Warm Springs Dam Reservoir Report

Nearby: Merlo Asti

Last Updated: December 5, 2025

Warm Springs Dam, also known as Lake Sonoma, is a federal-owned structure located in Healdsburg, California, completed in 1983 for flood risk reduction.


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Summary

Standing at a height of 319 feet, with a storage capacity of 449,000 acre-feet, the dam poses a high hazard potential due to the risk of overtopping during major storm events or seismic activity. In the event of a breach, surrounding areas such as Healdsburg, Windsor, Sebastopol, Santa Rosa, and Guerneville could face significant impacts, highlighting the importance of effective risk management measures.

To mitigate potential risks, the US Army Corps of Engineers (USACE) has implemented various measures at Warm Springs Dam, including enhanced monitoring, surveillance, and an emergency action plan. Weather forecasts are used to manage water levels in the reservoir, while trained staff continuously monitor dam safety concerns during storm conditions. Additionally, the EAP facilitates clear communication and coordinated response actions in the event of a dam-related emergency, ensuring public safety through timely warnings and evacuation orders. Despite the identified risks, ongoing efforts by the USACE aim to minimize the impact of potential dam failures on downstream communities and infrastructure.

Year Completed

1983

Dam Length

3000

Dam Height

319

River Or Stream

DRY CREEK

Primary Dam Type

Earth

Surface Area

2600

Hydraulic Height

313

Drainage Area

130

Nid Storage

449000

Structural Height

356

Outlet Gates

Slide (sluice gate) - 2

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

356
       
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.