Constructed Wetlands Offer Cost Effective Water Quality Solutions

By Andi Anderson

Constructed wetlands are becoming a popular conservation method among farmers to improve water quality. These wetlands are specifically designed to intercept tile drainage water and filter out excess nutrients, especially nitrate-nitrogen.

Included in Illinois’ Nutrient Loss Reduction Strategy (NLRS), this edge-of-field practice helps reduce water pollution while also creating habitats for wildlife.

There are two main types of wetlands—restored and constructed. A restored wetland is built on land that was once a natural wetland but was drained or modified for farming or other uses.

Its goal is to bring back the original wetland function and native plants. On the other hand, a constructed wetland is engineered on land that was not originally a wetland. It mimics natural wetlands and is usually built near tile drainage systems to filter water before it reaches streams or rivers.

These wetlands are especially effective in filtering tile-drained water from 30 to 200 acres. While plants in the wetland help absorb some nitrates, most of the work is done by microorganisms.

These tiny organisms convert nitrate into nitrogen gas, removing it from the water. If designed properly, constructed wetlands can remove 50% to 90% of nitrate-nitrogen from the water.

Farmer Rex Newton from Marshall County, Illinois, has used this method successfully. His 2.8-acre wetland not only filters water but also supports pollinators and local wildlife, including Monarch butterflies. He appreciates the low maintenance and is eager to see ongoing monitoring results that measure the nitrate levels entering and leaving the wetland.

Newton encourages other farmers to consider this approach, especially if they have support from conservation-minded landowners. He also advises patience, as while some construction is quick, plant growth takes time.

Overall, constructed wetlands are a sustainable, cost-effective tool for improving water quality and supporting biodiversity.

Photo Credit: gettyimages-shotbydave