Dane Ridge Watershed Site B-4 Reservoir Report
Last Updated: December 13, 2025
Dane Ridge Watershed Site B-4 is a dam located in Crawford County, Iowa, specifically in the city of Dunlap.
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Summary
Constructed in 1971 by the USDA NRCS, this earth dam serves multiple purposes including fire protection, stock, small fish pond, flood risk reduction, and recreation. With a height of 43 feet and a length of 363 feet, the dam has a storage capacity of 83 acre-feet and covers a surface area of 5 acres.
Managed by the local government, the dam is regulated by the Iowa Department of Natural Resources and undergoes regular inspections, enforcement, and permitting to ensure its safety and functionality. The hazard potential is rated as low, with a moderate risk assessment of 3. While the dam is not currently rated for condition, it meets state jurisdiction and permitting requirements, making it an integral part of the water resource infrastructure in the area.
The location of Dane Ridge Watershed Site B-4 along the TR-Boyer River in Iowa highlights its importance in managing water resources and mitigating flood risks in the region. With its diverse purposes and regulated status, this dam plays a crucial role in both water conservation efforts and recreational activities, making it a key site for water resource and climate enthusiasts to explore and understand its impact on the local environment.
Year Completed |
1971 |
Dam Length |
363 |
Dam Height |
43 |
River Or Stream |
TR-BOYER RIVER |
Primary Dam Type |
Earth |
Surface Area |
5 |
Drainage Area |
0.36 |
Nid Storage |
83 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
43 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Maple River At Mapleton
|
323cfs |
Soldier River At Pisgah
|
112cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Boyer River At Logan
|
417cfs |
West Fork Ditch At Hornick
|
80cfs |
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.
Dane Ridge Watershed Site B-4