose zone soil contamination within the proposed hangar project location. Based on a review of historical information in the area of construction, by the Geotechnical Engineer, vadose zone soil contamination is not expected to exist. and is substantiated by the review of the MCAS

Cherry Point POL Document Library.”

The work at the Aircraft Maintenance Hanger P199 includes the following:

2.1 SCOPE OF WORK

2.1.1 Aircraft Maintenance Hangar:

The two-squadron hangar will include a high bay space for a combined 12 aircraft, 01 Level aircraft support shops, 02 Level administrative spaces, and 02 Level Secure Spaces. The administrative and support shops part of the building will be constructed with non-load bearing

CMU walls. The hangar bays will have structural steel framing featuring long-span roof trusses and pre-finished insulated metal roof. The exterior walls will use insulated pre-cast concrete panels with integral brick veneer and textures. The building will be supported on concrete pile

2-2 April 2020 foundations. An extended roof element acts as a covered entry over the primary entrances to the squadron first floor lobbies. There will be a building expansion joint between the hangar bays and the administrative/support shops area. Special construction features include 400Hz and 270v DC power, F-35 aircraft maintenance workstations, under slab passive vapor barrier system, alarm systems, communication connections at aircraft parking locations, seismic construction, hazardous material storage areas, explosive material storage areas, sound attenuation, vaults, and aircraft cooling systems. Project includes taxiway remarking and the renovation and expansion to existing aircraft parking aprons in order to provide electrical grounding, work station kiosks and sun shades. Project also constructs additional aircraft apron and an aircraft wash rack with utility control building and provides two explosive storage ready service magazines. The project includes additional site work, secondary utilities, and other services to meet criteria as specified in this Request for Proposals (RFP). Built-in equipment will include a generator, aqueous film forming fire (AFFF) system, two 5-ton bridge cranes, two passenger elevators, sound attenuation with secure space rooms and for flight line noise, and seismic bracing as required.

2.1.2 Paraloft Facility:

The Paraloft building will contain rooms for packing of parachutes, storage and repair of ancillary aviation equipment, Parachute repair, Oxygen regulator shop, and general building support rooms. The design features a roof structure of conventional steel framing with standing seam metal roofing. CMU structured masonry cavity walls with utility brick above a split face

CMU wainscot provide the exterior wall finish to match with base design standards. An extended roof element acts as a covered entry over the primary entrance. Project includes one explosive storage ready service magazine, additional site work, including parking, exterior pedestrian spaces, secondary utilities, and landscaping as well as other services to meet criteria as specified in this Request for Proposals (RFP). The Paraloft Facility is not located within the

OU14 LUC boundaries and is not a subject of this review.

2.1.3 DEMOLITION AND DECONSTRUCTION:

Buildings/Structures as well as all associated hardscape, waste and debris to be demolished include:

Facility #140 (Paraloft – 11,108 SF)

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Facility #3769 (Brick Storage Facility – 10,134 SF)

Facility #209545 (Wash Rack – 7,695 SF)

Abandoned deep foundations for Facilities #130, 1700, and 1701

Abandoned utilities to mainline connections of facilities demolished under early demolition project

The buildings shall be completely removed, including below grade shallow foundations, slabs, and underground utilities within the project site. Any deep foundations will be saw cut a minimum of five feet below grade. The adjacent site shall be restored to provide continuous streets and capped utilities as indicated on the Civil drawings. Demolition also includes removal of salvaged items to be turned over to the Owner.

2.2 Concrete Slabs-On-Grade and Airfield Concrete Pavement

Concrete Slabs-On-Grade will be used as floor slab in the Paraloft Building and the Aircraft

Maintenance Hangar to support floor loadings. Additionally, concrete slab pavement will be used at the access road of the Aircraft Maintenance Hangar and the Airfield Apron.

