SOUTH DAKOTA FLOW REPORT
Last Updated: December 31, 2025
South Dakota's streamflows have shown significant variability, with some locations experiencing dramatic changes that could impact river enthusiasts and local communities. The Whetstone River near Big Stone City is a point of concern, with a current streamflow of 29,300 cubic feet per second (cfs), which is an astonishing 2426.97% of the normal flow, paired with an increase of 76,401.31 cfs in the last 24 hours. Such a high streamflow and rapid change suggest possible flooding conditions. Alternatively, the Inlet Canal above Belle Fourche Reservoir and the Redwater River above Belle Fourche are flowing below normal by 14.07% and 16.53%, respectively, indicating potential flow droughts in these areas. The Belle Fourche River near Elm Springs is also experiencing elevated levels at 17,900 cfs, 727.05% above normal, signaling an abnormal streamflow that needs monitoring.
The Cheyenne River at Redshirt has risen substantially, now flowing at 311 cfs, which is 126.58% of its typical rate, and the gage height at this location is at 9.92 feet, which white water enthusiasts might find noteworthy. Conversely, the White River near Oacoma is well below its normal flow at 47.95%, potentially affecting recreational activities. Regarding urban impacts, residents and authorities in Sioux Falls should be vigilant as the Big Sioux River at North Cliff Avenue is flowing at 471 cfs, 45.16% above normal levels. River users, including those interested in whitewater trails along the Big Sioux and Cheyenne Rivers, should stay informed about these fluctuations and any advisories from local water management authorities, as conditions can change rapidly, influencing safety and accessibility.
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.