Box I #1 Reservoir Report

Last Updated: December 5, 2025

Box I #1, also known as Box Eye #1, is a privately owned irrigation dam located in Larimer County, Colorado.


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Summary

Completed in 1967, this earth dam stands at a height of 18 feet and has a storage capacity of 200 acre-feet. The dam serves the primary purpose of irrigation, with a normal storage capacity of 108 acre-feet and a maximum discharge of 2354 cubic feet per second into the Boxelder Creek.

Despite being classified as having a low hazard potential and fair condition assessment, Box I #1 is regulated by the Colorado Department of Water Resources. The dam features an uncontrolled spillway with a width of 168 feet, helping to manage excess water during periods of high flow. The last inspection of the dam took place in September 2015, with an inspection frequency of 6 years and a moderate risk assessment rating.

Located 6 miles from Wellington, Colorado, Box I #1 plays a crucial role in the local water resource management system. With its strategic placement on the Boxelder Creek, this dam provides vital irrigation water for agricultural activities in the surrounding area. Climate and water resource enthusiasts will find Box I #1 to be an intriguing example of how infrastructure plays a key role in sustaining water availability in arid regions like Colorado.

Year Completed

1967

Dam Length

2300

Dam Height

18

River Or Stream

BOXELDER CR-TR

Primary Dam Type

Earth

Surface Area

23

Hydraulic Height

19

Drainage Area

3

Nid Storage

200

Structural Height

19

Hazard Potential

Low

Nid Height

19
       
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.