Mann Lake Dam Reservoir Report

Last Updated: December 12, 2025

Mann Lake Dam, located in Zavala, Texas, was completed in 1939 and serves primarily for irrigation purposes.


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Summary

This private earth dam stands at a height of 12 feet, with a length of 3500 feet and a storage capacity of 86 acre-feet. Situated on the TR-Palo Blanco Creek, the dam plays a crucial role in providing water supply for agricultural use in the region.

Despite being privately owned, Mann Lake Dam is subject to state permitting and inspection requirements to ensure its structural integrity and safety. With a high hazard potential rating, the dam poses a significant risk, prompting the need for risk management measures and emergency preparedness. However, the lack of available data on the dam's condition assessment and emergency action plans raises concerns about its readiness in case of a potential failure.

Climate and water resource enthusiasts may find Mann Lake Dam's historical significance and impact on local irrigation practices intriguing. As efforts to address climate change intensify, understanding the role of such dams in water management becomes increasingly important for sustainable resource utilization and mitigating potential risks associated with aging infrastructure.

Year Completed

1939

Dam Length

3500

Dam Height

10

River Or Stream

TR-PALO BLANCO CREEK

Primary Dam Type

Earth

Surface Area

14

Hydraulic Height

10

Nid Storage

86

Structural Height

12

Outlet Gates

None - 1

Hazard Potential

Not Available

Foundations

Unlisted/Unknown

Nid Height

12
       
Seasonal Comparison

Weather Forecast

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.