Wetlands and Flood Control in the Mississippi Watershed
From the August 1996 issue of the Environmental Review:
Volume Three Number Eight
Before the European colonization of North America there were about 45 million acres of wetlands in the Mississippi River watershed, approximately ten percent of the total area. There are now approximately 19 million acres of wetlands remaining in the watershed. Farmers have systematically drained the region's wetlands and put farms and towns in the fertile floodplains. The extensive drainage system that was put in place moves water out of the fields and into the rivers much faster than before. Water that would have taken weeks to months to move downstream now reaches the rivers in a matter of hours. As a result levees needed to be built to hold the higher peak flows of water in the river channels. The Army Corps of Engineers now maintains a vast network of levees, dikes, pumping stations, and channel dredging operations to try to keep the water out of the natural floodplains in the Mississippi watershed. Since 1960 the Corps has spent at least $30 billion on flood control efforts. In spite of these efforts, flood damages have steadily increased and are now estimated to cost $3.5 billion each year.
Wetlands serve in several ways to reduce flooding and improve water quality. Wetlands hold water back from the streams and rivers thus reducing the water's energy and ability to erode soil; wetlands store water so that peak flows are reduced in wet times, and stream flows are maintained during dry times. Wetlands function as natural water purification systems, allowing particles to settle out of the water and allowing microorganisms and plants to use and break down agricultural chemicals.
In their paper in Restoration Ecology, Hey and Philippi propose restoring wetlands to strategic points in the Mississippi watershed to reduce flooding and its attendant loss of property and life, to improve water quality in the region, and to restore wildlife habitat and recreational activities. Such an approach has economic and ecological advantages to our present attempts at flood control.
We spoke with Dr. Donald Hey, co-founder and director of the Wetlands Initiative about wetland functions in the Mississippi River watershed.
ER: Dr. Hey, what is your training?
DH: My training is in engineering and the applications of hydrology to engineering. I have a B.S. in civil engineering, a M.S. in water resources engineering, and a Ph.D. in environmental engineering, the latter from Northwestern University. I have done a great deal of work in the area of hydrologic simulation.
About twenty years ago I concluded that our investments in structural solutions to many of our water resources problems were simply not giving us the results we wanted and intended. They were an expensive, inefficient way to deal with flooding and poor water quality. That led to my interest in wetland restoration; that is, trying to restore the functional values of wetlands, such as flood storage, water quality management, and wildlife habitat.
ER: What is The Wetlands Initiative?
DH: The Wetlands Initiative is a not-for-profit organization dedicated to restoring wetlands for a wide variety of reasons; not just environmental reasons such as increasing wildlife habitat and biological diversity, although those are very important reasons. At The Wetlands Initiative we are also trying to solve our flooding problems and working to find commercial value to wetlands.For example, we are investigating alternative crops that can be grown in wetland environments, and other commercial applications of the resources that wetlands offer.
ER: Do you work with the academic community?
DH: Oh yes. One of the projects that I'm involved in, the Des Plaines River Wetlands Demonstration Project, is a consortium of universities and practitioners in the field. Twelve universities are involved in the project, and scientists from across the country have conducted research work there and are continuing to do so. The Des Plaines project has had three federal appropriations which were passed by Congress; and has won a number of grants from the various agencies: the Army Corps of Engineers, the US EPA notably, and some of the state agencies have been involved in the research as well.
ER: Can you give some history of flooding on the Mississippi? How did we come to this situation?
DH: When Europeans came to North America, they began to chip away
at the ecological structure of the landscape. By the early 1900s,
this structure had collapsed and flooding, poor water quality,
loss of biological diversity, and loss of wildlife habitat
followed. At the turn of the 20th century, flooding was a
national disaster. In 1935 we passed legislation, as we are wont
to do in the United States, to end flooding. We began to spend
billions of dollars on flood control.
Flood control projects, however, were not new prior to this. In fact, back in the 1600s the French were building levees around New Orleans. That practice began to extend upstream from New Orleans, and by the 1850s the levees built by the Corps of Engineers had reached St. Louis. Then, because of floods in the 1840s, an engineer by the name of Charles Ellet, Jr. was commissioned to study flooding on the Mississippi. He concluded that the levees were actually creating flooding. His report was promptly filed and buried in the Library of Congress. The Army Corps of Engineers continued to build more levees.
The ecological collapse, however, actually began before the Army Corps started building their levees in the 1850s; it started with the fur trade. In the early 1600s Europeans and Native Americans began trapping beaver out of our tributary streams. The beaver's river-controlling works, their dams, were washed out, the river waters started to increase in intensity, and flooding began to increase in frequency.
