Agate Allot 1 Dam Reservoir Report

Last Updated: December 6, 2025

Agate Allot 1 Dam, located in Ardmore SD, Nebraska, is a Federal-owned structure primarily designed for fire protection, stock, and small fish pond purposes.


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Summary

Completed in 1936, this Earth type dam stands at a height of 23.4 feet with a storage capacity of 153.4 acre-feet. The dam's location on TR-Long Branch Creek in Sioux County makes it an essential resource for water management in the region.

Despite its historical significance, Agate Allot 1 Dam is currently assessed to be in poor condition, with a low hazard potential. The dam's inspection frequency is set at 5 years, with the last assessment conducted in August 2019. The State of Nebraska, through the Nebraska Department of Natural Resources, regulates and inspects the dam to ensure its structural integrity and safety for the surrounding community.

Water resource and climate enthusiasts will appreciate the role of Agate Allot 1 Dam in providing essential water storage and fire protection services in Sioux County. As a Federal-owned structure with a long history, the dam's current poor condition raises concerns about its long-term sustainability and highlights the need for ongoing maintenance and upgrades to ensure its continued functionality for the community's benefit.

Year Completed

1936

Dam Length

564

Dam Height

23.4

River Or Stream

TR-LONG BRANCH CREEK

Primary Dam Type

Earth

Surface Area

13.7

Hydraulic Height

23.4

Drainage Area

1.3

Nid Storage

153.4

Structural Height

23.4

Hazard Potential

Low

Foundations

Soil

Nid Height

23
       
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.