Jefferson Park Watershed Site 1 Reservoir Report
Last Updated: December 6, 2025
Located in Ottumwa, Iowa, Jefferson Park Watershed Site 1 is a flood risk reduction structure designed by the USDA NRCS and completed in 1976.
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Summary
This Earth dam stands at a height of 36 feet and spans 454 feet along the TR-Des Moines River. The dam has a storage capacity of 130 acre-feet, with a normal storage level of 14 acre-feet, covering a surface area of 3.2 acres within a drainage area of 0.21 square miles.
Managed by the Iowa DNR, this watershed site is regulated and inspected regularly to ensure its structural integrity and flood risk reduction capabilities. With a high hazard potential, the dam is classified as satisfactory in condition and subject to a moderate risk assessment. The spillway, with a width of 3 feet, is uncontrolled, posing a potential risk during high flow events. Overall, Jefferson Park Watershed Site 1 serves as a critical infrastructure for managing water resources in Wapello County, Iowa, under the jurisdiction of the local government.
Enthusiasts of water resource and climate management will find Jefferson Park Watershed Site 1 a fascinating example of engineering for flood risk reduction. With its strategic location along the TR-Des Moines River and its vital role in protecting Ottumwa from potential inundation, this Earth dam showcases the importance of sustainable water infrastructure in mitigating the impacts of extreme weather events. As a state-regulated and inspected structure, Jefferson Park Watershed Site 1 stands as a testament to collaborative efforts in safeguarding communities against flooding and preserving the natural environment.
Year Completed |
1976 |
Dam Length |
454 |
Dam Height |
36 |
River Or Stream |
TR-DES MOINES RIVER |
Primary Dam Type |
Earth |
Surface Area |
3.2 |
Drainage Area |
0.21 |
Nid Storage |
130 |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
36 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Des Moines River At Ottumwa
|
1090cfs |
Fox River At Bloomfield
|
7cfs |
North Skunk River Near Sigourney
|
97cfs |
Chariton River Near Rathbun
|
15cfs |
Chariton River Near Moulton
|
34cfs |
South Skunk River Near Oskaloosa
|
485cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Jefferson Park Watershed Site 1