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<br />Central California Coast Steelhead (Oncorhynchus mykiss) Federal Threatened. Outmigrant <br />juvenile steelhead may disperse into the channel during high tides. These outmigrant movements <br />tend to occur in winter and spring. <br /> <br />Construction of the future bike path would not affect steelhead; however, driving of bridge pile <br />supports may affect juvenile salmonids due to acoustic disturbance. A mitigation measure is <br />proposed below to avoid impacts to juvenile steelhead. <br /> <br />Central Valley FalllLate Fall-Run Chinook Salmon (Oncorhynchus tshawytscha), CDFG Species <br />of Special Concern. Outmigrant juvenile chinook salmon may disperse into the channel during high <br />tides. These outmigrant movements tend to occur in winter and spring. Construction of the future <br />bike path would not affect chinook salmon; however, driving of bridge pile supports may affect <br />juvenile salmonids due to acoustic disturbance. A mitigation measure is proposed below to avoid <br />impacts to juvenile chinook salmon. <br /> <br />Based on a review of the resources and databases, 50 special status plant species have been <br />documented in the general vicinity of the study area. Most of the species generated by the literature <br />search were determined to be not present due to a variety of factors, including lack of unique soil <br />types (e.g., serpentine, clay), lack of typical habitat (e.g., freshwater wetland, vernal pool, chaparral, <br />woodland, riparian, native grassland), and/or inappropriate site elevation. In addition, no native soils <br />or seed banks are present due to past disturbance and import of fill materials during construction of <br />the wastewater treatment facility, Oakland Airport, and East Bay Regional Park District facilities. <br /> <br />Impact IV-I: Impacts to wetlands or waters of the United States <br /> <br />Mitigation Measure IV-I: To avoid or reduce impacts to special status wildlife species that could be <br />found in wetlands and waters of the Us. (California clapper rail and salmonids), implement <br />Mitigation Measure IV-3(b) and (d), below. <br /> <br />Impact IV-2: Construction ofthe bicyclepatb may affect the adjacent pickleweed marsh <br /> <br />Mitigation Measure IV.2: A protective fence shall be installed along the northern levee bank along <br />the proposed bicycle path to prevent accidental intrusion by construction equipment and/or workers <br />into the adjacent pickleweed marsh. In addition, erosion control measures shall be implemented to <br />prevent fill materials from the construction site from entering the marsh. <br /> <br />Impact IV -3: Construction may affect four special status species <br /> <br />Mitigation Measure IV-3: (a) To prevent the salt marsh harvest mousefrom dispersing across the <br />future bike path during construction, adjacent vegetation shall be cleared by hand within six feet of <br />the paved surface, and a temporary silt-fence barrier shall be installed The vegetation clearing will <br />help disperse any salt marsh harvest mice into adjacent dense cover, while the subsequent silt-fince <br />barrier will prevent mice from entering the construction area. <br /> <br />(b) Pre construction rail surveys shall be conducted to determine presence/absence. Ifrails are <br />absent, construction may proceed If a breeding pair of rails is detected, then pile driving shall not <br /> <br />Y 4204IS. 00693. doc - 4/5/07 <br /> <br />-18- <br />