Cucamonga Creek Debris Basin

About Cucamonga Creek Debris Basin

The primary purpose of Cucamonga Creek Debris Basin is debris control. The dam is designed to catch sediment, rocks, and debris carried by flowing water — particularly important in areas prone to mudslides or heavy erosion. The dam is owned by County Of San Bernardino Department Of Public Works (local government). It impounds the Cucamonga Creek near Rancho Cucamunga/upland.

The dam stands 60 feet tall and stretches 2,980 feet across, creates a reservoir covering 23 acres, has a maximum storage capacity of 355 acre-feet, and collects water from a drainage area of 12 square miles. Completed in 1980, the structure is 46 years old.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 03/10/2025.

At 60 feet, this dam is taller than 95% of all dams in the United States.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The California dam safety program can provide more specific information about emergency planning for this structure.

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