Cleaning water and controlling flooding with wetlands.

Constructed wetlands in planned communities can aid in surface-water cleanup and flood prevention, according to Purdue University scientists who have completed a five-year study on the management system.

The research, begun in 1998 on three constructed ponds, or wetland cells, on a newly renovated golf course on the university campus, showed that 11 of 17 measurable chemicals in surface water were reduced after water was run through the system, said Ron Turco, soil microbiologist and senior author of the report. The results of the study are published in the February 2005 issue of Ecological Engineering.

"Golf courses are a perfect place for constructed wetlands used as part of a water management system, because wetlands can filter chemicals out of surface water, and they can also store excess water during storms," Turco said.

In addition, constructed wetlands act as a holding area that can provide recycled water for irrigation, a system the scientists used on the golf course, he said.

Constructed wetlands can also be a very good water management system in planned communities. "When you build houses, roads, and driveways," Turco said, "lots of hard surface is added, leaving no place for water to go. Building dikes and levees just moves the water problem somewhere else, causing flooding elsewhere."

The wetlands also are of aesthetic value on golf courses and in residential areas, and they create homes for wildlife and flora, Turco said. Using the recycled water for irrigation ensures that the wetlands remain wet, and the recycled surface water is less expensive than pumped groundwater.

The researchers evaluated a three-pond system on Purdue's Pete Dye-designed Kampen Golf Course. The almost 11,000 water plants placed in the ponds were responsible, along with microbes, for retaining or degrading the various chemicals associated with surrounding urban sprawl and the course itself. Chemicals found in water entering the system included atrazine, chloride, nitrate, ammonia, nitrogen, organic carbon, phosphorus, aluminum, iron, potassium, and manganese. In all, 83 chemicals were monitored, though only 17 were present in measurable amounts.

Four water quality monitors located along the wetland system checked for chemical levels. The first monitor was at the golf course's east end where surface water enters the course. The fourth monitor was at the northwest end, where water leaves the course and enters the celery bog.

The scientists also measured how much water entered and how fast it flowed through the system, and then compared data taken during both storm and nonstorm days.

It's important to design wetlands so they have enough capacity to handle the runoff in the particular water management area, Turco said. The speed of the water flow and the depths of the ponds must vary to ensure that the microbes remain active so that they can degrade contaminants.

Currently the scientists are planning new constructed-wetlands studies in other venues. In addition to Turco, they are Eric A. Kohler and Zac Reicher, both of the Department of Agronomy, and Vickie L. Poole, of the Department of Forestry and Natural Resources. The United States Golf Association, the Indiana Water Resources Research Center, and U.S. Environmental Protection Agency (U.S. EPA) Region 5 provided funding for the study.