Filter Island


Project by UrbanLab.


In the 1909 Plan of Chicago, Daniel Burnham hybridized infrastructure and public amenity when he proposed combining roadways, railroads, and harbors with a continuous landscape of park and public buildings along Chicago’s lakefront. A decade before, Chicago’s engineers reversed the flow of the Chicago River away from Lake Michigan to prevent the river’s pollution from contaminating the lake. Today, Chicago faces new challenges. Because the Chicago River acts as an overflow for the city’s sewer system, raw sewage overflows into Lake Michigan every time there is a severe rainstorm.

It’s time to redesign the river. Our project—Filter Island—springs from Chicago’s legacy of leveraging infrastructural improvements to create new civic space. The first step is to dam the Chicago River and remove the existing lock system. Because the river will once again flow into the lake, a new infrastructure is needed to remove pollutants.

Filter Island cleans the new Chicago River by filtering pollutants in a series of large-scale biocells. Polluted water flows from the river into Filter Island over a shallow waterfall at the northern edge of the new island. Through a series of wetlands and biopools, polluted water is cleaned of contaminates before being discharged into the lake. The ratio of water cleansing landscape to park program landscape flips as the park extends southward. Park programs range from wetlands, marshes, and fields to swimming pools, water parks, sports fields, and playgrounds. The whole island is wrapped in beaches and breakwaters. A new dry-dock transfer exchange accommodates boat traffic between the river and the lake.

In keeping with Burnham’s legacy, Filter Island is a hybridized landscape, combining infrastructure with cultural space.


Sarah Dunn + Martin Felsen with Jeffrey Macias, Matthew Busscher, Matthew Schneider, Aishwarya Keshav, Anya Nair, Austin Tsai, and Michelangelo La Tona.


Illinois Institute of Technology, University of Illinois at Chicago, and the Chicago Architecture Foundation.