Structure 161 Reservoir Report

Last Updated: December 5, 2025

Structure 161, located in Hillsborough County, Florida, is a concrete dam built in 1975 primarily for water supply purposes.


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Summary

Standing at a height of 63.5 feet with a hydraulic height of 23 feet, this dam on the Palm River has a storage capacity of 11,000 acre-feet and covers a surface area of 173 acres. With a high hazard potential but deemed to be in satisfactory condition as of the last assessment in 2014, this structure plays a crucial role in flood risk reduction and ensuring a stable water supply for the region.

Managed by the Southwest Florida Water Management District, Structure 161 is regulated, permitted, inspected, and enforced by state agencies to ensure its safe operation. Despite being uncontrolled, the dam's spillway width of 18 feet can handle a maximum discharge of 4,000 cubic feet per second. The surrounding area has a drainage area of 192 square miles, emphasizing the significance of this structure in managing water resources and mitigating potential flood risks in the region.

Represented by Congresswoman Kathy Castor, Structure 161 serves as a vital component of water infrastructure in Tampa, Florida. With its strategic location and vital role in water management, this dam exemplifies the importance of sustainable water resource management and climate resilience in the face of increasing environmental challenges.

Year Completed

1975

Dam Length

200

Dam Height

19.5

River Or Stream

PALM RIVER

Primary Dam Type

Concrete

Surface Area

173

Hydraulic Height

23

Drainage Area

192

Nid Storage

11000

Structural Height

63.5

Outlet Gates

Uncontrolled

Hazard Potential

High

Nid Height

64
       
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.