New data collected by the Iowa Daily Erosion Project (IDEP) strongly suggests that the vast crop acreage within the state is eroding at rates far greater than USDA estimated. The IDEP data is derived from new modeling techniques that for the first time estimate the soil lost to individual storm events. Topographic and land use information captures the damage caused by high impact events. Environmental Working Group concluded that the USDA underestimated the erosion rate on more than 10 million acres of Iowa’s farmland. Here’s the site that updates the erosion maps daily