Plattsmouth 12-A Reservoir Report

Last Updated: December 13, 2025

Plattsmouth 12-A, located in Cass County, Nebraska, is a crucial structure designed by the USDA NRCS for flood risk reduction along the TR-Missouri River.


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Summary

Completed in 1962, this earth dam stands at a height of 32 feet, with a hydraulic height of 28 feet and a structural height of 39 feet. With a capacity for up to 76 acre-feet of storage and a drainage area of 0.15 square miles, Plattsmouth 12-A plays a vital role in safeguarding the surrounding area from potential flooding events.

Managed by the local government and regulated by the Nebraska Department of Natural Resources, Plattsmouth 12-A has a high hazard potential but is currently assessed as satisfactory in condition. The dam's primary purpose is flood risk reduction, and it has been inspected regularly, with the last assessment conducted in August 2020. Despite its age, the structure continues to meet safety guidelines and plays a critical role in protecting the community of Plattsmouth from the impacts of extreme weather events and rising water levels in the Missouri River.

With a history of successful operation and maintenance, Plattsmouth 12-A serves as a testament to effective collaboration between government agencies and design experts in ensuring the resilience of water resource infrastructure in the face of climate challenges. As climate change intensifies the frequency and severity of floods, structures like Plattsmouth 12-A will be essential in mitigating risks and protecting communities along the Missouri River from the devastating impacts of extreme weather events.

Year Completed

1962

Dam Length

642

Dam Height

32

River Or Stream

TR-MISSOURI RIVER

Primary Dam Type

Earth

Surface Area

4

Hydraulic Height

28

Drainage Area

0.15

Nid Storage

76

Structural Height

39

Hazard Potential

High

Foundations

Soil

Nid Height

39
       
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.