Monitoring
Lake Clarity
The
Upper Midwest
is characterized
by tens of thousands
of inland lakes,
networks of
rivers and streams,
and an abundance
of groundwater,
soil moisture,
and winter snow
pack. Although
this resource
is plentiful,
it is heavily
utilized to
support commerce,
recreation,
transportation,
agriculture,
and numerous
industries.
This heavy reliance
of infrastructure
and economy
on the regional
water resources
translates into
high vulnerability
to potential
changes in water
quality.
Human
activities
are impacting
the quality
of water resources
in many ways,
with eutrophication being
one of the
most pervasive
problems affecting
the lakes in
the Upper Great
Lakes region.
The primary
cause of this "accelerated
aging" of
the lakes is
excessive nutrient
input from
near-shore land
use as well
as urban and
agricultural
runoff. Understanding
this tie between
lake water
quality and
land use is
a major focus
for our research.
Protecting
and monitoring
lake water quality
is a major concern
for many local
and state agencies.
Organizations,
like the Citizen
Lake Monitoring
Program,
routinely measure
physical, chemical
and biological
properties of
the region's
water resources.
However, because
of expense and
time requirements
for this ground-based
monitoring,
it is impractical
to monitor more
than a small
fraction of
this large resource
by conventional
field methods.
The use of satellite
remote sensing
is a cost-effective
way to gather
the information
needed for water
quality assessments
in lake-rich
areas.
For
effective environmental
planning and
management,
it is vital
to have long-term
water quality
information
on a broad regional
scale. Although
it is not possible
to go back in
time and collect
additional water
quality information
using conventional
field methods,
Landsat satellite
data have been
collected regularly
since the early
1970s, allowing
the possibility
of extracting
historical water
quality information
from archived
images.
The
extraction of
historic and
current water
quality data
from satellite
images, coupled
with existing
data collection
efforts facilitates
the development
of comprehensive
regional databases
that can be
used to evaluate
regional differences
and water quality
trends over
time. If used
along with land
use data, this
information
can help determine
the impacts
different land
use practices
have on lake
conditions.
Results
of such analyses
will help local
and state agencies
make informed
decisions about
development
policy and improve
the management
of lake resources.
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