Terminal Lake Flooding and Wetland Expansion in Nelson County, North Dakota

Abstract

The Devils Lake Basin of North Dakota, an interior drainage basin located within a dry, subhumid environment, has experienced pervasive flood conditions since the 1993 onset of a wet spell of unprecedented magnitude and duration. This unique natural-hazard environment has resulted in flooding from both the expansion of the surface area of the basin's terminal lakes (Devils Lake and Stump Lake) and increases in the number and size of rural wetlands. To assess the relative extent of both terminal lake and rural wetland flooding, we focused on Nelson County, which contains Stump Lake and is representative of other counties in the basin. Remotely sensed data acquired by Landsat Thematic Mapper was used to map open-water extent in 2001, and results were compared to 1992 land-cover data provided by the United States Geological Survey (USGS). Our analysis indicates a 53% increase in the size of Stump Lake and a 426% increase in the area of rural wetland ponds. Stump Lake flooding is spatially restricted and has had limited impact upon the surrounding lakeshore environment. Rural wetland flooding is pervasive and has a deleterious effect upon the region's agricultural economic base.

Keywords:

• flooding
• wetlands
• terminal lake
• Prairie Pothole Region
• North Dakota