Let's stop for a moment and get a perspective on losing our beaver. Beaver were the architects of our drainage system in North America. Beaver, over some 10,000 years, built dams on our rivers in a stair-step fashion which is still obvious today. Estimates of the beaver population before European settlement are as high as 400 million. That's enough beaver to put a dam on all of our first, second, third, fourth, and fifth order streams about every 2,000 feet. If you consider that beaver were working on this landscape for 10,000 years, the effects are tremendous. By the early part of the 1800s, however, beaver had been just about wiped out; in 1844 they were considered extinct in Illinois.
Then we began to overlay an agricultural industry which needed
to drain the land, or at least believed that you needed to drain
the land. We constructed 155,000 miles of outlet ditches in the
lower forty-eight states. In Illinois in some of the flatter
areas, there are more miles of outlet ditch than there are miles
of road today. With those ditches in place, the water moved off
the land and downstream not in a matter of months, rather, it
moved off in a matter of hours. Then to those outlet ditches we
attached drain tiles which pulled the groundwater down four feet.
Then we built levees on either side of our mainstems so water
cannot get out into the floodplain where it used to be stored. It
is no wonder that now water stacks up higher and moves more
rapidly, causing more erosion and the escalating flooding that we
Given all the money we have spent on flood control, you would expect to see a decline in flood damages. Instead we have escalating damages.
ER: What proportion of the land in the Mississippi drainage was in wetland or needed to be drained for farming?
DH: In the Mississippi basin above Thebes, Illinois, which is south of St. Louis but north of the confluence of the Ohio River, the Fish and Wildlife Service estimates that around 45 million acres were wetlands in the 1780s. That is ten percent of the watershed. By that time beaver populations were on the decline and much below the carrying capacity of the area because of harvesting. About ten percent of the watershed was being ponded. By today's estimate we have 19 million acres of wetlands in that same area. We have lost more than 25 million acres of water storage capacity, five percent of our watershed area. That number relates well to the flood flows that went by St. Louis in the 1993 floods. You could have stored all the flood waters that went by St. Louis at flood stage on about 13 million acres of land at a depth of three feet. Compare that 13 million acres to the 20 million acres we have lost in wetlands, and it then becomes clear what we have done: we have prevented water from being stored in nature's reservoirs.
ER: Why is this so difficult for some people to accept?
DH: Why have we done this? One can point the finger at the Army Corps and other people, and, indeed, they have contributed to it. But they have been dupes in the process. They did what they were told to do and did not question it.
The real issue goes back to our concept of land ownership and who has the right to harvest or reap the economic benefits of an acre of land. From the beginning, the American way was that whoever owns the land can take its resources and use them. But what about fugitive resources, that is, those resources on the land that are only temporary? For example, when a duck sets down on your property, do you own that duck? Maybe not. Do you own the habitat that duck uses to feed and survive in? We don't know that. The ownership principle that says you can do whatever you want with the land led to development of a body of law which viewed water as a common enemy. Drainage law in the midwestern and eastern United States was based on the common enemy rule: that you could shed your land of water onto subservient land with impunity. That allowed for the development of our agricultural industry because the farmer upstream could say I want to plant corn and I can't do it when there is six inches of water on my property, therefore I am going to get rid of the water. He pulls the plug, and the farmer downstream pulls the plug; plugs get pulled all along, and that has led to our flooding problem. Everyone upstream was happy because they got rid of the water and everyone downstream was unhappy, and so we began to build levees. We redistributed where the water went, and the Army Corps tried to convince us that we could handle the water between our levees or in our flood control reservoirs. Of course, they have learned - and are not admitting it today, that approach does not work. The levees are never high enough, never strong enough; the reservoirs are not large enough.
We must change our attitude about land ownership to say that when you buy a parcel of land, you buy not only the resources but the liabilities of that land. Therefore, if your land stores water, you have to keep it there, and if it provides wildlife habitat for a fugitive resource that is an endangered species, you have to keep it there or make sure it is provided someplace on your property of equal significance.
ER: Is it reasonable to think we can make such a change of the rules of property ownership?
DH: It is rather like the agricultural subsidy. Many farmers
today consider their subsidy to be part of the land value. If you
take that subsidy away, the land value drops dramatically.
There is an experiment being done under section 404 of the Clean Water Act where wetlands are protected and a property owner cannot fill a wetland on his property without permission. Even if the Corps grants him permission, he usually must mitigate for that lost wetland by creating or restoring a wetland at another acceptable site. That is an experiment, and I often wring my hands because there have been times when it has not been well administered. Some districts of the Corps, however, are pushing this approach to wetland conservation. I just hope they don't push too hard and too rapidly because I think people are beginning to accept it.
ER: How did the government respond to the big floods of 1993?
