The lake is formed by a dam on the north fork of Pacheco Creek, whose waters reach Monterey Bay by way of the Pajaro River.

Located north of State Route 152 in eastern Santa Clara County, the lake is about an hour's drive from downtown San Jose.

In many years in late spring, prior to reservoir releases for agriculture, low stream flows and high-water temperatures severely impact steelhead fry and small juveniles.

Valley Water published the Draft Environmental Impact Report[11] on November 17, 2021, and the public comment period ended on February 15, 2022.

California Department of Fish and Wildlife commented that as a whole the draft report “lacks sufficient information for CDFW to fully assess the magnitude of the Proposed Project’s environmental impacts and which mitigation measure may be necessary.”[13]  Additionally, CDFW had concerns regarding changes in flow regimes, impacts to steelhead, improper water temperature analysis, harmful algal blooms and several others.

[13]  The DSOD commented that it had written a letter on November 1, 2021, rejecting the hardfill dam included in the proposed project due to significant uncertainties and risks to public safety.

National Marine Fisheries Service's (NMFS) commented on the lack of clarity between the potential for conflicts between project objectives, providing water reliability and increasing suitable steelhead habitat.

[18] During the meeting a member of the public asked when Valley Water would begin the National Environmental Policy Act (NEPA) process.

Additionally, the United States Environmental Protection Agency (EPA) commented that in an effort to avoid redundancy, improve efficiency, and interagency cooperation Valley Water should synchronize the NEPA and CEQA processes.