Sioux Falls Levee System

Image of SF levee system

The US Army Corps of Engineers (USACE) defines a levee as an embankment, floodwall, or structure along a waterway. It is designed to reduce flood risk or direct water flow. In Sioux Falls, there are eight federally authorized levee systems. They protect parts of the city from flooding by the Big Sioux River and Skunk Creek. The US Army Corps of Engineers (USACE) designed and built these levee systems and then turned them over to the City to operate, maintain, repair, and replace as needed.

Current Levee System

Levee System

Levee Miles

Floodwall Miles

Channel Miles

Big Sioux LB North & Diversion Channel RB

9.5

0.2

9.7

Big Sioux LB South

1.3

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1.3

Big Sioux LB Downtown

0

0.25

0.25

Big Sioux RB

1.6

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1.1

Big Sioux RB & Skunk Creek LB

8.0

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7.0

Big Sioux RB & Skunk Creek RB

4.2

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3.3

Diversion Channel LB - North

3.9

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2.7

Diversion Channel LB – South

1.0

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1.0

Levee Inspections

The USACE inspects the levee systems often. They do this to ensure the levees meet federal standards. During inspections, the USACE may find unsatisfactory items. Problems can include encroachments, unwanted vegetation, erosion, shoaling, gate deficiencies, and other items. The City has a levee maintenance program with a dedicated staff, operations, and capital plans to maintain the levee systems and address unsatisfactory items found during inspections.

The City is working with the USACE to develop a System-Wide Improvement Framework (SWIF). It will help fix complex deficiencies and may include the following corrective actions:

  • Detailed investigation
  • Engineering evaluation and design
  • Complex permitting

While the SWIF is in development, the City is also implementing Interim Risk Reduction Measures (IRRM). These include:

  • Maintaining an Emergency Operations Plan
  • Enhanced inspection and monitoring of the levee systems
  • Seepage and erosion mitigation as needed
  • General maintenance of the interior drainage systems (drainage ways and stormwater ponds)

Under Public Law 84-99, the USACE may supplement local efforts to repair flood control projects damaged by floods. The SWIF program allows public sponsors or operators to fix levee maintenance problems. However, not doing so within the required time makes the levee system inactive. In the USACE Rehabilitation and Inspection Program (RIP), inactive levee systems are not eligible for assistance.

The SWIF is a living document that is updated through routine inspections. It identifies needed improvements that are prioritized based on the level of risk. More information will be available as SWIF development continues.

 

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