Poso Detention Dam Reservoir Report

Last Updated: December 5, 2025

Poso Detention Dam, also known as Riprap, is a federal-owned structure located in Conejos, Colorado, designed for flood risk reduction along a tributary to the Conejos River.


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Summary

Built in 1963 by the Bureau of Land Management, this gravity dam stands at a structural height of 36 feet with a hydraulic height of 30 feet, spanning a length of 1171 feet. The dam has a storage capacity of 263.7 acre-feet, with a normal storage level of 46.7 acre-feet, covering a surface area of 307 acres.

Despite being classified as a low hazard potential structure and not yet rated for condition assessment, Poso Detention Dam is regulated by the Department of Water Resources, with state permitting, inspection, and enforcement in place. The dam has not undergone any modifications since its completion and is equipped with emergency action plans, although their details have not been updated recently. While the dam does not have outlet gates or associated locks, its primary purpose remains flood risk reduction, serving as a crucial asset in managing water resources and climate-related challenges in the region.

For water resource and climate enthusiasts, Poso Detention Dam represents a significant engineering feat in mitigating flood risks and protecting surrounding areas from potential inundation. Managed by the Bureau of Land Management, this gravity dam plays a crucial role in regulating water flow and storage along a vital tributary to the Conejos River. With its strategic location and design, the dam stands as a testament to effective water resource management, highlighting the importance of infrastructure in addressing climate-related challenges in Colorado and beyond.

Year Completed

1963

Dam Length

1171

River Or Stream

TRIBUTARY TO CONEJOS RIVER

Primary Dam Type

Gravity

Surface Area

307

Hydraulic Height

30

Nid Storage

263.7

Structural Height

36

Hazard Potential

Low

Foundations

Unlisted/Unknown

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.