Flood Control

Mission Statement
To ensure the City’s flood control system has the capability to provide a minimum of 100-year flood protection within the floodplain of the Big Sioux River and Skunk Creek in Sioux Falls.

Division Summary
Public Works is responsible for the overall operation and maintenance of the existing flood control system. Planned improvements to the system are designed to provide additional flood protection for Sioux Falls.

Construction activities are coordinated through the Engineering Division of Public Works, and Street Division personnel perform regular maintenance activities.

The City of Sioux Falls, in conjunction with the United States Army Corps of Engineers (Corps of Engineers), constructed the city’s flood control system between 1955 and 1961. The system has served the city through several floods in its forty-year existence.

The flood control system includes a system of levee protection and floodwall along the historic channel, diversion dam, diversion channel, and spillway. The system includes approximately 29.2 miles of levees adjacent to the Big Sioux River, Big Sioux River Diversion Channel, Silver Creek, and Skunk Creek. The diversion channel traverses approximately 15,000 feet from the diversion dam structure to a 118-foot vertical drop down to the historic channel at the spillway.

The intent of the system is to reroute flood flows in and around the City of Sioux Falls and contain these flows within the levee system. The system was designed based on a technical analysis completed in 1954. The feasibility study completed in the early 1990’s indicated that improvements were necessary for the system to protect the city from a once in 100-year event, as regulated by the Federal Emergency Management Administration (FEMA).

Because the system needs to be improved for a once in 100-year event, the city has been working with the Corps of Engineers to improve the levees and spillway so that protection can be provided.

When completed, the flood control system improvements will allow the city to protect properties adjacent to the system from damages caused by major flooding.