Moccasin Creek Fish Hatchery Permanent Recirculation Project

Moccasin Creek Fish Hatchery Permanent Recirculation Project

The San Francisco Public Utility Commission (SFPUC), a department of the City and County of San Francisco, owns and operates the Hetch Hetchy Water and Power System, which provides water to the California Department of Fish and Wildlife’s (CDFW’s) Moccasin Creek Fish Hatchery (Hatchery) from Moccasin Reservoir. In 2016, a pilot water recirculation system was constructed by CDFW at the Hatchery (with funding provided by the SFPUC), which allowed the Hatchery to continue operating with a smaller fish inventory and with only 3 cubic feet per second (cfs) of inflow from Moccasin Reservoir. This pilot recirculation system successfully operated during the SFPUC’s January 3, 2017 to March 4, 2017 shutdown of a segment of the Hetch Hetchy Water and Power System, which temporarily eliminated water deliveries through Mountain Tunnel to Moccasin Reservoir to accommodate necessary inspections and maintenance of Mountain Tunnel. Following the inspections and work performed during the 2017 Shutdown, the SFPUC determined that the project to complete the rehabilitation of Mountain Tunnel (Mountain Tunnel Improvement Project) would require multiple 60- to 100-day shutdowns of a segment of the Hetch Hetchy Water and Power System over a 5-year period, beginning in January 2022. In addition to the Mountain Tunnel Improvement Project, the SFPUC has other capital and maintenance projects that may affect water flow from Moccasin Reservoir to the Hatchery, and future unplanned outages of the Hetch Hetchy Water and Power System may limit water available for use at the Hatchery. There may also be circumstances when the SFPUC must reduce or interrupt water deliveries to the Hatchery, such as during multiple-year droughts when the SFPUC determines that it is necessary to curtail water use by its retail and wholesale water customers on a mandatory basis. Adding on to the pilot recirculation system that was constructed in 2016, CDFW proposes to construct a permanent water reuse system (Permanent Recirculation System) at the Hatchery, using funding provided by the SFPUC, that will allow the Hatchery to continue to operate, with no expansion of its existing or former use, when there are reductions or interruptions of SFPUC water deliveries to the Hatchery. The Permanent Recirculation System generally consists of the construction and installation of: 1) a new sump for existing pumps; 2) drum filtration; 3) a safe platform access for existing aeration towers; and 4) a fish exclusion screen at the existing settling pond. The SFPUC will provide power service for the Permanent Recirculation System with the construction and installation of a power distribution line, transformer, automatic transfer switch, disconnect switch, and meter designed to accommodate the final design specifications of the Permanent Recirculation System, and put a temporary back-up generator in service during Hetch Hetchy system shutdowns. Note, this Notice of Exemption clarifies and supersedes the Notice of Exemption for this project that CDFW filed at OPR on July 17, 2020.

Moccasin

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