Wisconsin's Role in Great Lakes Restoration - American Water ...

SESSION 3A:
Groundwater Studies
Friday, March 4, 2011
8:20 – 10:00 a.m.
Assessing the Effect of Pleistocene Glaciation on the Water Supply of Eastern
Wisconsin
**Nathan C. Magnusson, UW-Milwaukee, Milwaukee, WI, nathanm4@uwm.edu
Tim Grundl, UW-Milwaukee, Milwaukee, WI, grundl@uwm.edu
Water resource replenishment is of concern all over the world, including Wisconsin. The
primary municipal water source in eastern Wisconsin is the Paleozoic sandstone aquifer that
is confined beneath the Maquoketa Shale and Sinnippee Group. It is therefore important to
understand how and when the water in this aquifer was recharged. This research is looking to
determine the age and origin of water contained in the deep sandstone aquifer of eastern
Wisconsin in its entirety as an expansion of work done by Klump et al. 2008.
The primary means of obtaining the information for this work has been through sampling
municipal water wells in west-to-east transects through Brown County and Fond du Lac to
Ozaukee Counties. A total of 18 wells were sampled along the flow path starting just west of
the confining units and extending eastward toward Lake Michigan.
The water samples have been tested for standard ionic composition, stable isotopes including
18 O, D and 34 S, noble gas concentrations, and 14C isotopic signature. This data is being
used for general geochemical modeling, dating of groundwater along the flow path, and
determining the recharge history and temperature record through the late Pleistocene.
** Graduate student presentation
50