Preston Forebay

Offstream· Amador, California· Built 1892· Earth· 40 ft tall
Low Hazard Other Irrigation Public Utility

Key Takeaway

Preston Forebay is classified as low hazard in California. It was completed in 1892 and is 134 years old. Its primary use is other.

Physical Details

Dam Height 40 ft (taller than 46.3% in CA)
Dam Length176 ft
Dam TypeEarth
Max Storage30 acre-ft
Surface Area2 acres
Drainage Area0 sq mi
Year Completed1892 (134 years old)
NID IDCA00006

Safety Information

Low Hazard

No probable loss of human life and low economic/environmental losses expected.

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

Emergency Action Plan: No
Last Inspection: September 14, 2021
State Regulated: Yes
Regulatory Agency: DWR, Division of Safety of Dams

Ownership

Amador Regional Sanitation Authority

Public Utility

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Preston Forebay?

Preston Forebay is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Preston Forebay?

Preston Forebay is owned by Amador Regional Sanitation Authority (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Preston Forebay built?

Preston Forebay was completed in 1892, making it 134 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 Preston Forebay?

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

How tall is Preston Forebay?

Preston Forebay has a dam height of 40 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 Preston Forebay last inspected?

Preston Forebay was last inspected on September 14, 2021. 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.