Coyote Reservoir level dropping

District has turned to Coyote as other water sources experience algae blooms

Combating odor-causing algae blooms in imported water sources, particularly from San Luis Reservoir, the Santa Clara Valley Water District has shifted to using water from Anderson and Coyote reservoirs, located east of Morgan Hill. Currently, these local sources are supplying two of the water district’s three drinking water treatment plants. As a result, the water level at Coyote Reservoir will drop below the bottom of the reservoir’s boat ramp this week, forcing an early closure of boating on the reservoir.

Algae blooms in the Sacramento-San Joaquin Delta, San Luis Reservoir and the district’s Calero Reservoir have resulted in ongoing water treatment challenges.

This time of year, the district typically uses water from the Delta and San Luis Reservoir to supply most of the water processed at its three water treatment plants, preserving the Anderson-Coyote reservoir system as a back-up source. This year, water storage in San Luis Reservoir has dropped earlier and lower than normal due to a delay by federal officials in releasing water from Shasta Reservoir in northern California, to assist in salmon survival. The current algae blooms in the Delta and San Luis Reservoir have compelled the district to draw upon Anderson and Coyote reservoirs earlier in the summer than anticipated. While the district continues to meet all drinking water standards, an earthy or musty taste and odor may still remain in some areas.

Anderson and Coyote reservoirs serve primarily to provide water supply to Santa Clara County residents and businesses. While the district strives to accommodate recreational opportunities at its facilities, water supply and water quality remain its highest priority.

The water stored in Coyote Reservoir comes from storm run-off from the Coyote Watershed. Because there is no other source of water to re-fill the reservoir, the water level will remain too low for boating until rains return.

Anderson, which also allows motorized boating, is downstream of Coyote Reservoir, so the two water supplies work in tandem. If the algae issues persist, Anderson Reservoir’s boating season could also be impacted.

In early July, the district responded to an algae-caused taste and odor problem in its Delta water supply by shifting water sources, but algae problems have persisted.

In the future, the district hopes to experience fewer taste and odor challenges due to algae blooms. Currently, the Rinconada Water Treatment Plant is undergoing a major modernization project. By 2020, the plant will begin using ozone for disinfection, which is a superior method to remove taste and odor compounds.

As the district works to minimize the unpleasant taste and odor the water leaving its plants, customers who do experience a taste or odor can chill their tap water before drinking in order to make taste and smell issues less noticeable. It is not necessary to boil water as the water is safe to drink and meets all state and federal public health standards.

The water district will continue to strive to improve the taste and smell of the water in this unusual time. We put the highest priority on providing safe, clean water to Santa Clara County.

Learn more about taste and odor issues and how the district manages water quality.