IFB_126904_-Statement_of_Work.pdf

STATEMENT OF WORK

EXHIBIT A

California Military Department Facilities and Infrastructure-Environmental Programs

10601 Bear Hollow Drive, Box 17 Rancho Cordova, CA 95670

Author: Brian Pierskalla

Statement of Work

Rev. 20260805 Page 2 of 44

SECTION 1: The Introduction

1.1 Project Title: Installation and Monitoring of new Soil Vapor Gas Monitoring Wells and a

Groundwater Monitoring Well at Stockton Field Maintenance Shop (FMS) #24, Stockton, CA.

GeoTracker ID: T0607700742 and GeoTracker website:

https://geotracker.waterboards.ca.gov/profile_report.asp?global_id=T0607700742

1.2 Project Overview & Purpose: The purpose of these services is to enable the California

Military Department (CMD) to comply with requirements from the Central Valley Regional Water Quality Control Board (CVRWQCB) in support of CMD Facilities and Infrastructure’s (FI) broader mission to maintain land and facilities, and the Porter-Cologne Water Quality Control Act, revised January 2026. Specifically, the Contractor will be responsible for providing the following: project management, installation of two (2) new soil vapor gas monitoring wells, installation of one (1) groundwater monitoring well, decommission of four

(4) existing soil vapor gas monitoring wells, four (4) quarterly monitoring events for two (2) new nested soil vapor gas monitoring wells, and four (4) quarterly monitoring events for one new groundwater well. (see Attachment A-1 for maps of proposed well locations). By fulfilling these objectives, the Contractor will help CMD to investigate contamination from leaking underground storage tanks (USTs) at FMS #24 and a possible chlorinated volatile organic compounds (VOC)s release from the wash rack near the Stockton Combined Support Maintenance Shop (CSMS). All work must adhere to CMD’s policies, standards, and applicable regulations (AR200-1), and it will be evaluated against defined performance criteria (see Section 2).

SECTION 2: The Work (Scope)

2.1 What the Service Provider WILL Do (Tasks/Scope):

2.1.1 Meetings and Project Management

2.1.1.1 Meetings and Project Management. The Contractor shall participate in project meetings as requested but at least monthly and a contract closeout meeting, with written monthly status/progress updates to the CMD Environmental Programs Contract Manager (CM) due the fifth business day of the month following the reporting month via email, teleconference, or in person of all tasks completed under this Statement of Work (SOW) for that month. Also included in this task will be a handoff of all materials required to be provided to CMD under this SOW.

References to Contract Manager (CM) and Alternate Contract Manager (ACM) throughout this document shall be defined by name and with contact information when the Contract is executed.

2.1.1.2 Deliverables

Rev. 20260805 Page 3 of 44

2.1.1.2.1 Kickoff Meeting. Contractor will set up and hold the kickoff meeting via teleconference with the CM within fifteen (15) business days following Contractor’s receipt of the Notice to Proceed (NTP). The kickoff meeting will produce in writing the planned monitoring field and reporting schedules for CM approval.

2.1.1.2.1.1 Acceptance Criteria: Kickoff meeting occurs within fifteen (15) business days following Contractor’s receipt of the NTP. Kickoff Meeting includes all critical Contractor staff identified within your submitted proposal (see section 4.2.1). The planned monitoring field and reporting schedules shall be discussed and agreed upon with both the Contractor and CM, which will be captured in writing by the Contractor and submitted to the CM for approval

2.1.1.2.1.2 Acceptance Process: If after reviewing the proposed field and reporting schedules submitted by the Contractor, CM determines that more discussion is needed, CM will ask Contractor within five (5) business days following the kickoff meeting for a follow-up meeting and revised proposals until submittals meet CM approval.

2.1.1.3 Project Coordination. The Contractor will contact the Stockton FMS/CSMS point of contact (POC) or their designee along with the CM at least five (5) business days prior to sampling activities and other scheduled visits to the facility to ensure access availability. Storage of materials and investigation derived waste shall be arranged in writing with the facility prior to commencing work. Site visits must be scheduled with the current shop supervisor, currently: CW3 Alex P. Rangel, during normal shop hours of Monday-Friday 0730-1530; cell: (209) 235-7913; (alex.p.rangel.mil@army.mil) less Federal holidays as well as the CM. The alternate site POC is SGT Joe Zelaya; (279) 688- 5469; Joe.Zelaya@cmd.ca.gov If Contractor needs to work outside these hours, Contractor must get prior approval from CM before work begins. The Contractor shall meet with the installation and CM as needed to seek information, ensure installation requirements are being met, and to provide updates. These meetings can be held virtually. Finally, monitoring will be completed under a separate Contract. Contractor will need to coordinate well construction with the well monitoring contractor to ensure that monitoring can occur within an appropriate timeframe of well construction.

2.1.1.3.1 Deliverables

2.1.1.3.1.1 Monthly Status Reports. Contractor Status reports shall be submitted to the CM or ACM monthly by the fifth business day of the month following the reporting month via email.

Rev. 20260805 Page 4 of 44

2.1.1.3.1.1.1 Acceptance Criteria: Monthly Reports are submitted on time and accurately reflect requirements of Contract as determined by the CM.

2.1.1.3.1.1.2 Acceptance Process: Monthly Status Reports. CM will review and provide comments to the monthly status reports within two

(2) business days of receiving the reports from the Contractor.

Contractor will have up to two (2) business days to respond to CM questions. CM will have two (2) business days to backcheck and confirm document is complete or require more edits until submission meets CM approval

2.1.2 Installation of Groundwater Monitoring Well, Installation of Soil Vapor Gas Monitoring Wells, and Decommissioning of Soil Vapor Gas Monitoring Wells.

