Tiling is good for farmers’ land, but bad for water supplies

By Marv Rops

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As a consulting engineer, I have designed wells in the Jordan and Siberian aquifers and shallower wells in unconsolidated formations, all for various Iowa municipalities. At that time, the Iowa and U.S. Geological Surveys in Iowa City provided the information that made an intelligent design possible. We required that the well contractor collect and deliver formation samples and a drillers log to the Geological Survey as a payback for their help.

It is my opinion that present agricultural practices adversely affect the recharge of our aquifers. Agricultural land is too compacted and has too little crop residue on it for too many months of the year. This causes rainfall to run off too quickly and at a higher percentage.

The rainfall that does penetrate the surface barrier and start toward replenishing the groundwater aquifer encounters a second ag-related barrier: ever-increasing miles of field tiles that collect and conduct still more of it to a surface outlet and away from the aquifer. The field tiles' purpose is to keep the water content in the plant root zone “just right” for root growth.

Just right for root growth is not right for aquifer recharging.

Ethanol fuel and byproducts reportedly use up to 40 percent of the U.S. corn crop. The 45 cents per gallon subsidy has expired but there remains an increasing-use mandate. Most consumers don't like the mandated use of any product. They prefer an unsubsidized competition that promotes use of the most cost-efficient fuel.

It is reported that ethanol production requires the use of a lot of water. Farmers could put back the water that it takes for ethanol production by farming in ways that promote the recharge of our aquifers.

It is inequitable and unequal that construction on a quarter-acre residential lot requires erosion and runoff control but a farmer can operate on hundreds of acres every year with few restrictions. Two-thirds of my residential lot does not have rainfall runoff, yet the city charges a 15-cent-per-day storm damage fee. That fee is equivalent to $548 per acre per year. I don't object to the fee, but wonder what runoff fees (if any) farmland owners pay. Perhaps fees should be based more upon land area and less on spending. It might be palatable and passable.

A recent article in “The Iowan” about watersheds upstream from Des Moines promoted a “residue matters” campaign and discusses mandatory no-till farming on 5 percent or greater slopes. If mandatory solutions sound threatening to farmers, then they should voluntarily step forward while there is still an opportunity to work out a better solution than some bureaucratic, government mandated solution will provide.

Marv Rops of Cedar Rapids is a retired consulting civil engineer. Comments: (319) 362-4695