CATLIN recommends that design of concrete slabs-on-grade be based on a maximum Modulus of Subgrade Reaction (ks) of 150 pounds per cubic inch (pci), as related to a standard 30-inch diameter plate load test, for conditions above the water table. For analysis of a mat foundation against sliding, we recommend using a granular base material with a Coefficient of Friction () of

0.50, based on the soil’s angle of internal friction, , of 30 degrees.

Full displacement piles will be installed as part of the maintenance hangar project to minimize environmental impact. The piles will be driven to a depth of

30 feet below existing grade to attain optimal axial working capacities. (GER, Report of Geotechnical Site Characterization: “Summary and Recommendations

“, section 4 AMH Foundation Support.

We also recommend furnishing a passive vapor barrier below the slabs-on-grade, as well as a capillary cut-off layer of 12 inches of clean sand placed below the vapor barrier in the Paraloft Building which is to be inhabited. In addition, an ASTM E1745 Class A vapor barrier underlain with 6 inches of NCDOT dense graded aggregate base (ABC) should be placed under the concrete slab in the Aircraft Maintenance Hangar which support the

2-4 April 2020 aircraft loads and including the Shop and Admin areas. A minimum 6 inch of NCDOT dense graded aggregate base (ABC) should also be placed under the concrete pavement at the airfield apron and driveway. Additionally, a layer of geotextile should be placed under the ABC stone to improve the subgrade stiffness, pavement drainage and prevent the migration of subgrade soil into the aggregate base. These recommendations are predicated on the verification of suitable subgrade soils through proof rolling and compaction testing, as summarized in GER Section 4.7 . Trench utility Backfilling will be under the slab vapor barrier which will prevent vapor transmission from the utility trench.

Any piping will be sealed IAW manufacturer’s instructions. It is also noted that the hangar bay, shops areas, and all corridors will have resinous epoxy covering over the concrete adding layer of protection.

The Vapor barrier will be subject to a prep placement inspection to verify compliance with both manufacturer and design requirements. The vapor will have all seams sealed and taped and will lap up onto foundations, piers and caps. Penetrations will be sealed using manufacturer approved products. Any tears or puncture will be repaired prior to or during concrete placement. The barrier will be installed continuous under the full slab.

The vapor barrier installation instructions along with a prep placement inspection checklist are included in the appendix (D). In the OU14 Remedial Investigation, a vapor intrusion screening evaluation was performed to assess impacts from VOCs in the groundwater to indoor air. The OU14 vapor intrusion evaluation results determined no need to mitigate vapor issues resulting from chlorinated VOCs for OU14 buildings under current industrial exposure scenarios. Conservative estimates of indoor air concentrations were calculated by using the concentrations in groundwater of the surficial aquifer and comparing them to regulatory standards. Based on this vapor intrusion evaluation and with VOC concentrations in groundwater decreasing over time, no vapor intrusion sampling is currently proposed for this project. Please see the 2020 VI screening Letter located within Appendix D for additional information.”

2.3 Aircraft Maintenance Hangar Foundation Support – Driven Piles-

General Considerations:

The Aircraft Maintenance hangar will consist of a 180,000 square foot, multistory, low rise building with column loads ranging from about 350 kips in compression and 250 kips in tension. Buildings

2-5 April 2020

130, 1701 and several smaller buildings in this area have been demolished, and the pile foundations of existing structures will be left in place. Proposed site grading is unknown at this time, but new cuts and fills for new grading is anticipated to be one foot or less.

Driven Pile Recommendations:

Based on the current site conditions and structural loading, CATLIN recommends that the proposed Aircraft Maintenance Hangar be supported on prestressed concrete driven piles.

The GER Report of Preliminary Geotechnical Site Characterization originally recommended deep (approximately 65-70 feet BLS) driven Prestressed Concrete Piles

(PCP) for the Aircraft Maintenance Hangar. However, due to concerns that the deep piles will penetrate the soft clay layer and cause contamination of the aquifer below the clay layer, shorter pile options were evaluated. To meet the structural specifications and to minimize the potential for contamination of the aquifer the GER recommends 30 feet long piles to avoid penetrating the soft/silt clay layer at a depth of 40 feet BLS.