2.1.2.1 Permitting, Coordination, Underground Utility Clearance, and Waste Management. Prior to conducting any drilling activities, the Contractor will procure a well driving contractor or subcontractor who possesses a California C-57 drilling license (can be a subcontractor) to perform all intrusive work. All work will be coordinated with the appropriate regulatory agencies and airport authorities, including at a minimum but not limited to Central Valley Regional Water Quality Control Board and the San Joaquin County Environmental Health Department. A monitoring well permit, a soil boring permit, and a well destruction permit must be obtained from the San Joaquin County Environmental Health Department (SJCEHD). Contractor will be responsible for all coordination with SJCEHD, including any required scheduling or site visits with grout inspectors. The Contractor will schedule a meeting with the FMS/CSMS shop supervisor to discuss possible known utilities in the area. The Contractor will contact Underground Service Alert of Northern California (USA North, aka 811 DigAlert) to identify public and private subsurface utilities in the investigation area a minimum of 3 business days (72 hours) in advance of intrusive field work. Additionally, Contractor will hire a private utility locator to clear utilities prior to field work. All utilities will be marked in the field. Under the direct supervision of the Contractor, an independent utility locator will verify clearance of each proposed boring location from underground utilities and fuel systems. The utility clearance survey will include locating fuel system pipelines and associated components, water, electrical, natural gas, fuel, telecommunication, cable TV, storm water, and sewer utility lines. Upon completion of the independent utility clearance, the Contractor will confirm the proposed well locations with the CM, ACM, or other authorized representatives from the CMD identified in writing. Soil boring and monitoring wells will not disturb any fuel pipeline or other underground utility features.

Soil boring and monitoring wells will be placed at least six (6) feet beyond the safe drilling distance from any fuel pipeline or fuel system component to prevent damage to the fuel system components.

Rev. 20260805 Page 5 of 44

Prior to contacting Underground Service Alert of Northern California and prior to scheduling work, Contractor must coordinate with the CM, ACM, or authorized representatives designated by the CM in writing from the CMD and staff at Stockton FMS/CSMS to ensure that the site is ready for work.

Additionally, the CVRWQCB has requested to be present when determining the groundwater monitoring well location and to observe the soil vapor gas probe and groundwater monitoring well installations. Contractor to provide the scheduled field dates in writing to the CM as soon as available prior to commencing field activities in order to receive CM and CVRWQCB approval.

After a ticket has been issued from USA Alert, Contractor shall perform a utility check on site. Contractor will additionally perform a utility check with the private utility locator.

Contractor shall develop a Site-specific Health and Safety Plan (HASP).

Contractor to ensure that the HASP includes drilling and well development activities prepared in accordance with Occupational Health and Safety Administration (OSHA) guidelines. A printed copy of the HASP will be kept onsite for field personnel to reference. Contractor shall be responsible for maintaining and replacing copies of the HASP on-site as needed. The HASP lists the project’s key personnel, route to the nearest emergency room/hospital, Safety Data Sheets for the chemicals of concern, and proposed action response levels.

All soils and fluids generated from this field effort will be stored in Department of Transportation (DOT)-rated 55-gallon steel or polycarbonate drums with removable lids. It is anticipated that ten (10) drums will be sufficient for well construction and demolition. It is anticipated that an additional 2 drums per quarterly sampling event should be sufficient. Drum labels will identify contents as Non-Hazardous Waste Pending Classification. Labels will also indicate the project name, date, borehole(s), contents (soil or water), and anticipated chemical contaminants. All drums will be temporarily stored in a location designated by the CM or designated representatives and FSM/CSMS.

The Contractor will arrange for characterization and disposal of all waste soil and fluids in compliance with California Department of Toxic Substances Control regulations.

All drill cuttings will likely be classified as non-hazardous but shall be subject to testing to confirm correct disposal method. Laboratory reports will be required for waste characterization prior to disposal. Drums will be disposed

Rev. 20260805 Page 6 of 44 of within one-hundred eighty (180) calendar days of work being completed and within one-hundred eighty (180) calendar days of each sampling event.

2.1.2.1.1 Deliverables

2.1.2.1.1.1 Permitting. Contractor shall acquire all monitoring well permits, boring permits and well destruction permits from SJCEHD.

2.1.2.1.1.1.1 Acceptance Criteria: Well permits are timely acquired from

SJCEHD and were obtained following proper SJCEHD Standards.

2.1.2.1.1.1.2 Acceptance Process: Contractor will review draft permit applications with CM prior to submittal to SJCEHD. CM will provide comments on the draft permit application within two (2) business days. CM will have two (2) business days to backcheck and confirm documents are complete or require more edits until submittals are approved by CM

2.1.2.1.1.2 Coordination. Contractor shall coordinate with CM and prior to work to ensure locations are correct and to ensure the site is ready for work. Contractor shall coordinate with a private utility contractor to mark and check utilities three (3) business days (72 hours) prior to work. Contractor shall coordinate with Underground Service Alert of Northern California 3 business days (72 hours) before work. Contractor shall coordinate with licensed waste disposal company to test, characterize, and dispose of waste in compliance with state and federal environmental laws. Contractor shall coordinate waste pick up and disposal no later than one-hundred (180) calendar days after work is complete.

2.1.2.1.1.2.1 Acceptance Criteria: Contractor shall reach out to CM prior to work beginning. Utilities shall be marked by the Underground Service Alert of Northern California and a private utility locator prior to work beginning. Waste drums shall be dropped off onsite prior to work beginning and are removed from the site as required in this SOW. Drums shall be properly labeled and characterized prior to pick up. Drums shall be disposed of no later than one hundred eighty (180) calendar days of the completion of work.

