Navigation is travel or transportation over water. Many products we use today are transported by vessels on inland waterways. Towboats push barges loaded with products such as grain, coal and petroleum up and down rivers to loading and unloading facilities. The use of barges as opposed to semis produces around 90% less greenhouse gas emissions.
Navigation activities in the United States take place at thousands of ports and terminals along more than 25,000 miles of waterways. Roughly 25% of all waterborne commerce in the U.S. and 90% of the nation’s agricultural exports depend, specifically, on the Mississippi River, the fourth longest river in the world.
The St. Paul District’s navigation program provides a safe, reliable, cost-effective and environmentally sustainable waterborne transportation system on the Upper Mississippi River for the movement of commercial goods and for national security needs. The St. Paul District is responsible for maintaining the 9-foot navigation channel for 243.6 miles on the Mississippi River from Minneapolis at river mile 857.6 to Guttenberg, Iowa, at river mile 614.0. The district is also responsible for maintaining 40.6 miles on three tributaries: the Minnesota, St. Croix and Black Rivers.
Keeping this system open is vital to the nation’s economy. Nearly 17 million tons of commodities on average travel past Lock and Dam 10 in 2018. The industries making these shipments save approximately $430 million by using the inland waterways instead of overland shipping materials.
Locks and Dams
The Corps of Engineers maintains navigation channels, much like road crews maintain highways, as well as builds breakwaters or jetties to protect public property from shoreline erosion. A 9-foot navigation channel is maintained on the Upper Mississippi River so river vessels can transport goods north of St. Louis. To achieve a 9-foot channel in the Upper Mississippi River, Congress authorized the Corps of Engineers to construct a system of navigation locks and dams in the 1930s. Dams are built on rivers to hold back water and form a deeper navigation ‘pool.’
Dams make it necessary for river vessels to use a series of locks to "step" up or down the river from one water level to another. Additional benefits from the locks and dams include adding river recreational areas for public use, providing water supply for several river communities and serving as nesting grounds for migratory birds. In addition to the 13 locks and dams, the St. Paul district also manages more than 1,300 wing dams and 200 revetments.
Sedimentation in the channel is caused by the normal cycle of silt movement, erosion from high water or heavy rains and changes in river currents. To maintain the 9-foot navigation channel, the Corps must remove material that settles in the channel area. The St. Paul District removes around 1 million cubic yards of dredged material annually. This is enough sand to fill the Minnesota Capitol rotunda 21 times.
Mechanical or hydraulic dredging are methods used for the removal of that material. This material is placed in designated areas along the river. Some of these areas are beneficial use placement areas. Beneficial use of dredged material is the productive use of the material by the public or private sectors. Examples of common beneficial uses of dredged material in the St. Paul District are upland habitat development, aquatic habitat enhancement, creation of areas for bird nesting, beach nourishment, winter road maintenance and bank protection and general purpose fill.