Floods are natural phenomena, but natural landscapes can reduce both the severity of floods and the enormous damage they cause. This damage is estimated at roughly $40 million per year, on average, in the Chicago region.
Some floods happen in part because of the way people have constructed cities and suburbs. Impervious surfaces such as roads, parking lots and rooftops funnel water rapidly into rivers and streams. That means that during a heavy rain, water levels rise quickly, and sometimes cause floods. In contrast, natural areas allow much of the rainwater to sink into the ground and they hold water so that it flows more gradually through the soil and across the land. The result is a smaller amount of water reaching rivers and streams at a slower rate, and a lower risk of flooding.
Natural landscapes are far better than turf lawns at absorbing and slowing storm water. Turf grass lawns have short root systems that only go four to six inches into the ground. Native plants have root systems that can extend three to 10 feet underground. The longer roots help water penetrate deeper into the soil, reducing the amount of water that flows off the landscape. This not only reduces flood flows, but also helps replenish groundwater supplies and reduce future drinking water shortages.
Natural features such as ponds or swales also help slow the movement of water and improve absorption. In contract to turf lawns, natural landscapes are also beneficial because they do not require irrigation, so they save water, effort, and money.
According to a Northeastern Illinois Planning Commission study, natural landscaping can reduce the volume of storm runoff from a residential development by as much as 65 percent. Some municipalities, businesses and homeowners in the Chicago region are already using natural landscaping techniques to manage storm water, provide wildlife habitat, improve water quality, save money, and create attractive places to live and work. The Chicago Wilderness coalition promotes natural landscaping through the Chicago Wilderness Metropolitan Landscaping Initiative. To learn more about natural landscaping projects in your community, contact Stephanie Folk at (708) 485-0263, ext. 560.
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