Pexton No. 1 Reservoir Report

Last Updated: December 5, 2025

Pexton No.


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Summary

1, located in Guernsey, Wyoming, is a privately-owned earth dam completed in 1963 for irrigation purposes along Reid Creek. With a height of 38 feet and a storage capacity of 177 acre-feet, the dam serves multiple functions including fire protection, stock water supply, and small fish pond maintenance. The dam's spillway, with a width of 50 feet, is uncontrolled and can handle a maximum discharge of 804 cubic feet per second.

Despite being classified as having a low hazard potential, Pexton No. 1 is rated in fair condition as of the last inspection in September 2021. The dam's risk assessment is moderate (3) and it undergoes inspections every 5 years to ensure its structural integrity. The surrounding area of Converse County benefits from the dam's water storage capacity and its contribution to local agriculture and wildlife. Water resource and climate enthusiasts would find Pexton No. 1 a fascinating example of water management infrastructure in the region.

Year Completed

1963

Dam Length

590

Dam Height

38

River Or Stream

REID CREEK

Primary Dam Type

Earth

Surface Area

12

Hydraulic Height

33

Drainage Area

5.5

Nid Storage

177

Structural Height

40

Hazard Potential

Low

Foundations

Rock, Soil

Nid Height

40
       
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.