2.1.2.1.1.2.2 Acceptance Process: Coordination work shall be approved by the CM upon completion of each task as required by this SOW.

Soil Boring Advancement, Soil Sampling and Analysis. Contractor will conduct soil borings for soil investigations following the Additional Site Investigation Work Plan (ECM Consultants, August 2024)(https://documents.geotracker.waterboards.ca.gov/esi/uploads/geo_re port/4936463594/T0607700742.PDF, see Appendix A). Soil borings will be converted into nested soil vapor gas monitoring wells and a groundwater https://documents.geotracker.waterboards.ca.gov/esi/uploads/geo_report/4936463594/T0607700742.PDF

Rev. 20260805 Page 7 of 44 monitoring well as described below in sections (2.1.2.3 and 2.1.2.4).

Contractor shall take photographs and document work as necessary to include in the Final Additional Site Investigation Report (see section 2.1.4.1).

“Initial soil borings will be advanced using direct push technology (DPT) drilling. Before drilling, a hand auger or post-hole digger will be used at each boring location to advance the borings to a depth of 5 feet bgs [below ground surface] to avoid any potential contact with unidentified utilities. Once a depth of 5 feet bgs is reached, the drill rig will advance the DPT to the target depth to identify lithology. Borings will be converted into two nested soil gas wells and one groundwater monitoring well. Borings will be over-drilled with a small-diameter auger drill rod to install the wells. The continuous DPT soil core will be field screened and logged on a field boring log to determine lithology.

Soil samples from the vadose zone will be collected for laboratory analysis.

Under the direct supervision of a licensed California Professional Geologist, a California C-57 licensed driller will advance three DPT borings for soil investigation. The DPT [direct push technology] drilling will collect soil samples with a dedicated 3.25-inch-diameter by 4-foot-long acetate lined macro-core sleeve. Continuous soil core will be logged to determine lithology. Boring logs will include the Unified Soil Classification System (USCS) descriptions of soil types by visual and tactile methods; soil color, consistency (e.g., dense, loose, soft, stiff), particle angularity/ roundedness, and estimated gradation; time, date, depth below ground surface, and identification number of all soil samples; depth to first-encountered water; and depth of equilibrated water table if encountered.

Soil borings will be field screened using a photoionization detector (PID) at no less than 5-foot intervals. The PID will be calibrated using on-site gas calibration techniques at the beginning of each field day. Up to three (3) samples per soil boring will be collected from above, at, and below elevated PID readings. If no elevated PID readings are measured, one sample will be taken at the midpoint of the soil boring and the bottom of the boring (above the water table, if encountered). In the soil borings to be converted into nested soil gas wells, one soil sample will be collected from each proposed screen interval at approximately 10 and 15 feet bgs. Soil samples will be shipped to a California-certified laboratory and analyzed for COC [constituent of concern]s.

Rev. 20260805 Page 8 of 44

Conventional sampling procedures can be used to collect samples for analysis. Powderless nitrile gloves must be worn on hands before collecting samples, handling sample containers, or handling sampling equipment. The sampling Site should be evaluated prior to sampling to identify potential contamination risks and to select dedicated eating, staging, and sampling areas.

Each soil sample for laboratory analysis will be placed in an appropriate laboratory-approved container for submittal to the laboratory for analysis. The sample name will consist of the nomenclature, “FMS-MWnn-xx,” where “nn” = well ID, and “xx” = is the depth collected in feet bgs. A label on each sealed sample will identify the project name, sample number, sampling date and time, and requested laboratory analysis. Samples will be placed into a chilled cooler for transport to a State of California-licensed environmental laboratory for analysis. A completed chain-of custody form will accompany all samples.

Soil samples will be analyzed for COCs by the following methods:

• Total petroleum hydrocarbons as diesel (TPHd) by U.S.

Environmental Protection Agency (EPA) Method 8015B;

• Total petroleum hydrocarbons as gasoline (TPHg) by EPA Method 8260B; and

• Volatile organic compound (VOC)s (full list) by EPA Method 8260B, including BTEX, PCE, 1,2-DCA and TCE.

• One composite soil sample for Title 22 Metals, including mercury by EPA Method 6010/7471 (for waste profile)

• Extra volume of soil will be collected for toxicity characteristic leaching procedure (TCLP) by EPA Method 1611 (for waste profile)

The following field sampling quality assurance (QA)/quality control (QC) procedures will be observed for collecting soil and groundwater samples:

• One equipment blank per day will be collected by running deionized water through the DPT inner rod and/or HSA.

• One trip blank per cooler prepared by the laboratory will accompany the samples to the Site and back to the lab. [The trip blank would only need to be analyzed for the above analytes if there is breakage].

• One duplicate will be collected from a groundwater sample [and two soil samples] and submitted for analysis.”

Rev. 20260805 Page 9 of 44

Data associated with soil borings such as results for laboratory analyses and boring logs must be uploaded in GeoTracker following specifications in section 2.4.2.

2.1.2.1.2 Deliverables

2.1.2.1.2.1 Soil Boring Activities. Complete boring activities and soil collection for analysis following SJCEHD requirements. Document activities in boring logs with photographs to be included in the Final Additional Site Investigation Report.

2.1.2.1.2.1.1 Acceptance Criteria: Contractor shall complete boring activities and send soil out for analysis. Boring shall be completed following SJCEHD standards at the correct locations. Quality Assurance/Quality Control (QA/QC) shall be followed for sample collection. Soil samples go to a California State-Certified Laboratory. Borings shall be documented with sufficient photos and detailed notes to provide a comprehensive discussion in the Final Additional Site Investigation Report.

