Removal Action Workplan Habitat for Humanity East Bay/Silicon Valley Property

Summary

SCH Number
2020100264
Lead Agency
Toxic Substances Control, Department of (Department of Toxic Substances Control)
Document Title
Removal Action Workplan Habitat for Humanity East Bay/Silicon Valley Property
Document Type
NOE - Notice of Exemption
Received
Posted
10/15/2020
Project Applicant
Habitat for Humanity East Bay/Silicon Valley
Present Land Use
vacant

Document Description
The project involves the approval of the Removal Action Workplan (RAW) for arsenic in soils at the Habitat for Humanity property (Site). The RAW summarized the evaluation of remedial alternatives and proposed remediation consisting of excavation, removal, and offsite disposal of approximately 866 cubic yards (cy) of arsenic contaminated soil to protect human health and the environment. Excavation of approximately 866 cubic yards of soil with arsenic concentrations above background levels (5 mg/kg) was selected as the removal action. Specific project activities consist of the following: • Clearing utilities and other underground obstacles prior to initiating soil excavation; • Excavating and stockpiling approximately 866 cubic yards of impacted soil (depth from 1 to 3.5 feet); • Conducting confirmation soil sampling and comparing confirmation data to the site-specific arsenic background concentration (cleanup goal), and continuing to excavate until the cleanup goal is achieved; • Sampling stockpiled soil to classify the hazard level of the waste and to determine the appropriate disposal facility; and • Transporting the stockpiled soil to the assumed receiving facility, Recology Hay Road landfill. Excavations will be sloped at a maximum 1:1 ratio to allow ingress/egress. The Site will be graded, leveled, and compacted as part of the planned future construction project; therefore, restoring excavated areas to their original grade or importing backfill material is not part of the removal action. During all soil-disturbing activities (e.g., excavation, stockpiling, loading), water will be utilized to minimize or prevent generation of airborne dust. Water will be sprayed in work areas prior to daily work activities, during excavation/loading activities, and at truck staging/loading locations. In addition, watering equipment will be continuously available to provide proper dust control as needed. Soil-disturbing activities will be not performed during periods of high winds or during conditions when these activities cannot be prevented from generating visible airborne dust. Trucks will be required to maintain slow speeds (less than 5 miles per hour) while onsite as a dust control measure. A site safety officer will monitor onsite dust conditions that could require cessation of work. Stockpiled soil will be managed to ensure that stormwater does not cause sediment-laden runoff from the stockpiles and that airborne dust is not generated. Excavated soil will be placed in designated stockpile areas on plastic sheeting. Plastic sheeting will also cover the excavated soil, be secured with weights, and be surrounded with stormwater best management practices (BMPs) such as straw wattles. Stockpiled soil will not be stored onsite longer than 90 days for classifying the hazard level of the waste and determining the appropriate disposal facility. Soil will be transported for offsite disposal in 20-yard, covered end-dump trailers/trucks. Approximately 72 truck trips will be required to transport the stockpiled soil to the Hay Road Landfill located in Vacaville. Work activities will be limited to hours between 7:00 am and 5:00 pm Monday through Friday, which conforms with the City of Walnut Creek Noise Ordinance. Transportation of excavated soil will occur on arterial streets and freeways approved for truck traffic to minimize noise and traffic impacts in local neighborhoods. The anticipated start date for this project has not been determined but is expected to begin sometime in the fall of 2020. Project activities will require disturbance of the Site for approximately two to four weeks during which time soil would be excavated and stockpiled. In the event biological, cultural, or historical resources are discovered during project activities, work will be suspended while a qualified biologist or cultural or historical resource specialist assesses the area and arrangements are made to protect or preserve any resources that are discovered. If human remains are discovered, no further disturbance will occur in the location where the remains are found and the County Coroner will be notified pursuant to the Health and Safety Code, Chapter 2, Section 7050.5.

Contact Information
Dean Wright
Department of Toxic Substances Control
8800 Cal Center Drive
Sacramento, CA 95826

Phone : (916) 255-3591
dean.wright@dtsc.ca.gov

Location

Cities
Walnut Creek
Counties
Contra Costa
Cross Streets
1250 Las Juntas Way
Total Acres
2.05

Notice of Exemption

Exempt Status
Categorical Exemption
Type, Section or Code
15330
Reasons for Exemption
Minor Actions Take to Prevent, Minimize, Mitigate or Eliminate the Release or Threat of Release of a Hazardous Waste or Hazardous Substance. 1. The project is a minor action designed to prevent, minimize, stabilize, mitigate or eliminate the release or threat of release of hazardous waste or hazardous substances. 2. The project is a removal action that will not exceed $1 million in cost. 3. The project does not involve the onsite use of a hazardous waste incinerator or thermal treatment unit or the relocation of residences or businesses and does not involve the potential release into the air of volatile organic compounds as defined in Health and Safety Code Section 25123. 4. The project will be consistent with applicable state and local environmental permitting requirements. A grading permit from the City of Walnut Creek will be obtained if one is needed apart from the site development permit. Habitat for Humanity has indicated no County permits are needed for the remediation. 5. The exceptions pursuant to Cal. Code Rags., tit. 14, § 15300.2 have been addressed as follows: - Cumulative Impact. The project will not result in cumulative impacts because it is designed to be a short-term, final remedy that would not lead to a succession of projects of the same type in the same place over time. - Significant Effect. The environmental safeguards and monitoring procedures that are enforceable and made a condition of project approval will prevent unusual circumstances from occurring so that there is no possibility that the project will have a significant effect on the environment. - Scenic Highways. The project will not damage scenic resources, including but not limited to, trees, historic buildings, rock outcroppings, or similar resources, because it is not located within view of a highway officially designated as a state scenic highway. - Hazardous Waste Sites. The project is not located on a site which is included on any list compiled pursuant to Section 65962.5 of the Government Code. - Historical Resources. The project will not cause a substantial adverse change in the significance of a historical resource because none are anticipated; however, a Native American tribe that has expressed interest in the project has entered into a Memorandum of Agreement with Habitat for Humanity to ensure any tribal cultural resources identified during the fieldwork will be handled appropriately. In addition, a Native America monitor has been invited to monitor removal activities.

Attachments

Notice of Exemption
Final NOE 10_14_2020   PDF 165 K

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