To meet the structural specifications for loadings and deformations, and to minimize the potential for contaminant transport below the soft clay strata, the GER recommends PCP driven piles for the Aircraft Maintenance Hangar. The pile vertical and lateral capacities and estimated settlement under loadings equal to the allowable compressive capacities are shown in the table below:

Pile Size (in.)

Penetration Depth, BLS (Tip

Elevation) (ft)

Allowable Compressive

Capacity (kips)

Allowable Uplift

Capacity (kips)

Settlement (in.)

Allowable Lateral Capacity, Free Head Pile Top

Deflection = 1 in. (kips)

14 x 14 -30 (-5 ) 102 20 <0.5 12

The ultimate vertical capacities and settlements of the driven piles were calculated using APILE program. A factor of safety of 2.0 was used for the allowable compressive capacity determination and a factor of safety of 3.0 was used for the allowable uplift capacity determination. Lateral capacities for the piles were calculated utilizing LPILE analysis. The allowable lateral capacities were determined under the criteria that the allowable horizontal deflection of the pile head is 1.0 inch. The axial thrust utilized in the lateral analysis is equal to the allowable axial compressive load corresponding to the pile length used (see previous table for values). Larger axial thrust

2-6 April 2020 values may reduce lateral capacities. The results of the APILE and LPILE analysis are included in Appendix (H) of CATLIN Reportlocated in Appendix B Geotechnical Report)

2.3.1 Driven Pile Spacing:

In order to prevent a reduction in axial capacity due to “group effect”, piles should be installed with a minimum center-to-center spacing of 3 times of pile side dimensions. If the existing piles are left in place, there is no reduction of capacity to the proposed piles in the foundation. It is recommended that the spacing of new piles to old piles be a minimum 2 feet center to center (or

1 foot edge to edge). It should be noted that although the capacities of the pile do not change, driving of the pile may be more difficult due to densification of the foundation from the existing piles.

2.3.2 Construction/Installation Considerations:

The pile tips are expected to terminate at a depth below the ground surface of approximately 30 feet but are not expected to penetrate a full 35 feet. The soil profile from the GER [Geotechnical

Engineering Report dated August 28, 2017] which shows the approximate location of the soft confining layer is provided. It is recommended that several overlength test piles (at least 5 feet longer than anticipated production piles), or indicator piles, be driven to establish pile driving criteria, production pile lengths, and the need to auger pilot holes prior to driving for production piles. Piles are typically ordered longer than production piles to provide space above the ground surface for static testing, not to drive it to full depth. The test pile is driven to determine the optimum capacity which occurs a few feet above the confining layer. The test pile driving is monitored with each stroke of the hammer, so that if the pile capacity decreases as the pile tip approaches the confining layer, the pile driving is terminated, and strength parameters are determined at that depth. The pile tip is expected to stop a few feet above the soft confining unit and is not expected to penetrate the confining unit. Avoiding the soft confining layer also maximizes the pile capacity and is the most advantageous to the pile designers in addition to restricting the environmental concerns.

Production piles should not be ordered until the length estimates have been determined and verified; however, the overlength test piles can be driven in the locations for production piles. A total of nine test piles will be utilized. Two of the test piles will be tested with static loads. The remaining seven test piles will receive PDA testing. The test piles will not be driven further than

2-7 April 2020

35 ft bgs with 30-32 bgs being the goal. The test piles can be used as production piles if testing demonstrates adequate and the excess length will be cut off. If there is any modification to the test pile or production pile depths or type, EPA and NCDEQ will be notified prior to implementing any changes. The test pile reports will be provided to NAVFAC for review who in turn will provide to NCDEQ and the EPA for review. The test pile reports should include the recommended production pile length. The start of production piles will be pending regulatory approval of the test pile data. During the installation of the test piles, vibration testing will be conducted and included in the test pile report. Vibration monitoring will be performed during test pile installation using seismometers. Instruments will be located on the ground surface adjacent to the nearest active well to pile driving operations. Peak particle velocity and frequency will be measured and monitored. Driving operations will be stopped and modified if PPV and frequency exceed Figure

B-1 Safe Levels of Blasting Vibration for Houses using a Combination of Velocity and

Displacement published in Report of Investigation 8507 “Structure Response and Damage

Produced by Ground Vibrations from Surface Mine Blasting.”

