Ohio Department of Natural Resources
Creating, Restoring, and Enhancing Wetlands
The Ohio Department of Natural Resources’ (ODNR) H2Ohio projects are focused on creating, restoring, and enhancing wetlands around Ohio.
In the News
Why We Need Wetlands: Runoff, Nutrients, and Phosphorus
Rain and snow events deliver water to the landscape surface. Some of this water is absorbed by plants, recharges groundwater sources or is lost to evaporation. Excess water runs off the landscape transporting sediments and nutrients to lakes and streams. This is runoff. Runoff is a natural process but over-fertilization of the landscape in urban and rural areas causes these waters to contain too many nutrients.
Fertilizers are tools used to encourage plant growth in lawns, gardens, and agriculture. Most fertilizers consist of nitrogen, phosphorus, and potassium which are three key nutrients for the growth of plants. Application of these nutrients can make our lawns greener and fields more productive, but some fertilizer often remains leftover in the soil. Thus, runoff from heavy rainfall events often moves this remaining fertilizer to our lakes and streams. These excess nutrients fuel the growth of algae in Ohio’s water bodies. Algal blooms can be unsightly, a nuisance and harmful.
Wetlands are a natural landscape feature that can help capture excess sediments and nutrients to reduce algal blooms.
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Wetlands have been called “nature’s kidneys” because of their ability to filter impurities and nutrients from the water. Wetlands also can trap sediment and help process nutrients from runoff.
How Do Wetlands Filter Water?
Wetlands offer a natural filtering process and help to achieve water quality goals in several ways:
Slow the flow
Wetlands slow the flow of water to allow nutrient-laden sediment to settle and help prevent further movement of contaminants
process and remove
Wetlands process and remove nutrients and other contaminants, helping to prevent their flow further down the waterway
Absorb and Hold
Soil can absorb and hold phosphorus and other nutrients, trapping them on the landscape and preventing them from moving further downstream
Visualizing Phosphorus Retention in Wetlands
The point at which a wetland becomes overloaded and can no longer retain additional phosphorus is called the wetland’s phosphorus retention capacity.
Explore the video to see how phosphorus moves through a coastal wetland at different rainfall events.
Wetlands: The Bottom Line
Research has proven that wetlands can be one of the most effective and cost-efficient ways to significantly improve water quality by preventing the flow of excess nutrients into our waterways and lakes where they provide fuel for algal blooms.
Wetlands are also critical habitat for a wide variety of wildlife and offer some of the best bird watching locations in Ohio, such as Magee Marsh along Lake Erie. The National Park Service estimates wetlands provide a home to at least one-third of all threatened and endangered species.