Granby Dike 1 Reservoir Report

Last Updated: December 5, 2025

Granby Dike 1, located in Grand County, Colorado, is a federally owned earth dam that serves multiple purposes, including hydroelectric power generation and irrigation.


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Summary

Completed in 1950, this impressive structure stands at a height of 98 feet and spans a length of 2170 feet, with a maximum storage capacity of 539,760 acre-feet. The dam is situated on the Colorado River and is regulated by the Bureau of Reclamation, with regular inspections and enforcement measures in place to ensure its safety and functionality.

With a high hazard potential and a very high risk assessment rating, Granby Dike 1 is a critical piece of infrastructure that requires careful monitoring and management. The dam features a controlled spillway with a width of 40 feet and has a maximum discharge capacity of 12,000 cubic feet per second. In the event of an emergency, it is essential to have an Emergency Action Plan (EAP) in place, although specific details about its preparation and guidelines adherence are not available at this time. Overall, Granby Dike 1 is a key component of the water resource system in Colorado, playing a vital role in water storage, flood control, and power generation in the region.

Year Completed

1950

Dam Length

2170

Dam Height

98

River Or Stream

COLORADO RIVER

Primary Dam Type

Earth

Surface Area

7260

Hydraulic Height

70

Nid Storage

539760

Structural Height

98

Hazard Potential

High

Foundations

Rock

Nid Height

98
       
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.