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4 Envirora�rrental Araalysis <br /> of 42-inch storm drain that would convey the existing starmwater runoff from the Bair Island Road <br /> area to the new purnp station and appro�mately 100 feet of 24-inch pipe to tie inta the exisring 24- <br /> inch discharge line to Aedwood Creek. (Less than Significant Impact) <br /> � Otherwise substantially degrade water quality.� <br /> With the proposed mirigation measures,the project would not substantiallt�degrade water yuality. <br /> See the response to a) above. (Less than Significant Impact with Miti�ation Incorporation} <br /> g)Place ho�rsing within a 100 year flood hazard ar�a as mapped on a federal Flood Hazard <br /> Baundary or Flood Insurarice Rate Map or other flood hazatd delr�eatior2 map? <br /> The proposed project would not place housing within a 100-pear flood hazatd area. (No Impact) <br /> h)Place withi� a 100 year flood hazatd area structures which would impede ot teditect flaad <br /> �OWS� <br /> The proposed facilities would be within a 1d0 year floodplain,but would not impede or redi_rect <br /> flood flows. (Less than 5ignaficant Irnpact}) <br /> i)Expose peaple or structures to a sigrlificaut risk ofloss,r�rjury ar death l�volving floodir�g, <br /> tncludirig floodirlg as a result of the failure ofa levee or dam? <br /> The project area is ridally influenced and would be subject to increased water levels during peak <br /> storm events. T`he present flood level and tidal data for Redwood Creek axe as follows: <br /> Datum E:Ic�:�tiut� �fi,NAVD 88) <br /> 100-Year (stillwater) 9.7 <br /> 50-Year (stillwater) 9.6 <br /> 10-Year(stillwater) 9.3 <br /> MHHW(tidal) 7.4 <br /> MLLW(tidal; -0.8 <br /> NAVD $8=Narth Amexican Vertical Datum 1988 <br /> The floodplain data is "still�uater data," which includes storm surge and astronomical tides, but not <br /> the effects of waves or tsunamis. The tida.l data is from the period October 1997 to October 2011. <br /> The City would construct the creek-side xetainii�g wall to a height of 10.0 feet,wl�ich would be higher <br /> than the current 100-pear stillwater elevation. <br /> The proposed facilities would not have a significant effect on fload levels in the cxeek,but would be <br /> subject to increased flooding. Futute sea level increases would modify the floodplain elevations in <br /> the project area. Assurning a sea level rise of 1.3 ft (16 inches) by the year 2050,the MHHW <br /> elevation would be $.7 feet, and the �0-year stillwater elevation would be 10.6 feet. If the sea levels <br /> 2-�� US 901 I'e�'estrian Undercrassing und Baar <br /> I.rland Kaad Stor»a Draan Pu'nj�Stataora I'roject <br />