As the waters continue to top levees, the debate has begun about what caused the massive floods in Iowa and Missouri over the past several weeks. In the Washington Post this morning, Joel Achenbach reports that "Iowa flooding could be an act of man…."It did rain cats and dogs, of course, but the people Achenbach talked with also said changes in the way Iowans use their land contributed to the second "500-year flood" in the last 15 years. (Remember the Great Flood of 1993?) The people Achenbach talked with argued that, for a variety of reasons, water was running more quickly into streams and rivers. Fields have been plowed up to streambeds, leaving little water-absorbing buffer. Fields have been engineered to speed drying by quickly draining water. More acres are planted and fewer are left in conservation programs. Wetlands have been removed. There is less crop rotation. All of these things have helped speed water into streams and that is increasing the severity of flooding.There are plenty of other reasons. The Midwest is in a very wet weather cycle. A result of global climate change? Who knows?