Jefferson Park Watershed Site 4 Reservoir Report

Last Updated: December 6, 2025

Located in Ottumwa, Iowa, the Jefferson Park Watershed Site 4 is a key component in flood risk reduction efforts along the TR-Des Moines River.


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Summary

Owned by the local government and regulated by the Iowa Department of Natural Resources, this earth dam stands at a height of 36 feet and stretches 510 feet in length. Completed in 1978, it has a storage capacity of 128 acre-feet and covers a surface area of 3.7 acres within a drainage area of 0.22 square miles.

Managed by the USDA NRCS, this site plays a crucial role in protecting the surrounding areas from potential flooding events. With a high hazard potential but a satisfactory condition assessment, the dam is inspected on a regular basis to ensure its integrity and functionality. Despite its age, the Jefferson Park Watershed Site 4 continues to serve its primary purpose of flood risk reduction effectively, making it a vital asset in the community's water resource management infrastructure.

Supported by state and federal agencies, including the Natural Resources Conservation Service, this dam exemplifies collaborative efforts to enhance water resource management and climate resilience. As climate change poses increasing challenges to water systems, structures like the Jefferson Park Watershed Site 4 play a vital role in safeguarding communities and ecosystems from the impacts of extreme weather events. With a focus on safety, efficiency, and sustainability, this site stands as a model of effective water resource management in the face of a changing climate.

Year Completed

1978

Dam Length

510

Dam Height

36

River Or Stream

TR-DES MOINES RIVER

Primary Dam Type

Earth

Surface Area

3.7

Drainage Area

0.22

Nid Storage

128

Hazard Potential

High

Foundations

Soil

Nid Height

36
       
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.