TMDL Report for West Branch Dupage River
Final Report Total Maximum Daily Loads for West Branch DuPage River, Illinois Submitted to P.O. Box 19276 1021 North Grand Avenue East Springfield, Illinois 62794-9276 October 2004 Prepared by 135 South 84th Street, Suite 325 Milwaukee, Wisconsin 53214 In association with AQUA TERRA Consultants Executive Summary This report discusses the development of total maximum daily loads (TMDLs) for the West Branch DuPage River, located mainly in DuPage County and a tributary to the DuPage River in the greater Chicagoland area. The 1998 Illinois Section 303(d) List identified the West Branch of the DuPage River as impaired for nutrients, ammonia, metals, salinity, total dissolved solids (TDS), chlorides, suspended solids, siltation, pathogens and habitat alterations. The 2000 305(b) Report updated these potential causes of impairment to be phosphorus, nitrogen, nitrates, salinity, total dissolved solids (TDS), chlorides, flow alterations, habitat alterations, copper and suspended solids. The Agency has adopted a policy of developing TMDLs only on potential causes of impairment that have a water quality standard, which, in this case, were salinity, TDS, chlorides and copper. This report describes and presents the methods and procedures used to develop a chloride TMDL for the West Branch DuPage River. The West Branch DuPage River watershed covers 127.2 square miles of northeastern Illinois. It is located in the Des Plaines hydrologic unit code (HUC 7120004). Almost one third (32.8 percent) of the land use in the watershed is residential; agriculture accounts for about 17 percent of the land use. Nearly 14 percent of the total watershed area is impervious surfaces (based upon 1990 land use data).
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