DH: In early spring of 1993 I was on a National Academy of Sciences panel where everyone was saying, How are we going to get ecological engineering implemented? How are we going to get people to use less concrete and steel and go back to more natural ways? My response was, Only after a national disaster. Well, along came the floods of 1993, and we went back to Washington and I was pushing the idea that we should not invest in rebuilding the levees, rather we should invest in converting levee districts back into wetlands where we could grow wetland crops or do something else. I went in to Senator Paul Simon, our senator from Illinois, and I made my case. His eyes rolled upward and he said, "Don, I can't tell you the pressure I am under from the agriculture community in our great state to support the reconstruction of the levees." That was the end of it. A few levee districts got bought out, but in large, they are all back in operation.
ER: Many farmers seem to be content with the occasional disaster and federal relief.
DH: The Wetlands Initiative has several publications that Nancy Phillipi wrote which looked at the cost of the 1993 floods from the landowners' perspective. In many cases landowners came out better than if they had harvested a crop because of the subsidized insurance program and other subsidies. We have put an economic kink in the system which encourages inappropriate use of floodplains.
ER: You propose to reinstitute about 13 million acres of strategically-placed wetlands. What would be the benefits of this approach to controlling the watershed?
DH: The emphasis should be on the strategic placement of wetlands. We could build more wetlands pretty inexpensively in northern Minnesota, but they would not do St. Louis much good. You want to put the storage upstream of the damage sites, but as close to the damage centers as possible. If I were put in charge of the program, I would develop a series of wetland complexes immediately upstream of St. Louis and Peoria.
ER: What is there now?
DH: Cornfields and agricultural levees throughout that entire region. There are flood walls and levees around St Louis, and you are not going to take those down. But if you go upstream a little ways and take down some levees, then it will increase their ability to prevent flooding. If we put the 13 million acres back, probably two-thirds of that acreage would have to be placed along the major floodplains.
ER: How would you do that? Would you knock down levees?
DH: I would argue that we leave most of the levees in place.
Let's put a wetland creation project on a floodplain that is
leveed now. I would simply put in a series of gates that would
let water into the floodplain much sooner than now gets into it
when the levees fail. We would let the water pour in once every
five years or once every ten years. This is a much more frequent
level of flooding than with the levee. I would also allow spring
floods to come in to maintain the habitat in certain areas. But
the entire floodplain would not have to be flooded.
The portion that is not flooded every year, I would say, Go
ahead and farm it. You are farming at risk, you understand, so
what you make in one year you are going to have to put in the
kitty to take you through the years you flood out, but you do
have rich soils. I would also look for crops that can sustain
higher water levels: paper pulp, woods, poplars, some fodder, cup
plant, rice, and marsh hay. There may be some areas, however,
that would be better served simply as wildlife habitat.
I would propose that we connect all these restored wetlands along the Mississippi, Illinois, and Missouri rivers to make a national wetland park. We have virtually no significant national parks in the Midwest. It could be a major park complex in which you could have recreational opportunities and wildlife habitat. The area would be better served because we would not be paying for the flood damage that occurs there every fifteen to twenty years.
ER: How does a wetland reduce flooding?
DH: First of all, when we talk about flooding what we are really talking about is flood damage. People don't care if a vacant lot or a park floods; it is when your home floods or the street is underwater that you notice. Let's consider a wetland in the upper watershed. When it begins to rain, the runoff pours into a wetland. Let's say the wetland is behind a beaver dam, so the water is stored there; it doesn't run downstream as rapidly as if the dam were not there. Furthermore, you are holding the water in this area that has a very broad surface to it, not in a narrow channel rushing downstream. That water has greater opportunity to infiltrate the ground. It also has a much greater opportunity to evaporate.
ER: Holding the water back in wetlands would increase the water flow during the dry times.
DH: That's right. During drought you have a higher base flow. Now let's move downstream onto the floodplain where you have stacked the water way up in between the levees. Let's say you take the levee down and that water can now spread out. Because the water is not as high, there is less energy in it and the discharge will be lower. And again, you increase the opportunity for that water to be trapped in plants, or infiltrate into the ground, or be trapped in depressions behind the levee. Again you slow the water and you begin to remove some of it. In addition, because you have wetlands there, you don't have factories, you don't have homes, you don't have farms, so you no longer have the property that can be damaged on the floodplain. So you have not only reduced flooding but you have reduced the potential for flood damage.
ER: Other cultures have incorporated seasonal flooding into their agriculture in rice farming. Is that a possibility for American agriculture?
DH: Absolutely. Our whole concept of farming is based upon a
European concept which over many centuries has developed into a
highly mechanized process. We have superimposed that industry on
the prairie and the wetlands. Rather than building an
agricultural industry within the matrix of the natural
environment, we just wiped the natural matrix out and built over
it. My argument is that we ought to rebuild that industry within
the matrix of natural landscapes. Then we will use less energy,
less fertilizers, less pumping, less irrigation.
