Allerman #1 Dam Reservoir Report

Last Updated: December 5, 2025

Allerman #1 Dam, located in Minden, Nevada, serves primarily for irrigation purposes along the Carson River.


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Summary

This earth dam, with a height of 20 feet and a length of 2800 feet, has a storage capacity of 500 acre-feet and a surface area of 10 acres. It is regulated and inspected by the Nevada Division of Water Resources, ensuring its safety and compliance with state standards.

The dam features a controlled spillway and outlet gates for water release, with the last inspection in September 2021 rating its condition as fair with a high hazard potential. Despite its age, with modifications in 1997, it continues to play a crucial role in water management and supply in the region. With a very high risk assessment, stakeholders must prioritize maintenance and risk management measures to ensure the safety and efficacy of Allerman #1 Dam for the surrounding communities and ecosystems.

For water resource and climate enthusiasts, Allerman #1 Dam presents an intriguing case study of a privately owned structure that plays a vital role in water allocation and management in Nevada. Its history, design, and current condition offer valuable insights into the challenges and opportunities associated with maintaining aging infrastructure in the face of evolving climate conditions and increasing water demands. As discussions around sustainable water practices and infrastructure resilience continue to gain importance, the story of Allerman #1 Dam serves as a reminder of the intricate relationship between human development and natural resources.

Years Modified

1997 - Hydraulic

Dam Length

2800

Dam Height

20

River Or Stream

CARSON RIVER-OS

Primary Dam Type

Earth

Surface Area

10

Hydraulic Height

19

Drainage Area

5

Nid Storage

500

Structural Height

21

Outlet Gates

Other Controlled - 1, Slide (sluice gate) - 1

Hazard Potential

High

Foundations

Soil

Nid Height

21
       
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.