A healthy headwater wetland acts like a sponge, taking in water from surrounding land and holding it while it filters out nutrients and other impurities before eventually releasing cleaner water downstream.
In a Mississippi-Alabama Sea Grant-funded project, Auburn University’s Chris Anderson is looking at nutrient retention at various headwater wetlands in Baldwin County, Alabama, to discover exactly how much of this naturally occurring filtration process is lost to over-development and excessive urban drainage.
Storm drains in developed areas frequently empty into the nearest wetland where they bring in a higher volume of water than comes in naturally during rain events. The speed and volume at which the water enters the wetland can cause deep, fast-moving streams to form, which reduces water storage and causes the surrounding wetland soils to dry up.
Now the microbes that live in the wetland soil no longer have the time and exposure they need to filter out the nutrients.
Anderson expects this study will provide some insight to city planners about the important ecological function of healthy wetlands. “It’s impossible to keep it pristine, but we could still keep it functional with the right planning,” he said.
*Tara Skelton is a freelance writer in Ocean Springs, Miss.*