Lily Lake Dam Reservoir Report

Last Updated: December 4, 2025

Lily Lake Dam, located in Larimer County, Colorado, is a federal-owned structure managed by the National Park Service for the primary purpose of creating a Fish and Wildlife Pond.


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Summary

Built in 1913, this Earth-type dam stands at a height of 15 feet and spans 240 feet in length, with a storage capacity of 91 acre-feet. It is situated on Fish Creek and is not regulated by the state, with inspections carried out by the Bureau of Reclamation.

With a Hazard Potential rated as high and a Risk Assessment of moderate, Lily Lake Dam poses some safety concerns that are being monitored. Although the condition assessment is listed as not available, emergency action plans have been prepared and updated periodically to ensure preparedness in case of any unforeseen events. The dam also serves as a recreational area, highlighting the balance between conservation efforts and public enjoyment of the natural surroundings.

Year Completed

1913

Dam Length

240

Dam Height

15

River Or Stream

FISH CREEK

Primary Dam Type

Earth

Nid Storage

91

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

15
       
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.