Wisconsin takes water storage underground
New aquifer rules may save Wisconsin communities millions
By DON BEHM
Milwaukee Journal Sentinel staff
Last Updated: Aug. 17, 2002
Wisconsin communities have been given a green light to
save millions of dollars by storing treated drinking water
Pumping clean water down wells during winter and spring
will enable municipalities to retrieve it quickly in summer
to slake thirsts and refresh vegetable gardens.
Below-ground storage also will enable communities to
postpone costly water treatment plant expansions or investments
in new water sources that otherwise would be needed to
meet heavy demand during hot months, local and state officials
Oak Creek will be the first community in Wisconsin to
take advantage of the technology, known as aquifer storage
recovery, now that the state Natural Resources Board last
week approved rules regulating the systems. The city's
potential savings: $5 million in the next three to four
"The more wells we can use for storage, the more money
we can save in future plant expansions," said Dan Duchniak,
assistant general manager of the city's Water and Sewer
Green Bay and nine other Brown County communities also
are considering pumping treated water into deep aquifers
at a savings of tens of millions of dollars.
"Wednesday was a huge step forward for using this technology,"
said Bill Nabak, general manager of the Green Bay Water
Green Bay is trying to persuade the nine suburbs to buy
treated Lake Michigan water from it. They would pay $37
million to connect to the city - nearly $100 million less
than it would cost them to build their own water treatment
plant and pipeline to the lake.
Waukesha, too, is seriously studying such a storage system
because the rapidly growing city knows it will need to
more than double its water capacity in the next 20 years,
just to quench average daily demand.
"We are looking for new water supplies, and we need to
look at new storage technologies," said Jeff Detro, acting
general manager of the city's Water Utility.
Had backed away
Although 14 other states, beginning with New Jersey in
1968, have authorized the technology, Wisconsin regulators
had backed away, citing concerns over groundwater contamination.
Tests at an Oak Creek well since 1999 have convinced
Department of Natural Resources officials and legislators
that such systems could operate without harming the environment.
Oak Creek found that pre-chlorinated water stored underground
for several months remained clean enough to drink, meeting
all state and federal standards. As important, levels
of chlorine byproducts in the stored water gradually declined,
and groundwater quality was not degraded.
Such tests, as part of a pilot study, will be required
for all communities applying for aquifer storage recovery
permits, said Jill Jonas, director of the DNR's bureau
of drinking water and groundwater in Madison. The tests
are needed to protect public health and groundwater quality,
Prior to approval of an operating system, communities
also will need to show that they have taken steps to conserve
Conservation requirements will ensure that communities
use water resources as efficiently as possible, Jonas
Now that the Natural Resources Board has approved guidelines
for using the storage technology, the DNR must complete
one last step that will make the technology more feasible,
The Legislature, in the recent state budget repair bill
signed by Gov. Scott McCallum, approved a key exemption
in groundwater law. Although stored water meets drinking
requirements, state groundwater protection standards are
Consequently, tests of stored water at an aquifer storage
well site could show that chlorine byproduct concentrations
exceed groundwater limits. The Legislature's budget repair
bill relaxed the law, allowing municipalities to exceed
those limits up to a distance of 1,200 feet or the nearest
private well. The extra distance from the storage well
will ensure the byproducts are diluted in groundwater.
Jonas and DNR officials say it will take them six months
to amend the regulation and bring it in line with the
change in state law.
Communities can apply for pilot projects in the meantime,
because it will take longer than six months to get them
approved, said Oak Creek's Duchniak.
Well at local park
The Oak Creek well selected for the state's first aquifer
storage study is at a city park and extends about 1,800
feet deep into a sandstone aquifer.
"We've been through two full cycles, pumping 42 million
gallons down to the aquifer and recovering it, and we've
had no complaints from our customers," Duchniak said.
"I believe we will move forward now, from our experimental
status to an operating system," he said.
Oak Creek now draws all of its drinking water from Lake
Michigan. The utility also serves Franklin residents.
By 2020, Oak Creek plans to boost its dependency on storage
aquifers, withdrawing up to 8 million gallons of stored
water a day in summer to meet peak demand, he said.
The most ambitious aquifer storage project being discussed,
however, is in Brown County.
The key to state approval there is whether future tests
of Green Bay's pilot well find that health-threatening
amounts of arsenic are not being released from bedrock
into the stored water, said Nabak.
"If we go to the lake on our own and build a $135 million
system, we'd still use aquifer storage for future expansion,"
said Len Teresinski, president of the Village of Hobart
and president of the nine-community Central Brown County
"If we go with Green Bay for our supply, we'd still need
six storage wells to begin with and a total of 10 storage
wells by 2010."
Final cost estimates are expected next week, Teresinski
said. The authority could make its decision by late September.
The other communities in the authority are: City of De
Pere; villages of Howard, Ashwaubenon and Allouez; and
towns of Scott, Lawrence, Ledgeview and Bellevue.