Something that may be surprising to many people is that much of the states of Indiana, Ohio and Michigan are covered in a vast web of subterranean drainage plumbing, or drain tile. If it was visible, ironically, it could hardly be believed.
There is a reason for this, and like many things agricultural, it has to do with the glaciers. The thinking goes that the glaciers compacted the soil beneath them like a giant bulldozer would, and we call such soil “dense till.” The high density and high clay percentage of the soil makes for poor subterranean drainage. This means the soil “lays wet” following rainfall, which means that roots the roots of most plants do not get enough oxygen, and so do poorly. Certain plants have adaptations that help them cope with this, and these plants come to dominate in these wettish areas (Reed Canarygrass and Alsike Clover are the only farm plants I know of that have such adaptations). Because the most favored farm plants need good drainage, for example, Alfalfa, farmers view wet soil as an enemy. In fact, the legal principle employed in the State of Indiana to resolve disputes among neighbors regarding draining and waterways is called the “common enemy doctrine.”
There are really only a few practical ways to “solve” the wet soil problem. One is to just ignore it and develop farming systems that can handle it. Use Reed Canarygrass and Alsike Clover in a hayfield setting, for example. Or dig a bunch of ponds and make it into a stocking fish farm. Or raise ducks, crawfish, etc. Or start a Overcup Oak pole-wood farm. But this is not satisfactory in many ways.
The other way to “solve” the problem is altering the drainage to our liking. You can dig ditches that carry away excess water to some place, or you can dig trenches and fill them with perforated pipe (called drain tile) then cover them up, and this is called subsurface drainage, which has the great advantage of not needing little bridges all over your place to drive/walk over. It can also be farmed over and doesn’t become a harbor for pests and weeds like ditches can. Old tiles were made of clay and put together in sections. The joints leaked a little and this is what admitted water into the tile. Since the tiles are large diameter, they don’t really suffer freezing if above the frost line. Water should rarely, if ever, completely fill the cavity. Modern tiles are made of flexible plastic pipe with little slits cut in the sides to admit water into the pipe but mostly hold back soil. Soil that does squeeze in can accumulate and eventually plug a tile, but if there is enough downward slope, the water in the pipe should mostly carry the soil away. Even the old clay tiles put in 100+ years ago are mostly still working on my place but occasionally one gets broken or plugged.
In this case, the track loader that dug my pond collapsed a tile, and it backed up, and created a huge wet mess in my garden area. This would not do. So I waited for a mini-drought, which we usually get, when the water table naturally receded below the 2 feet where the tile broke, and I connected a new length of tile to the broken tile to take the offending water away. I rented a trencher to do this, which I learned is the way to go, since I’ve always done this by hand with a shovel before. The trencher did in about one hour what would have taken weeks by hand. And it did a better job. Not perfect of course, and the shovel was still needed to do final adjustments, but well worth the $75 rental and the couple gallons of gasoline.
In many ways, though, I think tiling is misguided however. Sort of like tillage. It can be appropriate, but when applied on a massive scale or in places it really doesn’t need to be, it simply offsets the “water problem” somewhere else. The clearest example of this is Lake Erie.
Once there was an enormous swampland that extended from what today is Toledo, OH to roughly Ft. Wayne, IN. The landmass of the swamp was roughly the size of the state of Massachusetts. When the Ohio Buckeye Tiling Machine was invented, which was basically a steam powered tractor with a bucketwheel attached to it, people sort of went crazy and drained, almost entirely, the Great Black Swamp. What took monks centuries to do by hand in England was accomplished in decades in the USA with the help of steam power. And the Great Black Swamp became some of the richest farmland (after liming a bit) in the world because of it, as swamps often do once drained, since they contain large amounts of organic residue.
But there were consequences. The drainage system was so extensive and massive it basically altered the continental divide in the area. Water that once flowed into watersheds to the South (and therefore ultimately to the Gulf of Mexico) now flowed towards Lake Erie, and water that once stayed put in the swampland was now being sent away to Lake Erie. Every year there is an massive algal bloom that occurs near Toledo in Lake Erie due to all the fertilizer residues that now flow into it. The only solution to this problem, ultimately, is to stop sending water that way and stop overusing soluble fertilizers, as no one yet is proposing a giant drain tile going to the Atlantic ocean.
This is why I think tiling should be generally avoided. Ultimately you are just sending “the problem” somewhere else. And it is why I think more creative ways need to be developed for dealing with excess water. I think the most obvious and compelling is digging ponds. Though it might seem silly, putting a small pond in every couple acres or so of overly wet farmland would not only keep the water on the farm for when it is needed, but also not shunt the water off the farm where it becomes a problem for someone else. We have the digging equipment today. As anyone who has traveled through Eastern Kentucky or West Virginia knows, we can move mountains if the will is there, so we could put ponds in, too.
I also think building controlled wetlands could work, and there are a surprising number of wild water-adapted plants that could be domesticated. In the South, the Water Hyacinth seems like a compelling candidate. Cattle eat it, and cattle love water. Perhaps it could be worked out feeding cattle mainly on Water Hyacinth. The example of using phragmite reeds to feed cattle is already well known in more Temperate climates. Fish farming, like that of South East Asia, could be modified and implemented here, perhaps, and there was considerable effort put into this back in the 70s and 80s.