Declez Retention
Declez Retention is an earth dam located in Riverside County, California, built in 1984. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Declez Retention
The primary purpose of Declez Retention is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by County Of San Bernardino Department Of Public Works (local government). It impounds the Tr San Sevaine Cr near Riverside.
The dam stands 30 feet tall and stretches 1,500 feet across, creates a reservoir covering 21 acres, and has a maximum storage capacity of 331 acre-feet. Completed in 1984, the structure is 42 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 03/11/2025.
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.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | California |
| County | Riverside |
| Nearest City | Riverside |
| River/Stream | Tr San Sevaine Cr |
| Coordinates | 34.03180, -117.50200 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 1,500 ft |
| Year Completed | 1984 (42 years old) |
Storage & Hydraulics
| NID Storage | 331 acre-ft |
| Max Storage | 331 acre-ft |
| Surface Area | 21 acres |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | County of San Bernardino Department of Public Works |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 03/11/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CA01204 |
| Federal ID | CA01204 |
| More Info | State Dam Safety Program |