G113 Control Structure Reservoir Report
Nearby: G111 Control Structure S-65
Last Updated: December 5, 2025
The G113 Control Structure, also known as the Lake Marian Control Structure, is a vital flood risk reduction asset located in Osceola, Florida.
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Summary
Managed by the South Florida Water Management District (SFWMD), this concrete dam stands at 14 feet high and has a hydraulic height of 9 feet, helping to regulate water levels in the Prairie Lakes Preserve. Completed in 1993, it has a normal storage capacity of 40,000 acre-feet and a maximum storage of 51,500 acre-feet, covering a surface area of 5720 acres.
With a controlled spillway width of 700 feet, the G113 Control Structure plays a crucial role in managing water flow and protecting the surrounding area from flooding. While the dam is rated as having a low hazard potential, the risk assessment indicates a very high risk level (1), emphasizing the importance of careful monitoring and maintenance. Although the condition assessment is listed as "Not Rated", the structure is inspected, permitted, and regulated by the SFWMD to ensure its continued effectiveness in flood risk reduction and wildlife habitat preservation within the Prairie Lakes Preserve.
Year Completed |
1993 |
Dam Length |
100 |
Dam Height |
14 |
River Or Stream |
PRAIRIE LAKES PRESERVE |
Primary Dam Type |
Concrete |
Surface Area |
5720 |
Hydraulic Height |
9 |
Drainage Area |
50 |
Nid Storage |
51500 |
Structural Height |
22 |
Outlet Gates |
Other Controlled |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
22 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
G113 Control Structure