Below is a link to the industry standard of care regarding ground vibrations and damage to structures.

https://www.osmre.gov/resources/blasting/docs/USBM/RI8507BlastingVibration1989.pdf

CPT testing will also be utilized at each test pile location.

Note: If for any reason the Yorktown aquifer is impacted the regulatory authorities will be notified

ASAP but in no case later than 48 hours.

Pile driving criteria and actual pile penetration depths shall be established during driving through dynamic testing with a Pile Driving Analyzer (PDA) and by applying the North Carolina State

Building Code. All pile driving operations and dynamic testing should be observed by a soil technician working under the direction of a registered professional engineer. The engineer should develop driving criteria for the project using both a wave equation analysis (once the contractor has designated the pile hammer to be utilized for driving) and results from dynamic monitoring of test piles with signal matching analyses (CAPWAP). There are a total of 540 piles.

The potential exists that the recommended pile penetration depths of 30 feet may not meet the respective minimum criterion in some areas, due to the generation of excessive pore pressures within the clay and/or silt strata during driving, causing a temporary loss of shear strength. Once these large pore pressures have dissipated (assumed to take 3 to 7 days), the soil should regain

2-8 April 2020 strength and the piles should gain bearing capacity, a phenomenon known as pile “set-up”.

Dynamic testing with a PDA should be performed during restrike of the test piles after a sufficient waiting period for pile “set-up” to occur. It is recommended that pile restrikes be performed 3 days after initial driving. Results of these tests are to be provided for review as evidence of site conditions. It is recommended that the spacing of new piles to old piles be a minimum 2 feet center to center (or 1 foot edge to edge). Closer spacing may make the pile driving more difficult due to densification of the soils from the existing piles, however there is no reduction in new pile capacity.

Reference drawings for the work to be performed are included as Appendix (A). They include the following:

Civil Design and applicable Structural drawings

Pile driving activities and any associated vibrations caused by said activities will not affect existing monitoring wells as existing monitoring wells within the building construction footprint have been abandoned and will be reinstalled, as needed, to support future environmental sampling activities. Construction activities are not anticipated to impact monitoring wells outside the construction footprint. And overlay of the construction footprint and monitoring wells is included in Appendix (C). Existing monitoring wells were abandoned 10/08/2020 and abandonment records have been included in Appendix C. The proposed re-installation date of the abandoned wells is 6/15/2022

The addition of QuantArray sampling is dependent upon EPA and DEQ approval of the proposed OU14 LTM optimization efforts. If this additional sampling is approved, the proposed construction activities are NOT anticipated to negatively impact the microbial population of the aquifer.

2.4 Utility Locates

Precautions shall be taken to identify buried utilities and pipelines prior to performing intrusive activities at MCAS. Known buried utilities, process lines, and pipelines will be identified by a local underground utility service company and a private utility locator prior to beginning field work. The Cherry Point locate and Mark program will be utilized.

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2.5 Preliminary Data Review

The project sites are located within OU 14. The sites are in an area of potential petroleum, oil and lubricants (POL) or chemical spills. There are no reported spills in the immediate area of the projects. Pre-characterization or soil sampling is not required prior to excavation. Potential constituents of concern include:

1,1-DCA

1,2-DCA

Chloromethane cis-1,2-DCE

Methylene Chloride

Tetrachloroethene

TCE

VC

Polyfluoroalkyl (PFAS)

2.6 Excavation

Soils will be excavated as part of the Aircraft Hangar Maintenance projects. During the excavation work, if any soil exhibits an abnormal or unnatural color, a chemical or petroleum odor, or is saturated with a chemical or petroleum, as determined by a photoionization detector

(PID), is encountered, work will be immediately stopped and the EAD will be advised of the situation. The suspect soil will be segregated in a protected stockpile to avoid leaching. The protection will follow E&SC guidelines with the installation of plastic sheeting wrapped up and around hay bales to form a berm and the soil will be covered in plastic when not in use.

