Draining the land goes on

Staff Writer
Story City Herald

Naturally Speaking

—by Steve Lekwa

Most of the land that is currently farmed in Iowa was already under the plow 100 years ago. The land that wasn’t being farmed was, for the most part, either too steep or composed of thousands of small ponds too wet to plow in most years and too difficult to drain. Drainage work to make prairie pothole country easier and more efficient to farm began with little more than shovels late in the 1800s. Digging drainage ditches and hand-trenching in the first little three-inch clay tile lines was back-breaking labor. Many of the wet spots had to wait until more mechanized forms of drainage became available after World War 1. Fields were small then, though. A big one might be 40 acres. Crops were planted, cultivated, and often times harvested one or, at most, two rows at a time. It wasn’t too hard to work around the wet spots. They even had some value. Coarse slough grass grew around them, and it was useful as a thatch covering for loose hay stacks that were still a fairly common method of storing hay that every farm needed because they all had livestock.

Mechanized drainage began to appear with steam and then gasoline powered equipment. It continues to evolve yet today. The tiling spade of old is an almost forgotten artifact as are the kiln-fired clay tiles that required a man to hand-set each one in a trench that had been carefully surveyed to assure that water would flow. Many of those old clay tile lines are still functioning today, but even well-fired tiles eventually weaken and have to be replaced. Some of the lines have slowly clogged with silt, and no longer fulfill their intended purpose. The need for efficient drainage has increased over the years, too. Farms and fields have grown ever larger and it’s no longer easy or efficient to farm around the wet spots. Single farmers may now be planting and harvesting hundreds to even thousands of acres. It’s a serious problem when all those acres have to be dealt with, and parts of some fields are too wet to work for days or even weeks at a time. The likelihood of significant heavy rainfall and prolonged wet spells has increased over the past century, too.

Today’s drainage tiles are made of plastic and come in huge rolls. They’re increasingly installed by equipment that is GPS and laser-guided to insure that every foot of the new installation drains smoothly. Humans seldom have to touch the tile as it unrolls into trenches or is plowed directly into fields. Tile lines of past years tended to drain only the wet spots. The latest trend is a process called pattern tiling where entire fields are drained by evenly spaced tile lines that are installed at much closer intervals than the old clay tiles. The result is fields that are very efficiently drained of excess water. These upgraded systems allow more of the farm to be planted and harvested on time with fewer spots drowned out even after heavy rains and prolonged wet spells.

All of this sounds like progress, and it certainly is when viewed entirely from a production agriculture standpoint. It comes with a price, though, as altering nature usually does. Even as individual farms and fields are improved for crop production, the natural drainage systems that must accept all that artificial drainage become more and more burdened. Rivers and streams ultimately must carry away whatever precipitation the soil can’t hold, and with each newly upgraded drainage system, the excess water gets to them faster. It once took days, weeks, or even months for excess water to enter streams as slow surface runoff or seepage through the soil as ground water. Precipitation now begins arriving in streams in only a few hours, and entire fields can be ready to work again only a few days after a big storm. Expanding and improved drainage from growing cities adds to the runoff, as well, unless extra effort is made to provide enough storm water retention.

The cost of constantly increased drainage of the land includes rapidly eroding stream banks and deepening of stream beds. This, in turn, leads to the need for expensive rip-rap armoring at bridges and culverts. Stream bed habitat is destroyed. Flooding becomes more frequent and flood crests continue to rise. Material eroded by heavy stream flows ends up clogging lakes and even the Mississippi River. An old joke from the Mississippi Delta asks “what do you call your land?” The answer is “Iowa”.

I’m not sure where the eventual balance point lies. Modern farms depend on efficient drainage just as cities (including the lot I live on) do, but the damage done by ever-increasing drainage loads on our waterways continues to mount. Your land and the place you live may be safely high and dry, but we all share in the cost of constantly improving drainage.