Study Identifies Directions Of Ground- and Surface-Water Flow and Locations of Floating Oil in Northwestern Indiana and Northeastern Illinois

Robert Kay, USGS hydrologist and principal author of the report, noted that contamination of ground-water and surface-water supplies by municipal and industrial wastes is a problem in northwestern Indiana and northeastern Illinois. "Knowledge of the directions of surface- and ground-water flow and the location of the floating oil is essential to defining the potential extent of the contamination problem," Kay said. "Compounds in the oil dissolve in ground water and migrate deep within the ground-water flow system or discharge to surface water. Mapping water levels not only enables the migration pathway to be identified, but it also allows for the rate of ground-water flow to be estimated," he said.

Kay said that the shallow ground water usually flows toward surface-water bodies, including Lake Michigan and Lake Calumet. Some shallow ground water also flows into sewers and to pumped shallow wells. Deeper ground water generally flows toward deep pumped wells. Nonaqueous-phase liquids (liquids, that are not readily dissolved in water, such as gasoline) are confined to the vicinity of some gas stations, industrial facilities, and petrochemical storage and handling facilities.

The report, titled "Geohydrology, Water Levels and Directions of Flow, and Occurrence of Light-Nonaqueous-Phase Liquids on Ground Water in Northwestern Indiana and the Lake Calumet Area of Northeastern Illinois," by Robert T. Kay, Richard F. Duwelius, Timothy A. Brown, Frederick A. Micke and Carol A. Witt-Smith is published as U.S. Geological Survey Water- Resources Investigations Report 95-4253. Copies are available for inspection at the U.S. Geological Survey, 221 N. Broadway, Urbana, Ill. 61801, and at most large libraries nationwide. Paper and microfiche copies can be purchased at cost from the U.S. Geological Survey Information Services, Box 25286, Federal Center, Denver, Colo. 80225 (telephone 303-202-4700). Orders must include check or money order payable to U.S. Department of Interior-USGS and must specify report number WRIR 95-4253.