From a professor of geography at LSU: Suburban Sprawl and Poor Preparation Worsened Flood Damage in LA
* * * based on my experience studying risk and resilience in this region, I see parallels between the damage of current flooding and the damage caused by Katrina. In both cases, human decisions magnified the consequences of extreme natural events. Planning and permitting enabled development in areas that had experienced repeat floods, and agencies had failed to complete projects designed to mitigate flood damage before the storms hit.
Recovery Diva 
These issues were also discussed in a book about Katrina: The Great Deluge, by Douglas Brinkley. Any emergency manager in the area or who deals with flooding as a risk/threat should review both the book and this article.
Please explain. Some of us do not know what that means in terms of flood risk.
Many new houses are slab on grade.