Upper Stehly
Upper Stehly is an earth dam located in San Diego County, California, built in 1999. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Upper Stehly
The primary purpose of Upper Stehly is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Nicholas J. Stehly (private). It impounds the Tr Keys Creek near Lake Rancho Viejo.
The dam stands 29 feet tall and stretches 420 feet across, creates a reservoir covering 9 acres, has a maximum storage capacity of 229 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1999, the structure is 27 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. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 04/02/2025.
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 | San Diego |
| Nearest City | Lake Rancho Viejo |
| River/Stream | Tr Keys Creek |
| Coordinates | 33.30960, -117.06170 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 29 ft |
| Dam Height | 29 ft |
| Dam Length | 420 ft |
| Year Completed | 1999 (27 years old) |
Storage & Hydraulics
| NID Storage | 229 acre-ft |
| Max Storage | 229 acre-ft |
| Surface Area | 9 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Nicholas J. Stehly |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 04/02/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CA01254 |
| Federal ID | CA01254 |
| More Info | State Dam Safety Program |