Cornerstone Pond No. 4 Reservoir Report

Last Updated: December 4, 2025

Cornerstone Pond No.


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Summary

4, located in Montrose, Colorado, is a privately owned irrigation reservoir constructed with an earth dam in 2007. With a height of 46 feet and a storage capacity of 167 acre-feet, this reservoir serves the primary purpose of irrigation for the surrounding area. The dam is regulated by the Colorado Department of Water Resources and undergoes regular inspections to ensure its structural integrity and safety.

The reservoir's spillway type is uncontrolled, with a spillway width of 20 feet, and it has a significant hazard potential, although its condition assessment in 2019 was deemed satisfactory. The risk assessment for Cornerstone Pond No. 4 is moderate, indicating a level 3 risk. The reservoir is situated on the Cottonwood-OS river/stream and falls under the jurisdiction of the Albuquerque District of the US Army Corps of Engineers. With its strategic location and essential role in irrigation, Cornerstone Pond No. 4 is a critical water resource in the region.

Water resource and climate enthusiasts will find Cornerstone Pond No. 4 an intriguing case study due to its modern construction, regulatory oversight, and importance for irrigation purposes. The reservoir's efficient design, satisfactory condition assessment, and moderate risk profile highlight the balance between water management and safety considerations. As a key component of the local water infrastructure in Ouray County, Colorado, this reservoir exemplifies the intersection of human resource development and environmental stewardship in the face of changing climate patterns and water availability challenges.

Year Completed

2007

Dam Length

520

Dam Height

46

River Or Stream

COTTONWOOD-OS

Primary Dam Type

Earth

Surface Area

8

Hydraulic Height

41

Nid Storage

167

Structural Height

51

Hazard Potential

Significant

Foundations

Rock

Nid Height

51
       
Seasonal Comparison

Weather Forecast

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Nearby Streamflow Levels

Cornerstone Pond No. 4UNCOMPAHGRE RIVER BELOW RIDGWAY RESERVOIR Preview Uncompahgre River Below Ridgway Reservoir
44.1cfs
44cfs
Cornerstone Pond No. 4DALLAS CREEK NEAR RIDGWAY Preview Dallas Creek Near Ridgway
43.4cfs
43cfs
Cornerstone Pond No. 4UNCOMPAHGRE RIVER NEAR RIDGWAY Preview Uncompahgre River Near Ridgway
52.4cfs
52cfs
Cornerstone Pond No. 4UNCOMPAHGRE RIVER AT COLONA Preview Uncompahgre River At Colona
44.1cfs
44cfs
Cornerstone Pond No. 4SAN MIGUEL RIVER NEAR PLACERVILLE Preview San Miguel River Near Placerville
72.7cfs
73cfs
Cornerstone Pond No. 4UNCOMPAHGRE RIVER NEAR OURAY Preview Uncompahgre River Near Ouray
33.9cfs
34cfs

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.
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Nearby Reservoirs