View from the Cab: A look at wetlands

By: Kent Casson

Visitors to a farm in Marshall County last week had the chance to see a wetland that is smart, hard working and good looking.

This wetland is loaded with vegetation and aims to remove phosphorus and nitrates from ag drainage tile water. A nearby prairie is in bloom with multiple species doing well despite the recent dry weather conditions.

What is a smart wetland? According to the website www.smartwetlands.farm, it is specifically designed to use naturally occurring processes to remove excess nutrients from tile drainage before it leaves cropland. The constructed wetland is considered smart because it is specifically sited, a measurable practice in terms of monitoring nutrient removal and a time-saving practice which can remove nutrients for over 30 years with little maintenance.

The website indicates this practice reduces the number of crop nutrients flowing into Illinois waterways followed by the Mississippi River and the Gulf of Mexico where they create was is known as the annual “dead zone.” Key components of a smart wetland include position, size and depth.

Inside a waterway or adjacent to an existing ditch are the best positions for a smart wetland. This allows for the capture of drain tile outflow. The size of a constructed wetland is based on a ratio as the wetland treatment area should be .5 to 5 percent of the tile drainage area being captured. This ensures a wetland’s capacity is big enough to remove nutrients effectively.

An ideal depth for a smart wetland is listed as 12 to 18 inches. Denitrification results from the shallow marsh ecosystem with emerging vegetation. This is the process which removes nitrates. The depth is good for removing nutrients but not quite deep enough for fish.

Wetlands are described as the presence of water, hydrophytic plans and hydric soils. The ecosystems provide many direct and indirect benefits such as biodiversity, wildlife habitat, flood storage, water quality improvements and groundwater recharge. All wetlands can improve the quality of water – whether they are natural, restored or constructed.

If you feel a smart wetland could be the right fit for your farm, request a consultation by visiting www.smartwetlands.farm. This is a program of The Wetlands Initiative.

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