WEBVTT
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- Okay, my name is Reesa Evans.
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I will be moderating most of the
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ecology stream for
the next couple days.
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I'm going to
introduce Buzz Sorge,
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who I don't have a
written introduction for,
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but I've known him
a long time, so...
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Buzz is the lake manager for
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the West Central Region,
which is where I am,
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and he has been an
innumerable resource for me
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through the years as I've
learned lake science.
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So when I have a question,
I go to Buzz,
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and when he retires,
I'll be in big trouble.
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Thanks, Buzz, go ahead.
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- Well, good morning, everybody.
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Thanks for coming
in this morning.
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How many people understand
what the term limnology means?
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Well, limnology is the study
of fresh water ecosystems,
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and it incorporates
an understanding
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of the biological, physical,
and chemical factors
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that influence our rivers
and lakes and streams.
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So what we're going to be
talking about this morning
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is the basics of lake health.
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What makes a lake alake?
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So when we start
thinking about this,
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we have to think about
Wisconsin as a state.
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Well, how did we get all this
fresh water in our state?
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Well, it's really a product
of the periods of glaciation
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that came through the state
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and we really have
what we estimate as
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somewhat over
15,000 natural lakes
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and tens of thousands of miles
of rivers and streams.
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And so as the glaciers
came through this country,
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they gouged out
portions of the earth
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and created these basins then
in our natural lake ecosystems
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that filled with water
and created those lakes
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we love to recreate on.
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So when we think about
the history of these lakes
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across the state,
you know our lakes
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are 10,000+ years old,
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so what has been
our impact on them?
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We really started
impacting our lakes
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in Wisconsin about
150 years ago,
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just before the cutover,
when we took the pine off
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the northern parts of the state
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and the woods off,
and as Europeans colonized.
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So some of our earliest lake
users and development on lakes
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goes back to the mid-1800s,
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and that's when the
forests were clear cut.
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But then really,
most of the development
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started on Wisconsin's lakes
post-World War II,
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when we had those
resources in our economy
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to enjoy those
systems out there.
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So I'll talk more about that
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later with that
type of development,
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and then redevelopment
really came significantly
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as a lot of those
cabins were upgraded
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to the second homes and
first homes in the 1990s.
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How do we value our lakes?
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And lakes do provide
services to us as a society,
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they provide ecosystem
services, I mean,
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we love to be near our lakes.
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We are a creature that just
loves to be near water,
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and so the cultural and societal
values we have for lakes,
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but these ecosystems
services, the wildlife,
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the clean water they provide,
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are very valuable to us,
especially in the Upper Midwest
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and Minnesota and Wisconsin.
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But our lakes are
changing faster than ever.
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Some of these are indexed by
more frequent algal blooms.
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How we've developed
our shoreland areas
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has really impacted
in lake habitat,
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and aquatic invasive species.
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These are the three main
stressors that we see
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on Wisconsin's lakes today
that we are working on.
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If we think about
this, I don't know
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how many folks have had a
chance to look at this report,
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but it's Wisconsin's
Changing Climate report,
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it was published in 2011, and
really gave us some insight,
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so what we can expect to see,
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especially how it impacts
our water resources.
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Some of these major
drivers of climate change
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on our water resources are
simply thermal impacts.
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We're a bit warmer.
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That means ice on
for a shorter period of time.
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It comes on later,
goes off earlier in the
spring.
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Definitely, I think
folks who live in,
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especially north central
and northwestern Wisconsin,
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the drought we went through
6, 7 years ago.
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We're kinda out of that,
but it really
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impacted lake levels up there.
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We had many lakes that really
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had significant impacts
on their lake levels,
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and then in many other
areas of the state
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we've seen increased
storm densities.
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In western Wisconsin
when I worked,
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2014 and 2013 especially
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we had some incredibly
intense early summer storms
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that leave 5 inches, 6 inches
of rain in a few hours.
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And we had multiple storms like
that come through our area.
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Some of these key
water resource impacts
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associated with these changes:
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in those wetter areas
we definitely see
increased flooding.
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And in our reservoir ecosystems,
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this is a big problem for them.
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Increased frequency of
harmful algal blooms
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in some of these systems,
with those increased flooding
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comes increased pollutant load
to those systems.
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And then,
these warmer summer temps.
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I think if you think back,
especially to 2014.
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In August we were
seeing surface temps
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in our lakes pushing 90 degrees,
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that's very abnormal
for Wisconsin lakes.
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Conflicting water use concerns,
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when we get into some
of these drier areas,
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especially in more of
our agricultural areas,
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we have that competition
for that ground water
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especially to grow
our commodities,
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and then we're seeing
impacts on lake levels
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and stream flows
associated with that.
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Changes in water levels,
I talked a bit about that,
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especially in the north when
we're in the drought period.
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Increased sediment
and nutrient loading,
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this is very much associated.
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We put more water on the land,
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we got the ability to
transport more
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pollutant loading to
our lake resources.
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And increased spread of
aquatic invasive species.
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As we're changing
these water temps,
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we're changing the
characteristics of these lakes
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that can support new species.
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And it's very common
for somebody to be fishing
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either on the Mississippi
River, the Great Lakes,
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or on another state,
and then the next day,
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be on a northern Wisconsin
or southern Wisconsin lake.
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So we have the vector
transport because of
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how mobile we are
in society today.
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This is just some
examples of some
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of those things I was
just chatting about.
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Be it a very high
level of nuisance,
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blue-green algal growth, or
increased sediment loading.
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That's a shot on Lake
Mendota with a stream
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coming in carrying a
very high sediment load.
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So as we kinda flip
the switch a bit,
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what makes a lake a lake?
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So we really have
to understand these
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physical, biological,
and chemical properties.
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But when they're
in proper balance,
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that's when we are at that state
06:57.866 --> 07:00.000 align:left position:12.5%,start line:89% size:77.5%
of high quality lake health.
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And so, often our
goal is to either
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sustain a lake in high
quality lake health
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or restore its lake health.
07:07.533 --> 07:11.166 align:left position:15%,start line:83% size:75%
So let's talk a bit about the
physical properties of lakes.
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We really have to start with
physical property of water.
07:14.066 --> 07:15.966 align:left position:17.5%,start line:83% size:72.5%
Water is
a pretty unique substance.
07:16.066 --> 07:18.166 align:left position:17.5%,start line:89% size:72.5%
It is a universal solvent,
07:18.266 --> 07:20.333 align:left position:25%,start line:83% size:65%
so lots of stuff will
dissolve into water,
07:20.433 --> 07:23.433 align:left position:12.5%,start line:83% size:77.5%
but its physical properties
are most unique because
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water actually weighs the most
at 4° Centigrade.
07:28.133 --> 07:30.700 align:left position:15%,start line:83% size:75%
And that's like many other
chemical constituents,
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when you heat them
up they get lighter.
07:32.900 --> 07:35.000 align:left position:15%,start line:89% size:75%
Well, not so much with water.
07:35.100 --> 07:38.300 align:left position:22.5%,start line:83% size:67.5%
So as you cool water
down, it gets lighter,
07:38.400 --> 07:39.766 align:left position:15%,start line:89% size:75%
and that's a very good thing,
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especially in Wisconsin
and the Upper Midwest,
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cause that's what make
ice float, simply.
07:44.200 --> 07:46.433 align:left position:22.5%,start line:83% size:67.5%
So and we don't have a
lot of this fresh water
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on the earth's surface either,
07:48.033 --> 07:50.600 align:left position:12.5%,start line:83% size:77.5%
less than 1% of the water on
the planet is fresh water,
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and then about 1/1000 th
of that is actually
07:54.466 --> 07:57.733 align:left position:25%,start line:5% size:65%
in our earth's
freshwater lakes.
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So these are very, very
unique water resources
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that we have in Wisconsin.
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So thinking a bit
about water then,
08:05.733 --> 08:07.166 align:left position:22.5%,start line:5% size:67.5%
you have to
understand a bit about
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how does that water
get to the lake
08:09.033 --> 08:11.233 align:left position:22.5%,start line:5% size:67.5%
and why does that
lake have water in it?
