Res10 P-2095 - Laserfiche WebLink

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Less than Significant Potentially With Less Than Significant Mitigation Significant No 8. HYDROLOGY AND WATER QUALITY. Would the project: Impact Incorporated Impact Impact (a) Violate any water quality standards or waste discharge requirements? ❑ ❑ ® ❑ (b) Substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level(e.g.,the ❑ ❑ ❑ production rate of pre-existing nearby wells would drop to a level which would not support existing land uses or planned uses for which permits have been granted)? (c) Substantially alter the existing drainage pattern of the site or area,including through the alteration of the course of a stream or river,in a manner which El El ® Cl would result in a substantial erosion or siltation on-or off-site. (d) Substantially alter the existing drainage pattern of the site or area,including through the alteration of the course of a stream or river,or substantially ❑ ❑ ❑ IZI increase the rate or amount of surface runoff in a manner which would result in flooding on-or off-site? (e) Create or contribute runoff water which would exceed the capacity of existing or planned storm water drainage systems or provide substantial ❑ ❑ El additional sources of polluted runoff? (f) Otherwise substantially degrade water quality? Cl El El El (g) Place housing within a 100-year flood hazard area as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood hazard ❑ ❑ El delineation map? (h) Place within a 100-year flood hazard area structures which would impede or ❑ ❑ ❑ redirect flood flows? . (i) Expose people or structures to a significant risk of 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? ❑ ❑ (k) Potentially impact stormwater runoff from construction activities? ❑ (I) Potentially impact stormwater runoff from post-construction activities? 0 Z ❑ (m) Result in a potential for discharge of stormwater pollutants from areas of material storage,vehicle or equipment fueling,vehicle or equipment maintenance(including washing),waste handling,hazardous materials ❑ ❑ ® ❑ handling or storage,delivery areas,loading docks or other outdoor work areas? , (n) Result in the potential for discharge of stormwater to affect the beneficial ❑ ❑ ® ❑ uses of the receiving waters? (o) Create the potential for significant changes in the flow velocity or volume of ❑ ❑ ❑ stormwater runoff to cause environmental harm? (p) Create significant increase in erosion of the project site or surrounding ❑ ❑ ® ❑ areas? Impact Analysis: a) During the removal of the eight(8)existing piles and installation of the two new guide piles a temporary increase in water turbidity would occur,which would affect water quality within Redwood Creek Channel, localized at the project site,but possibly portions of the Bay as well.The pile removal/installation would affect bay water quality by creating turbidity plumes. However, substantial turbidity occurs naturally in the Redwood Creek Channel and SF Bay,particularly after heavy rains that result in increased runoff from local upland areas,creeks and sloughs. Turbidity also increases on a regular basis in the Bay from daily tidal scour. Tidal scour,currents, and increased turbidity are greatest during the shift from the highest-high to the lowest-low tide when the magnitude and rate of tidal drop is greatest.Turbidity plumes from the pile removal/installation will likely Port of Redwood City Multi-Agency Maritime Facility 30 February 2010 Initial Study