2.1.2.1.2.1.2 Acceptance Process: CM, ACM. or authorized representative delegated by CM in writing will be present onsite observing boring activities and CVRWQB may be present. CM or authorized representative and CVRWQB will immediately provide feedback as work is progressing if activities do not follow the Contract, the Additional Site Workplan, CVRWQB’s letter requesting work to be done (Central Valley Regional Water Quality Control Board Request for Sampling and Additional Investigation, California Army National Guard Stockton, Facility, Field Maintenance Shop #24 8020 South Airport Way, Stockton, San Joaquin County, California, dated 25 May 2023, https://geotracker.waterboards.ca.gov/view_document?docurl =/regulators/deliverable_documents/3256971061/2023%2D05 %2D25%20Water%20Board%20Request%20for%20Sampling %20and%20Additional%20Investigation%20CAARNG%20Stoc kton%20FMS%2024%2Epdf

2.1.2.1.2.1.3 {see Appendix A} California Well Standards (Bulletin 74-90), or SJCEHD Well Standards. Work shall incorporate all real-time feedback described above and will be considered complete once all feedback from CM and CVRWQB has been incorporated and executed for CM approval. .

2.1.2.1.2.2 Soil Boring Sample Analysis. Sample results shall be posted to GeoTracker in Electronic Data Format (EDF) format within thirty

(30) calendar days of receiving results.

https://geotracker.waterboards.ca.gov/view_document?docurl=/regulators/deliverable_documents/3256971061/2023%2D05%2D25%20Water%20Board%20Request%20for%20Sampling%20and%20Additional%20Investigation%20CAARNG%20Stockton%20FMS%2024%2Epdf https://geotracker.waterboards.ca.gov/view_document?docurl=/regulators/deliverable_documents/3256971061/2023%2D05%2D25%20Water%20Board%20Request%20for%20Sampling%20and%20Additional%20Investigation%20CAARNG%20Stockton%20FMS%2024%2Epdf https://geotracker.waterboards.ca.gov/view_document?docurl=/regulators/deliverable_documents/3256971061/2023%2D05%2D25%20Water%20Board%20Request%20for%20Sampling%20and%20Additional%20Investigation%20CAARNG%20Stockton%20FMS%2024%2Epdf https://geotracker.waterboards.ca.gov/view_document?docurl=/regulators/deliverable_documents/3256971061/2023%2D05%2D25%20Water%20Board%20Request%20for%20Sampling%20and%20Additional%20Investigation%20CAARNG%20Stockton%20FMS%2024%2Epdf https://geotracker.waterboards.ca.gov/view_document?docurl=/regulators/deliverable_documents/3256971061/2023%2D05%2D25%20Water%20Board%20Request%20for%20Sampling%20and%20Additional%20Investigation%20CAARNG%20Stockton%20FMS%2024%2Epdf

Rev. 20260805 Page 10 of 44

2.1.2.1.2.2.1 Acceptance Criteria: Contractor shall sample soil boring and send to lab for analysis. Contractor shall post results on Geotracker in EDF format within thirty (30) calendar days of receiving results.

2.1.2.1.2.2.2 Acceptance Process: Once QA/QC results are available, CM will review and approve that sampling is completed within three (3) business days. If QA/QC results indicate there is a problem with the data, Contractor will reach out to CM to develop a plan to address the problem as mutually agreed upon by the parties in writing.

2.1.2.2 Installation of one (1) Groundwater Monitoring Well. Prior to installing wells, Contractor shall gauge all existing Groundwater Monitoring wells (FMS-MW1, FMS-MW2, FMS-MW3, FMS-MW4, FMS-MW5, FMS-MW6, FMS-MW7, FMS-

MW8, and FMS-MW9; see Attachment A-1). The depth to groundwater at the site has varied between approximately 25-40 feet below ground surface (bgs). Contractor shall upload monitoring well - depth to water data in a GEO_WELL text file format and shall upload to the GeoTracker website not more than thirty (30) calendardays from field measurement.

Using soil boring from section 2.1.2.2, Contractor will install one (1) Groundwater Monitoring well at site location FMS-MW10 in Figure 2 of Attachment A-1 following the Additional Site Investigation Work Plan ( https://documents.geotracker.waterboards.ca.gov/esi/uploads/geo_report/4 936463594/T0607700742.PDF, see Appendix A ). Contractor shall follow all SJCEHD requirements for monitoring well construction. Contractor shall take photographs and document work in detail as necessary to include in the Final Additional Site Investigation Report (see section 2.1.4.1).

“Soil boring FMS-MW10 be over-drilled by a minimum 8-inch diameter hollow-stem auger for well placement. The well construction details are shown in Figure 7 [Figure 7 of attachment A-1]. The groundwater monitoring well will be completed to a total depth of approximately 50 to 60 feet bgs using 2-inch diameter Schedule 40 PVC [polyvinyl chloride] casing. The monitoring well will be screened from approximately 30 to 60 feet bgs, constructed with a 0.020-inch slotted screen, and #2/12 sand filter pack based upon static groundwater levels. The filter pack will be placed using tremie pipe from the bottom of the borehole to one foot above the top of the screened interval.

A minimum 2-foot-thick hydrated bentonite transitional seal will be placed using tremie pipe above the filter pack. The bentonite transitional seal will be composed of uncoated, bentonite pellets or

Rev. 20260805 Page 11 of 44 bentonite chips. Potable water [provided by the Contractor], will be used to hydrate the bentonite seal. The transitional seal will hydrate for one hour before placing any annular seal grout material. Actual time to hydrate will depend on Site-specific conditions and will be determined by the field geologist in consultation with the California-registered Professional Geologist. The annular seal will consist of a cement bentonite-grout mixture (3-5% Bentonite) set from the bentonite transitional seal the surface. The final step will be to install a flush-mount well box raised 0.25 inches above the surrounding grade [Figure 7 of attachment A-1].

