Years ago, I had to fly into western Kentucky to conduct an on-site safety training seminar for operators of chemical recovery boiler operators at a pulp mill. Approaching the airport in Paducah, I could see water practically everywhere. They had gotten 6" (15cm) of rain in less than 24 hours the previous day. Since this region is at the confluence of the Ohio and Mississippi rivers and is quite flat, it is prone to flooding. To protect property from flooding from up-river surges, the rivers are bordered with levees and flood walls. The problem is that these barriers impede the run-off of waters from heavy rains, so the lands "protected" by these barriers remained flooded, and when I took of for St. Louis at the end of the week, the low-lying areas were still covered with standing water.