By Scout Nelson
The Prairie Pothole Region in North and South Dakota formed thousands of years ago when glaciers melted and left behind shallow wetland areas known as potholes. These natural depressions fill with water and are important homes for migratory birds and other wildlife.
This region has experienced a steady rise in surface water levels. The U.S. Geological Survey tracks this change through the Annual National Land Cover Database (NLCD), which uses satellite images to map land and water. The data shows that the amount of open water in this area has increased over time, especially in places like Devils Lake in North Dakota and Waubay Lake, and Bitter Lake in South Dakota.
The land in this region is flat, so floodwater takes longer to drain. When there is more rain or snow, water from one season often stays until the next. As a result, each year’s wet conditions can build on the last, causing more widespread flooding.
Another reason for this increase in water is the connection between the potholes and the underground water table, or aquifer. When the aquifer fills up, it spills into the surface potholes. If the aquifer stays full, the water will stay on the surface for a long time.
Weather plays a big role in this process. Rain and temperature changes directly affect the water in the potholes. Wet years lead to more water, while dry years bring some relief. However, the long-term trend shows that wet periods are becoming more common.
Photo Credit: wetland-water-pexels-ron-lach
Categories: South Dakota, General, Weather