Inspections will be made at the same intervals and conditions of our SWPPP program.

Stockpiles will be posted accordingly. No soil sampling or testing will be conducted for the purpose of determining suspected contamination without consulting the MCAS Cherry Point

EAD. Samples will be analyzed by a NC and DOD ELAP certified laboratory capable of meeting industry standard reporting limits for the proposed analyses. Procedures for handling excavated materials is presented in Section 3.0.

2.7 Backfill

All disturbed areas will be backfilled and capped by either covering the surficial soil with an impervious material such as concrete or asphalt or covering the excavated area with 12 inches

2-10 April 2020 of compacted, clean fill. Backfill requirements are presented in Section 3.6. Clean backfill shall be utilized.

Management of Excavated Soils and Materials MCAS, Cherry Point, NC

3-1 April 2020

3.0 MANAGEMENT OF EXCAVATED SOILS AND MATERIALS

This section presents a framework for the management and disposal of materials excavated during land disturbance activities. Excavated materials will be managed in a manner that promotes the identification and segregation of potentially impacted materials, is efficient, and is in accordance with applicable regulations. (GER). In addition, storage of excavated material will be confined within SWPPP boundaries. The permits for both the Paraloft and AMH have been approved and issued and inspections of protective measures will follow SWPPP guidelines I.E.

weekly, after rain and land disturbance activities.

3.1 Management and Characterization of Excavated Materials

Prior to performing land disturbance activities, an approach to materials management will be established using the information obtained and/or generated during the preliminary activities.

The project land “disturbance” totals approximately 12 acres. Excavated material will be stockpiled in a manner that minimizes the spread of impact and segregates soils identified as

“clean” from potential impacted soils. Segregation will be based upon visual inspection of soil, Base Personnel knowledge, and field screening results.

Material that has been excavated and deemed potentially impacted will be segregated in a manner such that representative samples can be collected for soil characterization and/or to determine proper waste disposal. Samples will be analyzed for for disposal criteria as required by the accepting disposal facility. Upon review of all data collected thus far, an appropriate shipping container will be selected for materials that must be transported offsite. Additional information regarding soil testing is provided in Section 3.4.

Excavated soil may be re-utilized as backfill at the same location from which it was removed unless petroleum contamination or other contaminants are discovered. If a contaminant is discovered, the soil will be segregated, properly stockpiled, tested, and properly disposed. Any excess soil that cannot be re-utilized as backfill at the same location from which it was removed must be disposed of at an appropriate facility approved by EAD. Additional information regarding backfilling is provided in Section 3.5

3-2 April 2020

3.2 Soil Screening

Soils will be screened using a PID. Field instrument observations will be conducted in accordance with NCDEQ Standards. Soils exhibiting a PID reading greater than or equal to

COC levels 10 parts per million (ppm), will be segregated and stockpiled for testing and disposal. Field screening will be performed at an approximate frequency of one sample for every 30 cubic yards (yd3) excavated or more frequently if deemed necessary.

The basis for use of the PID screening level of 10 ppm to segregate “non-impacted” soil from

“potentially impacted” soil was a review of the Time Weighted Averages (TWA) exposure limits for the potential contaminants in the soil (based on the COCs for OU14 and JP5 Jet Fuel constituents). For example, the OSHA PEL TWA for Naphthalene is 10 ppm, the OSHA PEL

TWA for TCE and PCE is 100 ppm. We feel that 10 ppm is a conservative screening level and applicable for the subject site. Also, the 10 ppm screening level has been historically used at

MCAS Cherry Point under the Petroleum Cleanup Program and accepted by NCDEQ.

