Tiger Creek Afterbay

North Fork Mokelumne River· Amador, California· Built 1931· Concrete· 120 ft tall
High Hazard Hydroelectric Private

Key Takeaway

Tiger Creek Afterbay is classified as high hazard in California. It was completed in 1931 and is 95 years old. Its primary use is hydroelectric. 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 120 ft (taller than 85.7% in CA)
Dam Length448 ft
Dam TypeConcrete
Max Storage2.6K acre-ft
Normal Storage2.6K acre-ft
Surface Area70 acres
Drainage Area357 sq mi
Max Discharge194,370 cfs
Year Completed1931 (95 years old)
NID IDCA00401

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: July 11, 2023
State Regulated: Yes
Regulatory Agency: DWR, Safety of Dams

Ownership

Pacific Gas and Electric Company

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Tiger Creek Afterbay?

Tiger Creek Afterbay 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 Tiger Creek Afterbay?

Tiger Creek Afterbay is owned by Pacific Gas and Electric Company (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Tiger Creek Afterbay built?

Tiger Creek Afterbay was completed in 1931, making it 95 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 Tiger Creek Afterbay?

Tiger Creek Afterbay serves the following purposes: Hydroelectric. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Tiger Creek Afterbay?

Tiger Creek Afterbay has a dam height of 120 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 Tiger Creek Afterbay last inspected?

Tiger Creek Afterbay was last inspected on July 11, 2023. 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.