Low water levels and warm temperatures caused an algae bloom in San Luis Reservoir that produces an earthy, musty taste and odor, forcing the Santa Clara Valley Water District to pull more water out of Anderson Reservoir, which could end the boating season early – about a week before Labor Day this year.
Anderson Reservoir, which is the largest of the water district’s 10 reservoirs, does not currently have the algae issue that San Luis is experiencing, so we are now using more Anderson water to minimize the use of San Luis water at two of our treatment plants. Typically, the water district pulls water mostly from San Luis until late fall, when we shift to more Anderson water to continue supplying our water treatment plants and refilling our groundwater basins, and to make room for runoff from any upcoming rains.
But with the algae bloom in San Luis, we have had to switch to Anderson earlier than we had expected and that has lowered the water level in the reservoir. We expect to continue drawing water from Anderson, and in a couple of weeks, that will likely lower the water level too much to continue to allow the launching of boats. Santa Clara County Parks and Recreation, which manages recreation on and around water district facilities like Anderson, has notified boaters that boating at Anderson will be suspended on Aug. 27, when the water level is expected to be below the boat launch.
While this is unfortunate, it’s important to remember that the primary purpose of Anderson is to provide clean, safe water to Santa Clara County. The water district’s mission is to ensure the quality and delivery of that water.
Coyote Reservoir, which is connected to Anderson, was closed to boating in July after water levels decreased below the boat launch. That water was also being used to replace affected San Luis Reservoir water.
San Luis Reservoir has been hard hit by the algae bloom because its levels are much lower than normal this time of year. Some of the rain and snowmelt in the mountains of Northern California flows down into Shasta and then to the Delta, where much of it gets pumped into San Luis and other reservoirs. Normally, Delta water is pumped into San Luis in winter and drawn out during summer and fall. However, last winter, federal officials restricted the amount of water pumped into San Luis in order to protect fish in the Delta, and this year, federal agencies have delayed releasing water from Shasta to ensure there is enough cold water to release in the fall for the survival of endangered Chinook salmon.
This has also affected our ability to refill our underground aquifers, and has resulted in some of our percolation ponds drying out.
The water district takes water quality and water supply issues seriously. As you can see, we routinely need to strike a balance between the two, and in this case, that means the unfortunate early closure of certain reservoirs to boating. We will continue to work toward providing water of the highest quality to the community we serve.
Learn more about taste and odor issues.