[3] In the 19th century, the Calaveras Valley which the reservoir now fills was primarily an agricultural region known for its production of hay, strawberries, and tomatoes.

[5] The city and county of San Francisco owns and operates the dam and reservoir for municipal water supply.

[citation needed] The San Francisco Public Utilities Commission (SFPUC) owns 36,000 acres (150 km2) in the Alameda Creek Watershed.

Some lands in the watershed are leased to livestock companies for cattle ranching to control vegetation and prevent fires.

If the dam had collapsed when full, it would have flooded parts of Fremont, California with a wall of water 30 ft (9.1 m) high.

[12] The SFPUC did assure environmental groups that it will release water from the replacement dam to improve summer flows.

A smaller fish ladder is under construction at a separate diversion dam on upper Alameda Creek, regarded as prime trout habitat.

[6] Facing legal challenges to release flows to support steelhead trout (Oncorhynchus mykiss) in the 20 miles (32 km) of Calaveras Creek below the dam, the San Francisco Public Utilities Commission (SFPUC) began steady releases after the dam was re-built in 2018.

The steady flow releases, and accompanying lowered water temperatures, resulted in a sharp increase in the numbers of trout.

[13] In the late 1980s and early 1990s, a drought affected California, and water levels in reservoirs throughout the state became extraordinarily low.