The New York State Department of Environmental Conservation determined that Chautauqua Lake posed serious health risks to humans due to nutrient pollution and algal blooms. It required phosphorus loads from developed land into the lake be reduced by 46%.
Recognizing the problem, the Chautauqua Institution introduced three green infrastructure practices—stream stabilization, constructed wetlands and stream daylighting—to treat and capture water on its property. Scott Rybarczyk, project engineer for Wendel, the project designer, said the stream stabilization visibly reduced sediment and nutrient flows into the lake while the artificial wetlands constructed on a nearby golf course cut down on phosphorus loads. Stream daylighting was a more taxing problem.
“Daylighting is tricky in that flat grades are needed for bioswales,” Rybarczyk said. “The general slope of the existing park is over 5%, so grading was required to provide flat grades for these green infrastructure elements. Similarly, the team had to make sure not to have too steep a slope, because that could erode some of the planting areas.”
The daylighting served to filter runoff with the help of the bioswales. After some deliberation, another element to address the volume of water to be treated was added.
“It was determined that a forebay, an artificial pool of water in front of a larger body of water, and three bioswales, landscape elements designed to remove silt and pollution from the surface runoff water, would maximize the water quality volume treated,” Rybarczyk said.
The design of the wetland took the golf course operations into consideration and avoided problems with a nearby state highway.
Despite the difficulties, the project saw a considerable difference in the quality of Chautauqua Lake, and private citizens neighboring the property already have committed to building rain gardens to further help the watershed.