Fontenelle Reservoir Report

Last Updated: December 5, 2025

Fontenelle, situated on the Green River in Wyoming, is a captivating water resource marvel that serves multiple purposes, including fish and wildlife preservation, hydroelectric power generation, recreation, and water supply.


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Summary

Built in 1963 by the Bureau of Reclamation, this federal-owned earth dam stands at a height of 139 feet and has a storage capacity of 405,160 acre-feet, providing essential water management for the region. The dam's spillway, with a width of 40 feet, helps control water flow during periods of high discharge, ensuring safety and efficiency in its operations.

With a hazard potential rated as high and a moderate risk assessment, Fontenelle Dam is subject to regular inspections and enforcement measures by the Bureau of Reclamation to maintain its structural integrity and safeguard against potential emergencies. The dam's rich history includes a structural modification in 1989, highlighting its adaptability and resilience to evolving environmental conditions. Fontenelle's strategic location in Lincoln County, Wyoming, makes it a critical piece of infrastructure for water management in the region, reflecting the ongoing efforts to ensure sustainable water resource utilization for current and future generations.

Years Modified

1989 - Structural

Year Completed

1963

Dam Length

5450

Dam Height

139

River Or Stream

GREEN RIVER

Primary Dam Type

Earth

Surface Area

8058

Hydraulic Height

121

Drainage Area

4175

Nid Storage

405160

Structural Height

139

Outlet Gates

Valve - 3

Hazard Potential

High

Foundations

Soil

Nid Height

139
       
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.