Grand Mesa #1 Reservoir Report

Last Updated: December 5, 2025

Grand Mesa #1, located in Grand Junction, Colorado, is a vital irrigation dam constructed in 1887 on Reservoir Creek.


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Summary

Standing at 22 feet in height and stretching 800 feet in length, this earth dam with stone core serves the primary purpose of providing water for agricultural use in the region. With a storage capacity of 655 acre-feet and a drainage area of 1 square mile, Grand Mesa #1 plays a crucial role in supporting the local farming community.

Despite its historical significance and essential role in irrigation, Grand Mesa #1 is currently rated as having a significant hazard potential with an unsatisfactory condition assessment. The dam has undergone regular inspections, with the last assessment conducted in July 2019. While the risk assessment deems the dam's risk level as moderate, there is a need for further risk management measures to ensure the safety and structural integrity of this important water resource infrastructure.

Climate and water resource enthusiasts will find Grand Mesa #1 to be a fascinating case study in the management and maintenance of aging irrigation dams. As a regulated and permitted structure under the jurisdiction of the Colorado Division of Water Resources, the dam's design by Buckhorn GeoEch and its historical significance add to its intrigue. With its location in a scenic landscape and its critical role in sustaining agricultural activities, Grand Mesa #1 serves as a reminder of the intricate balance between water resource management and climate resilience in the face of changing environmental conditions.

Year Completed

1887

Dam Length

800

Dam Height

22

River Or Stream

RESERVOIR CREEK

Primary Dam Type

Earth

Surface Area

48

Hydraulic Height

22

Drainage Area

1

Nid Storage

655

Structural Height

22

Outlet Gates

Slide (sluice gate), Uncontrolled

Hazard Potential

Significant

Foundations

Rock, Soil

Nid Height

22
       
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.