Gonseth Dam Reservoir Report
Nearby: Granfield/Westrum Dam Koch Dam
Last Updated: December 11, 2025
Gonseth Dam, located in Thayer, Iowa, is a privately owned structure designed by USDA NRCS with a primary purpose of fire protection, stock, or small fish pond.
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Summary
Completed in 1992, this earth dam stands at a height of 26 feet and has a length of 385 feet, providing a storage capacity of 63 acre-feet. The dam is situated on TR-Four Mile Creek and is regulated by the Iowa Department of Natural Resources.
With a low hazard potential and a moderate risk assessment score of 3, Gonseth Dam plays a crucial role in water resource management in Clarke County, Iowa. The dam's reservoir covers a surface area of 3.4 acres and has a drainage area of 0.29 square miles. Despite its uncontrolled spillway type, the dam has not undergone a condition assessment and is currently rated as "Not Rated" in terms of its structural integrity.
Overall, Gonseth Dam serves as a vital asset for fire protection and agricultural purposes in the region. As water resource and climate enthusiasts, it is important to monitor and assess the condition of such structures to ensure their continued functionality and safety for the surrounding community and ecosystem.
Year Completed |
1992 |
Dam Length |
385 |
Dam Height |
26 |
River Or Stream |
TR-FOUR MILE CREEK |
Primary Dam Type |
Earth |
Surface Area |
3.4 |
Drainage Area |
0.29 |
Nid Storage |
63 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
26 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Raccoon River At Van Meter
|
1640cfs |
North River Near Norwalk
|
48cfs |
Middle River Near Indianola
|
48cfs |
South River Near Ackworth
|
18cfs |
Raccoon River Near West Des Moines
|
1300cfs |
Thompson River At Davis City
|
22cfs |
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.
Gonseth Dam