Lake Ranch Reservoir Outlet Works Improvements

Lake Ranch Reservoir Outlet Works Improvements

San Jose Water Co. is proposing rehabilitation of the Lake Ranch Reservoir in accordance with the requirements of the CA Division of Safety Dams. Lake Ranch Reservoir is a small, approx.. 70 million gallon reservoir constructed between 1874 and 1876. SJWC proposes to construct siphons over both dams and grout the existing outlet pipes, rather than replace them. Based on the DSOD's drawdown requirements, the siphon at Saratoga dam will consist of a 12-inch diameter pipe At Beardsley dam, the siphon will consist of 44-inch diameter pipe with 16 inch emergency pipe. The siphons will be constructed using high-density polyethylene (HDPE) piping. The pipes will be buried and concrete-encased where they cross over the dam abutments, and will be mounted on the lake bottom with floating intakes within the reservoir. For the Saratoga dam, the project proposes to demolish and remove the following structures: floating wood and aluminum outlet structure, B-inch floating HDPE pipe, concrete vault, and B-inch above grade steel pipeline. However, the existing mooring piles for the floating outlet structure will be protected and reused as part of the new improvements. In addition, the buried B-inch pipe will be abandoned by pressure grouting pipe. For the Beardsley dam, the project includes demolition/removal of the steel and concrete outlet structure, valve, extension stem, metal supports and handwheel (concrete supports to remain for reuse), 6 inch steel pipeline above grade, 10-inch ductile iron pipeline above grade, and wood discharge structure to Lyndon Canyon (or Beardsley) Creek. In addition, the buried 10-inch pipe and buried 6-inch steel pipe will be abandoned by pressure grouting pipe. A temporary cofferdam will be installed to create a dry work environment for construction work at the Beardsley dam.

Saratoga

Santa Clara