In one of the levee districts on the Illinois River they have huge pumps to evacuate the drainage from the leveed area because there are streams that run into it, and when it rains they have to pump the water up over the levee and into the river. Then in the summer they have to pump water back out of the river in to irrigate. They bear all the energy costs and the management costs associated with pumping, and then they dump tons of fertilizer, pesticides and herbicides on the ground. You end up having a substrate that holds a plant upright and all the rest of it is artificial. It is hydroponics.
ER: The only constraint there seems to be how much money you are willing lose.
DH: People don't get the second law of thermodynamics; many engineers don't get it. In the waste water industry we have to pump four tons of carbon into the atmosphere for every ton of carbon we pull out of the water in our advanced waste water treatment plant - and this is the version everyone is upgrading to! It is a dead loss. If we left that carbon in the water and had more wetlands, the natural processes would take care of it soon enough.
ER: Wetlands have a water purification function as well.
DH: Wetlands could solve most if not all of our water quality problems - from sediment to hazardous toxic wastes. According to the Fish and Wildlife Service assessment of the limitation to aquatic life in our nation's streams, the number one problem is suspended solids, turbidity. Turbidity is not the issue we have spent most of our money on; we have spent most of our money trying to improve dissolved oxygen and other things. Wetlands will take care of turbidity. At our experimental wetlands at Des Plaines River, we remove eighty to ninety percent of the suspended solids. It is gone; it settles out. We create the kind of hydraulic conditions, broad expanses of water at shallow depths, so that the particle can move from the water column to the substrate and stay there. It is a very simple, dumb process.
ER: Not very appealing to engineers.
DH: That's right! It is not fancy, it is really simple. Wetlands
do the same thing for nitrogen. We have been hearing about
problems in the Gulf of Mexico with the nitrates that are flowing
down the Mississippi into the Gulf and hurting the fisheries. If
given the proper flow balance, wetlands will remove eighty to
ninety percent of the incoming nitrogen. Microbes strip the
oxygen off of the nitrogen molecule and back to the atmosphere
goes nitrogen gas. Wetlands are great chemical reactors. They
will trap phosphorus and the herbicide atrazine, which causes
major problems in the corn growing areas of the U.S.
The benefits from wetlands come almost immediately. Within one year of restoring a series of wetlands on the Des Plaines River, we had endangered species living there. We had Yellow headed Blackbirds and Least Bittern, two state-designated endangered species, return to the site. Within a couple of years these wetlands were functioning at eighty to ninety percent of presettlement conditions.
ER: Are you encouraging beaver to take part in your project or are they volunteering?
DH: At the Des Plaines site they are volunteering. When we started the work, there were no beavers present. Today we have six to eight colonies within about a three mile stretch of river. It looks like quite a tribute to our design skill, but to be honest with you it was just dumb luck. We happened to make it attractive to beaver and the hydrology was just right. The beavers moved in and they have been there ever since, about ten years.
ER: You mentioned a park system. What would that look like? Are you thinking about connecting habitat, or is that necessary to have a functional wetland complex?
DH: What connects them all is the river. Collectively they could
be called the great Mississippi Wetlands National Park. They
could be isolated nodes along the river system that would provide
great recreational opportunities because you could boat from one
node to the next node. It would be ideal if there was a land
connection between wetlands, however, the road could zig and zag
to avoid towns and industries and recalcitrant farmers who want
to stay behind their levees.
First, we have to recognize the need to rebuild. There are very few natural wetlands left on the Mississippi River so it may take 100 years to do it. We would need to have a strategic plan and then pick off opportunities to keep adding to it when opportunities become available. If suddenly we run into a food crisis and we have to go back and plant some of these areas, well, we go back and plant them. Then another twenty years down the road, we take them back as wetlands again. In a sense we would let the land rejuvenate itself; let the carbon and the nutrients build up in the soil and then come back and use it again. I think once committed to a use, that land use shouldn't necessarily be forever and ever.
ER: The dynamic nature of a river says that we could go to a lot of trouble to put in a wetland and then the river moves and we might have farmland there again.
DH: Sure. That may be true. I think one needs to think about and talk about dynamic equilibrium. There are changes that are going to go on all the time. You are going to have a wetland here and then it is going to dry out and have something else for a while. We squander a lot of energy trying to maintain that stability. We don't need the stability at any rate, and we could make use of more dynamic systems if we just sit down and study and learn how to do it.
ER: It would be more intellectually gratifying than brute force anyway.
DH: It would. It would be a lot prettier too.
Hey, D.L. and Philippi, N.S. 1995 Flood Reduction through Wetland Restoration: The Upper Mississippi River Basin as a Case History. Restoration Ecology 3: 4-17
The Wetlands Initiative can be reached at
53 West Jackson Blvd. Suite 1015, Chicago, IL 60604
phone 312 922 0777
Copyright 1996 Environmental Review