levels dip in water tests
Amounts need to drop more for aquifer storage
By Peter Rebhahn
Green Bay Press Gazette
Water samples taken so far this month in Green Bayís test
of a new-to-the state water-storage technique continue
to show high levels of arsenic.
But the city remains optimistic about the outcome of
the test and the long-term role of aquifer storage and
recovery in the areaís drinking water future.
"Weíre looking at this data as very encouraging,"
said Bill Nabak, general manager of the Green Bay Water
In aquifer storage and recovery, ready-to-drink water
is piped underground into wells converted from groundwater
pumping to storage.
Aquifer storage and recovery is legal in Wisconsin, but
communities that want to use it must pass rigorous water-quality
tests. So far, only one has.
Workers began a second round of testing the technique
at the cityís well on North Military Avenue in early August
by injecting into it 2.3 million gallons of drinking water.
Water retrieved from a monitoring well drilled about
50 feet from the test well shortly after injection contained
dissolved arsenic at a concentration of 29 micrograms
per liter - nearly three times a 10-microgram standard
recently enacted by the federal Environmental Protection
But a week later the arsenic level had fallen to 20 micrograms
per liter, and a third test a week after that showed a
concentration of 17 micrograms. A microgram is one-millionth
of one gram; a gram is 0.04 ounce. A liter is 0.88 of
"The numbers are moving in the right direction,"
said Green Bay Mayor Jim Schmitt.
A first attempt to test aquifer storage at the Military
Avenue well, which began in June 2002, ran into problems
when 10 million gallons of injected water caused arsenic
levels to spike as high as 270 micrograms per liter.
Arsenic is a poisonous natural element that is released
from the rock where itís trapped when it reacts with oxygen
in the water injected beneath ground.
Before resuming the test, the city lined the well to
a depth of 625 feet to prevent water from contacting arsenic-bearing
rock lying 400 feet to 600 feet down.
Aquifer storage and recovery, or ASR, saves water utilities
and their ratepayers money because it allows utilities
to meet summer demand peaks with stored water - peaks
that otherwise could be met only by expensive upgrades
to size water systems to meet peak demands.
The outcome of Green Bayís test could be known as soon
as December, but the state Department of Natural Resources
probably wonít make a decision until June 2004, Nabak
The technique figures prominently in complicated negotiations
that could link Green Bay and eight suburbs in a shared
"The ASR is still the main plan," Schmitt said.
"Itís the best thing to do for the city and the suburbs."