|Location||Santa Clara County, California|
|Primary inflows||Cherry Canyon, Pine Tree Canyon|
|Primary outflows||Arroyo Calero|
|Catchment area||7.14 sq mi (18.5 km2)|
|Basin countries||United States|
|Managing agency||Santa Clara Valley Water District|
|Max. length||2.2 mi (3.5 km)|
|Surface area||349 acres (141 ha)|
|Water volume||9,934 acre feet (12,253,000 m3)|
|Surface elevation||476 feet (145 m)|
Watershed and Course
Calero Dam is an earthen dam 90 feet (27 m) high and 840 feet (260 m) long containing 550,000 cubic yards (420,000 m3) of material. Its crest is 490 feet (150 m) above sea level. The reservoir receives flows from the southwest via Cherry Canyon which has its origin at Fern Peak in the southeastern part of the Santa Cruz Mountains. It also receives minor inputs from the southeast via the ephemeral flows down Pine Tree Canyon
Calero Reservoir is the fourth largest reservoir owned by the Santa Clara Valley Water District. After capturing winter runoff from the nearby foothills and from water transferred, via a canal, from nearby Almaden Reservoir, reservoir water recharges groundwater basins and is also provided directly to water treatment plants, via the Almaden Valley Pipeline, to be treated and distributed to county residents. Calero Reservoir also can receive flows from Anderson Reservoir and San Luis Reservoir, via the recently restored Cross Valley and Calero pipelines which stretch 10.6 miles (17.1 km), starting from the Coyote Pump Plant in Morgan Hill, extending through parts of unincorporated Santa Clara County, and ending at the Calero Reservoir in South San Jose.
Because alluvium deposits were found beneath the dam in a 2012 independent engineering study, and these could liquify in an earthquake, reservoir levels are currently maintained 19 feet below the spillway with retrofit construction of the dam scheduled for 2021. This restriction limits Calero Reservoir to 45% of capacity or about 4,414 acre-feet. When the Calero Dam retrofit is completed, the capacity of Calero Reservoir could be restored to 9,738 acre-feet and increase the outlet capacity from 50 cfs to up to 100 cfs.
The California Office of Environmental Health Hazard Assessment released a "Do Not Eat" warning regarding eating any fish caught from this reservoir based on the elevated mercury level. The primary fish caught in Calero Reservoir are non-native, including largemouth bass (Micropterus salmoides), Eurasian common carp (Cyprinus carpio), and black crappie (Pomoxis nigromaculatus).
A 4,471-acre (1,809 ha) county park surrounds the reservoir and provides limited fishing ("catch-and-release"), picnicking, hiking, and horseback riding activities. Although swimming is prohibited, boating, water-skiing and jet-skiing are permitted in the reservoir.
- List of lakes in California
- List of lakes in the San Francisco Bay Area
- List of reservoirs and dams in California
- "Calero Reservoir". Geographic Names Information System. United States Geological Survey.
- "Cherry Canyon". Geographic Names Information System. United States Geological Survey.
- "Pine Tree Canyon". Geographic Names Information System. United States Geological Survey.
- "Arroyo Calero". Geographic Names Information System. United States Geological Survey.
- "Listing of Jurisdictional Dams in California" (PDF). California Department of Water Resources. Retrieved July 3, 2017.
- "Santa Clara Valley Water District: List of Reservoirs". Archived from the original on 2017-06-20. Retrieved 2017-07-03.
- "Santa Clara Valley Water District: Calero Dam and Reservoir". Archived from the original on 2017-06-20. Retrieved 2017-07-03.
Calero Reservoir provides water directly to drinking water treatment plants, which treat and test it for safety. The district then distributes the water to water retailers to sell to the county’s 1.8 million residents. Calero also captures and stores winter runoff to recharge groundwater basins, helps store water from the nearby Almaden Reservoir watershed and accepts imported water.
- U.S. Geological Survey Geographic Names Information System: Cherry Canyon
- U.S. Geological Survey Geographic Names Information System: Fern Peak
- U.S. Geological Survey Geographic Names Information System: Pine Tree Canyon
- "Crossing the Finish Line with the Cross Valley and Calero Pipeline Inspection and Rehabilitation Project". Valley Water News. July 1, 2020. Retrieved November 9, 2020.
- Calero Dam Retrofit Project (Report). Valley Water. Retrieved November 9, 2020.
- Monserrat, Laurie (2015-03-11). "Calero Reservoir". OEHHA. Retrieved 2018-06-11.
- "Calero Reservoir". FishBrain. Retrieved November 9, 2020.
- "Santa Clara County Parks: Calero Reservoir". County of Santa Clara. Retrieved 2017-07-03.
"Santa Clara County Parks: Fishing Guidelines". County of Santa Clara. Retrieved 2017-07-02.
Mercury has been found to accumulate in Almaden, Calero, Guadalupe, Anderson and Stevens Creek Reservoirs at levels that make the fish unsafe to eat.
- "Santa Clara Valley Water District: Recreation Restrictions". Archived from the original on 2017-06-20. Retrieved 2017-07-04.
Swimming at Almaden, Coyote, Anderson and Calero reservoirs is prohibited by the state Department of Health to protect the drinking water supply from potential bacteriological contamination.
"Santa Clara County Parks: Boating Guidelines". County of Santa Clara. Retrieved 2017-07-03.
Boating is permitted from 8am to ½ hour before sunset in the following reservoirs: Calero, Coyote Lake, Anderson, Stevens Creek and Lexington.