Lagerman Reservoir Report

Last Updated: December 5, 2025

Lagerman, located in Boulder, Colorado, is a significant water resource managed by a public utility.


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Summary

This Earth dam, completed in 1878, serves multiple purposes including fish and wildlife pond, recreation, and water supply. With a height of 34 feet and a capacity of 1832 acre-feet, Lagerman has a surface area of 94 acres and a drainage area of 1 square mile.

The dam overlooks Dry Creek-Tr and is regulated by the Colorado Department of Water Resources. With a spillway width of 42 feet and a high hazard potential, Lagerman poses moderate risk, although its condition assessment is deemed satisfactory as of the last inspection in October 2020. Recognized as a crucial habitat for fish and wildlife, the reservoir plays a vital role in maintaining ecological balance in the region.

Longmont residents, as well as visitors, enjoy the recreational opportunities offered by Lagerman while also benefiting from its water supply function. As climate change impacts water resources, Lagerman stands as a testament to the importance of sustainable management practices and the need to ensure the safety and integrity of vital infrastructure for both human and environmental well-being.

Year Completed

1878

Dam Length

5145

Dam Height

34

River Or Stream

DRY CREEK-TR

Primary Dam Type

Earth

Surface Area

94

Hydraulic Height

15

Drainage Area

1

Nid Storage

1832

Structural Height

36

Outlet Gates

Slide (sluice gate) - 0

Hazard Potential

High

Nid Height

36
       
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.