Here is a photo of flooding in Baton Rouge provided by Atmosphere Ariel to KTBS in August 2016.
And, from August 17, 2016, this is a photo of I-12 published by WDSU with an article titled "Walker mayor to sue state over I-12 construction."
An article in the Livingston Parish news states
The lawsuit says a 19-mile concrete barrier, from East Baton Rouge Parish to the Walker area in Livingston Parish is “acting as a man-made flood wall that interrupts the natural flow of surface waters.”
Is it possible that DOTD built these lane dividers without considering that they would act as a dam during heavy rain? It appears again that the answer is YES.
Now, the Louisiana DOTD wants to add large amounts of impervious surface in Lafayette by building the I-49 Con. Incredibly, the only mention of flood impacts in their Environmental Impact Statement is that they just plan to drain the roadway into local drainage or directly to the Vermilion. While they have taken decades to plan the I-49 Con, they have given the citizens of Lafayette nothing to gauge its flooding impacts. In past presentations, we have been told to trust them. We have been told that flooding analysis will be part of their final design. But, flood impact analysis should be a central part of the Environmental Impact Statement for public scrutiny and comment. Just ask the mayor of Walker how much he trusts DOTD's flood design expertise!
Proper flood mitigation would likely require construction of a large retention pond on land with an elevation above the highest historic flood height. Any private developer in our parish would be required to build retention/detention, but the DOTD is not constrained by local ordinances. I do not see any available large tract of land available within our urban center to accommodate the retention pond. Bypass alternatives to the east along the Teche Ridge, or west following the proposed LRX route would both have ample rural land available for such mitigation.
The most probable result of waiting until final I-49 Con design to consider flood mitigation is that there will be no flood mitigation.