The Circle, by Hoerr Schaudt Landscape Architects, is a roundabout intersection / park that uses filtration bogs, ultra violet sanitizers, and a structural cell system to collect, filter and reuse water. The system also makes use of an abandoned underground storm-sewer that was retrofitted into a 76,000- gallon holding tank to store water in peak events. After the system collects and cleans water, it then feeds it back to the site (in the form of a fountain) and helps irrigate the landscape features of adjacent streets. This project — sited in Normal, Illinois — is the center piece of the new district’s redevelopment agenda to revitalize its downtown…
In a recent review in The Architect’s Newspaper, Jennifer K. Gorsche elaborates that “the surrounding LEED-certified buildings will also fall under Uptown District requirements that any new construction over 7,500 square feet adopt minimum LEED standards, the first ordinance of its kind in the country.” In this way the project serves as an epicenter generating positive ripples effects for the benefit of future sustainable projects in its vicinity. In addition to the project’s innovative water management benefits, it also serves to reduce traffic accidents according to Federal Highway Administration.
The green space includes 12 London Plane trees and a 56-foot sloped lawn encircled by streetscape elements to allow foot traffic and other passive recreation uses. In an article in ASLA’s The Dirt, Hoerr Schaudt explains the process and features of the stormwater management system embedded in the new roundabout:
1. Water goes through a filter that traps excess debris.
2. The water is filtered, then travels through an ultra violet sanitizer.
3. 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.
4. 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.
5. Like ancient Roman aqueducts, the water then then uses gravity to move through four bog pools where it eventually terminates into the fountain turbulance pool.
In sum the Circle adds valuable community green space in the middle of the roundabout, cleans and irrigates stormwater into neighboring streets and improves the five-street intersection’s traffic circulation. Recently this project received a TIGER grant from the U.S. Department of Transportation.