West Fork One Subwatershed Site 1-5000 Reservoir Report
Last Updated: December 15, 2025
West Fork One Subwatershed Site 1-5000, located in Woodbury County, Iowa, was completed in 1955 by the USDA NRCS for the primary purposes of fire protection, stock, and small fish pond, as well as flood risk reduction.
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Summary
This earth dam stands at a height of 30 feet and has a length of 350 feet, providing a storage capacity of 62 acre-feet. With a low hazard potential and a moderate risk assessment rating, this dam on the TR-WEST FORK LITTLE SIOUX RIV stream is regulated by the Iowa DNR and is subject to state permitting, inspection, and enforcement.
Despite its age, the condition of West Fork One Subwatershed Site 1-5000 is currently not rated, indicating that further assessment may be needed to ensure its continued safety and functionality. The dam's uncontrolled spillway and soil foundation contribute to its design as a crucial infrastructure for water resource management in the region. With its location in ROLLY SPRINGS, Iowa, this dam plays a vital role in maintaining water supply for fire protection and livestock, while also serving as a small fish habitat and reducing flood risks for the surrounding area. As a part of the Omaha District, this dam exemplifies the collaboration between local government and federal agencies in safeguarding water resources and mitigating climate-related risks.
Year Completed |
1955 |
Dam Length |
350 |
Dam Height |
30 |
River Or Stream |
TR-WEST FORK LITTLE SIOUX RIV |
Primary Dam Type |
Earth |
Surface Area |
2 |
Drainage Area |
0.37 |
Nid Storage |
62 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
30 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
West Fork Ditch At Hornick
|
80cfs |
Little Sioux River At Correctionville
|
327cfs |
Floyd River At James
|
187cfs |
Missouri River At Sioux City
|
14400cfs |
Omaha Cr At Homer
|
45cfs |
Maple River At Mapleton
|
323cfs |
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.
West Fork One Subwatershed Site 1-5000