Richardson Reservoir Report

Last Updated: December 5, 2025

Richardson, also known as Hedgpeth Lake, is a privately owned dam located in Sonoma, California.


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Summary

Built in 1954, this earth dam stands at a height of 65 feet and serves primarily for water supply purposes, including irrigation. The dam has a storage capacity of 520 acre-feet and covers a surface area of 22 acres, with a drainage area of 0.5 square miles.

Managed by the California Department of Water Resources (DWR) under the Safety of Dams program, Richardson is regulated, permitted, inspected, and enforced by the state to ensure its structural integrity and safe operation. With a significant hazard potential, the dam has been assessed as satisfactory in condition as of September 2017. It is located in Soda Springs near an unnamed tributary to Pepperwood Creek, under the jurisdiction of the San Francisco District of the US Army Corps of Engineers.

Water resource and climate enthusiasts will be intrigued by the detailed information available about Richardson, from its design and construction by the Natural Resources Conservation Service to its emergency action plan and risk management measures. This dam serves as a crucial resource for water supply in the region, highlighting the intersection of infrastructure, regulation, and environmental stewardship in sustaining vital resources for communities in California.

Year Completed

1954

Dam Length

265

Dam Height

65

River Or Stream

Unnamed Tributary To Pepperwood Creek

Primary Dam Type

Earth

Surface Area

22

Hydraulic Height

60

Drainage Area

0.5

Nid Storage

520

Hazard Potential

Significant

Nid Height

65
       
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.