Dina Bob Lake Reservoir Report

Last Updated: December 12, 2025

Dina Bob Lake, located in Healdsburg, California, is a privately owned dam that serves as a vital water supply source for the surrounding area.


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Summary

Built in 1955, this earth-type dam stands at a height of 33 feet and has a storage capacity of 139 acre-feet. The dam is regulated and inspected by the California Department of Water Resources, ensuring its safety and compliance with state regulations.

This significant dam on Tr Franz Creek plays a crucial role in irrigation and water supply for the region, with a drainage area of 0.35 square miles. Despite its age, the dam's condition assessment in 2017 rated it as satisfactory, with a hazard potential deemed significant. The dam's emergency action plan status and risk assessment measures are not currently available, but regular inspections and maintenance contribute to its overall safety and functionality.

Managed by the Natural Resources Conservation Service, Dina Bob Lake Dam remains a key infrastructure for water resource management in Sonoma County. With its strategic location and essential role in the local water supply system, this dam serves as a testament to the importance of maintaining and regulating critical water infrastructure in the face of changing climate conditions and increasing water demands.

Year Completed

1955

Dam Length

635

Dam Height

33

River Or Stream

Tr Franz Cr

Primary Dam Type

Earth

Surface Area

14

Hydraulic Height

29.3

Drainage Area

0.35

Nid Storage

139

Hazard Potential

Significant

Nid Height

33
       
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.