The study area is comprised of the Fox-Wolf, Milwaukee, Menominee, Oconto, and Peshtigo River Basins in Wisconsin and the Ford and Escanaba River Basins in Michigan. Major cities include Milwaukee, Green Bay, Racine, and Appleton. The Green Bay area, along the lower Fox River, has one of the highest densities of paper mills in the world. The topography of the study area was shaped by glaciation.
Surficial deposits range in thickness from zero to several hundred feet.
Bedrock dips southeast toward Lake Michigan. The oldest rock subcrops in the northwest and the youngest in the southeast. Land use ranges from forests in the north to agriculture and urbanized land in the southern and eastern parts of the study area. About 50 percent of the area is forested, with streams and lakes offering excellent fishing, canoeing, and other recreational opportunities. Agriculture is a major activity in the study area, with 37 percent of the area devoted to cropland and pasture land.