Toreson Reservoir Report

Last Updated: December 5, 2025

Toreson, also known as Ballard Reservoir, is a privately owned earth dam located in Canby, California.


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Summary

Built in 1898, this dam serves primarily for water supply purposes, with a maximum storage capacity of 1140 acre-feet. Situated on Toms Creek, Toreson has a hydraulic height of 50 feet and a dam height of 55 feet, making it a significant structure in the region.

Managed by the California Department of Water Resources (DWR) and Safety of Dams agency, Toreson is regulated, permitted, inspected, and enforced to ensure its safety and compliance with state standards. Despite its age, the dam is in satisfactory condition as of the last assessment in September 2017, with a significant hazard potential due to its size and location. The reservoir covers a surface area of 92 acres and has a drainage area of 17.8 square miles, providing water for irrigation and domestic use in the surrounding area.

With its historical significance and vital role in providing water resources, Toreson stands as a testament to the importance of proper dam management and maintenance. As climate change continues to impact water availability and quality, ensuring the safety and efficiency of structures like Toreson becomes increasingly crucial for sustainable water management in California's evolving landscape.

Year Completed

1898

Dam Length

315

Dam Height

55

River Or Stream

Toms Creek

Primary Dam Type

Earth

Surface Area

92

Hydraulic Height

50

Drainage Area

17.8

Nid Storage

1140

Hazard Potential

Significant

Nid Height

55
       
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.