8F Consent 2007 0618 - Laserfiche WebLink

Home

DISCUSSION: A Phase I Environmental Site Assessment!Initial Site Assessment (Phase I/ISA) has been prepared for the project site (BASELINE, 2005). The following discussion is summarized from that report. Historical Land Uses The project site was submerged until the mid-1950s. The northern landing and connecting path are on a perimeter dike built in the mid-1950s. The southern landing is also on a dike constructed of fill between 1958 and 1965 within Oyster Bay Regional Shoreline Park. The materials used to construct the dikes are of unknown origin, and could contain contaminants that may affect the health and safety of construction workers and/or require special management during construction at the bridge abutment locations. Three petroleum pipelines (two active and one inactive) are embedded in the dike on the northern shore of the slough. While the pipelines may not have had any releases, construction activities near the pipelines will require coordination with the pipeline operators to ensure that construction activities do not affect the integrity of the pipelines. No staining, odors, stunted vegetation, or other evidence of hazardous materials releases that could affect subsurface conditions at the project site were noted during a site reconnaissance in April 2005. Approximately 200 cubic yards offill material are proposed to be excavated during construction of this project. No information regarding the chemical quality of the f1l1 material or the material used to create the north and south dikes, placed during the 1950s and 1960s, was available for the Phase I investigation. A geotechnical investigation has indicated that the fill contained some concrete rubble, indicative of possible construction debris (parikh, 2004). There may be a potential for these materials to contain chemical constituents, which could pose a concern for construction worker health and safety or require special soil management and disposal procedures at either bridge abutment. Database Search A regulatory database search was performed to identify hazardous materials sites, including those compiled pursuant to Government Code Section 65962.5, which could affect human health and the environment in the project vicinity (EDR, 2005a). The proposed site trail and bridge locations were not identified on any hazardous material site lists. Two hazardous materials sites were identified on Neil Armstrong Way, north of the project site: a former leaking gasoline underground storage tank site (Chevron, Shell, and Avis Rent-a-Car), and a registered hazardous waste generator (pST Oakland Storage). The Chevron/Shell/Avis site had underground tank storage for gasoline. At the time of a planned tank closure, a structural failure was discovered that had allowed an unreported quantity to leak. A preliminary site assessment work plan was submitted 10 May 1990 and work began 21 May 1990. Information from the environmental database report indicated that soil only was affected, and contaminated soil was excavated and treated. The case was closed on 8 August 1994. The leaking Y4204IS.00693.doc - 4/5/07 -24-