SOUTH DAKOTA FLOW REPORT
Last Updated: December 17, 2025
South Dakota's river systems have displayed a varied range of streamflow conditions recently, with some watercourses experiencing significant surges, while others are showing signs of flow reductions. Notably, the Whetstone River near Big Stone City reported an extraordinary current streamflow of 29,300 cubic feet per second (cfs), a staggering 76401.31 cfs rise in the last 24 hours, indicating potential flooding conditions, especially relevant for water enthusiasts and communities along the river. The Bois De Sioux River near White Rock also exhibited a considerable flow increase to 2,430 cfs, at a gage height of 12.97 feet, suggesting a possible impact on the nearby whitewater trails and the watershed in the region. Conversely, rivers like the Cheyenne River near Wasta and the Redwater River above Belle Fourche witnessed lower than average streamflows, at -44.32% and -2.56% of normal, respectively, which suggests a flow drought that could affect local ecosystems and water availability.
Rivers like the James River at Huron and the Belle Fourche River near Elm Springs are experiencing elevated streamflows, 548 cfs and 17,900 cfs respectively, much above their normal rates (73.87% and 727.05% of normal, in that order), potentially impacting cities such as Huron and water activities near Elm Springs. The Big Sioux River, which flows through major cities including Sioux Falls, also bears monitoring, with the river at North Cliff Avenue showing a streamflow of 471 cfs at a gage height of 5.86 feet, which is above average and could pose a risk for waterside communities. These streamflow variations underscore the importance for residents and river enthusiasts to stay informed about current conditions, especially during seasons of extreme weather that South Dakota experiences, to ensure safety and the sustainable enjoyment of the state's aquatic resources.
South Dakota has a humid continental climate with four distinct seasons. The Missouri River, which forms the eastern border of the state, is the largest and most significant surface flow. It is subject to extreme flooding during spring and summer due to snowmelt and heavy rainfall. Other major rivers include the Cheyenne, James, and Big Sioux. The state has several reservoirs and dams, including the Oahe, Fort Randall, and Big Bend dams, which provide flood control, irrigation, and hydroelectric power. South Dakota's hydrology is influenced by its topography, soil type, and vegetation cover, which affect the amount and rate of water infiltration and runoff. The state's snowpack and precipitation patterns are important factors in determining water availability and storage.