Hemenway Valley Flood Control Dam Reservoir Report

Last Updated: December 5, 2025

The Hemenway Valley Flood Control Dam, also known as the Ville & Trailhead Detention Basin, is a crucial structure located in Henderson, Nevada, designed for flood risk reduction along the Hemenway Wash.


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Summary

Completed in 1994, this earth dam stands at a height of 10 feet with a hydraulic height of 32 feet, providing a structural height of 11 feet. With a capacity to store 21.7 acre-feet of water, this dam plays a significant role in mitigating potential flooding in the area.

Owned by the local government and regulated by the Nevada DWR, the Hemenway Valley Flood Control Dam has a spillway type of uncontrolled and one uncontrolled outlet gate. The dam has been assessed as being in fair condition as of May 2021, with a high hazard potential. With a moderate risk assessment rating and a drainage area of 1.8 square miles, this dam serves as a critical infrastructure in managing flood risks and protecting the surrounding community.

Located in Clark County, Nevada, the Hemenway Valley Flood Control Dam is inspected regularly for safety measures, with the last inspection conducted in May 2021. With its strategic design and operational capabilities, this dam stands as a testament to effective flood control infrastructure in the region, ensuring the safety and security of residents in the face of potential climate-related challenges.

Year Completed

1994

Dam Length

825

Dam Height

10

River Or Stream

HEMENWAY WASH

Primary Dam Type

Earth

Surface Area

3.4

Hydraulic Height

32

Drainage Area

1.8

Nid Storage

21.7

Structural Height

11

Outlet Gates

Uncontrolled - 1

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

32
       
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.