Zone 7 Water Agency (Zone 7) delivers safe, reliable, efficient, and sustainable treated drinking water to retailers serving over a quarter million people in the cities of Pleasanton, Livermore, Dublin, and the Dougherty Valley area. Zone 7 source water consists of surface water and groundwater. One reservoir and ten groundwater wells are located on the west side of the system, and two surface water treatment plants, Del Valle Water Treatment Plant (DVWTP) and Patterson Pass Water Treatment Plant (PPWTP), are located on the east.
During drought periods, the system depends almost solely on groundwater to meet daily demands that range between 32 million gallon per day (MGD) to 42 MGD. The additional pressures required to convey water to near DVWTP and PPWTP on the east side exceed the rated system pressures of certain well stations, which would result in system leaks and ruptures. In 2014, Zone 7 and Advanced Hydro Engineering completed the study, Modeling Results for Proposed Intermediate
Pump Station (2014 Study), which demonstrated that adding an intermediate pump station would alleviate the issue of excessive facility pressure. Figure 1 illustrates the configuration of the overall system with the added Valley Pump Station.
The new pump station will decrease the transmission system pressure in the wellfield zone (west side) of our service area. This decreased pressure will allow higher water production from our existing wells while also reducing stress on equipment and components. The Valley Pump Station is planned to be operated continuously for system recirculation to improve water quality.