| Abstract: | The Cowles Unit of Indiana Dunes National Lakeshore in Porter County, northwest Indiana, contains a broad dune-beach complex along the southern shoreline of Lake Michigan and a large wetland, called the Great Marsh, that occupies the lowland between the shoreline dunes and an older dune-beach complex farther inland. These lacustrine sediments form a surficial aquifer that extends from the Lake Michigan shoreline to the northern edge of the Lake Border moraine. Water levels and water quality in the surficial aquifer were monitored from 1977 to 1984 near settling ponds on adjacent industrial property at the western end of the Cowles Unit. Seepage from the settling ponds from 1967 to 1980 created a water table mound that extended north into the shoreline dune complex and caused perennial flooding of several intradunal lowlands on National Lakeshore property. Since 1980, when the settling pond bottoms were sealed , these intradunal lowlands contained standing water only during periods of high snowmelt or rainfall. Water level declines following the cessation of seepage ranged from 6 feet at the eastern-most settling pond to nearly 14 feet at the westernmost pond. No general pattern of water table decline was observed in the Great Marsh or in the shoreline dune complex at distances > 3,000 ft east or north of the settling ponds. Since the settling ponds were sealed, the concentration of boron has decreased while concentrations of cadmium, arsenic, zinc, and molybdenum in shallow groundwater downgradient of the ponds show no definite trends in time. Arsenic, boron and molybdenum have remained at concentrations above those of shallow groundwater in areas unaffected by settling pond seepage. (Author ‘s abstract) |
| Genre: | USGS Numbered Series |
| ProdID: | 26617 |
| Citation Author: | Cohen, D. A.; Shedlock, R. J. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | iv, 25 p. :ill., maps ;28 cm. |
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| Citation Publisher: | U.S. Geological Survey, |
| Citation Series: | Water-Resources Investigations Report |
| Citation Series Code: | WRI |
| Citation Series Number: | 85-4340 |
| Citation Search Results Text: | Shallow ground-water flow, water levels, and quality of water, 1980-84, Cowles Unit, Indiana Dunes National Lakeshore; 1986; WRI; 85-4340; Cohen, D. A.; Shedlock, R. J. |
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| Citation Year: | 1986 |
| Type: | citation/reference |
| Text: | Shallow ground-water flow, water levels, and quality of water, 1980-84, Cowles Unit, Indiana Dunes National Lakeshore; 1986; WRI; 85-4340; Cohen, D. A.; Shedlock, R. J. |
| URL (THUMBNAIL): | http://pubs.usgs.gov/wri/1985/4340/report-thumb.jpg |
| URL (DOCUMENT): | http://pubs.usgs.gov/wri/1985/4340/report.pdf |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | U.S. Geological Survey, |
