The Big Sioux River watershed drains several counties in Southeastern South Dakota and also some in southwestern Minnesota and northeastern Iowa. Do you live in the Big Sioux River watershed? In South Dakota, all or parts of the following counties drain into the Big Sioux River: Roberts, Marshall, Day, Codington, Clark, Hamlin, Deuel, Brookings, Kingsbury, Moody, Lake, Minnehaha, Lincoln, and Union. The headwaters of Big Sioux River is located in Summit, South Dakota. From there, the river flows through the towns of Watertown, Brookings, Flandreau, Dell Rapids, and Sioux Falls before emptying into the Missouri River at Sioux City, Iowa.
Follow these links to learn more about this project:
Program Guidelines

Cooperator Stories

Final Report for Segment 1 of this Project
Appendices of Final Report
Photos of Implementation Designs
Several smaller streams feed the Big Sioux River as it winds through southeastern South Dakota. These smaller streams collect runoff from surrounding farmland and towns. What about lakes? Lakes are also an important part of the Big Sioux River watershed. Some lakes serve as a place for the water to drain when the Big Sioux River over flows its banks. This actually helps save homes located downstream from the flooding. Major lakes in the Big Sioux River watershed include Lake Kampeska, Lake Pelican, Lake Poinsett, Lake Campbell, Oakwood Lakes, Lake Madison, and Wall Lake.

Did you know that many cities along the Big Sioux River use surface or shallow groundwater from the river for drinking water? Currently, Sioux Falls is the only city to use surface water for drinking water (roughly two-thirds of their supply), while the other one-third of their drinking water comes from shallow groundwater which is hydraulically connected to the Big Sioux River. Other cities and rural water facilities along the Big Sioux River also use shallow groundwater wells for a drinking water source. This means that even though you may reside in rural Moody County, if you eat at a restaurant in Sioux Falls, the water used to make ice for your drink was from the Big Sioux River watershed. This is why it is very important for us to think about what comes in contact with water as it travels down the Big Sioux River. Remember, water in the Big Sioux River empties into the Missouri River and then into the Mississippi River. This means that people downstream of you are using the water that you may have affected. Many cities downstream of us use the Mississippi River for drinking water also.

As of today, portions of the Big Sioux River watershed between Watertown and Brandon have been identified as unsuitable for fish life propagation, fishing/boating, and/or swimming. The water quality assessment studies completed by the District detail the exact impairments and what the causes of these impairments are.

As a result of the findings in the water quality assessments, the District received $1,618,078 in US EPA 319 grant funds to begin reducing sediment and bacterial loadings into the watershed under the Big Sioux River Watershed Project. The project was designed to reduce non-point source pollution from within the watershed to improve the quality of water in the Big Sioux River. Improving animal waste management facilities and returning riparian buffers back to a natural state will improve the water quality in the Big Sioux River.

August 14, 2007 marked the closing of the first permanent conservation easement along the Big Sioux River under this project!

The Big Sioux River Watershed Project is a 10-year implementation project that will be completed in multiple segments and parts. The first segment of this project was completed by the East Dakota Water Development District from August 2005 to Septemter 2010. The second segment of this project is currently underway. The Hamlin County Conservation District is taking the lead for the north portion (from Bruce, north) of the watershed and the Moody County Conservation District is taking the lead for the southern portion (from Brookings, south) of the watershed.