Midwest Wetland (IMAGE) Oregon State University Caption Riverine wetlands such as these in northwest Iowa used to be commonplace across much of the Midwest, but millions of acres of them have disappeared since European settlement. Credit (Photo courtesy of the USDA Natural Resources conservation Service) Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.