Arapahoe Lake Reservoir Report

Last Updated: December 5, 2025

Arapahoe Lake, located in Arapahoe County, Colorado, is a privately owned reservoir primarily used for recreation.


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Summary

The dam, completed in 1974, is an earth structure standing 20 feet high and spanning 425 feet in length. With a maximum storage capacity of 45 acre-feet, the lake covers an area of 4 acres and is fed by Goldsmith Gulch.

Despite its fair condition assessment and significant hazard potential, Arapahoe Lake is regularly inspected, with the last assessment conducted in June 2019. The dam has a spillway width of 104 feet and a maximum discharge capacity of 2100 cubic feet per second. The risk assessment for the reservoir is moderate, indicating a level 3 threat.

Water resource and climate enthusiasts visiting Arapahoe Lake will appreciate its scenic beauty and recreational opportunities, while also being aware of the dam's condition and risk factors. The lake's location in the Denver area, along with its regulated state jurisdiction, make it a noteworthy site for those interested in water management and environmental conservation in Colorado.

Year Completed

1974

Dam Length

425

Dam Height

20

River Or Stream

GOLDSMITH GULCH

Primary Dam Type

Earth

Surface Area

4

Hydraulic Height

23

Nid Storage

45

Structural Height

23

Hazard Potential

Significant

Nid Height

23
       
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.