Guest Column: Promoting the good
Critics assail modernization of agricultural drainage systems.
May 2, 2018 By Warren Formo
Few innovations have contributed as much to the rise of agricultural productivity across the Northern Great Plains as the ability to remove excess water. Drainage, through a combination of underground tile and ditches, has made development for crop production, urban growth and transportation possible in conditions where it would not otherwise be feasible.
Much of our oldest drainage infrastructure needs repair. In addition, modern technology, coupled with advances in water quality research, has introduced changes in drainage design and layout that improve crop productivity and address environmental concerns. In my view, one of the biggest environmental success stories of the past quarter century is simply the practice of installing tile drains to follow field contours, often referred to as pattern tiling.
Unfortunately, critics of pattern tiling use the visual of rolls of plastic pipe to raise alarms about alleged loss of wetlands, increased downstream flooding and water pollution. These concerns have become the key talking points of those calling for even more regulation of drainage, usually relying on a combination of inaccurate, incomplete and conflicting information.
The fact is, drainage is highly regulated already, and the chief objective of current regulations is to prevent wetland loss. In Minnesota, state wetland regulations require review of drainage projects by a drainage authority, usually the county or watershed district, as outlined by the Wetland Conservation Act. Only after it is determined that there are no wetland impacts, or that any unavoidable wetland impacts are being mitigated through the creation of replacement wetlands, is the project allowed to proceed. As many as seven different federal and state agencies are involved in this process. Statistics available from state agencies show that the primary goal of the Act is being achieved, as wetland area is increasing in Minnesota, not decreasing, as is often claimed by drainage critics.
Peak flows and water quality are more complicated issues. Anecdotally, critics attempt to connect rapid jumps in water level following large rains to tile drainage, without noting that these jumps are largely driven by surface runoff, which is conveyed in the same channels as tile drainage but flow virtually without limits. In short, it takes rain to make floods. One can easily find numerous examples of drainage projects coupling modest storage basins with more underground tile that actually reduce peak flows.
State regulators also recognize the value of storing water in soils to reduce peak flows and help reduce sediment and nutrient pollution. This realization has moved them to join the soil health discussion, which is a good thing, but they have not yet widely credited the value of tiling in improving soil health.
Healthy soils contain both water and oxygen. Many of our most productive soils do not have the ability to drain naturally, starving the microorganisms in the soil of oxygen. This in turn affects nutrient cycling in the soil and can reduce crop productivity, which is important in returning organic matter to the soil to continue the cycle. Yields continue to set records due to many factors including better genetics, improved nutrient application practices, and improved drainage design that contributes to improved soil health.
Beyond soil health, drainage has many benefits, but these aren’t communicated as often as they should be. The entire agricultural community – farmers, land improvement contractors and conservation authorities included – has a role in fixing this. I encourage you to promote productive discussions about drainage practices when given the opportunity.
Warren Formo is the executive director of the Minnesota Agricultural Water Resource Center, a coalition of agricultural organizations formed to help farmers evaluate and address water resource concerns.
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