Midway Village Bayshore Park Remedial Action Plan Amendment

3 Documents in Project


SCH Number
Lead Agency
City of Daly City
Document Title
Midway Village Bayshore Park Remedial Action Plan Amendment
Document Type
NOD - Notice of Determination
Document Description
The project involves approval of a Remedial Action Plan (RAP) Amendment for the Midway Village/Bayshore Park site (Site). This site is the location of the Midway Village public housing project and Bayshore Park owned by the Housing Authority of the County of San Mateo (HACSM). DTSC is overseeing Site cleanup under a voluntary agreement (HAS-FY17/18-113). Soil vapor on the Site contains polycyclic aromatic hydrocarbons (PAHs) greater than residential screening levels; therefore, a vapor mitigation system (VMS) is proposed as the remedy to prevent exposure of future on-Site residents to Site-related vapor in indoor air. The VMS will consist of the following elements: • Continuous, spray-applied vapor barrier membrane immediately beneath the structural foundation slab to mitigate vapor migration into the building; • Horizontal collection and venting system consisting of 3-inch diameter perforated polyvinyl chloride (PVC) pipe embedded in a 4-inch gravel layer installed below the vapor barrier to allow soil vapors that may otherwise collect beneath the slab to instead migrate and vent to the atmosphere outside the building; • Perimeter grade beam vents to facilitate convective airflow up the vertical riser pipes of the collection and venting systems by allowing fresh air to enter the space beneath the foundation slab; • A series of risers fitted with wind-assisted turbines to vent vapors to the atmosphere at roof level; and • Electrical service at the roof level if the VMS needs to be converted from a passive to active system (VMS design drawings included in Remedial Design and Implementation Plan (RDIP) will require that electrical service be provided at the roof level).

Contact Information

Kimberly Walsh
Agency Name
Department of Toxic Substances Control
Contact Types
Responsible Agency


Daly City
San Mateo
Cross Streets
45-47 Midway Drive

Notice of Determination

Approving Agency
Department of Toxic Substances Control
Approving Agency Role
Responsible Agency
Approved On
County Clerk
San Mateo
Final Environmental Document Available at


(1) The project will have a significant impact on the environment
(2a) An Environmental Impact Report was prepared for this project pursuant to the provisions of CEQA
(2b) A Mitigated or a Negative Declaration was prepared for this project pursuant to the provisions of CEQA
(2c) An other document type was prepared for this project pursuant to the provisions of CEQA
(3) Mitigated measures were made a condition of the approval of the project
(4) A mitigation reporting or monitoring plan was adopted for this project
(5) A Statement of Overriding Considerations was adopted for this project
(6) Findings were made pursuant to the provisions of CEQA


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