Colwil Lake Dam

MATTHEWS BRANCH· Shannon, Missouri· Built 1959· Earth· 47 ft tall
Low Hazard Recreation Other Private

Key Takeaway

Colwil Lake Dam is classified as low hazard in Missouri. It was completed in 1959 and is 67 years old. Its primary use is recreation.

Physical Details

Dam Height 47 ft (taller than 93.7% in MO)
Dam Length180 ft
Dam TypeEarth
Max Storage360 acre-ft
Normal Storage299 acre-ft
Surface Area15 acres
Drainage Area4 sq mi
Max Discharge3,200 cfs
Year Completed1959 (67 years old)
Year Modified1995
NID IDMO30058

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: October 23, 2019
State Regulated: Yes
Regulatory Agency: Dam and Reservoir Safety Program

Ownership

RON DASSOW

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Colwil Lake Dam?

Colwil Lake Dam 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 Colwil Lake Dam?

Colwil Lake Dam is owned by RON DASSOW (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Colwil Lake Dam built?

Colwil Lake Dam was completed in 1959, making it 67 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 Colwil Lake Dam?

Colwil Lake Dam serves the following purposes: Recreation, Other. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Colwil Lake Dam?

Colwil Lake Dam has a dam height of 47 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 Colwil Lake Dam last inspected?

Colwil Lake Dam was last inspected on October 23, 2019. 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.