Well Development

After allowing groundwater to stabilize and cement to cure for 24 hours, the field geologist will measure static groundwater elevations (and free product if present) using an interface probe. After measuring groundwater elevation, wells will be developed by surging and bailing.

Once the well has been sufficiently cleared by bailing, a submersible pump will be used to clean the length of the well screen by running the pump at the highest flow without significant drawdown from the top to bottom in 1 to 2-foot increments. Water quality will be considered stable at the following parameter markers.

• Turbidity less than 10 nephelometric turbidity units (NTUs)

• pH varying less than 0.1 pH units between readings

• Temperature change 0.8-degree Celsius (°C) or less

• Conductivity change of less than 3 percent (%)

All constructed wells will be developed in compliance with the California Department of Water Resources Bulletin 74-90.

Decontamination

Sampling equipment must be cleaned and decontaminated prior to use. Conventional procedures for cleaning and decontaminating sampling equipment can be used but must adhere to the following decontamination guidance:

• The use of laboratory-supplied deionized water is preferred for cleaning and decontamination;

• Commercially available deionized water may be used for cleaning and decontamination;

• Municipal drinking water may be used for cleaning or decontamination;

• Do not use Decon 90®;

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• Alconox®, Liquinox®, Citranox®, and SimpleGreen® or equal can be used for equipment cleaning and decontamination;

and

• Sampling equipment can be scrubbed using a polyethylene or PVC brush to remove particulates.”

CVRWQB has indicated that the screen length listed in the Final Additional Site Investigation Report can be reduced based on the geology found at the site. Contractor can work with CMD and CVRWQB to adjust the screen length based on what is seen in the field. Boring logs, well completion data, and Reports must be submitted into GeoTracker within 30 days of sampling following specifications in section 2.4.2.

2.1.2.2.1 Deliverables

2.1.2.2.1.1 Drilling Activities. Contractor shall upload monitoring well - depth to water data in a GEO_WELL text file format and upload to the GeoTracker. Contractor shall complete drilling activities for groundwater monitoring well following SJCEHD requirements.

Contractor shall document activities in boring/well logs with sufficient photographs and written detail to be included in the Final Additional Site Investigation Report. Complete well completion data and upload into GeoTracker.

2.1.2.2.1.1.1 Acceptance Criteria: Well depth data shall be uploaded into GeoTracker within 30 days of measurement. Drilling shall be completed following SJCEHD standards, following permits, and at the correct locations. Borings shall be documented with sufficient photos and detailed notes to provide a comprehensive discussion in the Final Additional Site Investigation Report. Well completion data and boring/well logs shall be uploaded into GeoTracker in the proper format within 30 days of drilling completion.

2.1.2.2.1.1.2 Acceptance Process: CM, ACM. or authorized representative delegated by CM in writing will be present onsite observing drilling activities and CVRWQB may be present. CM and CVRWQB will immediately provide feedback as work is progressing if activities do not follow the Contract, the Additional Site Workplan, CVRWQB’s letter requesting work to be done (Central Valley Regional Water Quality Control Board Request for Sampling and Additional Investigation, California Army National Guard Stockton, Facility, Field Maintenance Shop #24 8020 South Airport Way, Stockton, San Joaquin County, California, dated 25 May 2023), California Well Standards (Bulletin 74-90), or SJCEHD Well Standards. Work

Rev. 20260805 Page 13 of 44 shall incorporate all real-time feedback described above and will be considered complete once all feedback from CM and CVRWQB has been incorporated and executed for CM approval

Contractor shall first provide drilling documents to CM. CM will review data within five (5) business days of receiving it.

Contractor will have up to three (3) business days to provide CM updated documents. CM will have two (2) business days to backcheck and confirm documents are complete or require more edits until submittals are approved by CM.

2.1.2.3 Installation of two (2) Soil Vapor Gas Monitoring Wells. Using soil borings from section 2.1.2.2, Contractor will install two (2) nested soil vapor gas monitoring wells at site location FMS-SGP-5 and FMS-SGP-6 in Figure 2 of Attachment A- 1 following the Additional Site Investigation Work Plan ( https://documents.geotracker.waterboards.ca.gov/esi/uploads/geo_report/4 936463594/T0607700742.PDF, see Appendix A). The C-57 Licensed Contractor installing the Soil Vapor Gas Monitoring Wells must have at least three (3) years of experience with installing soil vapor gas monitoring wells.

Contractor must follow all SJCEHD requirements for monitoring well construction. Contractor to take photographs and document work as appropriate to include in the Final Additional Site Investigation Report (see section 2.1.4.1).

“Two (2) nested soil gas wells will be installed at the Site. Each soil gas well will be advanced to a target depth of 15 feet bgs. The shallow soil gas screens will be set at approximately 5 feet bgs (based on coarse-grained lithology) and signified with an “A.” The deep soil gas screens will be set at approximately 15 feet bgs (based on coarse-grained lithology) and signified with an “B.” For example, soil gas well FMS-SGP- 5B is the soil gas probe at approximately 15 feet bgs. If depths are modified based on lithology, soil gas probe points will be set a minimum of 5 vertical feet apart.

