Urban watershed restoration: Use attainability analysis for the Chicago Area Waterway System

The Illinois Environmental Protection Agency (IEPA) has conducted a Use Attainability Analysis (UAA) for the Chicago Area Waterway System (CAWS).  The primary focus of the UAA was on Calumet and Chicago River basin waterway reaches currently classified in Illinois Code as Secondary Contact and Indigenous Aquatic Life, excluding the reach of the Lower Des Plaines River currently being evaluated through a separate UAA. 
The Chicago Sanitary and Ship Canal, the Calumet-Sag Channel and the North Shore Channel are artificial waterways constructed about 100 years ago to facilitate navigation and to protect Lake Michigan from the wastes of a growing Chicago.  The Little Calumet River North Leg, the Chicago River, the South Branch of the Chicago River and the North Branch of the Chicago River downstream of its confluence with the North Shore Channel are natural rivers that have been extensively modified through deepening, widening and channelizing, and their flow direction is reverse of what it was before the artificial channels were constructed; the Chicago and Calumet Rivers flow away from Lake Michigan toward Lockport and into the Des Plaines River.  Most of CAWS’s flow is dominated by treated wastewater from 5 million Cook County residents and an additional industrial load of approximately 4.5 million population equivalents.
The purpose of the UAA was to determine if other use classifications are more appropriate for CAWS or any portion thereof.  Stakeholder involvement was critical to defining how the waterways where designated based upon existing uses, and identifying the water quality standards to protect those uses (aquatic and recreational). The study entailed an extensive review of benthic, fisheries, water quality and sediment data for the Chicago Area Waterways.
Based upon the review and evaluation of the chemical, physical, biological and waterway use data for CAWS, five use designation sub-categories are being proposed to protect aquatic life and recreational uses in CAWS.  The recreational and aquatic life use sub-categories and the applicable water quality standards for CAWS include the following beneficial uses:  General Warm-Water Aquatic Life, Modified Warm-Water Aquatic Life, Limited Warm-water Aquatic Life, Limited Contact Recreation and Recreational Navigation. These new sub-category use designations have been presented to the Illinois Pollution Control Board for review, approval and adoption.  Once these new use designations are in place, then appropriate management strategies for the waterways need to be implemented to protect the water quality and recreational uses.  This will require modifications to existing wastewater reclamation plants, applying best available technology to improve instream water quality, applying new pretreatment standards for selected metals and interacting closely with governmental agencies, communities and the public to achieve the water quality goals for the Chicago area waterways.