3.3 Soil Stockpiling

Soils will be segregated and stockpiled following soil screening. Refer to section 2.6 for stockpile protection details. Soils with PID readings less than COC levels will be stockpiled for potential re-use. Soils with PID readings greater than or equal to COC Levels shall be stockpiled for hydrocarbon and VOC testing. Refer to paragraph 3.4 for testing.

The potentially impacted soil will be segregated in a protected stockpile to avoid leaching. In addition, storage of excavated material will be confined within our SWPPP boundaries.

Stormwater and Erosion & Sedimentation Control permits for the project have been approved and issued. Inspections of protective measures will follow SWPPP and E&SC permit guidelines.

Soils shall be placed on two polyethylene liners to prevent cross contamination during the lag time between placement and re-use or off-site disposal. These stockpiles will be isolated from surface drainage channels and storm water drains. If necessary, the exposed outer edges of the polyethylene liners can be pulled up over the bottom edge of the staging pile, anchored, and then covered with a piece of polyethylene liner. This facilitates full encapsulation of the soil pile during extended periods of inactivity, (after three weeks of no activity). If necessary, clean soil can be placed on the overlapping liner to anchor the liner in place. This will minimize exposure to the elements (i.e., floodwater, snow, or ice), form an impermeable seal, and will prevent

3-3 April 2020 undermining that could result from prolonged exposure to the elements. Care shall be taken to ensure that the polyethylene liner is not punctured during stockpile formation. The side slopes of the stockpiles shall be no steeper than a 2.5:1, horizontal to vertical. The edges will be gently rounded and sloped to provide positive drainage off the stockpile. The down-slope perimeter of the soil stockpiles will be protected by silt fence and hay bales. Stockpiles shall be no larger than 20 feet in height.

3.3.1 Stockpile Inspections

In accordance with the substantive requirements of 40 Code of Federal Regulations (CFR)

264.554, routine stockpile inspections shall be performed at the same intervals of the SWPPP during site operations to make sure security, engineering controls, and site management practices are being implemented. Inspections shall be conducted immediately following a significant weather event. A significant weather event is generally defined as extraordinary high-speed winds (greater than 80 miles per hour), unusually severe rainfall (100-year storm event), a tornado (path within 5 miles where windspeeds exceed 80 miles per hour), and/or a severe snowstorm (blizzard conditions that present unusually severe and prolonged exposure to heavy ice and snow).

The inspection shall be performed by a competent person (engineer) who is capable of assessing the physical integrity of the stockpile and can evaluate the effectiveness of surface drainage controls. A stockpile inspection form must be completed on a weekly basis, at a minimum, and immediately after a significant weather event. Base EAD’s soil stockpiling SOP will be followed by field personnel working with storing, testing, and handling of stockpiled soils.

3.3.2 Stockpile Maintenance

At the time of inspection, any observed damage to the cover, polyethylene under-liner, silt fences, and hay bales will be documented. Corrective actions to address failed or damaged engineering controls shall be performed within 72 hours of discovery. Stockpile protection measures found to be deficient will be promptly corrected and documented accordingly. Any stockpiled soil that escapes into the environment within any “open” 72-hour period will be cleaned up promptly. In the event of a major breach, the contractor will be responsible for providing prompt remedies to return the soil back to the stockpile and apply the appropriate control to prevent re-occurrence.

3.4 Soil Testing

3-4 April 2020

Significant areas of vadose soil contamination are not known to exist at the project site. In the instance that contamination is suspected during excavation activities, the removed soil will be screened with a PID. Headspace sampling techniques will be used to screen the soil as the excavation activities proceed. In addition to the use of a PID, any visible staining, abnormal colors and/or petroleum odors will be used to assist in the detection of suspect contaminated soil during excavation activities. If PID screening results are below 10 ppm and there is no other physical evidence of contamination (i.e. staining, petroleum odors, abnormal colors) then this soil will be deemed “non-impacted” and can be reused on the project site (in the same excavation). If PID screening results are above 10 ppm and/or there is physical evidence of contamination (i.e. staining, petroleum odors, abnormal colors) then this soil will be properly stockpiled and tested for proper disposal. Refer to section 3.2 for Soil Screening information.

