Hallenbeck #1 Reservoir Report

Last Updated: December 5, 2025

Hallenbeck #1, also known as Purdy Mesa, is a vital water resource infrastructure located in Mesa, Colorado.


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Summary

This earth dam was completed in 1970 and serves multiple purposes, including water supply and recreation. With a height of 41 feet and a storage capacity of 1155 acre-feet, Hallenbeck #1 plays a crucial role in managing water resources in the region.

Owned by a local government entity, Hallenbeck #1 is regulated by the Colorado Department of Water Resources and undergoes regular inspections to ensure its structural integrity. The dam has a spillway width of 30 feet and is equipped with slide and uncontrolled gates for water release. Despite being classified as having a high hazard potential, the dam is assessed to be in fair condition as of April 2020, with a moderate risk rating.

Situated on the Kahnah Creek-TR river system and managed by the Omaha District of the US Army Corps of Engineers, Hallenbeck #1 stands as a significant piece of infrastructure for water supply and management in the Whitewater area. With its strategic location and functionality, this dam continues to play a vital role in the overall water resource management efforts in Colorado.

Year Completed

1970

Dam Length

1000

Dam Height

41

River Or Stream

KAHNAH CREEK-TR

Primary Dam Type

Earth

Surface Area

62

Hydraulic Height

41

Drainage Area

3

Nid Storage

1155

Structural Height

43

Outlet Gates

Slide (sluice gate), Uncontrolled

Hazard Potential

High

Foundations

Soil

Nid Height

43
       
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.