Lilly Bayou Control Structure Reservoir Report

Last Updated: January 11, 2026

Located in East Baton Rouge, Louisiana, the Lilly Bayou Control Structure is a federal-owned dam designed by the US Army Corps of Engineers to manage the flow of the Comite Diversion Channel.


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Summary

Completed in 2011, this concrete dam stands at a height of 86 feet and serves primarily for flood risk reduction purposes. With a storage capacity of 5800 acre-feet and a maximum discharge of 46500 cubic feet per second, the structure plays a crucial role in mitigating flood risks in the area.

The dam features an uncontrolled spillway with a width of 132 feet and flap outlet gates. It has a low hazard potential and is currently assessed to be in fair condition, with inspections conducted every 5 years. The surrounding area is regulated by the Louisiana Department of Transportation and Development, with state permitting, inspection, and enforcement in place. Despite moderate risk assessments, the Lilly Bayou Control Structure continues to effectively protect the region from potential flooding events.

With its strategic location, state-of-the-art design, and essential flood risk reduction functions, the Lilly Bayou Control Structure stands as a vital asset in safeguarding the East Baton Rouge community from the impacts of extreme weather events and ensuring the sustainable management of water resources in the region.

Year Completed

2011

Dam Length

308

Dam Height

38

River Or Stream

COMITE DIVERSION CHANNEL

Primary Dam Type

Concrete

Hydraulic Height

38

Drainage Area

308

Nid Storage

5800

Structural Height

86

Outlet Gates

Flap

Hazard Potential

Low

Foundations

Soil

Nid Height

86
       
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.