08:11.333 --> 08:13.566 align:left position:25%,start line:83% size:65%
So we think about
the hydrologic cycle.
08:13.666 --> 08:17.466 align:left position:15%,start line:83% size:75%
So in Wisconsin, we get about
30+ inches of rain a year.
08:17.566 --> 08:20.000 align:left position:17.5%,start line:83% size:72.5%
As that falls to the earth,
some of that
08:20.100 --> 08:24.266 align:left position:15%,start line:83% size:75%
is intercepted by vegetation
and evaporates right back up.
08:25.433 --> 08:27.266 align:left position:25%,start line:83% size:65%
Some of it falls on
our lakes and streams
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and evaporates back up,
08:29.766 --> 08:32.033 align:left position:25%,start line:83% size:65%
and some of it that
seeps into the earth,
08:32.133 --> 08:34.100 align:left position:15%,start line:89% size:75%
is taken up by the plants,
08:34.200 --> 08:37.200 align:left position:15%,start line:83% size:75%
and then evapotranspired back
by plant growth.
08:37.300 --> 08:40.000 align:left position:12.5%,start line:83% size:77.5%
But when we think about
these lake basins out there,
08:40.100 --> 08:43.000 align:left position:10%,start line:83% size:80%
as the glaciers did gouge these
holes in the earth's surface
08:43.100 --> 08:45.600 align:left position:25%,start line:83% size:65%
they simply filled
with groundwater.
08:45.700 --> 08:48.000 align:left position:12.5%,start line:83% size:77.5%
So when you see a lake,
what you're really looking at
08:48.100 --> 08:52.200 align:left position:12.5%,start line:83% size:77.5%
is the interception of that
lake surface representing
08:52.300 --> 08:55.300 align:left position:22.5%,start line:5% size:67.5%
the ground water
table in that area.
08:56.866 --> 08:59.100 align:left position:22.5%,start line:5% size:67.5%
So as far as lake
types in Wisconsin,
08:59.200 --> 09:03.566 align:left position:15%,start line:5% size:75%
we really can classify them
often by their water source,
09:03.666 --> 09:06.500 align:left position:15%,start line:83% size:75%
and so we have seepage lakes,
groundwater drainage lakes,
09:06.600 --> 09:10.833 align:left position:15%,start line:83% size:75%
drainage lakes, impoundments,
and then oxbow lakes.
09:10.933 --> 09:13.333 align:left position:27.5%,start line:83% size:62.5%
A seepage lake is
where an ice block
09:13.433 --> 09:15.933 align:left position:22.5%,start line:83% size:67.5%
was gouged into the
earth's surface,
09:16.033 --> 09:18.666 align:left position:22.5%,start line:83% size:67.5%
created this depression
in the earth's surface,
09:18.766 --> 09:20.566 align:left position:25%,start line:83% size:65%
and then as the
glaciers receded,
09:20.666 --> 09:22.866 align:left position:25%,start line:83% size:65%
it simply filled
with groundwater.
09:22.966 --> 09:25.700 align:left position:15%,start line:83% size:75%
And the major source of
water to our seepage lakes
09:25.800 --> 09:28.400 align:left position:15%,start line:83% size:75%
is groundwater, we have no
streams coming in or out,
09:28.500 --> 09:30.966 align:left position:25%,start line:83% size:65%
generally have
groundwater coming in
09:31.066 --> 09:33.933 align:left position:20%,start line:83% size:70%
one side of the lake
and going out the other.
09:34.033 --> 09:36.400 align:left position:15%,start line:83% size:75%
And so some of these lakes
are some of our lakes
09:36.500 --> 09:40.066 align:left position:12.5%,start line:83% size:77.5%
that are most susceptible
to water level fluctuations
09:40.166 --> 09:44.300 align:left position:22.5%,start line:77% size:67.5%
during periods of
drought, because if
we aren't getting that
09:44.400 --> 09:46.366 align:left position:10%,start line:89% size:80%
rainfall on the earth's surface,
09:46.466 --> 09:49.033 align:left position:22.5%,start line:83% size:67.5%
then those groundwater
levels go down
09:49.133 --> 09:52.000 align:left position:20%,start line:83% size:70%
and that's characterized
in our lake levels.
09:52.100 --> 09:54.333 align:left position:12.5%,start line:83% size:77.5%
The other thing that
happens on these systems too
09:54.433 --> 09:56.200 align:left position:22.5%,start line:83% size:67.5%
when we're in
drought-ier periods,
09:56.300 --> 09:59.266 align:left position:20%,start line:83% size:70%
the evaporation actually
from the lake's surface
09:59.366 --> 10:01.466 align:left position:12.5%,start line:89% size:77.5%
exceeds the amount of rainfall.
10:01.566 --> 10:05.366 align:left position:20%,start line:83% size:70%
So if we're in a 20 inch,
20-some inch rainfall year, and
10:05.466 --> 10:08.800 align:left position:15%,start line:77% size:75%
our normal is like 34 inches,
32 inches, something like
that,
10:08.900 --> 10:11.933 align:left position:15%,start line:5% size:75%
in a warm summer we
might have an evaporation
10:12.033 --> 10:14.933 align:left position:22.5%,start line:5% size:67.5%
that exceeds 30 inches
on that lake's surface.
10:15.033 --> 10:17.433 align:left position:22.5%,start line:5% size:67.5%
So the water budget
becomes out of balance
10:17.533 --> 10:19.533 align:left position:25%,start line:5% size:65%
and then our lake
levels go down.
10:19.633 --> 10:22.000 align:left position:22.5%,start line:5% size:67.5%
This is just a shot of
a piece of landscape
10:22.100 --> 10:24.166 align:left position:22.5%,start line:83% size:67.5%
up in Chippewa County,
where I work,
10:24.266 --> 10:26.433 align:left position:15%,start line:83% size:75%
where the glacier left
many of these small ponds
10:26.533 --> 10:29.833 align:left position:12.5%,start line:89% size:77.5%
and lakes across the landscape.
10:29.933 --> 10:32.833 align:left position:22.5%,start line:83% size:67.5%
The lake in the central
portion of the photo
10:32.933 --> 10:34.166 align:left position:22.5%,start line:89% size:67.5%
there is Round Lake.
10:34.266 --> 10:36.933 align:left position:10%,start line:89% size:80%
Has no inlet or out, Round Lake,
10:38.833 --> 10:41.033 align:left position:25%,start line:83% size:65%
and really it's just
groundwater coming in
10:41.133 --> 10:43.666 align:left position:22.5%,start line:83% size:67.5%
largely from the north,
the top of the photo
10:43.766 --> 10:45.166 align:left position:25%,start line:89% size:65%
and out the side,
10:45.266 --> 10:49.633 align:left position:12.5%,start line:83% size:77.5%
and it just represents that
groundwater level in the area.
10:49.733 --> 10:51.233 align:left position:12.5%,start line:89% size:77.5%
Groundwater drainage lakes,
10:51.333 --> 10:54.533 align:left position:10%,start line:83% size:80%
these are lakes that are
placed high up in the landscape
10:54.633 --> 10:57.866 align:left position:10%,start line:83% size:80%
but there's enough water coming
to them from the groundwater
10:57.966 --> 11:00.300 align:left position:12.5%,start line:89% size:77.5%
that they've created an outlet.
11:00.400 --> 11:04.066 align:left position:15%,start line:83% size:75%
And so they definitely are
dominated by groundwater
11:04.166 --> 11:06.066 align:left position:25%,start line:83% size:65%
coming through the
system, but they also
11:06.166 --> 11:08.766 align:left position:12.5%,start line:89% size:77.5%
have a stream leaving them.
11:08.866 --> 11:10.666 align:left position:27.5%,start line:83% size:62.5%
A good example of
that is Sand Lake,
11:10.766 --> 11:13.933 align:left position:22.5%,start line:83% size:67.5%
up on the Rusk/
Chippewa County border.
