West Fork One Subwatershed Site 4-4300 Reservoir Report

Last Updated: December 14, 2025

West Fork One Subwatershed Site 4-4300 in Woodbury, Iowa, is a significant water resource managed by the local government with assistance from the USDA NRCS.


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Summary

This site, completed in 1955, serves multiple purposes including fire protection, stock watering, and flood risk reduction. The dam at this site is classified as an earth dam with a height of 36 feet and a storage capacity of 761 acre-feet.

Located on the TR-WEST FORK LITTLE SIOUX RIV, this site covers a drainage area of 0.34 square miles and has a surface area of 1.1 acres. The dam's spillway is uncontrolled, and it has a low hazard potential with a moderate risk assessment rating. While the condition assessment is not rated, the site is regulated by the Iowa DNR, with state permitting, inspection, and enforcement in place to ensure its safety and functionality for the surrounding community. Overall, West Fork One Subwatershed Site 4-4300 plays a crucial role in water resource management and climate resilience efforts in the region.

Year Completed

1955

Dam Length

500

Dam Height

36

River Or Stream

TR-WEST FORK LITTLE SIOUX RIV

Primary Dam Type

Earth

Surface Area

1.1

Drainage Area

0.34

Nid Storage

761

Hazard Potential

Low

Foundations

Soil

Nid Height

36
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.