The soil gas well construction details are shown in Exhibit 1 (DTSC 2015) [below]. The wells will have a total depth of 15 feet with a diameter of 3.25 inches. Approximately six inches of Monterey #3 sand (filter pack) will be placed at the bottom of the borehole to minimize airflow disruption to the sampling tip, and a temporary stainless steel or ceramic soil gas point will be set at 14.5 feet bgs. The soil gas point will be attached to 0.25-inch full or lined Teflon® tubing and shut off at the surface using a Luer lock valve (or similar). An additional six inches of sand will be placed on top of the soil gas probe (deep sand filter pack between 14 to 15 feet bgs). One foot (13 to 14 feet bgs) of dry bentonite

Rev. 20260805 Page 14 of 44 granules will be placed immediately above the filter pack. Eight feet of hydrated bentonite (5 to 13 feet bgs) will be placed above the dry bentonite as the transitional seal. The shallow zone will be constructed similarly with the shallow filter pack is between 4 and 5 feet bgs.

The bentonite should be hydrated in a container at the surface, slowly placed, and tamped down the borehole. The dry granular bentonite between the sand pack and the hydrated bentonite prevents hydrated bentonite from infiltrating the filter pack. A cement/bentonite mixture may be used above the dry bentonite to seal the borehole annulus, consistent with California Department of Water Resources Bulletin 74- 90 (California Well Standards) (DWR 1991).

A down-hole rod or tremie pipe should be used to support the well tubing in the borehole. The support rod ensures that the probe tip is placed at the proper depth and that the tubing is not touching the well walls. The support rod should be constructed to avoid cross-contamination or ambient air intrusion. Once fill material enters the support rod, the rod will be lifted incrementally to ensure direct connection of well materials and surround lithology. The support rod is only for installation aid and will not remain in the soil boring.

Wells will be completed at the surface in well boxes, and tubing will be closed off using a Luer lock valve, gas-tight valve, or a fitting for capping the tubing to minimize air intrusion from the surface. Well boxes will be completed 0.25-inch above the existing grade to prevent surface runoff infiltration.

Department of Toxic Substances Control (DTSC) 2015. Active Soil Gas Investigations

Advisory, July.

Department of Water Resources (DWR) 1991. Bulletin 74-90”

Rev. 20260805 Page 15 of 44

The well box must be traffic rated and components inside the well box should be waterproof as previous gas wells in the area were known to flood in the past.

Contractor to complete a purge volume test and a leak test once well installation is complete so that CM can know how long sampling will likely take at the two new wells.

Well completion data, boring logs and Reports must be submitted into GeoTracker within 30 days of sampling as discussed in section 2.4.2.

2.1.2.3.1 Deliverables

2.1.2.3.1.1 Drilling Activities. Contractor shall complete drilling activities for soil vapor gas monitoring wells following SJCEHD requirements.

Contractor shall document activities in boring logs with sufficient photographs and detailed notes to be included in the Final Additional Site Investigation Report. Contractor shall complete well completion data and upload into GeoTracker EDF format as described in this SOW.

2.1.2.3.1.1.1 Acceptance Criteria: Drilling shall be completed following SJCEHD standards, following permits, and at the correct locations. Borings shall be documented with enough photos and notes to provide a comprehensive discussion in the Final

Rev. 20260805 Page 16 of 44

Additional Site Investigation Report. Well completion data and boring logs shall be uploaded into GeoTracker in the proper format within 30 days of drilling completion.

2.1.2.3.1.1.2 Acceptance Process: CM, ACM. or authorized representative delegated by CM in writing will be present onsite observing drilling activities and CVRWQB may be present. CM and CVRWQB will immediately provide feedback as work is progressing if activities do not follow the Contract, the Additional Site Workplan, CVRWQB’s letter requesting work to be done (Central Valley Regional Water Quality Control Board Request for Sampling and Additional Investigation, California Army National Guard Stockton, Facility, Field Maintenance Shop #24 8020 South Airport Way, Stockton, San Joaquin County, California, dated 25 May 2023), California Well Standards (Bulletin 74-90), or SJCEHD Well Standards.Work shall incorporate all real-time feedback described above and will be considered complete once all feedback from CM and CVRWQB has been incorporated and executed for CM approval

Contractor shall first provide drilling documents to CM. CM will review data within five (5) business days of receiving it.

Contractor will have up to three (3) business days to provide CM updated documents. CM will have two (2) business days to backcheck and confirm documents are complete or require more edits until submittals are approved by CM.

2.1.2.4 Boring Location Surveys. Well locations and top-of-casing will be surveyed by a California-licensed Land Surveyor as licensed by the Board for Professional Engineers, Land Surveyors, and Geologists. The survey data will be reported in North American Datum of 1983 (NAD 83) and North American Vertical Datum of 1988 (NAVD 88). The well survey data will be submitted electronically and in hard copy for GeoTracker submittal requirements (see section 2.4.2 for additional specifications) with a new site map within 30 days of completion.

Contractor shall ensure that the points uploaded are in the correct coordinate system for GeoTracker and visually look at the locations to ensure locations are in the correct geographic location by virtual topographical tools such as Google Earth.

2.1.2.4.1 Deliverables

2.1.2.4.1.1 Surveys. Contractor shall survey locations of new wells and upload data into GeoTracker.

2.1.2.4.1.1.1 Acceptance Criteria: The locations of the new wells shall be collected by a California-licensed Land Surveyor. Locations are

Rev. 20260805 Page 17 of 44 reported in the proper format and submitted into GeoTracker on time.

2.1.2.4.1.1.2 Acceptance Process: Contractor shall first provide data to CM.

CM will review data within three (3) business days of receiving it.

Contractor will have up to three (3) business days to provide CM updated data. CM will have one (1) business days to backcheck and confirm document is complete or require more edits until submittals are approved by CM.

2.1.2.5 Soil Vapor Gas Well Decommissioning. Contractor will decommission four (4) nested bas monitoring wells at site location FMS-SGP-1, FMS-SGP-2, FMS- SGP-3 and FMS-SGP-4 in Figure 2 of Attachment A-1 following the Additional Site Investigation Work Plan ( https://documents.geotracker.waterboards.ca.gov/esi/uploads/geo_report/4 936463594/T0607700742.PDF, see Appendix A).

