Cottonwood Creek Lower

COTTONWOOD CREEK BOISE RIVER· Ada, Idaho· Built 1961· 15 ft tall
Significant Hazard Flood Risk Reduction Local Government

Key Takeaway

Cottonwood Creek Lower is classified as significant hazard in Idaho. It was completed in 1961 and is 65 years old. Its primary use is flood risk reduction. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 15 ft (taller than 10.5% in ID)
Dam Length1,710 ft
Normal Storage88 acre-ft
Surface Area9 acres
Drainage Area17 sq mi
Max Discharge3,540 cfs
Year Completed1961 (65 years old)
NID IDID00477

Safety Information

Significant Hazard

No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.

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

Emergency Action Plan: No
Last Inspection: September 11, 2018
State Regulated: Yes
Regulatory Agency: IDWR

Ownership

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Cottonwood Creek Lower?

Cottonwood Creek Lower is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Cottonwood Creek Lower?

Cottonwood Creek Lower is owned by information not available (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Cottonwood Creek Lower built?

Cottonwood Creek Lower was completed in 1961, making it 65 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 Cottonwood Creek Lower?

Cottonwood Creek Lower serves the following purposes: Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Cottonwood Creek Lower?

Cottonwood Creek Lower has a dam height of 15 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 Cottonwood Creek Lower last inspected?

Cottonwood Creek Lower was last inspected on September 11, 2018. 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.