College Creek in Ames is a prime example of an urban landscape where pollution can taint groundwater but citizen involvement can help mitigate the problem, researchers say.

A year's worth of research results were shared at the 2008 Ames Clean Water Festival on the banks of College Creek near Thackeray Drive Sunday and Monday.

Mimi Wagner, associate professor from Iowa State University's Landscape Architecture Department, and Bill Simpkins, professor of hydrology from ISU's Geological and Atmospheric Sciences Department, led about 60 people on Sunday afternoon's tour, explaining the effects of fertilizer run-off from neighborhood yards.

Also featured were efforts to reduce run-off effects including stream edge plantings on city property adjacent to the creek and storm water gardens installed by neighboring residents on Emerson Drive.

Rick Cruse, director of the Iowa Water Center, spoke to festival attendees while operating a groundwater flow model, a device constructed of layers of sand sandwiched between sheets of glass.

"This is how we demonstrate how groundwater and surface water are connected," he explained as green dye traveled through water from ground to stream in the model.

University researchers installed 12 monitoring wells along ground water flow paths between residential yards and College Creek last fall, to track levels of nitrogen and phosphorus entering the creek.

They also installed plantings of trees, shrubs, native grasses and wildflowers in an effort to filter surface water and reduce pollutants in the groundwater.

Simpkins said all the wells contained nitrogen concentrations exceeding federal drinking water standards as well as high phosphorus levels, with the biggest spikes occurring in the spring. He said while data did not show why, the assumption was that it was caused by residential fertilizer use.

While reduced nitrogen concentrations were shown in groundwater as it moved along one of the testing paths, Simpkins said data over following years would give a better picture of the effect of vegetation strips.

Although the vegetation strips and rain gardens were planted in an effort to intercept and use nitrogen and phosphorus before it reaches ground water, "the best prevention is not to let the stuff get into the groundwater in the first place," Simpkins said.

The researchers recommend using zero-phosphorus fertilizer and reduced amounts of fertilizer and lawn watering to reduce groundwater contamination.

The Ames Clean Water Festival was sponsored by the Iowa Water Center, the U.S. Geological Survey and ISU's departments of landscape architecture and geological and atmospheric studies.

Laura Millsaps can be reached at 232-2161, Ext. 342, or lmillsaps@amestrib.com.