Granby Reservoir Report

Last Updated: December 5, 2025

Granby is a federal-owned dam located in Grand County, Colorado, along the Colorado River.


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Summary

Built in 1949, this Earth-type structure stands at a height of 298 feet and serves primarily for hydroelectric and irrigation purposes. With a storage capacity of 539,760 acre-feet and a surface area of 7,260 acres, Granby plays a crucial role in water resource management in the region.

Managed by the Bureau of Reclamation, Granby has a high hazard potential and is regulated by the Colorado Department of Water Resources. The dam boasts a controlled spillway with a width of 40 feet and a maximum discharge capacity of 12,000 cubic feet per second. Despite its age, Granby continues to be a vital component of the water infrastructure system, providing essential services for the surrounding communities and supporting the local economy through its hydroelectric operations.

Granby's strategic location and impressive engineering make it a key asset in the sustainable management of water resources and climate resilience efforts in Colorado. As a significant contributor to the local water supply and energy production, Granby stands as a testament to the importance of infrastructure maintenance and monitoring to ensure the safety and reliability of critical water infrastructure in the face of changing environmental conditions.

Year Completed

1949

Dam Length

880

Dam Height

298

River Or Stream

COLORADO RIVER

Primary Dam Type

Earth

Surface Area

7260

Hydraulic Height

221

Drainage Area

187

Nid Storage

539760

Structural Height

298

Hazard Potential

High

Foundations

Rock

Nid Height

298
       
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.