Cottonwood-Green Valley Subws 75+70 #2

TR-LITTLE SIOUX RIVER· Monona, Iowa· Built 1966· Earth· 26 ft tall

Key Takeaway

Cottonwood-Green Valley Subws 75+70 #2 is classified as low hazard in Iowa. It was completed in 1966 and is 60 years old. Its primary use is fire protection.

Physical Details

Dam Height 26 ft (taller than 24.7% in IA)
Dam Length518 ft
Dam TypeEarth
Max Storage50 acre-ft
Normal Storage18 acre-ft
Surface Area3 acres
Drainage Area1 sq mi
Max Discharge0 cfs
Year Completed1966 (60 years old)
NID IDIA00744

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
State Regulated: Yes
Regulatory Agency: IOWA DNR

Ownership

Monona County SWCD

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Cottonwood-Green Valley Subws 75+70 #2?

Cottonwood-Green Valley Subws 75+70 #2 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 Cottonwood-Green Valley Subws 75+70 #2?

Cottonwood-Green Valley Subws 75+70 #2 is owned by Monona County SWCD (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Cottonwood-Green Valley Subws 75+70 #2 built?

Cottonwood-Green Valley Subws 75+70 #2 was completed in 1966, making it 60 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-Green Valley Subws 75+70 #2?

Cottonwood-Green Valley Subws 75+70 #2 serves the following purposes: Fire Protection, Stock, Or Small Fish Pond, 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-Green Valley Subws 75+70 #2?

Cottonwood-Green Valley Subws 75+70 #2 has a dam height of 26 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.

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.