11:15.100 --> 11:17.000 align:left position:25%,start line:83% size:65%
This lake gathers
the groundwater
11:17.100 --> 11:19.233 align:left position:22.5%,start line:83% size:67.5%
from the groundwater
shed around it
11:19.333 --> 11:23.633 align:left position:12.5%,start line:83% size:77.5%
and then flows out to the
Chippewa River to the north.
11:23.733 --> 11:26.900 align:left position:15%,start line:83% size:75%
Drainage lakes, now we're
changing things up a bit.
11:27.000 --> 11:29.366 align:left position:12.5%,start line:83% size:77.5%
These types of lakes, where
they're more dominated,
11:29.466 --> 11:31.566 align:left position:22.5%,start line:83% size:67.5%
their water source,
by surface water,
11:31.666 --> 11:33.700 align:left position:25%,start line:83% size:65%
and groundwater's
less influential
11:33.800 --> 11:36.333 align:left position:22.5%,start line:83% size:67.5%
on the characteristics
of the lake.
11:36.433 --> 11:38.633 align:left position:15%,start line:83% size:75%
So we got a stream coming
in, stream going out,
11:38.733 --> 11:41.033 align:left position:20%,start line:83% size:70%
and because of that we
have a larger catchment,
11:41.133 --> 11:43.800 align:left position:12.5%,start line:83% size:77.5%
a larger watershed that's
bringing water to the lake,
11:43.900 --> 11:45.100 align:left position:12.5%,start line:89% size:77.5%
and I'll talk more about that.
11:45.200 --> 11:46.833 align:left position:12.5%,start line:89% size:77.5%
And as you think about this,
11:46.933 --> 11:49.866 align:left position:20%,start line:83% size:70%
a seepage lake often has
a very small catchment,
11:49.966 --> 11:52.233 align:left position:22.5%,start line:83% size:67.5%
and they tend to be our
higher quality lakes.
11:52.333 --> 11:54.766 align:left position:20%,start line:83% size:70%
Those are most of our
clear water lake systems
11:54.866 --> 11:56.866 align:left position:25%,start line:89% size:65%
across Wisconsin.
11:56.966 --> 11:58.500 align:left position:22.5%,start line:83% size:67.5%
And we get into
our drainage lakes.
11:58.600 --> 12:00.166 align:left position:10%,start line:89% size:80%
These are a bit more productive,
12:00.266 --> 12:02.933 align:left position:22.5%,start line:83% size:67.5%
and often water quality
is a little bit less
12:03.033 --> 12:05.400 align:left position:22.5%,start line:5% size:67.5%
than what we see in
our seepage lakes.
12:05.500 --> 12:09.266 align:left position:22.5%,start line:5% size:67.5%
This lake is Long Lake
up in Chippewa County.
12:10.400 --> 12:12.166 align:left position:22.5%,start line:83% size:67.5%
It's a pretty unique
lake ecosystem,
12:12.266 --> 12:15.433 align:left position:20%,start line:83% size:70%
and I'll talk more about
it's physical nature,
12:15.533 --> 12:18.933 align:left position:12.5%,start line:83% size:77.5%
but it drains a stream in from
the bottom of the photograph,
12:19.033 --> 12:20.900 align:left position:12.5%,start line:89% size:77.5%
up into the shore of the lake,
12:21.000 --> 12:23.666 align:left position:15%,start line:83% size:75%
and then it goes out
through another lake chain
12:23.766 --> 12:26.166 align:left position:10%,start line:5% size:80%
over to the Chippewa River also.
12:26.266 --> 12:28.200 align:left position:22.5%,start line:5% size:67.5%
It'd be a surface flow.
12:29.700 --> 12:33.300 align:left position:12.5%,start line:5% size:77.5%
Alright, impoundments are what
we have lots of in Wisconsin,
12:33.400 --> 12:35.200 align:left position:25%,start line:5% size:65%
or reservoirs,
they are referred to.
12:35.300 --> 12:37.233 align:left position:12.5%,start line:83% size:77.5%
And they're not really lakes--
they're dammed up rivers.
12:37.333 --> 12:40.233 align:left position:22.5%,start line:83% size:67.5%
These are often some
of our more significant
12:40.333 --> 12:42.933 align:left position:22.5%,start line:83% size:67.5%
management challenges,
because we're really
12:43.033 --> 12:45.466 align:left position:22.5%,start line:83% size:67.5%
taking an ecosystem
function of the river,
12:45.566 --> 12:48.600 align:left position:12.5%,start line:83% size:77.5%
which is to transport
material out of a watershed,
12:48.700 --> 12:50.266 align:left position:10%,start line:89% size:80%
and we're stopping that function
12:50.366 --> 12:53.233 align:left position:22.5%,start line:83% size:67.5%
and creating the
surface water body.
12:53.333 --> 12:55.900 align:left position:25%,start line:83% size:65%
This is Lake Altoona
on the east side
12:56.000 --> 12:58.200 align:left position:15%,start line:89% size:75%
of Eau Claire, Wisconsin,
12:58.300 --> 13:00.933 align:left position:12.5%,start line:83% size:77.5%
and it's a lake that I've
been engaged with management
13:01.033 --> 13:04.200 align:left position:22.5%,start line:83% size:67.5%
over the last 30 years
of my career.
13:04.300 --> 13:08.300 align:left position:25%,start line:83% size:65%
The Eau Claire River
is a very high sand port,
13:08.400 --> 13:10.933 align:left position:22.5%,start line:89% size:67.5%
sand transport system.
13:11.033 --> 13:13.966 align:left position:25%,start line:83% size:65%
When we first started
looking at this lake
13:14.066 --> 13:18.000 align:left position:22.5%,start line:83% size:67.5%
back in the early '80s,
the delta had moved
13:18.100 --> 13:20.533 align:left position:22.5%,start line:83% size:67.5%
about a third of the way
down the lake.
13:20.633 --> 13:23.266 align:left position:15%,start line:83% size:75%
The lake had filled
about a third full with sand.
13:23.366 --> 13:25.000 align:left position:22.5%,start line:5% size:67.5%
Its sedimentation rate
13:25.100 --> 13:28.066 align:left position:12.5%,start line:5% size:77.5%
was tens of thousands of yards
of sand every year.
13:28.166 --> 13:31.366 align:left position:20%,start line:5% size:70%
We estimated that as high
as 70,000 yards of sand a year
13:31.466 --> 13:34.133 align:left position:22.5%,start line:5% size:67.5%
were being deposited
in this system.
13:34.233 --> 13:36.100 align:left position:25%,start line:5% size:65%
It's a huge
management challenge.
13:36.200 --> 13:39.766 align:left position:15%,start line:5% size:75%
It comes down to, how much
does society value this lake?
13:39.866 --> 13:42.333 align:left position:25%,start line:5% size:65%
Is this lake going
to be sustained
13:42.433 --> 13:45.066 align:left position:22.5%,start line:5% size:67.5%
as part of the greater
Eau Claire community?
13:45.166 --> 13:47.033 align:left position:25%,start line:5% size:65%
And the people that
lived around the lake
13:47.133 --> 13:48.766 align:left position:10%,start line:5% size:80%
have a lake management district,
13:48.866 --> 13:50.766 align:left position:22.5%,start line:5% size:67.5%
and in concert with
Eau Claire County
13:50.866 --> 13:52.166 align:left position:15%,start line:5% size:75%
have found the resources.
13:52.266 --> 13:54.700 align:left position:20%,start line:5% size:70%
This has just finished
another dredging project
13:54.800 --> 13:57.300 align:left position:10%,start line:5% size:80%
literally a couple of weeks ago,
13:57.400 --> 14:01.000 align:left position:15%,start line:5% size:75%
and it was like the third
time it's been dredged,
14:01.100 --> 14:03.266 align:left position:25%,start line:5% size:65%
so they're dredging
almost once a decade
14:03.366 --> 14:05.400 align:left position:22.5%,start line:5% size:67.5%
and they took
almost 200,000 yards
14:05.500 --> 14:08.200 align:left position:12.5%,start line:89% size:77.5%
of sand out of this system.
