I think there are certainly man-made contributors to the devastation there. Have friends in Houston whose homes were destroyed by the city / Army Corps of Engineers deciding to open certain reservoirs / dams that resulted in flooding of entire neighbourhoods. That was done to avert worse problems / loss of life, but there was zero communication around this decision. So people went to bed thinking they were out of harm's way and woke up in the middle of the night to their houses being flooded with chest deep water and needing to evacuate immediately. There's talk of a class action lawsuit around this as people could have saved their homes with some notice.
85% of Houston doesn't have flood insurance coverage and part of this has to do with the zoning rules and definitions put into place about what kind of areas are required by law to have flood protection. Those definitions weren't changed in spite of there being several events in recent years to suggest it needed adaptation. So it could be argued the lack of planning adaptation put people into a position where they are financially not going to able to recover from this.
And now we do have chemical plants, pipelines and the oil patch production facilities adding to the nature induced damage. It's tough to plan for a biblical floods when designing a facility but if this weren't a major hub for energy production they wouldn't have the now toxic clean up to contend with.