Reso 1996-006 to 010 - Laserfiche WebLink

Home

San Lorenzo Creek would not significantly affect the physical conditions of the downstream mud flat/delta. GPD EIR Mitigation Measures 3.2.6 through 3.2.10 are designed to reduce pollutant loads by street cleaning and monitoring unauthorized substances in the GDP area and to manage, using "best technologies and management practices," contaminants collected in the stormwater detention pond. C. HAZARDOUS MATERIALS AND PUBLIC SAFETY CA POTENTIAL IMPACT: The existence of any soil or groundwater contaminants remaining following remediation could expose workers or new residents of Phases 2A, 2B or 3 to hazardous materials. FINDING: Although the probability of exposure is remote, changes or alterations have been required in, or incorporated into, the project that further avoid or substantially lessen the potential significant environmental effect. STATEMENT OF FACTS: All known soils containing levels of contaminants that exceed threshold limits established by DTSC have been removed from the site or will be capped on -site. Additional fill will be brought to the site and the asphalt cap will be placed at the beginning of the 1996 construction season, which starts approximately April 15, 1996. When this is done, DTSC will prepare a "certification package," which states that DTSC's conditions of approval have been met. The remediation program approved by DTSC eliminates potential pathways by either removing the soils altogether (i.e., offsite) or by providing a physical barrier between soil contaminants and receptors. Although the probability of exposure is remote, the mitigation measures identified below will reduce the impact to a less than significant level. At the request of DTSC, Harding Lawson Associates estimated the migration time for lead detected in "hot spot" areas in Phase 3 to travel towards the planned residential areas in Phases 1 and 2, assuming that groundwater flows in that direction. On the basis of the analysis results, HLA found that it would take thousands of years for lead to migrate in groundwater from the source areas in Phase 3 to Phase 2. Even then, the concentrations of lead detected in groundwater beneath Phase 3 are below drinking water standards. Furthermore, the lead -containing soils in the Phase 3 areas have been removed. Following completion of all remediation activities, DTSC representatives will inspect the site and certify the remediation. Prior to the design and installation of underground water mains and services for the proposed development, EBMUD's Regulatory Compliance Office will be provided with site information on the soil contaminants in the pipeline alignment area. During construction, the City shall regularly inspect the property and notify the DTSC if any unidentified substances are encountered. Finally, the Applicant shall construct a fence and/or post signs to discourage access along the eastern edge of the retained upland adjacent to the Phase 3 development to reduce potential human access to that area. C.2 POTENTIAL IMPACT: High concentrations of explosive compounds in soil could create explosion hazards. 7