14:08.300 --> 14:12.500 align:left position:12.5%,start line:83% size:77.5%
And that is just to
sustain it as a lake basin.
14:12.600 --> 14:14.800 align:left position:20%,start line:83% size:70%
Another interesting
lake we have in our area
14:14.900 --> 14:17.100 align:left position:22.5%,start line:83% size:67.5%
north of Eau Claire,
this is Lake Hallie
14:17.200 --> 14:19.133 align:left position:15%,start line:89% size:75%
in the village of Hallie.
14:19.233 --> 14:21.633 align:left position:12.5%,start line:89% size:77.5%
This lake is an Oxbow Lake,
14:21.733 --> 14:24.000 align:left position:20%,start line:83% size:70%
it was part of the
Chippewa River one time,
14:24.100 --> 14:27.333 align:left position:10%,start line:83% size:80%
and at the time of the cutover,
when a lot of the water,
14:27.433 --> 14:31.666 align:left position:12.5%,start line:83% size:77.5%
the timber was coming out
of the Chippewa River basin,
14:31.766 --> 14:34.633 align:left position:25%,start line:83% size:65%
this lake was used
for log storage.
14:34.733 --> 14:36.500 align:left position:27.5%,start line:83% size:62.5%
And so they put a
dam on this system
14:36.600 --> 14:39.233 align:left position:22.5%,start line:83% size:67.5%
and it's what we refer
to as a raised lake.
14:39.333 --> 14:41.500 align:left position:22.5%,start line:83% size:67.5%
So this lake only
has a mean depth of
14:41.600 --> 14:43.666 align:left position:25%,start line:83% size:65%
about 9 feet
in average depth.
14:43.766 --> 14:48.200 align:left position:15%,start line:83% size:75%
But the uniqueness about this
lake, up until the mid-1990s
14:48.300 --> 14:50.933 align:left position:12.5%,start line:83% size:77.5%
it had very, very, high levels
of groundwater flow into it.
14:51.033 --> 14:53.533 align:left position:25%,start line:83% size:65%
So it's a very
shallow ecosystem,
14:53.633 --> 14:54.966 align:left position:25%,start line:83% size:65%
we would think
it'd be very warm,
14:55.066 --> 14:57.100 align:left position:22.5%,start line:83% size:67.5%
but it had such high
groundwater inputs,
14:57.200 --> 14:59.866 align:left position:20%,start line:83% size:70%
we could sustain trout
in this lake year round,
14:59.966 --> 15:02.133 align:left position:25%,start line:83% size:65%
because on the far
end of the lake
15:02.233 --> 15:03.966 align:left position:25%,start line:83% size:65%
near the bottom
of the photograph,
15:04.066 --> 15:07.066 align:left position:22.5%,start line:83% size:67.5%
we had very high spring
flow into this system
15:07.166 --> 15:10.166 align:left position:22.5%,start line:83% size:67.5%
and it would keep the
water cool enough where
15:10.266 --> 15:14.033 align:left position:10%,start line:5% size:80%
it would sustain a stocked
trout fishery for the community.
15:14.133 --> 15:16.733 align:left position:15%,start line:5% size:75%
And the other thing that
that high groundwater flow
15:16.833 --> 15:20.100 align:left position:12.5%,start line:5% size:77.5%
did in to this system, was
it's warm water in the winter.
15:20.200 --> 15:21.833 align:left position:12.5%,start line:5% size:77.5%
Groundwater's about 50 degrees
15:21.933 --> 15:24.066 align:left position:25%,start line:5% size:65%
as it comes in to
lake ecosystems,
15:24.166 --> 15:27.466 align:left position:12.5%,start line:5% size:77.5%
and it kept the upper 20 acres
of this lake open
15:27.566 --> 15:30.433 align:left position:15%,start line:5% size:75%
all through the winter,
no matter how cold it got.
15:30.533 --> 15:33.233 align:left position:20%,start line:5% size:70%
Well, as we've developed
its groundwater shed,
15:33.333 --> 15:36.666 align:left position:25%,start line:83% size:65%
here on the left side
of the photograph,
15:37.700 --> 15:39.033 align:left position:10%,start line:89% size:80%
a couple of things have gone on.
15:39.133 --> 15:41.066 align:left position:22.5%,start line:83% size:67.5%
We've put some high
capacity wells in
15:41.166 --> 15:43.133 align:left position:22.5%,start line:83% size:67.5%
to provide water supply
for the community.
15:43.233 --> 15:45.666 align:left position:22.5%,start line:83% size:67.5%
But we've put a lot of
impervious surface down,
15:45.766 --> 15:49.200 align:left position:17.5%,start line:83% size:72.5%
and that impervious surface
now is running water off
15:49.300 --> 15:51.033 align:left position:22.5%,start line:83% size:67.5%
that used to infiltrate
into the ground.
15:51.133 --> 15:53.500 align:left position:30%,start line:83% size:60%
And we lost our
groundwater flow.
15:53.600 --> 15:55.633 align:left position:25%,start line:83% size:65%
And the consequences
of that have been
15:55.733 --> 15:58.566 align:left position:12.5%,start line:83% size:77.5%
we are no longer able to, say,
net trout,
15:58.666 --> 16:02.933 align:left position:12.5%,start line:83% size:77.5%
to keep this lake as a put and
take trout fishery in the summer
16:03.033 --> 16:05.600 align:left position:22.5%,start line:83% size:67.5%
so the lake has lost
that ecosystem service
16:05.700 --> 16:07.133 align:left position:30%,start line:89% size:60%
to the community.
16:07.233 --> 16:09.333 align:left position:25%,start line:83% size:65%
Because we have less
groundwater coming in
16:09.433 --> 16:12.166 align:left position:12.5%,start line:83% size:77.5%
we don't keep the lake
open anymore in the winter.
16:12.266 --> 16:15.166 align:left position:12.5%,start line:83% size:77.5%
And in the mid-'90s, when
some fishermen were out there,
16:15.266 --> 16:17.033 align:left position:12.5%,start line:89% size:77.5%
we got some calls in the office
16:17.133 --> 16:20.000 align:left position:22.5%,start line:83% size:67.5%
and said, "The fish are
dying in Lake Hallie."
16:20.100 --> 16:21.900 align:left position:10%,start line:5% size:80%
And, sure enough, now this lake,
16:22.000 --> 16:25.000 align:left position:12.5%,start line:5% size:77.5%
we have to sustain the fishery
in the lake
16:25.100 --> 16:26.933 align:left position:10%,start line:5% size:80%
through a winter aeration system
16:27.033 --> 16:29.933 align:left position:15%,start line:5% size:75%
because we don't have that
open water area out there.
16:30.033 --> 16:34.566 align:left position:10%,start line:5% size:80%
And I'll talk more about why
that occurs in lakes like this.
16:34.666 --> 16:36.200 align:left position:12.5%,start line:5% size:77.5%
So as we think now more about,
16:36.300 --> 16:38.166 align:left position:12.5%,start line:5% size:77.5%
that's the lake types we have,
16:38.266 --> 16:41.233 align:left position:22.5%,start line:5% size:67.5%
we have these physical
characteristics
that impacts lakes,
16:41.333 --> 16:43.466 align:left position:15%,start line:83% size:75%
and we'll talk about
mixing and stratification,
16:43.566 --> 16:45.466 align:left position:12.5%,start line:89% size:77.5%
why lake depth's important,
16:45.566 --> 16:47.933 align:left position:25%,start line:83% size:65%
how long water
stays in a system,
16:48.033 --> 16:49.633 align:left position:10%,start line:89% size:80%
retention time or flushing rate,
16:49.733 --> 16:53.900 align:left position:12.5%,start line:83% size:77.5%
and watershed or drainage
basin area to lake area ratio,
16:55.200 --> 16:57.500 align:left position:12.5%,start line:83% size:77.5%
where this lake is
positioned in the landscape,
16:57.600 --> 17:00.366 align:left position:25%,start line:83% size:65%
and influences of
watershed runoff.
17:00.466 --> 17:02.800 align:left position:15%,start line:83% size:75%
So when we think about
mixing and stratification,
17:02.900 --> 17:06.800 align:left position:20%,start line:83% size:70%
most lakes in Wisconsin,
we call them dimictic.