“Soil gas wells will be decommissioned in accordance with the

California Well Standards (Bulletin 74-90) and SJCEHD requirements (Well Standards, SJCEHD, 2005). The SJCEHD requires wells to be destroyed by over drilling to remove soil gas well materials. A minimum one-foot diameter opening will be excavated to at least 3 feet bgs and filled with cement to accommodate future use of the site. The existing soil gas probes (FMS-SGP-1, FMS-SGP-2, FMS-SGP-3, FMS-SGP-4) will be decommissioned by first removing the well casings followed by over drilling and tremie pipe cement grout from the bottom of the boring to the surface and completed to match the surrounding grade. Over-drilled material to be placed in drums to be managed with IDW [investigative derived waste].

Department of Water Resources (DWR) 1991. Bulletin 74-90 San Joaquin County Environmental Health Department (SJCEHD), 2005. Well

Standards (San Joaquin County Ordinance Code Section 9-1115.6).

February 2005.”

2.1.2.5.1 Deliverables

2.1.2.5.1.1 Soil Vapor Gas Well Decommissioning. Contractor shall decommission wells FMS-SGP-1, FMS-SGP-2, FMS-SGP-3, and FMS-SGP-4 following SJCEHD requirements. Contractor shall document decommissioning activities with sufficient photograph and detailed written notes to be included in the Final Additional Site Investigation Report.

2.1.2.5.1.1.1 Acceptance Criteria: Decommissioning shall be completed following SJCEHD standards and in accordance with all relevant permits necessary to perform this SOW. Contractor shall document all decommissioned wells with sufficient photos and

Rev. 20260805 Page 18 of 44 detailed written notes to provide a comprehensive discussion in the Final Additional Site Investigation Report.

2.1.2.5.1.1.2 Acceptance Process: CM, ACM. or authorized representative delegated by CM in writing will be present onsite observing boring activities. CM will immediately provide feedback as work is progressing if changes are needed. Work shall incorporate all real-time feedback described above and will be considered complete once all feedback from CM has been incorporated and executed for CM approval.

2.1.3 Monitoring New Groundwater Well and New Soil Vapor Gas Monitoring Wells

2.1.3.1 Monitoring of one (1) New Groundwater Well and Reporting. New wells are required to be monitored quarterly for the first year after installation.

Gauging

Contractor shall conduct groundwater elevation (gauging) which will occur prior to groundwater sample collection. The depth to groundwater at the site has varied between approximately 25-40 feet below ground surface (bgs).

Contractor shall upload monitoring well - depth to water data in a GEO_WELL text file format and uploaded to the GeoTracker website not more than thirty

(30) calendar days from field measurement.

Sampling

The Additional Site Investigation Work Plan ( https://documents.geotracker.waterboards.ca.gov/esi/uploads/geo_report/4 936463594/T0607700742.PDF, see Appendix A), will be followed for groundwater sampling at FMS-MW10. The new groundwater well shall be sampled per Table 4 (below) requirements and will be purged using a low-flow bladder pump, prior to sample collection. For required constituents to be measured, frequency and required methods, refer to Table 3 (below), Table 4 (below), and Table 5 (below).

During the low-flow purging, physical water parameter measurements will be made before, during and after for oxidation-reduction potential (QRP), electrical conductivity, dissolved oxygen, pH, temperature, and turbidity, and recorded along with a tally of total gallons purged. Sample collection will be conducted after the measurements become consistent (within 10 percent) from one measurement to the next, indicating that the well water is characteristic of the surrounding aquifer. If sampling at the same time as older

Rev. 20260805 Page 19 of 44 wells, Contractor will use separate tubing for each individual well to reduce risk of cross contaminating the wells. In the past, tubing left by a previous contractor has gotten stuck within the monitoring wells. Contractor shall be responsible for removing old tubing and shall bring adequate tools and equipment to complete this task as needed.

The groundwater samples will be collected directly from discharge tubing associated with the pump and/or free-flow cell, transferred directly into the appropriate sample containers, and processed for shipment to the laboratory.

The Contractor must wear appropriate personal protective equipment including gloves when sampling and must sample over a container (such as a bucket) to catch any overflow. Powderless nitrile gloves must be worn on hands before collecting samples, handling sample containers, or handling sampling equipment. Equipment must be decontaminated with deionized water between each well sample. Sampling shall also include at least one blind field duplicate, one equipment blank and one trip blank. The trip-blank will be sampled only if bottle breakage should occur within sample shipment.

Table 3: Field Sampling

Groundwater Parameters Units Type of Sample1

Depth to Groundwater Feet Measurement2 Oxidation-Reduction Potential Millivolts Grab

Electrical Conductivity µhmos/cm Grab

Dissolved Oxygen mg/L Grab pH pH Units (to 0.01 units) Grab

Temperature Degrees, ° (to 0.1°) Grab

Turbidity NTU Grab

Soil Gas Parameters Units Type of Sample1

Oxygen Percent Measurement Helium Percent Measurement Carbon Monoxide Percent Measurement Lower Explosive Limits Percent Measurement Hydrogen Sulfide mg/L Measurement Volatile Organic Compounds µg/L Measurement

1Please ensure instruments are calibrated prior to each monitoring Event.

