Lake can take some pollution, but experts
still worry about overflows, runoff
By Lee Berquist
Milwaukee Journal Sentinel
Published July 11, 2004
Sewage overflows are never good.
But many experts say Lake Michigan can swallow this spring's
pollution from Milwaukee's largest sewage overflows since
construction of the deep tunnel system in 1994.
The Milwaukee Metropolitan Sewerage District's overflows
are, "clearly, problems Milwaukee has to continue
to work on," said Russell G. Kreis Jr., station director
at the U.S. Environmental Protection Agency's Office of
Research and Development in Grosse Ile, Mich.
"But as time goes on, (the pollution) will be diluted
out," he said. "The lake does recycle, and it
does clean itself up - it has the capacity to do that."
In fact, the overflows were not the only thing fouling
local waterways. Regulators are worried about the even
greater volumes of polluted runoff that carried everything
from Ozaukee County cow manure to Milwaukee street grime
into the lake during May.
Both the overflows and runoff sent bacteria levels skyrocketing
on local waterways, but after a few days in the cold waters
of Lake Michigan, much of the bacteria died out.
One reason experts believe the lake can handle MMSD's
overflows is that most of it was water. The state Department
of Natural Resources estimates that most overflows are
90% or more water, plus sewage and other pollutants.
And then there is Lake Michigan's size. MMSD's overflow
of 4.6 billion gallons - the biggest to date, and followed
by an unexpected overflow of more than 1.6 million gallons
July 4 - is tiny compared with the 1.3 quadrillion gallons
in the lake. (There are 1,000 trillions in 1 quadrillion.)
Before construction of the deep tunnel, MMSD reported
an average of 50 overflows a year.
"Compared to when there was no deep tunnel, and
many more billions of gallons were going out into the
lake, the lake's survived much worse," said Charles
Melching, a civil and environmental engineer at Marquette
Discharges demand attention
Still, some scientists and environmentalists say MMSD's
big discharges can't be ignored.
"If this is a long-term occurrence, a big lake can
only absorb so much until you reach a point where it becomes
overpowering," said Art Brooks, a specialist in aquatic
ecology at the Great Lakes Water Institute at the University
"Lake Michigan is certainly big enough to absorb
an awful lot, but we don't need to throw insults at it
to test its limits."
Joel Brammeier, acting executive director of the Lake
Michigan Federation, said the overflows can't be pooh-poohed
because "sewage overflows are a known source of contamination
for Great Lakes beaches. That's something that we can
do something about."
The DNR has begun an enforcement action against the sewerage
district. Mary Schlaefer, executive assistant to DNR Secretary
Scott Hassett, said Friday that it would be Aug. 1 before
the agency decided what steps it would take.
MMSD's troubles come at a time when there are other big
worries about the Great Lakes.
Great Lakes state governors will soon get a long-awaited
report on how the region can protect its supply of fresh
water amid drought and growing water demand.
While it is improving, Lake Michigan's waters still need
to get better. Southern Lake Michigan is more polluted
than the northern part of the lake. Lower portions of
the Milwaukee, Menomonee and Kinnickinnic rivers, the
Milwaukee Harbor and the near shore area of Lake Michigan
constitute one of 26 areas in the Great Lakes region considered
the most polluted and are targeted for cleanup.
Runoff poses many problems
And then there are the problems with runoff.
During May, polluted water poured into the lake at near
There have been only five months since 1914 when more
water moved through the Milwaukee River, according to
the U.S. Geological Survey.
Huge volumes of brown, turbid water were racing through
the Kinnickinnic and the Menomonee rivers, as well. All
three of the rivers, mingling with MMSD's overflows, flushed
into the harbor, leaving tendrils of brown water to mix
with the lake.
"The wake of the water looked like Leinie's Red,"
said Tom Schulz, former commodore of the South Milwaukee
Yacht Club. He motored his 32-foot boat through the harbor
after the overflows. "It was atrocious-looking."
The DNR considers runoff the state's biggest water quality
threat. The agency estimates that runoff threatens 40%
of the state's streams and rivers and 90% of its lakes
with the pollutants and sediments it picks up along the
On June 22, Kevin L. Shafer, executive director of the
district, told members of the Wisconsin Natural Resources
Board that runoff is a bigger worry than the district's
But state auditors concluded in a July 2002 audit that
after the deep tunnel was built in 1994, MMSD overflows
were polluting more than expected. The district dumped
13.2 billion gallons of untreated wastewater into local
waterways between 1994 and 2002, auditors found.
Water quality during that period improved only in the
areas served by the combined sewer system - an area that
represents 7% of MMSD's territory. But because of overflows
and runoff, water quality did not improve in the rest
of Milwaukee and the suburbs, the auditors found.
Overflows' effects under study
Scientists and government agencies are still assessing
the effects of the overflows this spring.
MMSD records show sharp increases for one type of bacteria
in the Milwaukee, Menomonee and Kinnickinnic rivers during
the overflows. Public health experts use fecal coliform,
found in the waste of people and animals, as a marker
for other disease-causing bacteria.
The highest count was on May 14 - 54,000 units per 100
milliliters on the Menomonee in the Menomonee River Valley.
Counts hit 21,000 and 27,000 at two locations on the Kinnickinnic
north of W. Oklahoma Ave. The state standard is 400 for
recreational swimming, but, according to the DNR, counts
that high are not uncommon after rains. Levels also increased
in Lake Michigan, but never as high.
By June 9, bacteria levels had all fallen to acceptable
The test results mirror the work of UWM researcher Sandra
McLellan, who was looking for a different bacteria, E.
She found E. coli levels 10 times higher in the river
and in the harbor than government-recommended limits for
recreational water. But the bacteria almost disappeared
as water from the harbor moved into the lake.
"The lake conditions are pretty harsh," said
McLellan, whose research is partially funded by MMSD.
"The water's cold, and we see E. coli drop off pretty
There are unknowns, however. Little is understood about
the lives of more harmful bacteria such as Cryptosporidium
and Giardia in the lake, she said. These organisms might
live longer in the lake, she said.
A saving grace of the overflows and accompanying runoff
is that Lake Michigan water in May is cold, and virtually
nobody was swimming in it.
From May 17 to June 6, the beach at South Shore Park
was either closed or posted with signs advising people
not to swim because of high levels of E. coli, Milwaukee
Health Department records show.
North at McKinley Beach, conditions were only slightly
better. The beach was closed or posted 16 out of 21 days.
At Bradford, depending on the location, the beach was
closed or posted eight to 10 times during the three-week
period, monitoring data shows.
But afterward, bacteria levels sharply improved. UWM's
McLellan, a beach water quality expert, said it is simplistic
to blame MMSD for high bacteria counts.
Beaches are influenced more by local factors. Studies
have shown that bacteria can remain in the sand for months.
Runoff, a nearby storm pipe, wave action and the slope
of the beach can all play roles in beach pollution.
Gulls are also a big factor, McLellan said. Ounce for
ounce, the birds excrete far more E. coli than their pesky
urban neighbor, the Canada goose.
Steve Schultze and Marie Rohde of the Journal Sentinel
staff contributed to this report