17:06.900 --> 17:09.400 align:left position:15%,start line:83% size:75%
That's simply a term
that means our lakes mix,
17:09.500 --> 17:11.066 align:left position:12.5%,start line:89% size:77.5%
top to bottom, twice a year.
17:11.166 --> 17:12.900 align:left position:25%,start line:83% size:65%
So if we think why
does this happen,
17:13.000 --> 17:15.200 align:left position:12.5%,start line:89% size:77.5%
as I was talking about earlier,
17:15.300 --> 17:18.633 align:left position:22.5%,start line:83% size:67.5%
water is most dense
at four degrees,
17:18.733 --> 17:21.500 align:left position:25%,start line:83% size:65%
so in the spring
where the ice is off,
17:21.600 --> 17:24.333 align:left position:15%,start line:83% size:75%
what we see when we're--let's
start with winter.
17:24.433 --> 17:26.500 align:left position:12.5%,start line:89% size:77.5%
As we're coming out of winter,
17:26.600 --> 17:30.066 align:left position:15%,start line:83% size:75%
and we have zero degree water
virtually on the surface.
17:30.166 --> 17:32.733 align:left position:12.5%,start line:83% size:77.5%
So that's the lightest water
in the lake at that time,
17:32.833 --> 17:34.900 align:left position:10%,start line:89% size:80%
that's why that ice is floating.
17:35.000 --> 17:36.833 align:left position:12.5%,start line:89% size:77.5%
And then as that ice melts,
17:36.933 --> 17:39.800 align:left position:25%,start line:83% size:65%
that lake water warms
to about four degrees,
17:39.900 --> 17:42.533 align:left position:15%,start line:83% size:75%
and once it's the same
temperature top to bottom,
17:42.633 --> 17:44.266 align:left position:12.5%,start line:89% size:77.5%
or what we call isothermal,
17:44.366 --> 17:46.900 align:left position:15%,start line:89% size:75%
that lake easily is mixed.
17:47.000 --> 17:50.100 align:left position:12.5%,start line:83% size:77.5%
So if we put wind energy
with our spring wind events
17:50.200 --> 17:53.700 align:left position:12.5%,start line:83% size:77.5%
onto a lake's surface, then we
get the spring mixing event.
17:53.800 --> 17:55.766 align:left position:30%,start line:83% size:60%
And we call that
spring turnover.
17:55.866 --> 17:58.000 align:left position:25%,start line:83% size:65%
And that really
rejuvenates the lake,
17:58.100 --> 18:00.666 align:left position:20%,start line:83% size:70%
so then our water
chemistry in this system
18:00.766 --> 18:02.766 align:left position:15%,start line:89% size:75%
is the same top to bottom.
18:02.866 --> 18:05.300 align:left position:12.5%,start line:83% size:77.5%
It's just like kinda putting
a blender into the lake,
18:05.400 --> 18:07.133 align:left position:22.5%,start line:89% size:67.5%
it mixes top to bottom.
18:07.233 --> 18:08.966 align:left position:25%,start line:83% size:65%
So as we come out
of spring here,
18:09.066 --> 18:11.933 align:left position:10%,start line:83% size:80%
as we approach that time period
in a month or so from now,
18:12.033 --> 18:14.933 align:left position:25%,start line:83% size:65%
that summer condition
begins to set up.
18:15.033 --> 18:19.166 align:left position:10%,start line:83% size:80%
As that surface water warms,
as that lake temperature warms,
18:19.266 --> 18:21.833 align:left position:22.5%,start line:83% size:67.5%
that water now
becomes lighter water,
18:21.933 --> 18:25.066 align:left position:10%,start line:83% size:80%
and it sets up a stratification
is what we call it.
18:25.166 --> 18:27.900 align:left position:15%,start line:83% size:75%
The lake actually layers
into three distinct layers
18:28.000 --> 18:30.100 align:left position:15%,start line:89% size:75%
as we go into the summer.
18:31.266 --> 18:33.966 align:left position:22.5%,start line:83% size:67.5%
So that top layer
over there on summer
18:34.066 --> 18:36.600 align:left position:22.5%,start line:89% size:67.5%
is called a epilimnion,
18:36.700 --> 18:39.533 align:left position:17.5%,start line:83% size:72.5%
and it's a fancy term for
the top layer of the lake,
18:39.633 --> 18:41.600 align:left position:25%,start line:83% size:65%
and that layer is
really dependent
18:41.700 --> 18:43.500 align:left position:12.5%,start line:89% size:77.5%
somewhat on the depth of lake,
18:43.600 --> 18:45.966 align:left position:22.5%,start line:5% size:67.5%
but how warm or
cool the summer is.
18:46.066 --> 18:47.900 align:left position:12.5%,start line:5% size:77.5%
So in most lakes in the summer,
18:48.000 --> 18:50.333 align:left position:10%,start line:5% size:80%
that top layer is anywhere from,
18:50.433 --> 18:54.633 align:left position:20%,start line:5% size:70%
it could be as little as
six feet, or two meters,
18:54.733 --> 18:56.700 align:left position:25%,start line:5% size:65%
on some lakes that
are very protected
18:56.800 --> 18:59.266 align:left position:22.5%,start line:5% size:67.5%
that do not get much
wind energy on them,
18:59.366 --> 19:03.166 align:left position:22.5%,start line:5% size:67.5%
to up to ten meters or
approximately 30 feet.
19:03.266 --> 19:06.266 align:left position:22.5%,start line:83% size:67.5%
And then below that is
the transitional layer,
19:06.366 --> 19:08.100 align:left position:15%,start line:89% size:75%
we call that the thermocline,
19:08.200 --> 19:10.166 align:left position:25%,start line:83% size:65%
and any people who
love to swim or dive,
19:10.266 --> 19:12.633 align:left position:10%,start line:89% size:80%
when you swim down into the lake
19:12.733 --> 19:14.833 align:left position:22.5%,start line:83% size:67.5%
you'll feel that great
temperature change,
19:14.933 --> 19:16.800 align:left position:22.5%,start line:83% size:67.5%
and that happens
very, very quickly.
19:16.900 --> 19:19.733 align:left position:22.5%,start line:83% size:67.5%
Then our coolest water,
our most dense water,
19:19.833 --> 19:21.566 align:left position:10%,start line:89% size:80%
stays on the bottom of the lake.
19:21.666 --> 19:23.933 align:left position:15%,start line:89% size:75%
So then as we move into fall,
19:24.033 --> 19:26.500 align:left position:22.5%,start line:83% size:67.5%
as that top layer then
begins to cool again,
19:26.600 --> 19:29.033 align:left position:22.5%,start line:83% size:67.5%
once it reaches four
degrees centigrade
19:29.133 --> 19:32.533 align:left position:12.5%,start line:83% size:77.5%
or 39 degrees Fahrenheit, it
becomes the most dense water
19:32.633 --> 19:34.400 align:left position:12.5%,start line:89% size:77.5%
in the lake so what's it do?
19:34.500 --> 19:35.833 align:left position:30%,start line:89% size:60%
It simply sinks.
19:35.933 --> 19:38.033 align:left position:22.5%,start line:83% size:67.5%
And then causes this
fall mixing period
19:38.133 --> 19:40.666 align:left position:25%,start line:83% size:65%
that will continue on
until ice up.
19:40.766 --> 19:45.133 align:left position:12.5%,start line:5% size:77.5%
And then again we rejuvenate
that whole lake ecosystem.
19:45.233 --> 19:49.400 align:left position:12.5%,start line:5% size:77.5%
So let's go into, you know,
why does lake depth matter?
