Twin Falls

Snake River· Jerome, Idaho· Built 1935· Concrete· 16 ft tall
Low Hazard Hydroelectric Recreation Private

Key Takeaway

Twin Falls is classified as low hazard in Idaho. It was completed in 1935 and is 91 years old. Its primary use is hydroelectric.

Physical Details

Dam Height 16 ft (taller than 13.6% in ID)
Dam Length809 ft
Dam TypeConcrete
Max Storage955 acre-ft
Normal Storage955 acre-ft
Surface Area85 acres
Drainage Area19,000 sq mi
Max Discharge60,000 cfs
Year Completed1935 (91 years old)
NID IDID00051

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 19, 2017
State Regulated: Yes
Regulatory Agency: IDWR

Ownership

Idaho Power Company

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Twin Falls?

Twin Falls 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 Twin Falls?

Twin Falls is owned by Idaho Power Company (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Twin Falls built?

Twin Falls was completed in 1935, making it 91 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 Twin Falls?

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

How tall is Twin Falls?

Twin Falls has a dam height of 16 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 Twin Falls last inspected?

Twin Falls was last inspected on September 19, 2017. 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.