Mccormack Dam Reservoir Report

Last Updated: December 30, 2025

Mccormack Dam, located in Oregon, Missouri, was completed in 1937 and is owned and operated by the USDA Forest Service.


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Summary

With a primary purpose of recreation, this earth dam stands at 27 feet tall and spans 366 feet in length, providing a storage capacity of 148 acre-feet of water from the Mc Cormack Hollow river or stream. The dam covers a surface area of 10 acres and has a drainage area of 4 square miles, with a maximum discharge capacity of 4000 cubic feet per second.

Despite being classified as having a significant hazard potential, Mccormack Dam received a satisfactory condition assessment in October 2019, indicating that it is currently in good working order. The dam has an uncontrolled spillway with a width of 50 feet and is regularly inspected by the Forest Service to ensure its safety and functionality. While the risk assessment for Mccormack Dam is moderate, with a DSAC risk rating of 3, there are currently no specific risk management measures or emergency action plans in place for the dam.

Overall, Mccormack Dam serves as an important recreational resource in the area, offering opportunities for boating, fishing, and other water-based activities. While the dam presents a moderate level of risk, its satisfactory condition assessment and regular inspections by the Forest Service help to ensure the safety of the structure and surrounding community.

Year Completed

1937

Dam Length

366

Dam Height

27

River Or Stream

MC CORMACK HOLLOW

Primary Dam Type

Earth

Surface Area

10

Drainage Area

4

Nid Storage

148

Hazard Potential

Significant

Nid Height

27
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.