Northern Prairie Wildlife Research Center
In eastern South Dakota, most drainage and stream channelization have occurred in areas with high stream densities, that is, the James River Lowland and the Big Sioux River Valley (Fig. 41). In the latter, most drainage has occurred east of the Big Sioux River, or within the river's floodplain. In the James River Lowland, most drainage and channelization have occurred in the central part of the region east of the James River, modifying streams originating on the west slope of the Prairie Coteau. East of the James River row crop and small grain agriculture is the principal land use. West of the river, livestock production is more common, drainage ditches are fewer, and dugouts and impoundments are more abundant.
|Figure 41. Distribution of channelized streams and drainage ditches with wetland characteristics linking two or more natural basins.|
Drainage and channelization is most limited along the west slope of the Missouri Coteau where rangeland predominates and basin density is low, in the Lake Dakota Plain where low relief and relatively low basin and stream density discourage drainage, and in the interior of the northern Prairie Coteau where most drainage is internal and steep rolling terrain discourages construction of large drainage ditches.