Mitigation Measure 4.H-4a requires that all site-specific development include systemwide drainage improvements to protect proposed development. Onsite drainage systems would be designed to tie into any related systems for U.S. 101, and would be in conformance with all applicable City and Caltrans design standards to prevent flooding the freeway. Mitigation Measure 4.H-4a requires that an on-site storm drainage system be installed that is capable of accommodating a 25-year storm event entirely within the piping system. Thus, the Bay Trail and Sierra Point Parkway would be provided with protection from a 25-year storm. To clarify required protection levels, Mitigation Measure 4.H-4a is revised to read as follows.
Mitigation Measure 4.H-4a: Prior to issuance of a building permit, all site-specific development plans within the Project Site shall include systemwide drainage improvements that shall accommodate all increased runoff in accordance with City requirements and correct known existing deficiencies (e.g., Levinson Overflow Area and the PG&E property). On-site storm drainage collection facilities shall be sized to convey the peak flow rate from a 25-year storm event entirely within the piping system such that Baylands roadways and recreational facilities are not flooded. Drainage improvements shall accommodate the 100-year peak storm event within the piping system and within streets such that building finished floor elevations provide a minimum of 1-foot of freeboard above the 100-year storm event hydraulic grade line water elevation with tidal flow and 100 years of estimated sea level rise. Key roadways including Sierra Point Parkway, Lagoon Road, and Tunnel Avenue shall be designed such that these roadways are available as evacuation routes in the event of a 100-year storm event. The proposed system design shall be submitted to the City Engineer for approval and shall hydraulically isolate existing drainage inlets fronting Levinson Overflow Area and the PG&E property from existing Brick Arch Sewer system.
[See page 5-152 for the original comment] Under CEQA, an EIR must describe a reasonable range of alternatives to a proposed project that would feasibly attain most of the project’s basic objectives while reducing or avoiding any of its significant effects. (CEQA Guidelines 15126.6(a).) A lead agency is not required to consider potential alternatives that would not reduce the project’s environmental effects. The relocation of South Visitacion Park would not reduce or avoid any significant impacts of the DSP or DSP-V scenario due to site contamination, since remediation of such contamination is a prerequisite for site development. The appropriateness of the proposed location of South Visitacion Park will be considered as part of the planning review being undertaken by the City for the Baylands.
[See page 5-153 for the original comment] The comment raises no significant environmental issues regarding the analyses or conclusions of the Draft EIR. The appropriate location for the community garden proposed in the Brisbane