Long Slough Reservoir Report

Last Updated: December 5, 2025

Long Slough, also known as Stubb Mckinny Clark Reservoir, is a privately owned water resource located in Mesa, Colorado.


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Summary

This reservoir, completed in 1912, serves primarily for irrigation purposes, with additional functions for fire protection, stock, and small fish pond support. The dam is of earth construction with a height of 11 feet and a length of 405 feet, providing a storage capacity of 350 acre-feet and a surface area of 46 acres.

Maintained with regular inspections and a fair condition assessment as of July 2019, Long Slough has a low hazard potential and a moderate risk assessment rating. The reservoir has undergone modifications in 1931 for structural improvements, and in 2005 for both hydraulic and structural upgrades. The spillway, with a width of 15 feet, is uncontrolled, and there is a single slide (sluice gate) outlet gate for water management. The location along Spring Creek in Grand Junction, Colorado, showcases the vital role this water resource plays in supporting the surrounding agricultural and ecological landscapes.

Climate and water enthusiasts can appreciate Long Slough as a historic irrigation reservoir with a rich heritage dating back to the early 20th century. The reservoir's presence contributes to the local water management infrastructure, ensuring a reliable water supply for irrigation activities in the region. With its low hazard potential and moderate risk assessment, Long Slough stands as a testament to sustainable water resource management practices, reflecting a balance between human needs and environmental conservation efforts.

Years Modified

1931 - Structural, 2005 - Hydraulic, 2005 - Structural

Year Completed

1912

Dam Length

405

Dam Height

11

River Or Stream

SPRING CREEK

Primary Dam Type

Earth

Surface Area

46

Hydraulic Height

11

Nid Storage

350

Structural Height

11

Outlet Gates

Slide (sluice gate) - 1

Hazard Potential

Low

Foundations

Rock, Soil

Nid Height

11
       
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.