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Potentially Potentially Significant unless Less than Significant Mitigation Significant No Impact Incorporated Impact Impact e) Create or contribute runoff water which would 0 0 (gl 0 exceed the capacity of existing or planned storm water drainage systems or provide substantial additional sources of polluted runoff? t) Otherwise substantially degrade water quality? 0 0 0 (gl g) Place housing within a IOO-year flood hazard area 0 0 0 [8] as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map? h) Place within a 100-year flood hazard area 0 0 (gl 0 structures which would impede or redirect flood flows? i) Expose people or structures to a significant risk of 0 0 (gl 0 loss, injury or death involving flooding, including flooding as a result of the failure of a levee or dam? j) Inundation by seiche, tsunami, or mudflow? 0 0 0 [8] DISCUSSION: The construction of the bridge and trail project has the potential to violate water quality standards or waste discharge requirements if construction materials were discharged to surface waters, including waters of the Bay. The construction of the bridge portion of the project includes two possible techniques: use of shallow barges to bring in bridge pieces and cranes or, alternatively, construction of a temporary trestle from which a crane could drive piles and assemble the bridge. Pile driving the piers into the slough bottom to construct the bridge could release Bay mud and soil into the slough and Bay waters. Construction activities related to the trail and bridge abutments could also result in sediments and! or contaminants being entrained in storm water runoff leaving the site and potentially entering the slough and Bay. A mitigation measure is proposed below to avoid water quality impacts. The proposed proiect does not involve groundwater extraction for construction or operation. Therefore, there would be no depletion of groundwater resources or effects on any wells. On-going maintenance of the bridge could also affect water quality. The bridge would require periodic painting to protect it from the marine environment. A measure has been proposed to ensure maintenance activities are addressed in the project's Storm Water Pollution Prevention Plan. The Port would have the responsibility for erosion and sediment control measures as part oftheir repair and maintenance of that portion of the Preferred Trail Alternative located on lands under their iurisdiction and the City would be responsible for erosion and sediment control measures on the remaining portions of the proiect. Y4204IS.00693.doc - 4/5/07 -28-