Northern Prairie Wildlife Research Center
Temporary basins are the most abundant type of basin in the Lake Dakota Plain physiographic region. During glacial retreat, drainage from the northern James River Lowland flowed northward. Because no outlet for this water existed, glacial Lake Dakota formed in what is now Brown and Spink counties. Many temporary basins within this physiographic region represent remnants of initially deeper basins that were partially filled by silt deposited under glacial Lake Dakota.
Temporary basins are less abundant on the Prairie Coteau where terrain relief is typically greater because of more extensive deposition of glacial debris. Greater relief generally results in deeper basins and may result in reduced upland infiltration and increased runoff. Temporary wetland basins also occur at low density on the western slope of the Missouri Coteau and within the dissected Pierre Hills physiographic region where all types of natural basins are uncommon because of a more ancient glacial history.
|Figure 30. Distribution of temporary basins expressed as number of basins/10 mi2.||Figure 31. Distribution of temporary basins expressed as acres of basins/10 mi2.|