Lexington Reservoir is located on Los Gatos Creek (downstream of Lake Elsman) and has an approximate capacity of 19,000 acre-feet. Lexington Reservoir is owned and operated by Santa Clara Valley Water District (Valley Water, VW) to store water, meet water supply, flood risk reduction, and to provide secondary recreational benefits. Water is captured during the rainy season and gradually released to Los Gatos Creek throughout the year for groundwater recharge and to meet instream flow requirements. Water that is not beneficially captured is released into the San Francisco Bay.
Montevina Water Treatment Plant (MWTP) is a 30 MGD WTP located on the western shore of Lexington Reservoir. MWTP treats water from surface stream diversions and from Lake Elsman. While MWTP is directly adjacent to Lexington Reservoir, it does not draw water from Lexington Reservoir on a regular basis. Water is treated at Montevina only during emergency events, subject to VW’s approval.
In collaboration with Valley Water, San Jose Water Company (SJW) sought to optimize the use of local water resources by constructing a water intake structure within Lexington Reservoir to deliver excess water to MWTP where it will be treated to serve customers in Santa Clara County. This project included a hydrologic analysis to identify whether there is sufficient water to divert to MWTP during specific periods of the year, and an assessment of various raw water intake structures and intake locations taking into consideration engineering, operational, environmental, and social factors.
As a subconsultant to Kennedy Jenks, Myriad Engineering performed the alternative evaluation analysis, reviewed the hydrologic modeling results report and provided comments for the draft and final report, prepared the draft feasibility report outline and several of the report sections. Assisted with the hydraulic calculations for pipe and pump station sizing. We prepared report figures and prepared alternative layout and conceptual designs for a floating pump station and an incline submersible pump station. We reviewed limnological, geotechnical, and environmental reports.
Scope of services:
- Hydraulic analysis
- Report review and prepare recommended changes
- Conceptual design preparation
- Prepare evaluation criteria
- Perform alternatives evaluation