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2Report feet above mean sea level and depth to groundwater from top of casing to nearest 0.01 foot µhmos/cm = micromhos per centimeter mg/L = milligrams per liter µg/L = micrograms per liter NTU = Nephelometric Turbidity Units

Table 4: Groundwater Sampling Frequency and Constituent Suite at New Well1

Well ID Well Type Gauging2 TPHg TPHd VOCs3 SVOCs Title 224 Metals

FMS-MW10 New Monitoring Well

Quarterly Year 1, Annual Thereafter

Quarterly Year 1, Annual Thereafter

Quarterly Year 1, Annual Thereafter

Quarterly Year 1, Annual Thereafter

- Quarterly Year 1, Annual Thereafter

FMS-SGP5 New Soil Vapor Well

- Quarterly Year 1, Annual Thereafter

Quarterly Year 1, Annual Thereafter

Quarterly Year 1, Annual Thereafter

FMS-SGP6 New Soil Vapor Well

- Quarterly Year 1, Annual Thereafter

Quarterly Year 1, Annual Thereafter

Quarterly Year 1, Annual Thereafter

1Table represents minimum sampling and gauging frequencies; additional sampling and gauging activities may occasionally be conducted to assess remedial progress.

2Gauging consists of measuring depth to groundwater and presence and thickness of free product.

3Full list of VOCs including BTEX, PCE, 1,2-DCA and TCE.

4Including mercury TPHg = total petroleum hydrocarbons as gasoline TPHd = total petroleum hydrocarbons as diesel VOCs = volatile organic compounds SVOCs = semi- volatile organic compounds

Table 5: Analytical Methods

Groundwater Constituents Method Maximum Practical Quantitation Limit (µg/L)

Total Petroleum Hydrocarbons as Gasoline USEPA 8260B 50 Total Petroleum Hydrocarbons as Diesel USEPA 8015B 50

Volatile Organic Compounds USEPA 8260B Various

Title 22 Metals USEPA 6020/7472 Various

Soil Vapor Constituents Method Maximum Practical Quantitation Limit (µg/m3)

Total Petroleum Hydrocarbons as Gasoline USEPA TO-15 50

Total Petroleum Hydrocarbons as Diesel USEPA TO-17 50

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Volatile Organic Compounds USEPA TO-15 Various

Atmospheric Gases Method Units

Oxygen (Coeluted with Argon) ASTM D1946 Percent

Helium ASTM D1946 Percent USEPA = United States Environmental Protection Agency ASTM = American Society for Testing and Materials µg/L = micrograms per liter µg/m3 = micrograms per cubic meter

“Decontamination

Sampling equipment must be cleaned and decontaminated prior to use.

Conventional procedures for cleaning and decontaminating sampling equipment can be used but must adhere to the following decontamination guidance:

• The use of laboratory-supplied deionized water is preferred for cleaning and decontamination;

• Commercially available deionized water may be used for cleaning and decontamination;

• Municipal drinking water may be used for cleaning or decontamination;

• Do not use Decon 90® or commercially similar alternatives;

• Alconox®, Liquinox®, Citranox®, and SimpleGreen® or commercially similar alternatives can be used for equipment cleaning and decontamination; and

• Sampling equipment can be scrubbed using a polyethylene or PVC brush to remove particulates.”

Quality Assurance/Quality Control Program

Sample analysis shall be performed by a California Environmental Laboratory Approval Program (ELAP) Laboratory for groundwater. All analysis shall be conducted on a 14-day turnaround time. All monitoring instruments and equipment shall be properly calibrated, maintained, and recorded daily to ensure accuracy of measurements. Proper quality assurance/quality control (QA/QC) shall be followed including: proper chain of custody procedures for samples, equipment blanks, equipment rinsate(s), and the use of trip blanks.

Contractor will follow a QA/QC program whereby sample collection of 10% QA/QC will be achieved by using equipment blanks, equipment rinsate(s), trip blank samples, and blind sample duplicates (reported as relative percent difference). Contractor shall provide laboratory analytical reports in electronic

Rev. 20260805 Page 22 of 44 data format (EDF) and shall upload the reports to the GeoTracker website not more than (thirty) 30calendar days from laboratory receipt.

Reporting

Contractor shall uploaded results into Geotracker in EDF format within thirty

(30) calendar days after sampling. Results will also be summarized by another Contractor into an Annual Report. Contractor must provide results to a separate contractor identified by the CM within thirty (30) calendar days of sampling to be summarized into an Annual Report. The data must be signed and stamped by either a California Professional Geologist or a California Professional Engineer and must include a cover letter which includes the following:

“I certify under penalty of perjury I have personally examined and am familiar with the information submitted in this document and all attachments and, based on my inquiry of those individuals immediately responsible for obtaining the information, I believe the information is true, accurate, and complete. I am aware there are significant penalties for submitting false information, including the possibility of a fine and imprisonment.”

Additionally, the cover letter must summarize the sampling methods conducted the day of sampling, QA/QC practices followed, and any problems that occurred during sampling.

2.1.3.2 Sampling and Reporting of two (2) New Nested Soil Vapor Gas Monitoring

Wells. FMS-SGP5(A & B) and FMS-SGP6 (A&B) must also be sampled quarterly.

Sampling

For required constituents to be measured, frequency, and required methods refer to Tables 3, 4, and 5 above.

Contractor shall complete a purge analysis (how much purge time) at least seven (7) calendar days prior to field day to collect soil vapor gas and shall send the report via email to the CM. Contractor shall be responsible for having this work performed by professional staff who have completed successful soil vapor gas sampling in the past to include setting up shroud/shut-in testing and leak testing on the proper sampling equipment.

Rev. 20260805 Page 23 of 44

In the past Contractors have had issues sampling at other soil gas vapor wells in the area due to soil tightness. Contractor to provide as a separate Optional line item (see section 2.1.3.3).

Soil vapor gas sampling must not occur during a significant rain event and must only occur after five (5) calendar days without a significant rain event. A significant rain event is defined as 1/2 inch or greater of rainfall during a 24-hour period.