Simpson Dam Reservoir Report

Last Updated: December 5, 2025

Simpson Dam, located in Comanche, Texas, is a privately owned irrigation dam constructed in 1986 by the USDA NRCS.


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Summary

Situated on the Horse Branch Sabana River, this earth dam stands at 15 feet in height and has a storage capacity of 80 acre-feet. With a primary purpose of irrigation, it serves a drainage area of 1.47 square miles and covers a surface area of 6 acres.

Despite lacking a spillway, Simpson Dam is deemed to have a high risk potential and is not rated for its condition assessment. With no inspection frequency or emergency action plan in place, the dam's hazard potential remains unknown. Although it has not been modified over the years, it holds essential importance in managing water resources for agricultural purposes in the region. For water resource and climate enthusiasts, Simpson Dam presents an intriguing case study of a privately owned irrigation structure with significant implications for its surrounding environment.

Year Completed

1986

Dam Height

15

River Or Stream

HORSE BRANCH SABANA RIVER

Primary Dam Type

Earth

Surface Area

6

Hydraulic Height

15

Drainage Area

1.47

Nid Storage

80

Structural Height

15

Outlet Gates

None - 1

Hazard Potential

Not Available

Foundations

Unlisted/Unknown

Nid Height

15
       
Seasonal Comparison

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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.