Dumping may be worse than reported
New study says MMSD understated numbers
By Steve Schultze and Marie Rohde
Milwaukee Journal Sentinel
The Milwaukee sewerage district has grossly underreported
the volume of raw sewage it has dumped since completion
of the deep tunnel system nearly a decade ago, according
to a consultant's study.
During three rainstorms that prompted dumping, the reported
volumes were off by an average of 72%, according to the
study by Milwaukee-based Triad Engineering Inc. The revised
dumping tally for those storms should be nearly 4.9 billion
gallons instead of the 2.9 billion gallons that the Milwaukee
Metropolitan Sewerage District has reported to the state,
the study said.
The new study does not give a corrected dumping figure
for the entire decade since the deep tunnel system was
completed. The tunnel system was originally touted as
the cure for dumping. However, if the district underreported
all its overflows by the same 72% margin, the revised
overall dumping tally would jump from about 13 billion
gallons to more than 22 billion gallons.
That finding could mean a much larger quantity of pollutants
has been dumped into Lake Michigan than MMSD has previously
acknowledged, said John Hoops, a civil engineering professor
at the University of Wisconsin-Madison. Hoops reviewed
the Triad study at the request of the Journal Sentinel.
"Based on what Triad did, you are talking 22 billion"
gallons of sewage dumped, Hoops said. "That seems
pretty significant in terms of the (pollution) loading
to the streams and eventually Lake Michigan."
MMSD Commission Chairman Dennis Grzezinski said he hadn't
seen the Triad study, but wasn't overly concerned about
"It doesn't shock me because there isn't any more
pollution in it," said Grzezinski, an environmental
lawyer. He reasoned that in a big storm, the amount of
wastes flushed into combined sewers remains the same,
while the amount of storm water increases. That means
whether 1.5 billion gallons or 2.4 billion gallons are
dumped in a big storm, the pollutant load remains constant,
according to Grzezinski.
Looked at combined sewers
The study, commissioned by MMSD, looked at dumping from
sewers in older parts of Milwaukee and Shorewood that
carry both sanitary waste and storm water. Other parts
of the metro area have separate storm and sanitary sewer
lines. MMSD Executive Director Kevin Shafer said Tuesday
he doubted the accuracy of the Triad study, which included
a review of local water pollution and cost about $500,000.
"Even though that report is final, we haven't accepted
the results yet," Shafer said in an interview. A
computer expert hired by MMSD to review the Triad study
already has found "glitches" in Triad's work,
The formulas used by Triad will be retested using a corrected
program to find out if the much larger dumping totals
are wrong, he said. If that test still shows massive underreporting
by MMSD, the agency will assemble a team of engineers
to further review the findings, he said.
"We felt that there were some errors and mistakes
in their analysis," Shafer said of the Triad study.
Triad's figures were so different from MMSD's dumping
numbers that "it raised a red flag," Shafer
The Triad study found MMSD's indirect method of estimating
sewage dumping, or overflows, was lacking in several respects.
Instead of measuring water levels where sewers overflow,
MMSD compares water levels in streams before and after
receiving dumped sewage, the study said.
Inaccuracies crop up in measuring stream elevations,
and gauges sometimes don't work properly, the study said.
The report also said the mathematical model MMSD used
for calculating sewer overflow rates was outdated.
MMSD has been using a technique to estimate the amount
of sewage dumped during a storm that was developed in
1986 before the deep tunnel system was completed.
Although the report examined only three storms when sewage
was dumped, it also concluded that MMSD has likely vastly
underestimated the amount of sewage dumped since the tunnel
system opened in late 1993.
To improve measuring
The study recommended 10 steps for improving the measuring
of sewage dumping, including replacing the old mathematical
formulas and updating the technique for computing river
Willie Gonwa, the engineer who did most of the work for
Triad on the study, said he had not been contacted by
MMSD about any concerns with the study. Triad provided
a preliminary version of its report to MMSD in January
2002, another draft version in August and its final report
Shafer said he had not given a copy of the study to MMSD
commissioners because he didn't consider it done yet.
Gonwa called the project "as complicated as anything
I've seen in my career." He said he understood MMSD's
interest in ensuring accuracy but declined to comment
on Shafer's criticism of the results until he has a chance
to see the specific grounds.
"I'd let the district decide which (set of results)
they want to stand by," Gonwa said. "If they
have some question and they are performing an independent
review, I'd defer my opinion until the independent review
Warning from Darling
State Sen. Alberta Darling (R-River Hills) said the study
was of great concern. If it appears MMSD is avoiding accountability,
she said, she will try to prod the state Department of
Natural Resources into action or seek a new legislative
audit of the district.
"It makes me feel very nervous about having all
that dumped into the lake," said Darling, a frequent
critic of MMSD. "We can't keep doing this."
The underreporting could be a serious violation of environmental
regulations governing MMSD, said Laurel O'Sullivan, a
lawyer for the Lake Michigan Federation, a Chicago-based
environmental group that's suing MMSD over past dumping.
She said the Triad report raised questions about whether
MMSD has been honestly reporting both sanitary and combined
Charles Burney, a DNR official who oversees MMSD, said
he couldn't comment on the study because he hadn't seen
it. MMSD's operating permit issued by the DNR allows it
to dump up to six times a year from its combined sewers,
without regard to the quantity dumped. Burney said that
standard was based on guidelines from the U.S. Environmental
The deep tunnel system is the cornerstone of a $2.8 billion
court-ordered project that was designed to improve the
quality of the waterways. The deep tunnel system - essentially
a massive underground storage chamber for rain and sewage
- has greatly reduced the frequency of sewage dumping,
but its performance still has disappointed some.