Mariposa Dam Reservoir Report
Last Updated: December 21, 2025
Mariposa Dam, located in Bernalillo, New Mexico, was completed in 1983 and is owned by the local government.
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Summary
It serves the primary purpose of flood risk reduction along the Boca Negra Arroyos, with a dam height of 15.5 feet and a length of 5150 feet. The dam has a storage capacity of 670 acre-feet and a surface area of 44.5 acres.
Despite its important role in flood risk reduction, Mariposa Dam has been assessed as being in poor condition with a high hazard potential. The last inspection in September 2020 revealed the need for improvements and maintenance. The dam has an uncontrolled spillway with a width of 300 feet and a maximum discharge capacity of 4500 cubic feet per second, making it crucial for managing water flow during heavy rainfall events.
Given its critical role in flood control, the local government and the Office of the State Engineer in New Mexico are responsible for regulating, inspecting, and enforcing the safety of Mariposa Dam. With a moderate risk assessment rating and a history of poor condition, there is a pressing need for continued monitoring, maintenance, and potential upgrades to ensure the long-term safety and effectiveness of this vital water resource infrastructure.
Year Completed |
1983 |
Dam Length |
5150 |
Dam Height |
15.5 |
River Or Stream |
BOCA NEGRA ARROYOS |
Primary Dam Type |
Earth |
Surface Area |
44.5 |
Drainage Area |
21 |
Nid Storage |
670 |
Structural Height |
22 |
Outlet Gates |
Uncontrolled - 0 |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
22 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Mariposa Dam