O'Brien #1 Reservoir Report

Last Updated: December 13, 2025

O'Brien #1 is a privately owned earth dam located in Yuma, Colorado, along the South Republican River.


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Summary

Built in 1959 for the primary purpose of flood risk reduction, this dam stands at a height of 25 feet with a hydraulic height of 18 feet and a length of 306 feet. It has a storage capacity of 115 acre-feet and a maximum discharge of 526 cubic feet per second, serving as a critical infrastructure for managing water resources in the region.

Despite being rated as having a low hazard potential, O'Brien #1 is considered to have a high risk due to its condition assessment not being rated. The dam has not undergone a condition assessment since its last inspection in 1988, indicating a potential need for further evaluation and maintenance. While it currently does not have a spillway, the dam's structure and design aim to mitigate flood risks and protect the surrounding areas from potential inundation events.

Water resource and climate enthusiasts monitoring O'Brien #1 should be aware of its importance in flood risk reduction and water management efforts in the region. With its high risk rating and outdated inspection date, there is a need for continued oversight and potential updates to ensure the dam's safety and effectiveness in protecting the community and environment from flooding events.

Year Completed

1959

Dam Length

306

Dam Height

11

River Or Stream

SOUTH REPUBLICAN RIVER-TR

Primary Dam Type

Earth

Surface Area

4

Hydraulic Height

18

Drainage Area

2

Nid Storage

115

Structural Height

25

Hazard Potential

Low

Nid Height

25
       
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.