Radioactivity, salt taint goundwater as inland areas
dig ever deeper
Milwaukee Journal Sentinel
An ongoing study of water use in southeastern Wisconsin
shows that the level of a deep sandstone aquifer is dropping
at such a fast pace that communities away from Lake Michigan
will need to reduce their dependence on this resource
for drinking water.
As wells in Waukesha, Brookfield, Germantown and other
municipalities tap ever lower levels of saturated sandstone,
they will encounter water containing more and more radioactivity,
salt from dissolved minerals and other pollutants that
must be removed.
The combination of dropping water levels and declining
water quality indicates that there are limits on the use
of the deep aquifer, said Robert Biebel, chief environmental
engineer for the Southeastern Wisconsin Regional Planning
Commission. The commission is sponsoring the aquifer performance
Eastern Waukesha County communities already are pumping
so much out of the sandstone that historic groundwater
flows have been reversed and water in and beneath Lake
Michigan is now being drawn west to fill the void, said
Ken Bradbury, a hydrogeologist with the Wisconsin Geological
and Natural History Survey.
According to the study's preliminary findings:
Groundwater in sandstone beneath Washington and Ozaukee
counties, too, is being pulled south toward Waukesha and
Consequently, water levels in the sandstone over a broad
region are declining.
While northern Racine County sandstone is contributing
water to Waukesha County wells, water in the sandstone
below the southern half of Racine county and all of Kenosha
county is being pulled to the south.
That water is flowing toward the well pumps supplying
suburban Chicago communities away from Lake Michigan.
The amount of southeastern Wisconsin groundwater flowing
toward those Illinois suburbs has doubled since 1900.
Those neighbors might account for as much as 20% of the
drawdown in Kenosha and southern Racine counties, Bradbury
Since the early 1900s, water levels in the sandstone
beneath Waukesha County have dropped between 400 and 500
feet. The decline might have even been greater in the
region but for Milwaukee's switch to Lake Michigan water,
completed in the 1960s with construction of the Howard
Ave. treatment plant.
Even so, water levels in the deep sandstone will continue
to drop - as much as 100 feet by 2020 - even with moderate
growth in the inland communities, according to preliminary
findings of the study.
"That pace is not sustainable forever because the aquifer
is not infinitely thick," Bradbury said.
Even so, long before the aquifer could be drained dry,
communities will face increasingly higher costs for pumping
water up from great depths and "dramatically declining
water quality" with increasing levels of radioactivity
or salinity, he said.
The City of Waukesha recently sidestepped a salt problem
in one of its deep wells, said Jeff Detro, the city's
water supply manager. Well No. 9 had been drilled to a
depth of 2,266 feet years ago, but as levels dropped in
the sandstone aquifer, the well was drawing water with
To avoid the salinity, the utility earlier this year
completed pouring concrete into the bottom of the well,
raising it to a depth of 1,725 feet. Its water no longer
contains high amounts of chloride and dissolved minerals,
Waukesha has not found such an easy fix for another set
of problems - levels of radium and radioactivity exceeding
federal drinking water standards.
The city has filed a lawsuit against the U.S. Environmental
Protection Agency claiming that its standards are too
strict. If the city loses that battle, it might need to
invest as much as $67 million to remove radium and the
sources of other radioactivity.
Simply switching aquifers and drilling more wells into
shallower, saturated dolomite rock is not a solution available
to all inland communities, according to Biebel. The regional
planning commission, state geological survey and U.S.
Geological Survey are working together on the regional
water use study.
"If more wells were placed in the shallow aquifer, that
could reduce the amount of groundwater flowing into surface
streams, lakes and wetlands," Biebel said.
Aquifer storage technology - pouring treated water into
wells during periods of low use, such as winter, and withdrawing
it for summer's peak demand - could provide partial relief
for some communities.
But a complete solution to the region's looming water
woes likely will require cooperative planning among communities,
he said. The study's preliminary findings convinced the
regional planning commission to seek support for a first-ever
water supply plan for southeastern Wisconsin.
One option - tapping into Lake Michigan - is not available
for communities west of the subcontinental divide separating
the Great Lakes and Mississippi River watersheds. A binational
charter signed by the United States and Canada, as well
as state and federal laws, restrict diverting Great Lakes
water out of its drainage basin.
Restrictions on use of Great Lakes water will become
even more strict, Biebel said.
Even so, there may be opportunities to expand the use
of Lake Michigan water.
One example is New Berlin, which is negotiating to buy
lake water from the Milwaukee Water Works. The eastern
third of New Berlin lies within the Great Lakes watershed,
and the community's wastewater already drains to the lake
through the Milwaukee Metropolitan Sewerage District's
The eastern half of Brookfield and all of Germantown
are in the same situation, he said.
"If some of these communities obtain water from Lake
Michigan, that would reduce their use of the sandstone
aquifer and conserve the groundwater supply for the future,"
Milwaukee's two treatment plants have adequate capacity
for more customers, according to a regional water supply
The Milwaukee Common Council decides if the Milwaukee
Water Works sells water to other customers, Superintendent
Carrie Lewis said.
Mariano Schifalacqua, Milwaukee's Public Works commissioner
and a member of the advisory committee that proposed the
regional water supply planning effort, agreed that there
is an opportunity for more communities east of the divide
to buy water from Milwaukee.
"We would discuss selling our water to others, but under
no circumstances would we agree to pump water over the
subcontinental divide," he said.