Hayden Reservoir Report

Last Updated: December 4, 2025

Hayden, located in Boulder, Colorado, is a privately owned dam with a primary purpose of irrigation.


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Summary

Built in 1905, this Earth dam stands at 27 feet tall and has a length of 1820 feet, holding a maximum storage capacity of 765 acre-feet. The dam overlooks Boulder Creek-OS and serves as a crucial water resource for the region, with a normal storage capacity of 502 acre-feet.

Despite its age, Hayden has undergone modifications in 1931 and 1974 to enhance its foundation, hydraulic, mechanical, and structural components. The dam features an uncontrolled spillway with a width of 220 feet and is equipped with one slide (sluice gate) outlet gate. Inspected most recently in October 2020, Hayden has been deemed to have a high hazard potential but is in satisfactory condition, meeting regulatory standards set by the Colorado Division of Water Resources.

Hayden's risk assessment indicates a moderate risk level (3) and the dam's Emergency Action Plan (EAP) was last revised in 2015. With a captivating history and significant role in irrigation and recreation activities, Hayden stands as a key infrastructure in the water resource management of Boulder, Colorado, under the jurisdiction of the Department of Water Resources.

Years Modified

1931 - Foundation, 1931 - Hydraulic, 1931 - Mechanical, 1931 - Structural, 1974 - Hydraulic, 1974 - Structural

Year Completed

1905

Dam Length

1820

Dam Height

27

River Or Stream

BOULDER CREEK-OS

Primary Dam Type

Earth

Surface Area

41

Hydraulic Height

25

Nid Storage

765

Structural Height

27

Outlet Gates

Slide (sluice gate) - 1

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

27
       
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.
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