East Fork Big Cr Watershed Site Z-1 Reservoir Report
Last Updated: December 11, 2025
East Fork Big Cr Watershed Site Z-1, located in Decatur County, Iowa, is a key flood risk reduction structure designed by the USDA NRCS and completed in 1990.
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Summary
This earth dam, standing at 20 feet high and 500 feet long, serves the primary purpose of flood risk reduction in the region. With a drainage area of 0.48 square miles and a storage capacity of 155 acre-feet, the dam plays a crucial role in managing water resources in the area.
Managed by the Iowa Department of Natural Resources, this low hazard potential structure on TR-Zadie Creek is regulated, inspected, and enforced to ensure its optimal performance. While the condition of the dam is not rated, the risk assessment for the site is moderate. The structure's surface area of 9.8 acres and normal storage of 36 acre-feet contribute to its effectiveness in mitigating potential flood risks in the watershed.
East Fork Big Cr Watershed Site Z-1 is a vital infrastructure in the region, providing flood protection and contributing to overall water resource management efforts. With its controlled spillway and soil foundation, this dam plays a crucial role in safeguarding the surrounding areas from potential flooding events. Climate and water resource enthusiasts can appreciate the significance of this structure in maintaining the ecological balance and resilience of the watershed.
Year Completed |
1990 |
Dam Length |
500 |
Dam Height |
20 |
River Or Stream |
TR- ZADIE CREEK |
Primary Dam Type |
Earth |
Surface Area |
9.8 |
Drainage Area |
0.48 |
Nid Storage |
155 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
20 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
East Fork Big Cr Watershed Site Z-1