Tanner

Cowell Creek· Calaveras, California· Built 1959· Earth· 35 ft tall
High Hazard Water Supply Irrigation Recreation Private

Key Takeaway

Tanner is classified as high hazard in California. It was completed in 1959 and is 67 years old. Its primary use is water supply. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Height 35 ft (taller than 38.2% in CA)
Dam Length335 ft
Dam TypeEarth
Max Storage124 acre-ft
Surface Area12 acres
Drainage Area3 sq mi
Year Completed1959 (67 years old)
NID IDCA01002

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: February 9, 2022
State Regulated: Yes
Regulatory Agency: DWR, Division of Safety of Dams

Ownership

Lake Mont Pines Homeowners

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Tanner?

Tanner is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Tanner?

Tanner is owned by Lake Mont Pines Homeowners (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Tanner built?

Tanner was completed in 1959, making it 67 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Tanner?

Tanner serves the following purposes: Water Supply, Irrigation, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Tanner?

Tanner has a dam height of 35 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Tanner last inspected?

Tanner was last inspected on February 9, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.