Managing the Mississippi

by Thomas E. Rice

But what words shall describe the Mississippi, great father of rivers, who (praise be to heaven) has no children like him! An enormous ditch... running liquid mud. CHARLES DICKENS, American Notes

The English novelist obviously wasn't impressed with the Mississippi River, as reflected in this passage written shortly after his first visit to America in 1842. The particular section of the river he described was near Cairo, Illinois, where he traveled as a passenger on a mosquito-infested steamboat. At the time of Dicken's river voyage, a six-year-old future novelist lived not far upstream in a Missouri riverfront town. Just beginning his lifetime enchantment with the Mississippi, he would later write more lovingly about the river under the name Mark Twain.

TWENTIETH-CENTURY CONCERNS
Dickens's slow-moving boat, with its large paddle wheel, added little to the murky appearance of the river; the waves created by the vessel drifted slowly and splashed gently against the riverbank. Today's heavier, faster river traffic -commercial barges and recreational boats, such as speedboats- can impact the river, including adding tothe erosion of the shoreline.

"However, riverbank erosion cannot be laid completely at the doorstep of twentieth-century river traffic," cautions Illinois State Water Survey hydrologist Nani Bhowmik. "There are a number of natural causes as well. In some areas, just the natural river flow, the river's meandering patterns, and wind-generated waves can and do initiate bank erosion."

The river system in the Midwest is a vital link in the transportation system of the United States, moving a myriad of goods. As a matter of fact, barges on the Mississippi River carried more than 472 million tons of cargo between St. Paul-Minneapolis and New Orleans in 1990, including about 46% of the grain transported in the entire United States.

"Equally important," stresses Bhowmik, "the Mississippi and Illinois rivers are also unparalleled natural resources, providing rich wetland and aquatic habitats that harbor great varieties of plants and animals -many of them threatened or endangered."

TWENTIETH-CENTURY RESEARCH
In order to get a first-hand idea of the amount and extent of bank erosion on the Upper Mississippi and Illinois waterway, a team of Illinois State Water Survey researchers, with the support and cooperation of the U.S. Army Corps of Engineers (COE), set out to identify and catalog the riverbank sites where erosion is taking place. The evaluation covered the Upper Mississippi River from St. Paul, Minnesota, to the southern tip of Illinois at Cairo -some 850 river miles- and the banks of one of the Mississippi's major tributaries, the Illinois River, from Joliet to Grafton -another 300 miles.

The field research effort extended over a three-month period last summer. Also joining in the study were representatives of the Illinois Natural History Survey, the Huntington District of the COE, and the University of Iowa. The National Biological Service and the Illinois Department of Natural Resources also have assisted the researchers' efforts.

Bhowmik and Water Survey colleague David Soong are heading this cooperative project for the Corps of Engineers as part of a larger study of the impacts of navigation traffic on the Upper Mississippi River System. "Although there have been previous studies of bank erosion," Bhowmik notes, "this is the first time that anyone on any river system has undertaken a comprehensive mapping of the erosion sites on both sides of the river.

"This is an important project for the entire navigation system," Bhowmik explains. "Many locks and dams were built in the 1930s, and they have undergone a lot of wear and tear. How should the navigation system be managed in the future? How should repairs be conducted? These and many other questions need to be answered as societyprepares to make decisions. The Corps of Engineers is in charge of recommending future directions and this is just one of many studies they are now supporting."

Twenty-nine sites were selected on the Illinois River and 43 on the Mississippi, where survey teams collected additional data. Further detailed investigation may be done with the assistance of the COE to determine the actual rate of erosion, depending on the results of the present study.

Bhowmik says the researchers "were extremely lucky. There was not much rain." The first month of the trip, August 1995, was oppressively hot. "However," he adds, "the heat did not bother us. Every boat was equipped with plenty of food and lots of water to drink.

"Conditions weren't always peaceful on the river. We went through plenty of choppy water," Bhowmik notes. "But we had good people, including Corps of Engineer staff who were skilled navigators. The COE, in fact, played a vital role in the research project, providing highly qualified staff to work side-by-side with other research members, as well as providing funding for the project."

A typical day began at 6:00 A.M. with the study party on the river by 7:00 A.M. During the preplanning stages of the project, locations where the boats could be docked for the night were found and lodging close to the river was arranged. A "chaser" car on shore followed the riverborne researchers, communicating with them by cellular phone, to assist in the event of emergencies or to supply any unforeseen needs. The chaser car also delivered gas cans for refueling the boats.

According to Soong, the first order of business each day was an all-staff meeting at which time video tapes of various sections of the river were reviewed. The Corps of Engineers-Rock Island District provided valuable information on the locations of high traffic areas of the rivers, such as the tonnage hauled by barges as measured at the locks. The team would estimate how large an area would make up the day's work, and the researchers would then divide into groups and go to work on their separate boats. The research force varied between two and three boats with three or four people on each boat.

"When we reached an erosion site," Soong explains, "a cross-section of the river and detailed bank profiles were measured." The identification of each bank erosion site included its precise location as determined on a portable global positioning system. During this reconnaissance study, researchers marked bank conditions on navigation charts and took samples of soil and other bank materials. They described each site, noting soil types, vegetation, and probable causes of erosion, such as nearby development and land-use (urban, agricultural, or industrial development, forest, or levees). Sediment samples were taken from the river itself at one and two-foot depths.

"The days were very long," Soong admits, "and we took as many samples as possible. We worked hard because we knew this was a unique opportunity." After a tiring day's work, dinner on shore was quickly followed by a shower and bed. On many nights, dinner consisted of McDonald's or Hardee's, whatever was close to the area where the crews docked.

Data collected during the field trips are currently being compiled and analyzed, and bank material samples are being analyzed at the Water Survey's Sediment Laboratory. Scientists are also in the process of selecting five sites -three on the Mississippi and two on the Illinois- for possible future intensive study. These sites are to be representative of the river system.

DATA FOR THE FUTURE
To document the research, Bhowmik points out, "We took many photographs, including videotapes of the whole river system. Twenty or thirty years from now someone will be able to view these images and compare them with the conditions as they exist then, showing the changes that have occurred over time."

Bhowmik offers an example of a good record of research from the past. "In the early 1900s a hydrogeographic survey of the Mississippi River was done, primarily with basic surveying techniques. This survey produced some excellent data sets and maps, mostly hand-drawn. We have copies of them and we still use them today.

"We can only wonder what technology will be available in the future, but with the research and visual documentation we are doing today, we can be sure there is good, scientifically sound information for important decision-making for the management of the Mississippi and Illinois rivers now and in the future -management that will help maintain a healthy balance among the commercial, recreational, and environmental uses of these important natural resources for generations to come."