Wiregrass Reservoir Report

Last Updated: January 1, 2026

Wiregrass is a privately owned irrigation dam located in Bannock, Idaho, with a primary purpose of irrigation.


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Summary

Built in 1943, this earth dam stands at 17 feet tall and spans 330 feet in length, creating a storage capacity of 86 acre-feet. The dam is situated on Wiregrass Springs and Marsh Creek, serving the local agricultural community by providing water for irrigation purposes.

The dam is regulated by the Idaho Department of Water Resources, with state permitting, inspection, and enforcement protocols in place to ensure its safe operation. Despite being classified as having a low hazard potential, the condition assessment of Wiregrass dam is rated as fair. The last inspection in 2017 revealed this moderate risk dam to be in satisfactory condition, with a spillway width of 14 feet and a maximum discharge capacity of 49 cubic feet per second.

For water resource and climate enthusiasts in the area, Wiregrass represents a vital infrastructure supporting agricultural activities in Bannock County. Its relatively small storage capacity and low hazard potential make it an important but manageable structure in the local water management system. Continual monitoring and maintenance efforts are crucial to ensure the long-term reliability and safety of Wiregrass dam for the surrounding community.

Year Completed

1943

Dam Length

330

Dam Height

17

River Or Stream

WIREGRASS SPRINGS MARSH CREEK

Surface Area

15.3

Hydraulic Height

14

Drainage Area

5.8

Nid Storage

86

Hazard Potential

Low

Foundations

Rock, Soil

Nid Height

17
       
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.