Water Experts Provide a Reservoir of Knowledge
by John Gagnon, Michigan Tech Research Magazine
Above:
Noel Urban (left) and Marty Auer, both environmental engineering professors,
"write equations for the way lakes behave." Below:
Marty Auer (in yellow) on a research vessel in Lake Superior, working
on the KITES project. Below,
right: Noel Urban on that same boat working on his KITES-related project. It’s a long way from the shores of Lake Superior to the banks of
the Hudson River, but two Michigan Tech researchers have bridged the two
waters.
“Michigan Tech is involved with protecting the water supply in the
largest city in the United States,” says Martin Auer, professor of
civil and environmental engineering. The project was begun in 1993, is
ongoing, and has implications “far beyond New York.”
“This applies everywhere,” he says.
For its drinking water, New York City relies on 19 reservoirs and three
lakes—all situated on three watersheds: the Hudson River, the Delaware
River, and the Catskill Mountains.
The immense system contains 580 billion gallons of usable water that
provides 1.46 billion gallons of drinking water to 9 million people every
day. Scientists are studying the condition of the lakes and reservoirs
and investigating ways to improve the quality of the water.
How did Michigan Tech get involved in a project so far afield?
New York City is surrounded by salt water (including the lower reaches
of the Hudson). To satisfy its thirsty masses, the city, in the 1800s,
began to create reservoirs—first along the Hudson River to the north
of the city, then along the Delaware River to the west of the city—to
supplement the water from lakes.
Auer says that the quality of the water in the lakes and reservoirs varies
from “very bad” to “excellent.” The first reservoir
studied was Cannonsville. Located 120 miles west of New York City, near
the Catskill Mountains, Cannonsville is the westernmost reservoir, the
second-biggest in the state, and the most polluted. Cannonsville is among
several New York City reservoirs that may require treatment to meet federal
guidelines for drinking water. The price tag for the treatment has been
placed at $8 to $10 billion.
As an alternative, New York proposed to investigate ways to clean up
the source waters in the reservoirs and lakes, thus avoiding the need
for treatment. To explore that option, the Environmental Protection Agency
granted the city an exemption from treatment until 2002.
One major problem—what Auer calls “the same old story”
because it is commonplace—is too many nutrients, especially phosphorus,
entering the water. Phosphorus is the by-product of all kinds of human
activity (including the discharge of detergents, sewage, and fertilizers),
and it is a nutrient that feeds algal growth in most lakes.
More phosphorus in water means more algae; more algae means more turbidity;
too much turbidity makes water unsuitable for drinking. The process can
be reversed. Reducing the phosphorus reduces the algae, which increases
the clarity and makes the water suitable for drinking.
In the New York project, Tech’s role was to measure, describe, and
explain mathematically the chemical and biological processes going on.
“We write equations for the way lakes behave,” Auer says.
Those equations help provide a mathematical model for the entire drinking
water system that enables scientists to assess different water quality
scenarios and propose prescriptions, such as how much phosphorus needs
to be removed from a given lake or reservoir to limit algae.
“It’s always easier to keep something out than it is to take
it out,” Auer says.
With respect to phosphorus, it’s a question of amelioration, not
elimination. “You can’t just stop it,” Auer says. “People
are flushing toilets and farmers are raising cows and fertilizing. It
can’t all go away.”
But there is a prescription for restoration, including better waste water
treatment plants, extensive buffer zones to keep cattle and fertilizer
away from streams, and restrictions on the placement of septic systems.
New York is grappling with these “serious—even thorny—land-use
implications,” Auer says.
“Our work is going to help people all over the country meet these
new standards for cleaner, safer water,” he says. The New York work
will be a template for other work around the country—“a tool
for the future,” Urban says. ”It will show others how to evaluate
their options as they try to upgrade their drinking water.”
As for the Lake Superior watershed?
With scientists engaged in a comprehensive assessment of Lake Superior
proper, not much work has been done on the drinking water around Lake
Superior, but Urban says the watershed is in “quite good shape.”
The reasons: the Lake Superior watershed is small relative to its size,
so there is less potential for trouble, the watershed is sparsely inhabited
and has little industrial activity and little agriculture.
Nevertheless, Urban says, with land use and water quality being so tightly
connected, there are two land-use issues that might come into play along
the Keweenaw: the destruction of wetlands and the residual effects of
copper mining.
At this point the wetlands issue is a worry. The Lake Superior watershed
has little topographic relief, which, combined with climate, results in
extensive wetlands that flow into the lake. But wetlands are being drained
for agriculture, filled for building, and dried up by logging. The effect
of those human activities needs to be studied, Urban says, because the
wetlands are an important source of nutrients for Lake Superior.
The second land-use issue is an historical fact: stamp sands containing
copper that were deposited all over Michigan’s Keweenaw Peninsula.
Urban says Lake Superior took a “big hit” along the peninsula,
adding that copper concentrations are 10 times higher in Portage Lake
than in Lake Superior, and 10 times higher in Torch Lake than in Portage
Lake.
Copper doesn’t adversely affect humans; but, dissolved in surface
water around the peninsula, especially in small lakes, it reached concentrations
that were toxic to wildlife, specifically zooplankton, which is food for
fish, and algae which is food for zooplankton. Copper also inhibits photosynthesis.
The concentrations of copper in the stamp sands of Torch Lake were so
high that organisms couldn’t live in the sediments and the fish eggs
couldn’t survive. Remediation of the mining spoils is needed, Urban
says. Two possibilities: build wetlands along the shore and construct
spawning grounds for the fish. In time, Urban says, sediments will safely
cover the copper tailings in Torch Lake and Portage Lake, but that remedy
is a long way off. The natural cleansing of Lake Superior will take even
longer.
With respect to drinking water, only one town on the peninsula, Ontonagon,
uses Lake Superior water for drinking water. All other towns use groundwater.
It is not known whether aquifers along the peninsula operate independently
of Lake Superior. “No one has really explored that,” Urban says.
Overall, though, “There is no reason to expect big problems with
the drinking water. There is no reason to expect contamination.”
Mainly
through Auer’s academic contacts, made while working on other bodies
of water, in particular New York’s Onondaga Lake (which has been
called the dirtiest lake in the country), Lake Michigan’s Green Bay
(which is merely dirty), and Lake Superior, which, in comparison, is an
elixir.
Enter
Auer and Noel Urban, environmental engineering professors at Michigan
Tech. They joined a team of scientists, led by Steven W. Effler and the
staff of the Upstate Freshwater Institute in Syracuse, to gather data
on Cannonsville and the rest of the Delaware system.
Auer’s
colleague, Noel Urban, says that, across the nation, drinking water standards
have been tightened incrementally over the past decade.