Treated water for Amador Water Agency’s Central Amador Water Project (CAWP) is stored in two 500,000-gallon and 250,000-gallon capacity welded steel tanks at the head of the CAWP system off Buckhorn Ridge Road in Pioneer, CA. The smaller Tank B serves customers at the highest elevations of the CAWP system which the Tank A distribution system cannot pressurize by gravity. A dedicated booster pump station, on the same site as the tanks, pumps water from Tank B to these residents. The booster pump station was under-sized, and this restricts the ability to meet both normal daily demands (these have increased over time through population growth) and fire flow requirements. In addition, the facility was aging and reaching the end of its working life. Coleman Engineering prepared a fast-track design of a new booster pump station in a CMU building adjacent to the existing facility. Three in-line 150 gpm vertical turbine pumps with VFDs operating up to a TDH of 150 feet are provided. The new pump station and building includes a hydropneumatic tank, design for snow loading at the project site elevation of 3,560 feet, and a new standby generator. The design period was substantially reduced to 3 – 4 months due to imminent funding agency deadlines.
Key Challenges & Solutions
- The replacement pump station location was heavily constrained by the existing station that had to remain in operation during construction, the site boundary fence, and the two tanks due for demolition and replacement under Phase 3. We fast-tracked a detailed site layout to a 30% design level of completion for the planned 10% design submittal in order to check the location could be used.
- During design, the Agency advised that only single-phase power was available from PG&E at the site. Our team worked through multiple pump options and station layouts, modified VFD arrangements, and coordinated with PG&E to improve the electrical service in order to resolve this issue.
February 14, 2022