The water-table configuration in the vicinity of the Grand Calumet River/Indiana Harbor Canal reflects the complexity of the shallow groundwater-flow system in this area. Large depressions in the water table in sewered areas interrupt broad groundwater divides between rivers. Digital-model simulations of the study area indicate that the shallow aquifer discharges approximately 15 cu ft/s of groundwater to sewers, 10 cu ft/s to the Grand Calumet River/Indiana Harbor Canal, 4 cu ft/s to Lake Michigan, and 0 to 10 cu ft/s to the carbonate bedrock aquifer. Water samples from 35 wells were analyzed for 24 inorganic constituents and 88 organic chemicals. Twenty-four different organic compounds were detected. Four of the organic compounds--phenols, bis-2-ethyl-hexyl phthalate, benzene, and toluene--were detected in greater than 5 wells. Water samples from steel and petrochemical land-use areas generally had higher median concentrations of inorganic ions and more detections of organic chemicals than samples from commercial/light industry, residential, and park land-use areas. Groundwater probably contributes greater than 10 percent of the total chemical load of ammonia, chromium, and cyanide to the Grand Calumet River; 2 to 6 percent of the dissolved solids, chloride, sulfate, fluoride, hardness, copper, iron, and lead; and probably less than 1 percent of the nitrate plus nitrite, mercury, phenols, and zinc. In comparison, about 1 to 3 percent of the total streamflow in the Grand Calumet River is from groundwater. Within the study area, the east branch of the Grand Calumet River and the Indiana Harbor Canal generally receive the greatest chemical loads from groundwater, whereas Lake Michigan generally receives the smallest loads.
Additional publication details
USGS Numbered Series
Geohydrology and water quality of the Calumet aquifer, in the vicinity of the Grand Calumet River/Indiana Harbor Canal, northwestern Indiana
Water-Resources Investigations Report
U.S. Geological Survey ;
U.S.G.S. Earth Science Information Center, Open-File Reports Section [distributor],