North Block Tailings Impoundment Dam Reservoir Report
Last Updated: December 15, 2025
The North Block Tailings Impoundment Dam, located in Dunphy, Nevada, is a private-owned structure designed by Knight Piésold LLC and Tetra Tech.
°F
°F
mph
Wind
%
Humidity
Summary
This earth-type dam stands at a height of 520 feet and was completed in 1993 for the primary purpose of tailings storage. With a storage capacity of 103,194 acre-feet, the dam is regulated and inspected by the Nevada Division of Water Resources.
This significant dam on Rodeo Creek-OS poses a high risk due to its hazard potential and lack of a spillway. The last inspection in May 2020 highlighted a need for structural modifications, which were completed in 2008. The dam's condition remains unrated, and emergency action plans have not been updated recently. With a drainage area of only 1 square mile, the dam's capacity to handle a maximum discharge of 10 cubic feet per second raises concerns among water resource and climate enthusiasts.
Despite its high risk profile, the North Block Tailings Impoundment Dam continues to be a key structure in Eureka County, Nevada. As water resource and climate enthusiasts track its condition and regulatory oversight, the dam serves as a reminder of the critical importance of maintaining and monitoring infrastructure to ensure the safety and sustainability of water resources in the region.
Years Modified |
2008 - Structural |
Year Completed |
1993 |
Dam Length |
16200 |
Dam Height |
520 |
River Or Stream |
RODEO CREEK-OS |
Primary Dam Type |
Earth |
Surface Area |
611 |
Hydraulic Height |
517 |
Drainage Area |
1 |
Nid Storage |
103194 |
Structural Height |
520 |
Outlet Gates |
Other Controlled - 1 |
Hazard Potential |
Significant |
Foundations |
Rock |
Nid Height |
520 |
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.
North Block Tailings Impoundment Dam