19:51.166 --> 19:53.233 align:left position:22.5%,start line:5% size:67.5%
Deep lakes, definitely
we'd use this term,
19:53.333 --> 19:55.266 align:left position:15%,start line:5% size:75%
they layer up, they stratify,
19:55.366 --> 19:57.733 align:left position:22.5%,start line:83% size:67.5%
and shallow lakes stay
continuously mixed
19:57.833 --> 19:59.800 align:left position:22.5%,start line:83% size:67.5%
so there's a couple of
things going on here
19:59.900 --> 20:03.300 align:left position:15%,start line:83% size:75%
that really can influence
lake characteristics,
20:03.400 --> 20:05.766 align:left position:20%,start line:83% size:70%
especially in the summer
and in the winter.
20:05.866 --> 20:07.566 align:left position:25%,start line:83% size:65%
In our deep lakes,
what's going on,
20:07.666 --> 20:09.266 align:left position:15%,start line:89% size:75%
and in our shallow lakes,
20:09.366 --> 20:11.200 align:left position:15%,start line:89% size:75%
you think of our lakes again,
20:11.300 --> 20:13.033 align:left position:10%,start line:89% size:80%
they're 10,000 years old, right?
20:13.133 --> 20:15.400 align:left position:12.5%,start line:83% size:77.5%
So we've been growing plants
and algae in these systems
20:15.500 --> 20:18.466 align:left position:25%,start line:83% size:65%
for 10,000 years,
and we've accumulated
20:18.566 --> 20:20.700 align:left position:25%,start line:5% size:65%
all this really rich,
organic sediment
20:20.800 --> 20:22.233 align:left position:15%,start line:5% size:75%
on the bottom of these lakes.
20:22.333 --> 20:24.366 align:left position:12.5%,start line:5% size:77.5%
Well what happens when you put
20:24.466 --> 20:27.766 align:left position:12.5%,start line:5% size:77.5%
organic matter and oxygen
together, you grow bacteria.
20:27.866 --> 20:30.800 align:left position:15%,start line:5% size:75%
Same thing happens in your
compost pile in your yard,
20:30.900 --> 20:32.733 align:left position:12.5%,start line:5% size:77.5%
you're decomposing that, well,
20:32.833 --> 20:34.400 align:left position:22.5%,start line:5% size:67.5%
that same process is
virtually occurring
20:34.500 --> 20:37.000 align:left position:22.5%,start line:5% size:67.5%
on the bottom of every
lake in the state
20:37.100 --> 20:39.800 align:left position:15%,start line:5% size:75%
and it goes on 24/7, 365.
20:39.900 --> 20:43.066 align:left position:15%,start line:5% size:75%
Well, now does that
bottom portion of the lake
20:43.166 --> 20:45.466 align:left position:15%,start line:5% size:75%
maintained as habitat or not?
20:45.566 --> 20:47.000 align:left position:22.5%,start line:5% size:67.5%
Well it may or may not,
20:47.100 --> 20:48.733 align:left position:10%,start line:5% size:80%
it depends upon the volume of it
20:48.833 --> 20:50.633 align:left position:22.5%,start line:5% size:67.5%
and the rate at
which those bacteria
20:50.733 --> 20:53.266 align:left position:15%,start line:5% size:75%
are consuming that oxygen out
of the bottom of the lake.
20:53.366 --> 20:55.966 align:left position:22.5%,start line:5% size:67.5%
So in our state we only
have a handful of lakes
20:56.066 --> 20:59.333 align:left position:12.5%,start line:5% size:77.5%
where the oxygen concentration
remains high enough
20:59.433 --> 21:01.600 align:left position:22.5%,start line:5% size:67.5%
to sustain a fishery
in that portion
21:01.700 --> 21:03.300 align:left position:12.5%,start line:5% size:77.5%
of the lake as a trout fishery.
21:03.400 --> 21:05.466 align:left position:22.5%,start line:5% size:67.5%
So that's why we have
Trout Lake, Green Lake,
21:05.566 --> 21:07.433 align:left position:22.5%,start line:5% size:67.5%
are a couple of the
more common lakes,
21:07.533 --> 21:10.733 align:left position:22.5%,start line:5% size:67.5%
that still have
lake trout in them.
21:10.833 --> 21:13.300 align:left position:25%,start line:5% size:65%
But we also need that
oxygen down there
21:13.400 --> 21:15.633 align:left position:22.5%,start line:5% size:67.5%
for many of our
cool water species,
21:15.733 --> 21:17.933 align:left position:22.5%,start line:5% size:67.5%
especially our walleye
fisheries because
21:18.033 --> 21:21.766 align:left position:12.5%,start line:5% size:77.5%
there's a fish species named
ciscothat lives down there
21:21.866 --> 21:25.066 align:left position:15%,start line:5% size:75%
and they need that cool water
place for the cisco to live.
21:25.166 --> 21:26.933 align:left position:25%,start line:5% size:65%
That is a very
important resource
21:27.033 --> 21:30.000 align:left position:22.5%,start line:5% size:67.5%
for sustaining many of
our walleye fisheries.
21:30.100 --> 21:32.633 align:left position:15%,start line:5% size:75%
It doesn't need it in all
lakes, but some lakes.
21:32.733 --> 21:35.700 align:left position:12.5%,start line:5% size:77.5%
So if we've changed the
characteristics of the lake,
21:35.800 --> 21:37.100 align:left position:12.5%,start line:5% size:77.5%
where we've increased the rate
21:37.200 --> 21:39.166 align:left position:22.5%,start line:5% size:67.5%
of that organic
material being produced
21:39.266 --> 21:41.900 align:left position:15%,start line:5% size:75%
by putting more nutrients
into that system,
21:42.000 --> 21:45.366 align:left position:22.5%,start line:5% size:67.5%
we increase the rate at
what oxygen depletes.
21:45.466 --> 21:48.366 align:left position:12.5%,start line:5% size:77.5%
If we don't have enough oxygen
21:48.466 --> 21:50.366 align:left position:22.5%,start line:5% size:67.5%
stored in that
portion of the lake
21:50.466 --> 21:53.000 align:left position:17.5%,start line:5% size:72.5%
because of this high rate
of sediment decomposition,
21:53.100 --> 21:57.133 align:left position:12.5%,start line:5% size:77.5%
that area goes without
oxygen, we call that anoxia,
21:57.233 --> 22:00.400 align:left position:25%,start line:5% size:65%
and then fish species
and other aquatic life
22:00.500 --> 22:01.966 align:left position:15%,start line:5% size:75%
can't really live down there.
22:02.066 --> 22:03.600 align:left position:12.5%,start line:5% size:77.5%
Some invertebrate species can,
22:03.700 --> 22:06.333 align:left position:22.5%,start line:5% size:67.5%
that can sustain really
low oxygen levels,
22:06.433 --> 22:07.966 align:left position:25%,start line:5% size:65%
but the things we
might relate to
22:08.066 --> 22:09.866 align:left position:22.5%,start line:5% size:67.5%
can't live in that
portion of the lake.
22:09.966 --> 22:12.466 align:left position:25%,start line:5% size:65%
So conversely, in
a shallow lake,
22:12.566 --> 22:14.966 align:left position:12.5%,start line:5% size:77.5%
that same process is going on.
22:15.066 --> 22:17.666 align:left position:20%,start line:83% size:70%
And as long as that lake
stays continually mixed
22:17.766 --> 22:20.466 align:left position:22.5%,start line:83% size:67.5%
we're fine, but the
whole chemistry changes
22:20.566 --> 22:23.100 align:left position:22.5%,start line:83% size:67.5%
when we go without
oxygen in the bottom
22:23.200 --> 22:25.466 align:left position:25%,start line:83% size:65%
of the lakes down
there and lakes start
22:25.566 --> 22:28.600 align:left position:15%,start line:83% size:75%
to release nutrients back
into the water column.
