N & S Reservoir Report

Last Updated: December 5, 2025

N & S is a federal-owned earth dam located in Big Horn, Wyoming, along the Five Springs Creek.


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Summary

Completed in 1946, this dam serves primarily for irrigation purposes with a height of 20 feet and a storage capacity of 98 acre-feet. The dam has a fair condition assessment and a low hazard potential, making it a relatively safe structure.

With a spillway width of 15 feet and an uncontrolled spillway type, N & S has a moderate risk assessment rating. Despite its age, the dam still meets regulatory standards with state jurisdiction, permitting, inspection, and enforcement in place. The last inspection in June 2017 showed the dam to be in fair condition, and emergency action plans are in place in case of any unforeseen events.

Located in a picturesque setting in BIGHORN, N & S stands as a testament to effective water resource management in the region. With Liz Cheney (R) as the Congressional representative overseeing this area, enthusiasts of water resources and climate will find N & S to be a fascinating example of how infrastructure can support agricultural needs while maintaining safety standards in the face of changing environmental conditions.

Year Completed

1946

Dam Length

1490

Dam Height

20

River Or Stream

FIVE SPRINGS CREEK

Primary Dam Type

Earth

Surface Area

7

Hydraulic Height

15

Nid Storage

98

Structural Height

20

Outlet Gates

Valve - 1

Hazard Potential

Low

Foundations

Soil

Nid Height

20
       
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.