Stillwater #1 Reservoir Report

Last Updated: December 5, 2025

Located in Garfield County, Colorado, Stillwater #1 is a privately-owned earth dam with a primary purpose of irrigation.


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Summary

Completed in 1939, this structure spans 1500 feet in length and stands at a height of 75 feet, providing critical water storage of up to 7410 acre-feet. The dam's design includes an uncontrolled spillway with a width of 125 feet, ensuring proper water release during high discharge events.

Despite its significant storage capacity, Stillwater #1 has been assessed as having a high hazard potential and an unsatisfactory condition as of October 2020. The dam's risk assessment indicates a moderate risk level, prompting the need for proactive risk management measures. With a history of state regulation, inspection, and enforcement, the dam remains under the jurisdiction of the Colorado Division of Water Resources, ensuring continued compliance with safety standards and protocols.

As a pivotal component in the irrigation infrastructure of the Bear River watershed, Stillwater #1 serves as a vital resource for agricultural activities in the region. Its strategic location in the city of Yampa and proximity to the Bear River highlights the importance of sustainable water resource management in the face of changing climate conditions. Enthusiasts of water resources and climate resilience will find Stillwater #1 to be a compelling case study in the intersection of infrastructure, regulation, and environmental stewardship.

Year Completed

1939

Dam Length

1500

Dam Height

75

River Or Stream

BEAR RIVER

Primary Dam Type

Earth

Surface Area

129

Hydraulic Height

59

Drainage Area

8

Nid Storage

7410

Structural Height

89

Hazard Potential

High

Nid Height

89
       
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.