Hartzell Reservoir Report

Last Updated: December 5, 2025

Hartzell is a significant earth dam located in Atascadero, California, along the Santa Rita Creek.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1965, this privately-owned structure serves multiple purposes including irrigation, recreation, and water supply with a storage capacity of 300 acre-feet. With a height of 50 feet and a hydraulic height of 42 feet, Hartzell plays a crucial role in water resource management in the region.

Managed and regulated by the California Department of Water Resources (DWR) under the Safety of Dams program, Hartzell is inspected regularly to ensure its structural integrity and safety. The dam has been assessed to be in satisfactory condition as of September 2017, with a significant hazard potential due to its location and purpose. Despite its age, Hartzell continues to meet the water supply needs of the area and provides essential support for irrigation and recreational activities.

With a drainage area of 3.85 square miles and a surface area of 30 acres, Hartzell is a vital component of the water infrastructure in San Luis Obispo County. The dam's proximity to Atascadero and its role in the local ecosystem make it a key focus for water resource and climate enthusiasts interested in understanding the dynamics of water supply and management in California.

Year Completed

1965

Dam Length

275

Dam Height

50

River Or Stream

Santa Rita Cr

Primary Dam Type

Earth

Surface Area

30

Hydraulic Height

42

Drainage Area

3.85

Nid Storage

300

Hazard Potential

Significant

Nid Height

50
       
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.