Feasibility of Fish Passage at Alameda Creek Diversion Dam

2.0 SettingRainbow trout are the same species as steelhead, but rainbow trout spend their entire life-cycle infresh water, while steelhead have an anadromous life history. Rainbow trout are currently present inthe Alameda Creek Watershed, including in areas above and below the ACDD (SFPUC, 2004).There are well-documented reports of steelhead in the lower Alameda Creek channel below theBART weir (approximately 10 miles upstream of San Francisco Bay and approximately 18 milesdownstream of ACDD; Figure 1-1). This weir currently presents an impassable upstream migrationbarrier 4 (Gunther et al., 2000; Hayes, 2001). Small numbers of adult steelhead have been observedattempting to pass the BART weir (Gunther et al., 2000), some of which have been relocated abovethe weir and subsequently tracked to Stonybrook Creek (approximately 13 miles upstream of SanFrancisco Bay and approximately 15 miles downstream of ACDD), where they were observedspawning (San Jose Mercury News, 2008). Additional structures and natural cascades upstream ofthe BART weir also present obstacles for upstream movement of fishes (Gunther et al., 2000).A number of existing facilities under the jurisdiction of Alameda County Water District (ACWD),ACFCWCD, California Department of Water Resources, SFPUC, and Zone 7 Water Agency, amongothers, strongly affect hydrological and fisheries habitat conditions in the Alameda Creek Watersheddownstream of ACDD. Many of these structures and facilities have been in existence for well over80 years, and have resulted in substantial changes to the natural conditions that existed before thetwentieth century when a steelhead run is presumed to have been present throughout the basin.Although built in the past, these existing facilities and influences continue to operate and affecthabitat conditions for steelhead in the Alameda Creek Watershed. Some of these are direct barriers tofish migration; others pose various degrees of control/influence over habitat conditions (Gunther et al.,2000). The major facilities are listed below by sub-watershed.In the Arroyo de la Laguna Sub-Watershed:■■■■Del Valle Dam and Reservoir/South Bay Aqueduct, including State Water Project releases;Quarry lakes recharge facilities;Various channelized and culverted stream segments; andExpanding urban development of the Tri-Valley Area.In the Upper Alameda Creek Sub-Watershed:■■■■■■Calaveras Reservoir and Dam;Alameda Creek Diversion Dam and Tunnel;Sunol Valley aggregate mining operations and quarries;Turner Dam and San Antonio Reservoir;Sunol Valley infiltration galleries; andPacific Gas and Electric Company (PG&E) pipeline crossing protection covering (drop structure).In the Lower Alameda Creek Sub-Watershed:■■■ACWD’s upper, middle, and lower inflatable dams and quarry pit recharge facilities;BART weir; andACFCWCD channelization project.4 Although the BART weir is typically considered to be the impassable barrier that is the farthest downstream in thewatershed, a large inflatable dam, used for water division by the Alameda County Water District, is downstream of theBART weir. Plans have been provided to have this rubber dam removed and foundation notched in 2009 (CEMAR,2009).ACDD Passage June 2009 Page 2-13