Rancho Cielito Reservoir Report

Last Updated: December 5, 2025

Rancho Cielito, also known as Lake Los Serranos, is a privately owned dam located in San Bernardino, California, specifically in the city of Los Serranos.


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Summary

Built in 1912, this earth dam stands at a height of 9 feet and has a hydraulic height of 6.9 feet. Its primary purpose is for water supply, serving irrigation and domestic water needs in the area. The dam has a storage capacity of 110 acre-feet and a surface area of 25 acres, with a drainage area of 0.8 square miles.

Managed by the California Department of Water Resources (DWR) under the Safety of Dams program, Rancho Cielito is regulated, permitted, inspected, and enforced by the state authorities. Its last inspection took place in March 2021, with a hazard potential rated as high but a satisfactory condition assessment as of September 2017. Despite being privately owned, the dam plays a crucial role in water resource management and climate resilience in the region, showcasing the importance of maintaining and monitoring such structures for the safety and security of communities dependent on them for water supply.

With a rich history dating back over a century, Rancho Cielito continues to be a vital component of the local water infrastructure, ensuring a reliable water supply for agricultural and residential purposes in the surrounding area. As climate change impacts water resources, dams like Rancho Cielito play a critical role in water management and flood control. By adhering to state regulations and regular inspections, this dam remains a key asset in safeguarding against potential hazards and supporting sustainable water practices for the community it serves.

Year Completed

1912

Dam Length

1000

Dam Height

9

River Or Stream

Tr Chino Creek

Primary Dam Type

Earth

Surface Area

25

Hydraulic Height

6.9

Drainage Area

0.8

Nid Storage

110

Hazard Potential

High

Nid Height

9
       
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.