Diemer Reservoir Reservoir Report

Last Updated: December 4, 2025

Diemer Reservoir, located in Pitkin County, Colorado, is a federal-owned Earth dam constructed in 1929 by the USDA Forest Service with a primary purpose of serving as a Fish and Wildlife Pond.


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Summary

With a dam height of 13 feet and a hydraulic height of 18 feet, this reservoir has a storage capacity of 100 acre-feet and a normal storage level of 60 acre-feet. The reservoir is situated along the tributary North Fork Frying Pan River, providing a crucial habitat for various aquatic species in the region.

Despite being categorized as having a low hazard potential, Diemer Reservoir is subject to moderate risk (rated 3) due to its condition assessment being marked as "Not Rated." The reservoir features an uncontrolled spillway with a width of 8 feet and outlet gates that are also uncontrolled. The last inspection was conducted in July 2017, with a scheduled inspection frequency of every 10 years. While the risk management measures and emergency preparedness plans are not currently assessed or updated, the reservoir continues to play a vital role in supporting fish and wildlife populations in the area.

Water resource and climate enthusiasts are drawn to Diemer Reservoir for its historical significance as an early 20th-century water management structure, as well as its ecological importance as a habitat for local flora and fauna. As part of the USDA Forest Service's portfolio of water conservation projects, this reservoir stands as a testament to the agency's commitment to preserving natural resources while balancing the needs of various stakeholders. With its serene location in the Colorado wilderness, Diemer Reservoir serves as a reminder of the delicate balance between water resource management and environmental conservation in the face of a changing climate.

Year Completed

1929

Dam Length

150

Dam Height

13

River Or Stream

TRIBUTARY N FORK FRYING PAN

Primary Dam Type

Earth

Hydraulic Height

18

Drainage Area

1

Nid Storage

100

Structural Height

18

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Rock, Soil

Nid Height

18
       
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.