22:28.700 --> 22:31.033 align:left position:15%,start line:83% size:75%
Well, that's not a problem
up in our deep lake,
22:31.133 --> 22:33.000 align:left position:25%,start line:83% size:65%
where those nutrients
stay down there
22:33.100 --> 22:34.966 align:left position:15%,start line:83% size:75%
on the bottom of the
lake and aren't available
22:35.066 --> 22:38.200 align:left position:12.5%,start line:83% size:77.5%
for algal production
through the growing season,
22:38.300 --> 22:39.933 align:left position:25%,start line:83% size:65%
but in some of
our shallow lakes,
22:40.033 --> 22:41.633 align:left position:22.5%,start line:83% size:67.5%
which one I'm gonna
show you shortly,
22:41.733 --> 22:43.966 align:left position:25%,start line:83% size:65%
that can be extremely
problematic,
22:44.066 --> 22:46.266 align:left position:25%,start line:5% size:65%
cause we call that
internal loading,
22:46.366 --> 22:48.500 align:left position:25%,start line:5% size:65%
or the ability of the
lake to self-fertilize
22:48.600 --> 22:50.600 align:left position:12.5%,start line:5% size:77.5%
itself from its lake sediments.
22:50.700 --> 22:52.900 align:left position:22.5%,start line:5% size:67.5%
And in some of those
lake ecosystems,
22:53.000 --> 22:55.400 align:left position:25%,start line:5% size:65%
we have approximately
200 of these lakes,
22:55.500 --> 22:59.600 align:left position:10%,start line:5% size:80%
we call them polymictic, or
they mix many times per summer,
22:59.700 --> 23:02.733 align:left position:22.5%,start line:5% size:67.5%
and every time they mix
after a period of anoxia
23:02.833 --> 23:05.333 align:left position:25%,start line:5% size:65%
or when that sediment
water interface
23:05.433 --> 23:07.966 align:left position:22.5%,start line:5% size:67.5%
has gone without oxygen
for several days,
23:08.066 --> 23:10.433 align:left position:20%,start line:83% size:70%
you get a pulse of
nutrients buildup there,
23:10.533 --> 23:13.100 align:left position:12.5%,start line:83% size:77.5%
boom, the lake mixes, where
does that nutrients go,
23:13.200 --> 23:15.766 align:left position:15%,start line:83% size:75%
it goes up in the water
column, it becomes available.
23:15.866 --> 23:18.466 align:left position:22.5%,start line:83% size:67.5%
The other issue
with shallow lakes,
23:18.566 --> 23:21.266 align:left position:22.5%,start line:83% size:67.5%
especially lakes,
let's say, shallower
23:21.366 --> 23:24.233 align:left position:22.5%,start line:83% size:67.5%
than maybe 12, 13
feet and shallower,
23:24.333 --> 23:27.033 align:left position:20%,start line:83% size:70%
when that ice layer goes
on in the winter time
23:27.133 --> 23:28.633 align:left position:15%,start line:89% size:75%
that creates a barrier now
23:28.733 --> 23:30.633 align:left position:22.5%,start line:83% size:67.5%
between the atmosphere
and the lake.
23:30.733 --> 23:33.766 align:left position:12.5%,start line:83% size:77.5%
Well, as long as sunlight is
getting through that ice layer
23:33.866 --> 23:36.800 align:left position:22.5%,start line:83% size:67.5%
the lake still sustains
a relatively high amount
23:36.900 --> 23:39.900 align:left position:12.5%,start line:83% size:77.5%
of dissolved oxygen to
sustain a fishery in there.
23:40.000 --> 23:42.433 align:left position:22.5%,start line:83% size:67.5%
But when we put the
snow on that ice,
23:42.533 --> 23:44.700 align:left position:12.5%,start line:83% size:77.5%
we turn the lights out,
when we turn the lights out,
23:44.800 --> 23:46.400 align:left position:25%,start line:83% size:65%
we turn off the
algal production,
23:46.500 --> 23:49.200 align:left position:15%,start line:83% size:75%
the ability of that lake
to produce its own oxygen.
23:49.300 --> 23:51.600 align:left position:15%,start line:83% size:75%
Then that fishery becomes
at the mercy
23:51.700 --> 23:54.700 align:left position:15%,start line:83% size:75%
of the amount of oxygen
that's stored in that water.
23:54.800 --> 23:57.200 align:left position:22.5%,start line:83% size:67.5%
And so, if you hear the
term "winter-kill lakes,"
23:57.300 --> 24:01.066 align:left position:17.5%,start line:83% size:72.5%
well, what's really gone on
in that system is the lake,
24:01.166 --> 24:04.866 align:left position:10%,start line:5% size:80%
simply because of the bacterial
decomposition in the sediments,
24:04.966 --> 24:08.266 align:left position:12.5%,start line:5% size:77.5%
has used up all the oxygen
in the lake, and the fish die.
24:08.366 --> 24:12.033 align:left position:20%,start line:5% size:70%
So lake depth definitely
does matter and impact.
24:12.133 --> 24:14.866 align:left position:15%,start line:5% size:75%
This is a lake that I've
worked on for many years now.
24:14.966 --> 24:18.700 align:left position:22.5%,start line:83% size:67.5%
Now, folks, if you
have your own lakes,
24:18.800 --> 24:22.000 align:left position:12.5%,start line:83% size:77.5%
and you want to get like an
average depth of your lake,
24:22.100 --> 24:25.733 align:left position:12.5%,start line:83% size:77.5%
this is Cedar Lake, it's up in
Polk and St. Croix Counties.
24:25.833 --> 24:28.100 align:left position:15%,start line:89% size:75%
This is a polymictic lake.
24:28.200 --> 24:31.066 align:left position:22.5%,start line:83% size:67.5%
Well, if you look at
that darker gray center
24:31.166 --> 24:33.000 align:left position:12.5%,start line:89% size:77.5%
where the words Cedar Lake are,
24:33.100 --> 24:35.266 align:left position:22.5%,start line:83% size:67.5%
that's the only
portion of the lake
24:35.366 --> 24:37.433 align:left position:25%,start line:83% size:65%
that's about 25
feet or different.
24:37.533 --> 24:39.766 align:left position:22.5%,start line:83% size:67.5%
The wind fetch on this
lake is north to south,
24:39.866 --> 24:42.066 align:left position:12.5%,start line:89% size:77.5%
it's almost two miles long,
24:43.233 --> 24:44.600 align:left position:25%,start line:83% size:65%
and what happens
with Cedar Lake is
24:44.700 --> 24:49.333 align:left position:12.5%,start line:83% size:77.5%
that 25 foot from really
about 18 feet and shallower,
24:49.433 --> 24:51.266 align:left position:10%,start line:89% size:80%
when we go to quiescent periods,
24:51.366 --> 24:53.500 align:left position:10%,start line:89% size:80%
not much wind during the summer,
24:53.600 --> 24:55.600 align:left position:22.5%,start line:83% size:67.5%
Cedar Lake will set
up and stratify,
24:55.700 --> 24:58.900 align:left position:25%,start line:83% size:65%
but has very enriched
bottom sediments.
24:59.000 --> 25:02.366 align:left position:20%,start line:83% size:70%
Those bottom sediments
are releasing phosphorus
25:02.466 --> 25:05.900 align:left position:15%,start line:83% size:75%
into that lake water and then
when we get a thunder storm
25:06.000 --> 25:08.033 align:left position:25%,start line:83% size:65%
or a large wind event
that comes through,
25:08.133 --> 25:10.033 align:left position:12.5%,start line:89% size:77.5%
the lake will mix top to bottom
25:10.133 --> 25:12.133 align:left position:22.5%,start line:83% size:67.5%
and we'll end up
with an algal bloom.
25:12.233 --> 25:14.300 align:left position:25%,start line:83% size:65%
But one of the things
I wanted to show you
25:14.400 --> 25:15.733 align:left position:15%,start line:89% size:75%
here with this slide was,
25:15.833 --> 25:18.266 align:left position:20%,start line:83% size:70%
you can simply calculate
your mean depth
25:18.366 --> 25:20.000 align:left position:15%,start line:89% size:75%
of your lake very easily,
25:20.100 --> 25:22.966 align:left position:15%,start line:83% size:75%
and it's simply the volume
of water in the lake,
25:23.066 --> 25:27.200 align:left position:12.5%,start line:83% size:77.5%
which in this lake it's
about 20,000 plus acre feet,
25:27.300 --> 25:29.533 align:left position:12.5%,start line:89% size:77.5%
divided by the number of acres,
25:29.633 --> 25:32.533 align:left position:22.5%,start line:83% size:67.5%
and that gives us
your mean depth of 18.