Any excess soil that cannot be re-utilized as backfill at the same location from which it was removed must be disposed of at a proper facility approved by EAD. Soil testing will be required to characterize the soil in the stockpile for each 200 yd3 of potentially impacted material per

NCDEQ guidelines. Stockpile sample(s) shall be analyzed for the following but not limited to:

Liquid Chromatography Tandem Mass Spectrometry (LCMSMS) Compliant with QSM v.

5.3 Table B-15” for the 18 PFAS analytes referenced in EPA Method 537.1 (PFAS)

EPA SW846-8260 – Volatile Organic Compounds (VOCs);

EPA SW846-1311/SW846-8260 – Toxicity Characteristics Leaching Procedure (TCLP)

VOCs;

Gasoline Range Organics (GRO);

Diesel Range Organics (DRO); and

Oil and Grease with silica gel wash.

For each 200 yd3 of potentially impacted material one five-point composite sample and one grab sample will be collected per State soil stockpile sampling guidance. The five-point composite sample will consist of one soil aliquot collected from the center of the stockpile and the remaining four soil aliquots will be collected at locations approximately midpoint from the center to each corner. Samples will be collected using a hand trowel or equivalent. PID readings of each soil aliquot will be measured and recorded in the field logbook. After the soil aliquots are

3-5 April 2020 collected, the aliquots will be composited together into one sample to be analyzed for GRO, DRO, and oil and grease with silica gel wash. The soil aliquot exhibiting the highest PID reading will be resampled for the grab sample. The grab sample will be analyzed for VOCs and

TCLP VOCs. As the dimensions and thickness of soil stockpiles can vary, no specific depth component of the stockpile samples can be defined. Stockpile samples shall be collected from beneath the material exposed at the surface.

Samples shall be collected in accordance with NCDEQ guidelines. Samples shall be collected with a stainless-steel spoon and sealed in appropriate EPA approved containers and preserved on ice at 4° F. Samples shall be accompanied by a chain-of-custody form and transmitted to a

NCDEQ certified laboratory for analytical testing.

Soil sampling equipment will be decontaminated in the following manner:

Spray and/or scrub the reusable items with the alcohol, water or detergent/water mixture first.

Rinse with distilled water.

Wipe with Paper Towels as needed.

Repeat as necessary.

Waste paper towels, PPE and non-reusable items shall be properly disposed.

Potable water which has already been tested from a base hydrant with backflow preventer

3.5 Soil Disposal

For soil that requires off-site disposal, EAD will review and sign the waste manifests/bill of lading for the soil disposal prior to leaving the MCAS Cherry Point. The manifest shall contain the amount of soil (weight) and supporting laboratory results for EAD review. All wastes will be sampled for disposal and properly containerized for transport to an EAD-approved facility.

3.6 Backfilling

The disturbed area must be capped by either covering the surficial soil with an impervious material such as concrete or asphalt or topping the excavated area with 12 inches of compacted, clean fill. Backfilling operations shall be performed in accordance with the P-199 design specifications. MCAS Cherry Point’s Environmental Department (EAD) requires contractors to certify that all soil brought onsite have been analyzed showing no petroleum or

3-6 April 2020 hazardous or toxic materials as stated in DOD Instruction 4715.6, which implements 10 U.S.C.

2692.

3.7 Management and Characterization of Liquids

The following presents a management tool for liquids that may be encountered during land disturbance activities. Liquids typically associated with land disturbance activities include storm water or groundwater that may enter an excavation following significant rain events. Trenching inside building will be 5’ max and will be under slab. We do not anticipate going down to groundwater. There are no proposed underground facilities below the water table.

