US Army Corps of Engineers
St. Paul District Website


Lower Pool 2 Channel Management Study

Published Feb. 27, 2015
Updated: Sept. 19, 2019

The St. Paul District is responsible for maintaining 244 miles of the Upper Mississippi River 9-Foot Channel Navigation Project from the head of navigation at Minneapolis, Minnesota, to Guttenberg, Iowa.

Pool 2 is the navigation pool created by Lock and Dam 2 at Hastings, Minnesota, at river mile 815.2. The pool is approximately 32.4 miles long and stretches upstream to Lock and Dam 1 in Minneapolis. Between river miles 818 and 820, the navigation channel switches from one bank of the river to the other and back again creating a near 90-degree bend in the river at mile 819. Navigation in the pool is maintained by dredging, channel control structures such as wing dams, closing dams and bank revetments, snag removal, accurate channel marking and close monitoring of conditions.


To maintain the navigation channel in lower Pool 2, specifically between river miles 818 to 821, the U.S. Army Corps of Engineers has had to increase dredging activity.

  • Historically, it required dredging once every three years.
  • Since 2006, dredging has occurred almost annually.
  • Between 2007 and 2016, the Corps witnessed a 76 percent increase in dredging volume compared to the historic average, increasing annual dredging costs in this reach.
  • Placement site capacity has been reduced leading to accelerated unloading requirements.

The authorized channel width in Pool 2 is 200 feet, compared to 300 feet for areas downstream from Lock and Dam 2. The U.S. Coast Guard has expressed concern regarding the difficulty and expense to maintain the aids to navigation (buoys and day marks) in this stretch of Pool 2. The commercial navigation industry has experienced difficulty navigating the channel in this reach due to the sharp bend, shoaling, and the open windswept area. There have been 91 groundings reported in this reach from 1990 to 2018. These issues have resulted in delays from channel closures, reduced tow sizes and increased transport costs.


The Corps adopted a plan to increase the channel width via dredging and add two channel control rock structures to control erosion. The Corps completed the final feasibility study, plans and specifications for Phase I (rock structures) in July 2017, contracted construction in September 2017 and expects completion in November 2019. The Corps will complete plans and specifications for Phase II (dredging) and award a construction contract in 2020.


The 9-foot navigation channel was authorized by the River and Harbor Act approved July 3, 1930. It is 100 percent federally funded with the exception of short segments in Minneapolis and on the Minnesota River.


The estimated federal cost of this study and the construction is approximately $9 million.