Minnesota Department of Transportation

511 Travel Info

Hwy 169, Hwy 22 Minnesota River Flood Mitigation

Mankato, Saint Peter

Hwy 169 Mankato to St. Peter complete and open

Hwy 169 between Mankato and St. Peter is open to four lanes of traffic and the access to 7 Mile Creek Park has re-opened.

Asst. Secretary of Commerce to attend Oct. 13 celebration

Assistant Secretary of Commerce for Economic Development Jay Williams is expected to participate with other local, state and federal dignitaries at 2 p.m. on Thursday, Oct. 13 at the Happy Chef on Hwy 169 in Mankato.

The flood mitigation project received a $9.8 million grant from the U.S. Economic Development Administration that allowed MnDOT to raise the highway in four flood-prone areas (Hiniker Mill, 7-mile Creek, Old River Bluff Road, and State Hospital) between Mankato and St. Peter to above 100-year flood levels.

MnDOT partnered with the Region Nine Development Commission to apply for the grant that made history as one of the largest grants the EDA has given.

In addition to traditional state transportation funding, the 2013 Minnesota Legislature provided bond funds for flood mitigation projects, $6 million of which went to this third and last Minnesota River flood project.  The first two projects included raising the southbound lanes of Highway 169 in 2014 and adding a bridge on Highway 22 south of St. Peter in 2015 to manage the backwaters during flooding.

Mathiowetz Construction of Sleepy Eye, was awarded the $30 million Mankato to St. Peter project and worked closely with MnDOT and was able to open the road to two-lanes ahead of schedule.

Motorists will benefit from fewer emergency closures of Highway 169, and significant safety improvement thanks to new cable median barrier that protects drivers from cross-median crashes.  The project also will provide motorists with a smoother ride on new concrete pavement.

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 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