The closure will be from Exit 4, at McCook Lake, to Exit 26, near Vermillion.
Workers will be putting a berm over the interstate and on the east side of the overpass.
Below is the press release from the state that includes detour plans.
PIERRE, S.D. – State officials are closing Interstate 29 in southeast South Dakota at noon today (Thursday).
The Big Sioux River is predicted to crest in the morning or early afternoon hours of Friday, June 20 and is expected to send a significant amount of water into low lying areas of southeast South Dakota.
As Gov. Daugaard outlined in a media briefing on Wednesday, a berm, or levee, is being built across both lanes of interstate 29 at Exit 4. That protective structure will connect with an existing levee on the east side of North Sioux City.
Through traffic on Interstate 29 will be detoured as follows:
- Southbound I-29 Interstate traffic will be detoured onto I-90 east at Exit 84A at Sioux Falls, SD, then south on I-35 Exit 159A at Des Moines, IA, then west on I-80 at Exit 137A to Council Bluffs, IA, then to I-29 south.
- Northbound I-29 Interstate traffic will be detoured at Council Bluffs, IA onto I-80 eastbound, then north on I-35 in Iowa to Albert Lea, MN and west on I-90 to Sioux Falls.
Interstate through traffic detour on local roads:
- Southbound I-29 traffic in South Dakota will be detoured onto SD 50 West at Exit 26 to Vermillion, then south to SD 19 into Nebraska where it becomes Highway 15, then continue south to Highway 12 east in Nebraska to U.S 20 east in Nebraska, then to Exit 1A for I-29 south at South Sioux City, NE.
- Northbound I-29 traffic will exit onto Highway 20 west, then north on Highway 12 and Highway 15 in Nebraska, continuing onto Highway 19 in South Dakota to the Vermillion Exit to SD 50 eastbound to I-29.
At this time, local traffic will be allowed into the area until water is over the road.
Detour maps are available on http://disasterrecovery.sd.gov/flood_info_pubs.aspx.
Motorists are urged to use caution when driving on state and local roads in southeast South Dakota for the next several days and should not drive through rushing or standing water over roadways as the road may be washed out underneath.
Travelers are urged to visit safetravelusa.com/SD or to call 511 to check latest road conditions in their area.