Bear Gulch Water Intake Facility

Location: Woodside, California
Client/Partners: California Water Service Company, RiverMetrics

A diversion on Bear Gulch used for municipal water supply had an out-dated intake screen. The screen was upgraded with an ISI cone screen that meets National Marine Fisheries Service screening criteria. However, the screen lacked adequate submergence and the facility needed to monitor instream bypass flows. Michael Love & Associates (MLA) designed a series of two weirs to backflood the screen to provide adequate submergence, thus meeting screen approach velocity criteria. Two weirs were needed to create water surface drops of 6-inches or less over the weirs to provide upstream passage for juvenile steelhead. The lower weir also provided a v-notch to allow for accurate gaging of low streamflows. The facility included a water level logger with an innovative wave-dampening system, thus avoiding the need for a stilling well. Streamflows obtained using the measurement weir allowed for real-time operation of the intake pumps while maintaining required instream bypass flows.