Mc Lellan Reservoir Report

Last Updated: December 5, 2025

Mc Lellan, also known as Englewood #1 and Dad Clark Gulch, is a local government-owned dam in Arapahoe County, Colorado, designed by W.W.


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Summary

Wheeler. Completed in 1964, this Earth dam stands at a height of 111 feet and serves primarily for water supply purposes. With a maximum storage capacity of 9700 acre-feet and a normal storage of 6200 acre-feet, Mc Lellan plays a crucial role in water resource management in the region.

The dam has a spillway width of 102 feet and a high hazard potential, although its condition assessment was deemed satisfactory as of April 2020. The structure has undergone modifications in 1969, 1982, and 2002 to reinforce its foundation and structural integrity. Located in Littleton, Colorado, Mc Lellan overlooks the Dad Clark Gulch and has a drainage area of 9 square miles, with a surface area of 217 acres.

Despite its moderate risk assessment, Mc Lellan remains a key hydraulic infrastructure in the area, with state-regulated operations and inspections ensuring its continued functionality and safety for surrounding communities. Its presence highlights the importance of effective dam management practices in safeguarding water resources and mitigating climate-related risks in the region.

Years Modified

1969 - Foundation, 1982 - Structural, 2002 - Structural

Year Completed

1964

Dam Length

1940

Dam Height

111

River Or Stream

DAD CLARK GULCH

Primary Dam Type

Earth

Surface Area

217

Hydraulic Height

110

Drainage Area

9

Nid Storage

9700

Structural Height

125

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

125
       
Seasonal Comparison

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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.