There's been very heavy rain here, and the Mississippi was very high.
A hundred and fifty years ago, the settlers who came out here found a number of shallow prairie lakes covering up some of the soil. Thinking it wasteful not to use all of the extremely fertile soil in crop production, they constructed a system of pipes called "tile" several feet underground to drain off the excess water to rivers. Later, county governments built larger conduits to connect the patchwork of tile, and today most of the farmland in Iowa and Illinois is underlaid with it. It carries rainfall swiftly to rivers feeding the Mississippi before lakes can form.
Iowa soil is remarkable in more ways than one. Not only is it extremely fertile, it works as an excellent natural water filter. Farm chemicals -- nitrates, in particular -- are filtered out by the soil as the rain slowly leaches down to groundwater aquifers far below. However, tile interrupts this natural leaching process by carrying water directly to rivers, still carrying heavy concentrations of nitrates.
The city of Des Moines is downstream from the vast area of farmland underlaid by tile that drains to the Raccoon River. Des Moines, which gets its water from the Raccoon, is a very small city by world standards, yet the water works there has the most sophisticated nitrate-filtering system in the world. They remove literally tons of nitrates each year from the water to make it drinkable. Farther downstream, the Raccoon drains to the Mississippi, which eventually empties into the Gulf of Mexico, into a vast "dead zone" where fish can't live because the concentration of nitrates is too high. Experts estimate that 70% of the nitrates in the dead zone come from agricultural runoff from Iowa and Illinois. Runoff from states such as Nebraska, where tile isn't used because lower precipitation and a different, faster-draining soil type make tile unnecessary, contributes very little to the dead zone, even though nitrate-heavy farm chemicals are used there as well.
The settlers who put in the tile knew nothing of its environmental consequences, and they needed all the help they could get to increase production. It's partly due to their efforts to waste no soil that Iowa and Illinois are today the #1 and #2 corn-producing states in the nation, respectively. No one ever talks about how some of the tradeoffs for being number one are an increased risk of flash floods due to the fast drainage that tile affords, the high cost to taxpayers to keep water drinkable, and an ecological disaster in the Gulf of Mexico. Unlike, say, a large-scale hog confinement operation that everyone has to see and smell, tile is invisible except for the odd pipe sticking out here and there, and the eerie way the low-lying areas of fields can be covered with water one day and completely dry a day later. Water collects in the same places that used to be lakes, but quickly disappears before damage is done to the crops.
It would be easy to reverse the effect of tile -- we wouldn't have to remove the pipes, just break them in strategic places. This would probably cause lakes to reform permanently. It's unlikely that this will ever happen, though, because of the land that would have to be taken out of production. Never mind that the world corn market is often glutted, that the federal government has to artificially raise prices to keep farmers afloat and has occasionally resorted to paying some farmers to take dry land out of production in an effort to keep prices from getting lower. Never mind that shallow, wide lakes are another terrific natural water filter that allow nitrates to dissipate into the air, instead of staying in the water supply so they have to be filtered out downriver at great expense to taxpayers. I guess nothing is worth losing our coveted top spot.
If this system has any hope of sustaining itself, we're going to have to start asking an important question: "At what cost?" I'm not just talking about corn production in Iowa and Illinois, I'm talking about our entire food production and distribution system in this country. At what cost is American food so cheap compared to most of the rest of the world? There are hidden costs everywhere, and someone always pays. For instance, why is that prepackaged steak you buy at the grocery store so cheap? Maybe because the meat packing giant whose plant it comes from has cut costs by not providing its employees health insurance, so that when their highly dangerous jobs eventually send a disproportionate number of them to the emergency room with severed fingers or worse, taxpayers like you are footing the bill, so you didn't really save on the steak after all, plus someone's life got screwed up.