Agate No 1 Reservoir Report

Last Updated: December 5, 2025

Agate No 1, also known as Ball Reservoir, is a privately owned irrigation dam located in Elbert, Colorado.


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Summary

Built in 1890, this earth dam stands at a height of 18 feet and has a storage capacity of 3400 acre-feet. The dam, constructed with a stone core and resting on soil foundation, serves the primary purpose of irrigation along the East Bijou Creek-TR.

Despite its age, Agate No 1 has been well-maintained and is in satisfactory condition as of the last inspection in 2017. With a low hazard potential and a high risk assessment rating of 2, the dam presents a manageable level of risk. The absence of a spillway and presence of two slide gates for outlet control indicate the unique design features of this historic structure, which has seen modifications in 1925 to enhance its structural integrity.

The dam's location in Deer Trail, Colorado, highlights its importance in water resource management for the region. With a surface area of 286 acres and a drainage area of 25 square miles, Agate No 1 plays a crucial role in providing irrigation water to the surrounding agricultural lands. Enthusiasts of water resources and climate will find interest in the history and functionality of this key infrastructure within the Omaha District.

Years Modified

1925 - Structural

Year Completed

1890

Dam Length

4100

Dam Height

18

River Or Stream

EAST BIJOU CREEK-TR

Primary Dam Type

Earth

Surface Area

286

Hydraulic Height

18

Drainage Area

25

Nid Storage

3400

Structural Height

18

Outlet Gates

Slide (sluice gate) - 2

Hazard Potential

Low

Foundations

Soil

Nid Height

18
       
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.