Murphys Afterbay

Angels Creek· Calaveras, California· Built 1953· Earth· 43 ft tall
High Hazard Hydroelectric Irrigation Public Utility

Key Takeaway

Murphys Afterbay is classified as high hazard in California. It was completed in 1953 and is 73 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 43 ft (taller than 51.5% in CA)
Dam Length340 ft
Dam TypeEarth
Max Storage31 acre-ft
Normal Storage31 acre-ft
Surface Area3 acres
Drainage Area3 sq mi
Max Discharge1,450 cfs
Year Completed1953 (73 years old)
NID IDCA00410

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: May 31, 2023
State Regulated: Yes
Regulatory Agency: DWR, Safety of Dams

Ownership

Utica Water & Power Authority

Public Utility

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Murphys Afterbay?

Murphys 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 Murphys Afterbay?

Murphys Afterbay is owned by Utica Water & Power Authority (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Murphys Afterbay built?

Murphys Afterbay was completed in 1953, making it 73 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 Murphys Afterbay?

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

How tall is Murphys Afterbay?

Murphys Afterbay has a dam height of 43 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 Murphys Afterbay last inspected?

Murphys Afterbay was last inspected on May 31, 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.