Willow Reservoir Report

Last Updated: December 25, 2025

Willow is a private dam located in Delta, Colorado, specifically in the city of Hotchkiss.


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Summary

Built in 1948, this earth dam stands at 28 feet high with a hydraulic height of 30 feet and a structural height of 35 feet. It serves primarily for irrigation purposes, with a storage capacity of 165 acre-feet and a normal storage of 120 acre-feet. The dam spans a length of 860 feet and covers a surface area of 9 acres, impacting a drainage area of 1 square mile.

Despite its low hazard potential and fair condition assessment, Willow poses a high risk due to its location and design features. The dam has no spillway and its outlet gates consist of a slide and uncontrolled mechanisms. The dam has been inspected as recently as July 2020 and is regulated by Colorado's Department of Water Resources, with state permitting, inspection, and enforcement in place. While it has not undergone significant modifications in recent years, the risk management measures and emergency preparedness plans for Willow are not clearly documented in available data. Water resource and climate enthusiasts interested in the management and safety of dams in Colorado may find Willow's profile intriguing for further study and analysis.

Year Completed

1948

Dam Length

860

Dam Height

28

River Or Stream

LEROUX CREEK-TR

Primary Dam Type

Earth

Surface Area

9

Hydraulic Height

30

Drainage Area

1

Nid Storage

165

Structural Height

35

Outlet Gates

Slide (sluice gate), Uncontrolled

Hazard Potential

Low

Foundations

Soil

Nid Height

35
       
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.