Alta Loma Basin #2 Reservoir Report

Last Updated: December 5, 2025

Alta Loma Basin #2, located in Alta Loma, California, is a critical flood risk reduction structure along the Alta Loma Channel.


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Summary

Built in 1971, this earth dam stands at 22 feet in height and spans 3000 feet in length, with a storage capacity of 85 acre-feet. The dam's purpose is solely for flood risk reduction, serving as a crucial infrastructure to protect the surrounding areas from potential inundation during heavy rainfall events.

Managed by the local government and regulated by the California Department of Water Resources (DWR), Alta Loma Basin #2 is subject to regular inspections to ensure its structural integrity and safety. The dam has a high hazard potential but is currently assessed to be in satisfactory condition as of September 2017. Emergency action plans are in place, although details on their last revision and adherence to guidelines are not specified in the available data.

With its strategic location in San Bernardino County, California, and its vital role in mitigating flood risks along the Alta Loma Channel, Alta Loma Basin #2 serves as a key component of the region's water resource and climate resilience infrastructure. Enthusiasts and stakeholders in water management and climate adaptation can appreciate the significance of this dam in safeguarding the community from potential flooding events and the coordinated efforts involved in its regulation and maintenance.

Year Completed

1971

Dam Length

3000

Dam Height

22

River Or Stream

Alta Loma Channel

Primary Dam Type

Earth

Surface Area

26

Hydraulic Height

14

Drainage Area

0.54

Nid Storage

85

Hazard Potential

High

Nid Height

22
       
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.