Roundabout Like Roman Aquaducts

The new green space offered in the middle of the roundabout also adds valuable community space. The center lawn is somewhat insulated from car noise. ''The natural sounds of the flowing water help to mitigate the sounds of ongoing traffic.'' Image courtesy of Hoerr Schaudt

In Uptown Normal, Illinois, Hoerr Schaudt Landscape Architects completed work on The Circle, a multi-functional, sustainable roundabout that cleanses and re-circulates stormwater into a public fountain, improves traffic circulation at a busy five-street intersection, and provides community green space. The site's stormwater management system features innovative elements like filtration bogs, ultra violet sanitizers, and a ''structural cell system.'' The Circle plaza sits adjacent to the town's planned multi-modal transportation center, which will connect residents to bus, train, or bike routes. The plaza and center received a U.S. Department of Transportation TIGER grant.

Peter Schaudt, partner of Hoerr Schaudt, said: ''The heart of Normal's new downtown is a model of environmental awareness that addresses two key challenges in American urbanism today: responsible use of water and a reduced dependence on automobiles. We will see the need for spaces that combine creative infrastructure with public space increase dramatically in the next decade.''

The new roundabout features a stormwater management system that uses bog plants and ultra violet sanitizers to cleanse and recycle water. Hoerr Schaudt explains the process:

• Water goes through a filter that traps excess debris.
• The water is filtered, then travels through an ultra violet sanitizer.
• Ultra violet light energy helps destroy micro organisms without using harmful chemicals that create a ''dead zone'' which can be toxic to humans and animals.
• The water is pumped up through the ''bog'' plants that will also help to clean the water by filtering excess sediments and absorb remaining toxins in the water.
• Like ancient Roman aquaducts, the water then uses gravity to move through four bog pools where it eventually terminates into the fountain turbulence pool, creating a water feature for the community to enjoy.

While the water isn't drinkable, park visitors can dip their feet in the fountain. Excess runoff not captured by this system is funneled to a 76,000-gallon underground cistern, created from abandoned underground storm sewer infrastructure. Water in the cistern will be used to irrigate the surrounding street trees.

The new roundabout should reduce traffic accidents. According to Federal Highway Administration (FHA), installing roundabouts results in: 90 percent reduction in fatalities; 76 percent reduction in injury accidents; 75 percent fewer pedestrian and vehicular conflict points; and reduction in overall pedestrian injury. Hoerr Schmidt says roundabouts also help reduce idling, which in turn helps lower local air pollution.

Source: The Dirt