Tule Lake, also known as Moon Lake, is a privately owned reservoir located in Lassen, California, near the city of Likely. Built in 1904, this earth dam stands at a height of 16 feet and has a storage capacity of 39,500 acre-feet. The primary purpose of Tule Lake is for water supply, serving irrigation, recreation, and domestic needs in the region.

Managed by the California Department of Water Resources (DWR) under the Safety of Dams program, Tule Lake is subject to state regulations, including regular inspections and enforcement measures. With a high hazard potential but a satisfactory condition assessment, the dam is crucial for water management in the area. The reservoir covers a surface area of 2,650 acres and is fed by Cedar Creek, with a drainage area of 82 square miles.

Despite its age, Tule Lake continues to play a vital role in water resource management in the region. With its historical significance and ongoing importance for irrigation and water supply, this earth dam stands as a testament to the engineering feats of the past and the critical role of water infrastructure in sustaining communities and ecosystems.