Dutch Hollow Subwatershed Site M-1 Reservoir Report
Last Updated: December 14, 2025
Dutch Hollow Subwatershed Site M-1, located in Woodbury, Iowa, is a local government-owned earth dam designed by the USDA NRCS in 1983 for fire protection, stock, and small fish pond purposes.
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Summary
This dam, situated on Koker Creek, has a height of 26 feet and a length of 500 feet, providing a storage capacity of 97 acre-feet. With a drainage area of 0.48 square miles, the dam serves the community with flood risk reduction measures while also offering recreational opportunities.
Despite its low hazard potential, Dutch Hollow Subwatershed Site M-1 is regulated by the Iowa DNR with state permitting, inspection, and enforcement in place. The dam's condition assessment is currently not rated, indicating a need for further evaluation. With a moderate risk assessment score of 3, there is room for improvement in risk management measures to ensure the safety and longevity of this essential water resource infrastructure. As climate change continues to impact water availability and extreme weather events, the importance of maintaining and enhancing dams like Dutch Hollow Subwatershed Site M-1 becomes increasingly crucial for water resource and climate enthusiasts in the region.
Year Completed |
1983 |
Dam Length |
500 |
Dam Height |
26 |
River Or Stream |
KOKER CREEK |
Primary Dam Type |
Earth |
Surface Area |
4.9 |
Drainage Area |
0.48 |
Nid Storage |
97 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
26 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Little Sioux River At Correctionville
|
327cfs |
Maple River At Mapleton
|
323cfs |
West Fork Ditch At Hornick
|
80cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Missouri River At Decatur
|
14900cfs |
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.
Dutch Hollow Subwatershed Site M-1