EVE-LYNN SWAN The Standard
Over the past few years, large-scale farming has changed the look of the countryside. In this fourth article in a series, The Standard looks at the practice of burying plastic tubing in farm fields, known as tile drainage, to aid in surface water drainage.
Motorists capable of looking away from the road, while driving through rural areas of Durham Region and the City of Kawartha Lakes, may have noticed fresh, black lines of disturbed earth on the surface of farm fields. Spaced anywhere from 25 to 100 feet apart, the marks indicate a subsurface drainage system has been installed.
Aimed at removing excess surface water from the root zone as quickly as possible, and usually consisting of continuous plastic tubing, measuring about five inches across, the first systems buried consecutive pieces of four-inch round or horseshoe-shaped clay pipes, thus the name “tile drainage.”
Tile drainage systems are installed on poorly drained land, by licensed drainage contractors, and the practice itself is given considerable attention by the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). Considered a farming “Best Management Practice” (BMP), land is considered “improved” with drainage installed.
Durham Region seems to agree with OMAFRA. Currently reviewing its tree-cutting bylaw, the Region will allow farmers to cut as many trees as needed in order to install tile drainage systems.
Design considerations must account for the soil type, such as clay, sand, loam, and peat, and for topography, gravity, crop types, climate, and a place to send the drainage water, usually a ditch. Once these factors are considered, the depth, spacing, and pipe size can be calculated. All installations are mapped by the contractor and submitted to OMAFRA. However, a drainage system must have its outlets kept clear and the pipes kept free of tree roots, in order to prevent malfunction.
Farmers can apply to their municipality for a “tile loan,” featuring 10-year terms and annual repayments, and may be worth up to 75% of the project costs. The provincial government sets the interest rate, which is fixed for the full term of the loan. The municipality inspects the installation and then liaises between the landowner and OMAFRA, acting as the banker.
According to OMAFRA, “The benefits of tile drainage for crop productivity, farm efficiency, and even for reducing environmental impacts have been studied and are generally well known to farmers.” Crops don’t do well when they are under water and farm machinery can access the land sooner when it drains quickly. Expensive fertilizers and pesticides stay within reach of the roots when applied to dry land and are not as likely to migrate to wetlands and streams.
Conservation authorities, universities, environmental groups and farmer-led organizations have had the topic of nutrient loss and aquatic ecosystems in their sights for many years. One study, published in 1989 by Environment Ontario, made use of the early personal computers to record the impacts of tile drainage.
By 2009, more than 80% of some North American catchment basins may have been drained by tiles and surface ditches, said a study published in Critical Review in Environmental Science and Technology. The abstract noted, natural channels were being straightened and deepened, affecting aquatic habitat, connectivity, sediment dynamics and nutrient cycling.
An Associate Professor in University of Waterloo’s Geography and Environmental Management department, Merrin Macrae, supervises graduate students in subjects, including: agricultural water quality; agricultural tile drainage; and nutrients, revealing an ongoing interest in the subjects by the scientific community.
David Malcolm, who wrote a letter to The Standard expressing his concern about the changes to farm fields in Scugog Township, is clearly not alone in his concern about the negative effects of tile drainage on streams, lakes and wetlands.
With climate change and increasing population levels pressuring rural lands, “business as usual” needs a second look. Now, monitoring all kinds of activity can be seen as a best practice.
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