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Interaction of Lake Michigan with a Layered Aquifer Stressed by Drainage
Author(s) -
Cherkauer Douglas S.,
Carlson Douglas A.
Publication year - 1997
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.1997.tb00170.x
Subject(s) - aquifer , geology , groundwater recharge , hydrology (agriculture) , groundwater , hydraulic conductivity , hydrogeology , groundwater flow , drainage , geomorphology , geotechnical engineering , soil science , soil water , ecology , biology
Ground‐water interaction with lakes is often difficult to document because of both its diffusiveness and its spatial and temporal variability; reproducible measurements can be difficult to obtain. This paper takes advantage of the construction of a major drain stress in an aquifer system proximal to Lake Michigan to examine ground‐water/lake interactions in a complex hydrogeological setting. At the time of the measurements, the tunnel (4 to 8 m in diameter, 13 km in length, 1 to 3 km inland, and constructed in a low conductivity unit within a layered, fractured dolomite aquifer) had produced drawdowns of up to 50 m in the aquifer. In turn, the resulting trough of depression was inducing over 1600 m 3 /day (425,000 gpd) of water to flow from the lake to the tunnel. Seepage meters have been deployed over 40 km 2 of the lake bed to define the extent of the tunnel's impact. The results show that seepage through the lake bed is a combination of downward flow toward the tunnel and lateral inflow generated by recharge events in shallow unconsolidated sediments. Downward seepage is detectable to more than 2 km offshore, so an average of over 20 m of clay‐rich glacial deposits and 10 m of dolomitic shale (both with hydraulic conductivities < 3 × 10 ‐8 m/sec) does not isolate the lake from the aquifer. Seepage meters have proven to be a viable and cost‐effective means to provide an accurate spatial distribution of ground‐water/lake exchanges over a large area.