Erwin Dam Reservoir Report
Nearby: Potts Dam Countess Ranch Dam
Last Updated: December 5, 2025
Erwin Dam, also known as Farris Estate Ranch Dam, is a private structure located in Atascosa, Texas, along the TR-Lagunillas Creek.
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Summary
Built in 1968 by the USDA NRCS, this earth dam stands at a height of 14 feet and stretches 450 feet in length, with a primary purpose of water supply. With a storage capacity of 174 acre-feet, Erwin Dam plays a crucial role in ensuring water availability for the surrounding area.
Although not regulated by the state, Erwin Dam is equipped with state permitting and inspection processes to ensure its safety and functionality. The dam lacks a spillway and associated locks, but features an outlet gate for water release. With a high risk assessment rating of 2, there is a need for ongoing risk management measures to mitigate potential hazards and maintain the dam's structural integrity.
Water resource and climate enthusiasts will appreciate Erwin Dam as a key infrastructure supporting water supply in the region. Its design by the USDA NRCS, along with its location along the TR-Lagunillas Creek, showcases the importance of sustainable water management practices in Texas. As a private entity, Erwin Dam serves as a vital resource for the local community while also posing challenges in terms of risk assessment and management.
Year Completed |
1968 |
Dam Length |
450 |
Dam Height |
14 |
River Or Stream |
TR-LAGUNILLAS CREEK |
Primary Dam Type |
Earth |
Surface Area |
23 |
Hydraulic Height |
14 |
Nid Storage |
174 |
Structural Height |
14 |
Outlet Gates |
None - 1 |
Hazard Potential |
Not Available |
Foundations |
Unlisted/Unknown |
Nid Height |
14 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
San Miguel Ck Nr Tilden
|
0cfs |
Frio Rv At Tilden
|
0cfs |
Atascosa Rv At Whitsett
|
0cfs |
Atascosa Rv Nr Mccoy
|
1cfs |
Nueces Rv Nr Tilden
|
0cfs |
Choke Canyon Res Owc Nr Three Rivers
|
33cfs |
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.
Erwin Dam