R-4 Detention Dam Reservoir Report

Last Updated: December 6, 2025

R-4 Detention Dam, located in Las Vegas, Nevada, is a critical piece of infrastructure designed by the USA Corps of Engineers to address flood risk reduction in the area.


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Summary

Completed in 2004, this earth dam stands at a height of 37.7 feet and has a hydraulic height of 28.5 feet, with a structural height of 39 feet. It serves the primary purpose of flood risk reduction, with a storage capacity of 524 acre-feet and a drainage area of 10.5 square miles.

With a spillway width of 835 feet and a maximum discharge capacity of 31,271 cubic feet per second, R-4 Detention Dam is well-equipped to handle significant water flow during storm events. Despite being labeled as having a high hazard potential, the dam is currently assessed to be in fair condition as of the last inspection in May 2021. Additionally, the dam is regulated and inspected by the Nevada DWR, ensuring its safety and functionality for the surrounding community of Clark County.

Overall, R-4 Detention Dam plays a crucial role in managing water resources and mitigating flood risks in the Las Vegas area. Its strategic location and design features make it a key component of the local water infrastructure, contributing to the resilience of the region against the impacts of climate change and extreme weather events.

Year Completed

2004

Dam Length

1151

Dam Height

37.7

River Or Stream

LAS VEGAS WASH-TR

Primary Dam Type

Earth

Surface Area

35.8

Hydraulic Height

28.5

Drainage Area

10.5

Nid Storage

524

Structural Height

39

Outlet Gates

Uncontrolled - 1

Hazard Potential

High

Foundations

Soil

Nid Height

39
       
Seasonal Comparison

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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.