Round Mountain Detention Dam 2 Reservoir Report
Last Updated: December 5, 2025
Round Mountain Detention Dam 2, located in Lazy B Ranch Headquarters, Arizona, is a gravity dam designed by the Bureau of Land Management to mitigate flood risk along the Round Mountain Draw Wash.
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Summary
Completed in 1954, this federal-owned structure stands at a height of 30 feet and spans a length of 1200 feet, with a capacity to store 920 acre-feet of water. The dam has a low hazard potential and is deemed to be in fair condition, with a moderate risk assessment rating of 3.
Managed by the DOI BLM, Round Mountain Detention Dam 2 serves as a critical flood risk reduction measure in Greenlee County. The dam's uncontrolled spillway and stone buttress core contribute to its effectiveness in managing stormwater runoff from a drainage area of 32.35 square miles. With a normal storage capacity of 650 acre-feet and a maximum discharge rate of 5250 cubic feet per second, this dam plays a crucial role in safeguarding downstream communities and infrastructure from potential flooding events.
Despite not being regulated by the state, Round Mountain Detention Dam 2 undergoes inspections every five years to ensure its structural integrity and operational readiness. While the dam is classified as having a moderate risk level, its presence helps to mitigate flood-related hazards in the region. As climate change intensifies the frequency and severity of extreme weather events, the importance of well-maintained flood control structures like Round Mountain Detention Dam 2 becomes increasingly apparent in protecting water resources and communities in the face of a changing climate.
Year Completed |
1954 |
Dam Length |
1200 |
River Or Stream |
ROUND MOUNTAIN DRAW WASH |
Primary Dam Type |
Gravity |
Surface Area |
75 |
Hydraulic Height |
27 |
Drainage Area |
32.35 |
Nid Storage |
920 |
Structural Height |
30 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
30 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Gila River At Duncan
|
51cfs |
Gila River Below Blue Creek
|
61cfs |
Gila River Near Redrock
|
74cfs |
Gila River Near Clifton
|
65cfs |
Gila River At Head Of Safford Valley
|
93cfs |
San Francisco River At Clifton
|
14cfs |
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.
Round Mountain Detention Dam 2
Gila