G-90 Reservoir Report

Last Updated: December 5, 2025

G-90, also known as Jack Creek Structure, is a concrete dam located in Highlands County, Florida, specifically in the city of Leisure Lakes.


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Summary

Built in 1962, this dam serves the primary purpose of flood risk reduction along the Jack Creek river. With a height of 29 feet and a length of 550 feet, G-90 has a storage capacity of 44,676 acre-feet and a surface area of 3,662 acres, providing crucial protection to the surrounding area from potential flooding events.

Managed by the Southwest Florida Water Management District (SWFWMD), G-90 is classified as a state-regulated structure with state permitting, inspection, and enforcement procedures in place to ensure its safety and functionality. The dam has a high hazard potential but was last assessed to be in satisfactory condition in 2014. While it has not undergone recent modifications or upgrades, G-90 remains a vital component of the region's flood control infrastructure, contributing to the overall water resource management efforts in the area.

As a key flood risk reduction asset in the region, G-90 plays a crucial role in safeguarding communities and infrastructure from the impacts of extreme weather events and climate variability. With its strategic location along the Jack Creek river and its significant storage capacity, this concrete dam continues to be a cornerstone of water resource management in Highlands County, Florida. Ongoing monitoring, maintenance, and potential future enhancements will be essential to ensure the long-term effectiveness and resilience of G-90 in the face of changing environmental conditions and increasing demands on water resources.

Year Completed

1962

Dam Length

550

Dam Height

13

River Or Stream

JACK CREEK

Primary Dam Type

Concrete

Surface Area

3662

Hydraulic Height

11

Drainage Area

44

Nid Storage

44676

Structural Height

29

Hazard Potential

High

Nid Height

29
       
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.