Willow Creek Subwatershed Site M-4 Reservoir Report
Last Updated: December 14, 2025
Located in Woodbury County, Iowa, the Willow Creek Subwatershed Site M-4 is a local government-owned dam designed by USDA SCS in 1968 for fire protection, stock, and small fish pond purposes.
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Summary
Situated along the TR-Wolf Creek, this earth dam stands at a height of 25 feet with a length of 647 feet, providing a storage capacity of 50 acre-feet and covering a drainage area of 1.56 square miles. Despite its low hazard potential and moderate risk assessment, the dam's condition remains unrated as of the last inspection in October 1967.
With a spillway type of "Uncontrolled" and a surface area of 2 acres, the Willow Creek Subwatershed Site M-4 plays a crucial role in flood risk reduction within the region. While it has not undergone modifications in recent years and lacks a designated emergency action plan, the dam remains under the regulatory oversight of the Iowa DNR, ensuring state-mandated inspections, permitting, and enforcement measures are in place. As a vital infrastructure for water resource management in the area, this site serves as a reminder of the interconnectedness between climate resilience and sustainable water practices, highlighting the importance of continued monitoring and maintenance to safeguard against potential risks.
Year Completed |
1968 |
Dam Length |
647 |
Dam Height |
25 |
River Or Stream |
TR-WOLF CREEK |
Primary Dam Type |
Earth |
Surface Area |
2 |
Drainage Area |
1.56 |
Nid Storage |
50 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
25 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
West Fork Ditch At Hornick
|
80cfs |
Maple River At Mapleton
|
323cfs |
Little Sioux River At Correctionville
|
327cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Floyd River At James
|
187cfs |
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.
Willow Creek Subwatershed Site M-4