LWI Region 3 Modeling Overview

BOEUF

MACON TENSAS

COCODRIE

Updated Structural Configurations

Wham Dam Simulated in pre- and post-2018

configurations to reflect changes in structure and functionality following its reconstruction. The pre-2018 configuration had a higher weir elevation of 83.06 ft and a narrower width of 88 ft, while the post-2018 reconstruction featured a lowered weir crest at 65.48 ft and a widened spillway of 110 ft. These geometry changes allowed water to overtop at a lower elevation and across a broader span, influencing the timing and magnitude of downstream peaks. Refer to Figure 3-22 for a visual comparison of the dam geometry before and after reconstruction. Irwin Lake Weir Located downstream of the Boeuf confluence on Bayou Lafourche; was modeled with its current geometry and routing logic. Figure 3-22 highlights the Irwin Lake Dam, which plays a crucial role in diverging flow on the Boeuf and Bayou Lafourche Rivers. Rochelle Detention Basin { Added to the model post-2018 as part of Monroe’s flood mitigation improvements.

Figure 3-21: Boundary conditions on Ouachita and Bayou DeSiard, shown along the City of Monroe and with pump stations.

This storage area delayed stormwater surface flooding and was linked to the Rochelle Avenue pump.

{ Maintaining multiple geometry versions across different hydrologic events allowed for improved model calibration and assessment of mitigation effectiveness.

Figure 3-22: HEC-RAS representation of Wham Dam showing pre- and post-2018 geometry changes, including updated weir crest elevation and spillway width.

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LWI REGION 3 TRAINING

LOUISIANA WATERSHED INITIATIVE