Sebastian Martin Site 18 Dam
Sebastian Martin Site 18 Dam is an earth dam located in Rio Arriba County, New Mexico, built in 1985. It carries a High hazard potential classification and has a poor condition assessment.
About Sebastian Martin Site 18 Dam
The primary purpose of Sebastian Martin Site 18 Dam 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 Upper Rio Grande Watershed District (local government). It impounds the Rio Grande - Tr near Alcalde.
The dam stands 55 feet tall and stretches 1,010 feet across, has a maximum storage capacity of 235 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1985, the structure is 41 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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 03/29/2017. That was 9 years ago, which is on the longer end for a high-hazard structure.
At 55 feet, this dam is taller than 94% of dams nationwide.
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 New Mexico 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 | New Mexico |
| County | Rio Arriba |
| Nearest City | Alcalde |
| River/Stream | Rio Grande - Tr |
| Coordinates | 36.09276, -106.03760 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 55 ft |
| Dam Height | 39 ft |
| Dam Length | 1,010 ft |
| Year Completed | 1985 (41 years old) |
Storage & Hydraulics
| NID Storage | 235 acre-ft |
| Max Storage | 235 acre-ft |
| Drainage Area | 0 sq mi |
| Max Discharge | 1,870 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | UPPER RIO GRANDE WATERSHED DISTRICT |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 03/29/2017 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NM00518 |
| Federal ID | NM00518 |
| More Info | State Dam Safety Program |