Cornish Plains Reservoir Reservoir Report

Last Updated: December 5, 2025

Cornish Plains Reservoir, located in Weld County, Colorado, is a privately owned earth dam that was completed in 2007 for the primary purpose of irrigation.


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Summary

Managed by the Colorado Department of Water Resources, this reservoir has a maximum storage capacity of 4,870 acre-feet and a surface area of 308 acres. It is situated on the Crow Creek-TR stream and has a significant hazard potential due to its size and location.

The dam stands at a height of 21 feet and has a spillway width of 66 feet, ensuring controlled water release during periods of excess inflow. Despite its significant hazard potential, the dam's condition was assessed as satisfactory during the last inspection in August 2020. With a drainage area of 2 square miles, the reservoir plays a crucial role in providing water for irrigation in the surrounding agricultural areas. The overall risk assessment for Cornish Plains Reservoir is moderate, indicating the need for ongoing monitoring and maintenance to ensure its safety and functionality.

Overall, Cornish Plains Reservoir is a vital water resource for the Barnesville community, serving as a key source of irrigation water for local farms and agricultural activities. With its earth dam structure and controlled spillway, the reservoir provides essential water storage capacity while managing flood risks effectively. As a significant component of the local water infrastructure, ongoing inspections and risk management measures are essential to ensure the safety and reliability of this essential water resource in Colorado's agricultural heartland.

Year Completed

2007

Dam Length

2880

Dam Height

21

River Or Stream

CROW CREEK-TR

Primary Dam Type

Earth

Surface Area

308

Hydraulic Height

21

Drainage Area

2

Nid Storage

4870

Structural Height

21

Hazard Potential

Significant

Foundations

Soil

Nid Height

21
       
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.