Roy Tank Dam Reservoir Report
Nearby: Big Tank Dam Red Gate Tank Dam
Last Updated: December 5, 2025
Roy Tank Dam, located in McMullen, Texas, is a privately owned earth dam completed in 1968 for the primary purpose of water supply.
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Summary
Standing at a height of 12 feet and spanning 660 feet in length, the dam has a storage capacity of 130 acre-feet, with a normal storage level of 54 acre-feet. The dam, situated on TR-Elm Creek, serves as a vital water resource for the region.
Despite being not rated for condition assessment, Roy Tank Dam is considered to have a high risk potential, with limited information on hazard potential available. With no spillway and a single outlet gate, the dam presents challenges in the event of excessive water flow. While it is not regulated by the state, the dam undergoes regular inspections and has emergency action plans in place. Water resource and climate enthusiasts would find Roy Tank Dam an intriguing structure to study, given its importance in water supply and its risk assessment profile.
Year Completed |
1968 |
Dam Length |
660 |
Dam Height |
12 |
River Or Stream |
TR-ELM CREEK |
Primary Dam Type |
Earth |
Surface Area |
15 |
Hydraulic Height |
12 |
Nid Storage |
130 |
Structural Height |
12 |
Outlet Gates |
None - 1 |
Hazard Potential |
Not Available |
Foundations |
Unlisted/Unknown |
Nid Height |
12 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Nueces Rv Nr Tilden
|
0cfs |
Frio Rv At Tilden
|
0cfs |
San Miguel Ck Nr Tilden
|
0cfs |
San Casimiro Ck Nr Freer
|
0cfs |
Choke Canyon Res Owc Nr Three Rivers
|
33cfs |
Nueces Rv Nr Three Rivers
|
29cfs |
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.
Roy Tank Dam