Dewatering operations are expected to be extremely limited in nature and are not expected to alter plume dynamics. The depth to water below ground surface is approximately 10 feet and the majority of subsurface work will be in the vadose zone and not be approaching the water table.

Dewatering activities will likely be necessary during two tank installations.

The estimated flow rates have been calculated and range from approximately 30 gallons per minute (gpm) to 100 gpm to dewater the 88 ft. long x 12 ft. wide x 20 ft. deep trench assuming the depth to water is at 10 feet below ground surface. Water removed from the excavation will be containerized and sampled. Results will be evaluated and the proper disposal or treatment option(s) will be determined.

The groundwater in the areas where land disturbance activities will be performed are known to be impacted by VOCs, semivolatile organic compounds (SVOCs) petroleum, metals, and PFAS.

In the event groundwater or storm water is encountered during land disturbance activities, these liquids will be managed in the excavation in such a manner to limit human contact or removed from the excavation and treated in such a manner that would allow for discharging said fluids in accordance with applicable NPDES permits. Water will be collected, stored and analyzed. If concentrations are above the regulatory limits the waste will be disposed of at an off-site facility in accordance with NCDEQ guidelines.

The addition of QuantArray sampling is dependent upon EPA and NCDEQ approval of the proposed OU14 LTM optimization efforts conducted by the Cherry Point Installation Restoration

Program. If this additional sampling is approved, the proposed construction activities are NOT anticipated to negatively impact the microbial population of the aquifer.

3-7 April 2020

Water will be removed from excavations via mechanical methods (i.e. pumps and hoses) and properly containerized. Proper personal protective equipment (PPE) will be employed to ensure worker exposure to potentially contaminated water is limited. The containerized water will be sampled for VOCs, Semi-Volatile Organic Compounds (SVOCs), and Perfluoroalkyl Substances

(PFAS) Compounds. If PFAS results from the water sample are below 70 parts per trillion (ppt) and VOC and SVOC compounds are compliant, then the water may be disposed of via the air station’s Industrial Wastewater Treatment Plant (IWTP). If the results from the water sampling are above 70 ppt for PFAS, then the water will be properly treated to below 70 ppt prior to being released or disposed of at an approved disposal facility.

Leachate collected from Soil Stockpiles will be collected and sampled in accordance with groundwater procedures listed above.

3.7.1 Monitoring Wells

The UST Site 130 Remediation System southeast of the subject site is being removed and abandoned as it has been determined that the system has achieved it remediation objectives at the site. Any additional affected monitoring wells within the construction footprint will be identified, properly abandoned, and reinstalled as needed toward the final stages of construction.

Construction activities are not anticipated to impact monitoring wells outside the construction footprint. Existing wells, abandoned wells, and potentially impacted wells identified for closure are shown in Appendix C.

Health and Safety MCAS, Cherry Point, NC

4-1 April 2020

4.0 HEALTH AND SAFETY

Land disturbance activities will be conducted in accordance with OSHA safety standards, USACE EM 385-1-1 Safety and Health Requirements, and the project-specific safety and health plan developed by the contractor(s) performing the field activities detailed in this

LDWP. Once the contractor(s) complete their required project-specific safety and health plan it will be submitted under separate cover. A minimum of Level D PPE shall be used.

Base potable water which meets regulatory standards will be utilized for construction. All trenching and excavation PPE will be addressed under a specific Accident Hazard

Analysis developed for the project. The considerations include but are not limited to shoring, collapse prevention and confined space entry. Air quality will be monitored by

PID method.

Reporting MCAS, Cherry Point, NC

5-1 April 2020

5.0 REPORTING

The contractor shall prepare a completion report that details the field work performed as a result of land disturbance activities. The report shall contain, description of the work, field documentation, analytical reports, waste manifests, weigh tickets, chain-of-custody documents, and appropriate figures.