Deerwood Lake No.3 Dam

Deerwood Lake No.3 Dam is an earth dam located in Jefferson County, Missouri, built in 1960. It carries a High hazard potential classification.

About Deerwood Lake No.3 Dam

The primary purpose of Deerwood Lake No.3 Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Dewey Cook Jr (private). It impounds the Trib-isom Creek near Cedar Hill.

The dam stands 25 feet tall, creates a reservoir covering 3 acres, has a maximum storage capacity of 40 acre-feet, and collects water from a drainage area of 16 square miles. Completed in 1960, the structure is well into its service life at over 50 years old.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. The most recent inspection on record was 11/07/1980. That was 45 years ago — unusually long for a high-hazard dam, which typically requires more frequent inspections.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Missouri dam safety program can provide more specific information about emergency planning for this structure.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.

High HazardNot Rated ConditionEmergency Action Plan: Not Required

Location

StateMissouri
CountyJefferson
Nearest CityCedar Hill
River/StreamTrib-isom Creek
Coordinates38.34059, -90.60189

Physical Characteristics

Dam TypeEarth
NID Height25 ft
Dam Height25 ft
Year Completed1960 (66 years old)

Storage & Hydraulics

NID Storage40 acre-ft
Max Storage40 acre-ft
Normal Storage30 acre-ft
Surface Area3 acres
Drainage Area16 sq mi

Ownership & Safety

PurposeRecreation
OwnerDEWEY COOK JR
Owner TypePrivate
Hazard ClassificationHigh
Condition AssessmentNot Rated
Last Inspection11/07/1980
Emergency Action PlanNot Required

Identifiers

NID IDMO30460
Federal IDMO30460
More InfoState Dam Safety Program

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