Washout Reservoir Report

Last Updated: December 6, 2025

Located in Harding, South Dakota, Washout is a privately owned earth dam that was completed in 1947.


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Summary

This dam stands at a height of 30 feet and has a length of 350 feet, with a storage capacity of 144 acre-feet. Situated on the TRIB-N Fork Grand River, Washout is regulated by the South Dakota Department of Environment and Natural Resources (DENR) and is subject to state permitting, inspection, and enforcement.

Despite its low hazard potential and current "Not Rated" condition assessment, Washout serves as a vital water resource for the surrounding area. With a normal storage capacity of 130 acre-feet and a maximum discharge of 1470 cubic feet per second, this dam plays a crucial role in managing water flow and ensuring water availability for agriculture, wildlife, and other essential purposes in the region. As a climate enthusiast, understanding the infrastructure and management of dams like Washout is key to appreciating the interconnectedness of water resources and climate dynamics.

As an enthusiast interested in water resources and climate resilience, exploring the details of Washout provides valuable insights into the importance of dam infrastructure in managing water flow and storage. With its history dating back to the mid-20th century and its role in regulating the TRIB-N Fork Grand River, Washout stands as a testament to the ongoing efforts to balance water resource management with environmental conservation and community needs. As climate change continues to impact water availability and quality, the maintenance and regulation of structures like Washout will be crucial in ensuring sustainable water management practices for the future.

Year Completed

1947

Dam Length

350

Dam Height

30

River Or Stream

TRIB-N FORK GRAND RIVER

Primary Dam Type

Earth

Hydraulic Height

30

Nid Storage

144

Hazard Potential

Low

Nid Height

30
       
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.