Date of Award

5-2026

Degree Type

Thesis

Degree Name

M.S.E.

Degree Program

Civil Engineering

Department

Civil and Environmental Engineering

Major Professor

Dr. Gianna Cothren

Second Advisor

Dr. Satish Bastola

Third Advisor

Dr. Robert Clyde Mahon

Abstract

This research utilized an existing SWMM modeling framework of the Ormond area within St. Charles Parish, Louisiana. A micro scale PCSWMM model was updated using GIS Derived values for CN, percent imperviousness, and subcatchment slope and compared to an macro-scale model. Models were compared under several storm events, which included the recent May 14, 2020 storm as well as 2-, 10-, and 100-year design storms. Peak flow, total inflow volume, and hydrograph characteristics were analyzed to assess response of each model.

The results show that the macro-scale model generally produces higher peak flows and total volumes, while the micro-scale model captures localized storage, surcharge, and flow redistribution, resulting in attenuated peaks and delayed response. The 1D-2D integrated model was developed to check the flood extent behavior of macro and micro scales. The results were as expected; the micro model captured a more spatially distributed flood distribution compared to the macro model. In addition, it was observed that the resolution of the 2D model has a significant impact on capturing the extent of the flood. The simulation also revealed the 2D to 1D interaction during the recession period of the flooded water.

This model also highlighted the interaction of 2D into 1D during recession of flooded water. Assessment of converting the model from open-channel to closed conduits showed that predicted downstream response in the node was very similar in both models, only showing trivial differences in peak flow and total volume. A closer look into the internal hydraulic of each node showed that closing the conduits forced the model to operate under pressure and provided no visible storage. Ponding simulation was noted to have a larger impact on the model than conduit configuration.

Overall, the findings show that model scale, storage representation, and modeling assumptions, such as ponding, have a stronger impact on model behavior than conduit configuration alone. The results provide insight into how different modeling approaches influence predicted hydraulic response, while highlighting the need for improved model representation and calibration for more reliable flood assessment.

Rights

The University of New Orleans and its agents retain the non-exclusive license to archive and make accessible this dissertation or thesis in whole or in part in all forms of media, now or hereafter known. The author retains all other ownership rights to the copyright of the thesis or dissertation.

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