Sebastian Martin Site 6 Dam Reservoir Report

Last Updated: December 8, 2025

Sebastian Martin Site 6 Dam, also known as Estaca Arroyo Retard Dam, is a crucial structure in Rio Arriba, New Mexico, designed by the USDA NRCS to reduce flood risks along the Estaca Arroyo river.


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Summary

Completed in 1973, this earth dam stands at a height of 93 feet and stretches 550 feet in length, providing a storage capacity of 1022 acre-feet and covering a surface area of 45 acres. With a maximum discharge capacity of 1439 cubic feet per second, this dam plays a vital role in managing water flow and mitigating flood risks in the region.

Despite its importance, the dam is currently assessed to be in poor condition with a high hazard potential, prompting a moderate risk assessment rating. The Office of the State Engineer in New Mexico regulates and inspects the dam periodically to ensure its structural integrity and operational efficiency. With a spillway width of 200 feet and uncontrolled spillway and outlet gates, the dam poses significant challenges in emergency response and risk management. As water resource and climate enthusiasts, understanding the complexities and vulnerabilities of dams like Sebastian Martin Site 6 is essential for promoting sustainable water management practices and enhancing the resilience of our communities in the face of changing environmental conditions.

Year Completed

1973

Dam Length

550

Dam Height

80

River Or Stream

ESTACA ARROYO

Primary Dam Type

Earth

Surface Area

45

Hydraulic Height

80

Drainage Area

2

Nid Storage

1022

Structural Height

93

Outlet Gates

Uncontrolled

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

93
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.