Minnesota Department of Transportation

511 Travel Info

Hwy 169, Hwy 22 Minnesota River Flood Mitigation

Mankato, Saint Peter

Traffic impacts

Highway 169 Mankato to St. Peter partial opening Thursday, Aug. 25
Lanes restricted, speeds reduced, caution advised

The detour for Highway 169 between Mankato and St. Peter will be removed around 9 a.m. on Thursday, Aug. 25.  .  Highway 169 will carry one lane of traffic each way in the outside lanes with a 55 mph speed limit.

Motorists must use caution as the inside lanes will be closed with workers present and construction vehicles entering and exiting the open lanes. MnDOT has retained extra law enforcement and advises motorists to refrain from gawking to keep traffic moving safely.

Work remaining includes construction of the concrete intersection crossings, concrete median, left turn lanes, high tension guardrail and raised concrete barrier. 

Only the following Highway 169 intersections will open at this time:

  • Hiniker Saw Mill
  • Old River Bluff Road (south end)
  • 492nd Street
  • 381st Street
  • 367th Avenue
  • Freeman Drive
  • Washington Avenue

7 Mile County Park remains closed until the completion of the flood mitigation project in mid-October.

Traffic control on the detour (Hwy 99, CR 13) will have the temporary signals deactivated and previous conditions restored:

  • Nicollet County Road 13 (Lookout Drive) Howard Drive intersection –  returned to four-way stop
  • Westbound Highway 99/CR 13 (left turn lane removed)
  • Highway 99/CR 333 (Shepard Road) intersection – returned to two-way stop

Traffic control on Highway 22 will remain as is until traffic returns to normal.

Detour Information

Hwy 169 flood mitigation overview map
Click map for PDF detour route.

This project requires us to close Hwy 169 from Mankato to St. Peter. The narrow terrain between the bluff and the Minnesota River rebuilding the road under traffic in one season and carrying two-way traffic comes with other safety issues.

About this project

Summary of work

This last of three projects along the Minnesota River involves raising Hwy 169 from Mankato to St. Peter above the 100-year flood elevation to maintain traffic during high water events in four flood-prone areas (Hiniker Mill, 7-mile Creek, Old River Road, and State Hospital).

When these highways were originally constructed in the early 1960’s, the Minnesota River high-water elevation was assumed at 751 and the roads were constructed accordingly. 

The actual 100-year flood elevation in this area ranges from about 756.0 to 756.6. View overview map of all three projects (PDF).

  • Raising the grade in four flood-prone areas (Hiniker Mill, 7-mile Creek, Old River Road, and State Hospital) to raise the road above the 100 year flood
  • Six miles of resurfacing for a smoother road
  • New median barrier to prevent head-on crashes

Key issues

  • Unsuitable soils in reconstruction areas
  • Coordination with rehabilitation of Hwy 99 bridge over Minnesota River at Saint Peter
  • Management of traffic during construction and access to businesses during construction

Cost

Cost estimate (millions) 2014 2015 2016
Construction 10.7 2.5 29.7
Construction-related costs 1.1 0.15 1.5 - 2.0
Engineering 1.5 0.5 4.5-5.3
Right of way 0 0.05 0.1
Total $13.3 $3.2 $35.8-$37.1