New Thomas Reservoir Report

Nearby: Bass Holt

Last Updated: December 5, 2025

New Thomas is a key water supply infrastructure located in Weld County, Colorado, specifically in the city of Evans.


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Summary

Built in 1976, this earth dam stands at a height of 52 feet and has a maximum storage capacity of 5,354 acre-feet, serving the primary purpose of water supply. The dam's impressive structure spans 4,378 feet in length and has a spillway width of 153 feet, offering controlled discharge capabilities for managing water flow in the Howlett Gulch.

Managed by the Colorado Department of Water Resources and regulated by state agencies, New Thomas plays a crucial role in water resource management and climate resilience efforts in the region. With a significant hazard potential and a moderate risk assessment rating, the dam undergoes regular inspections to ensure its structural integrity and operational efficiency. Despite its age, New Thomas continues to provide satisfactory service in meeting the water supply needs of the local community, reflecting its importance in safeguarding water resources in Weld County.

As a public utility owned infrastructure, New Thomas stands as a testament to the collaborative efforts of designers McCall-Ellingson & Morrill in constructing a reliable water storage facility. With its strategic location along the Howlett Gulch and its capacity to store and manage water flow, the dam serves as a vital asset in ensuring water security and supporting sustainable development in the region. Climate enthusiasts and water resource experts alike can appreciate the critical role that New Thomas plays in safeguarding water resources and enhancing climate resilience in Weld County, Colorado.

Year Completed

1976

Dam Length

4378

Dam Height

52

River Or Stream

HOWLETT GULCH

Primary Dam Type

Earth

Surface Area

195

Hydraulic Height

40

Drainage Area

12

Nid Storage

5354

Structural Height

57

Hazard Potential

Significant

Nid Height

57
       
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.