CSRS Completed Central, La.’s First-Ever Master Drainage Plan Through Use of H&H Modeling


The City of Central, Louisiana is surrounded to the south, east, and west by the Comite and Amite Rivers. Extreme, heavy rains in August of 2016 resulted in catastrophic flooding with thousands of homes and businesses in the City of Central severely impacted. Following the disaster, the City began its recovery efforts and sought opportunities to improve its resiliency during the re-building process. Being a newly formed community, Central had yet to conduct a comprehensive Drainage Master Plan. The City then procured and selected CSRS to lead its flood recovery efforts and to conduct the City’s first comprehensive Drainage Master Plan.


CSRS identified and surveyed 48 linear miles of named streams, 155 culverts, and 54 bridges. In addition to stream assessments to identify storm damages, CSRS developed and calibrated 2-dimensional (2D) hydraulic models of the 6 major watersheds within the city utilizing the recently collected 2018 high-resolution LiDAR elevation data. Hydrologic and Hydraulic (H&H) modeling, used since the 1970s, is computer software that simulates rainfall runoff flow to predict the extent of water levels, flooding and to test ways to reduce the flooding prior to construction. These models were used to understand the hydraulic system of canals, identify problem areas, and simulate and develop proposed solutions to the problems. One example of the benefits of the 2D models in identifying these solutions is seen in the images below. The majority of water is jumping out of the main channel and flowing to Hooper Road east of the main crossing. With this realization, the improvement of the structure at this location results in the most efficient and effective solution to the relieve backwater flooding in the neighborhood just north of Hooper Road.


CSRS is working with the Planning and Zoning Commission and City Council to implement a process to utilize these models to estimate off-site drainage impacts from proposed developments on the surrounding properties. These models are the foundation for developing a flood forecasting system as well as supporting the continued effort in disaster recovery, grant applications, floodplain management and drainage maintenance for the City.

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