25:32.633 --> 25:34.233 align:left position:25%,start line:5% size:65%
So you can do this
in cubic meters,
25:34.333 --> 25:36.800 align:left position:15%,start line:5% size:75%
and square meters on top,
25:36.900 --> 25:39.066 align:left position:22.5%,start line:5% size:67.5%
but this information is
usually available to you
25:39.166 --> 25:41.533 align:left position:15%,start line:5% size:75%
on any of your lake maps.
25:41.633 --> 25:44.033 align:left position:25%,start line:5% size:65%
Retention time
and flushing rate,
25:44.133 --> 25:45.533 align:left position:22.5%,start line:5% size:67.5%
this is very important.
25:45.633 --> 25:50.200 align:left position:12.5%,start line:5% size:77.5%
Algae need times to get off
many generations to live,
25:50.300 --> 25:53.200 align:left position:15%,start line:5% size:75%
and pollutant flushing is
also dependent on this.
25:53.300 --> 25:56.266 align:left position:22.5%,start line:83% size:67.5%
So when we use the
term retention time,
25:56.366 --> 25:59.400 align:left position:22.5%,start line:83% size:67.5%
that is simply, if you
drained your lake down,
25:59.500 --> 26:02.533 align:left position:27.5%,start line:83% size:62.5%
how long would it
take it to refill?
26:02.633 --> 26:05.233 align:left position:22.5%,start line:83% size:67.5%
The inverse of that
is flushing rate,
26:05.333 --> 26:07.433 align:left position:25%,start line:83% size:65%
and that would
give you, in time,
26:07.533 --> 26:11.433 align:left position:22.5%,start line:83% size:67.5%
how many times per year
your lake would flush.
26:11.533 --> 26:13.766 align:left position:22.5%,start line:83% size:67.5%
So when we think about
a lake like Long Lake,
26:13.866 --> 26:16.600 align:left position:22.5%,start line:83% size:67.5%
that is relatively high
up in the landscape,
26:16.700 --> 26:18.866 align:left position:27.5%,start line:83% size:62.5%
it's a deep lake,
it's a large lake,
26:18.966 --> 26:21.300 align:left position:25%,start line:83% size:65%
without a lot of
water coming into it.
26:21.400 --> 26:24.400 align:left position:25%,start line:83% size:65%
If we drained Long
Lake out totally
26:24.500 --> 26:27.333 align:left position:15%,start line:83% size:75%
it would take seven years
for that lake to fill up.
26:27.433 --> 26:30.466 align:left position:22.5%,start line:83% size:67.5%
So water stays in that
lake at least seven,
26:30.566 --> 26:32.066 align:left position:12.5%,start line:89% size:77.5%
but when we think about a mass
26:32.166 --> 26:34.233 align:left position:22.5%,start line:83% size:67.5%
of pollutants coming
in to a system,
26:34.333 --> 26:37.866 align:left position:22.5%,start line:83% size:67.5%
it takes about three of
these flushing times,
26:37.966 --> 26:40.333 align:left position:20%,start line:83% size:70%
or the lake has to fill,
empty, fill, empty,
26:40.433 --> 26:42.400 align:left position:25%,start line:83% size:65%
three times before we
move the pollutant on.
26:42.500 --> 26:45.033 align:left position:22.5%,start line:83% size:67.5%
So it can have an
impact for a long time,
26:45.133 --> 26:46.733 align:left position:12.5%,start line:5% size:77.5%
so if we get a big storm event,
26:46.833 --> 26:49.033 align:left position:22.5%,start line:5% size:67.5%
would bring a lot
of pollutant loading
26:49.133 --> 26:51.300 align:left position:15%,start line:5% size:75%
or phosphorus into Long Lake,
26:51.400 --> 26:53.133 align:left position:22.5%,start line:5% size:67.5%
it would be potentially
26:53.233 --> 26:55.933 align:left position:22.5%,start line:5% size:67.5%
impacting water quality
for a couple of decades.
26:56.033 --> 26:58.933 align:left position:12.5%,start line:5% size:77.5%
That's opposed to Lake Altoona
which I showed you earlier,
26:59.033 --> 27:02.000 align:left position:15%,start line:5% size:75%
where they have a large river
coming into that system,
27:02.100 --> 27:04.300 align:left position:10%,start line:5% size:80%
it's a relatively shallow basin.
27:04.400 --> 27:08.200 align:left position:15%,start line:5% size:75%
The average time water stays
in Lake Altoona is 22 days,
27:08.300 --> 27:11.433 align:left position:22.5%,start line:5% size:67.5%
but when we get into
a high flow event,
27:11.533 --> 27:13.833 align:left position:22.5%,start line:5% size:67.5%
it may be only in
there less than a day,
27:13.933 --> 27:16.000 align:left position:22.5%,start line:5% size:67.5%
a few hours, during
a flood event.
27:16.100 --> 27:18.733 align:left position:22.5%,start line:5% size:67.5%
So we can take a lot
of pollutant loading
27:18.833 --> 27:21.233 align:left position:22.5%,start line:5% size:67.5%
and flush it through
a system like that.
27:21.333 --> 27:23.866 align:left position:12.5%,start line:5% size:77.5%
The other impact on lakes
when we think about that is
27:23.966 --> 27:28.166 align:left position:12.5%,start line:83% size:77.5%
how much land physically
drains to each acre of lake.
27:28.266 --> 27:32.266 align:left position:12.5%,start line:83% size:77.5%
When we have lakes that have
less than ten acres of land,
27:32.366 --> 27:35.433 align:left position:22.5%,start line:83% size:67.5%
ten acres of watershed
to each acre of lake,
27:35.533 --> 27:38.200 align:left position:12.5%,start line:83% size:77.5%
those tend to be our higher
water quality systems.
27:38.300 --> 27:40.433 align:left position:22.5%,start line:83% size:67.5%
There just isn't enough
land mass out there
27:40.533 --> 27:42.933 align:left position:15%,start line:83% size:75%
to produce enough inputs
of sediments and nutrients
27:43.033 --> 27:45.633 align:left position:22.5%,start line:83% size:67.5%
to impact water
chemistry that much.
27:45.733 --> 27:49.366 align:left position:15%,start line:83% size:75%
And that's opposed to some
of our lake ecosystems,
27:49.466 --> 27:52.133 align:left position:25%,start line:83% size:65%
and I'll talk about
that, or reservoirs,
27:52.233 --> 27:55.166 align:left position:15%,start line:83% size:75%
where we may often have
two, three thousand acres
27:55.266 --> 27:57.466 align:left position:22.5%,start line:83% size:67.5%
of land draining to
every surface acre
27:57.566 --> 28:00.133 align:left position:15%,start line:89% size:75%
in a reservoir ecosystem.
28:00.233 --> 28:03.033 align:left position:22.5%,start line:83% size:67.5%
So landscape
position, simply think
28:03.133 --> 28:04.833 align:left position:22.5%,start line:83% size:67.5%
about the land of
Wisconsin on a tilt,
28:04.933 --> 28:07.133 align:left position:25%,start line:83% size:65%
or your watershed
a bit on a tilt.
28:07.233 --> 28:10.533 align:left position:10%,start line:83% size:80%
Those lakes high up in the
system near the top of the hill,
28:10.633 --> 28:13.133 align:left position:22.5%,start line:83% size:67.5%
so to speak, those
are our seepage lakes.
28:13.233 --> 28:16.400 align:left position:25%,start line:83% size:65%
The ones highest up,
often don't even have
28:16.500 --> 28:19.300 align:left position:22.5%,start line:83% size:67.5%
a lot of groundwater
in flow to them
28:19.400 --> 28:23.033 align:left position:20%,start line:83% size:70%
so drought can produce
extreme effects on them.
28:23.133 --> 28:25.500 align:left position:22.5%,start line:83% size:67.5%
We have lakes up in the
Chippewa County forest
28:25.600 --> 28:28.266 align:left position:22.5%,start line:83% size:67.5%
and the Chippewa marine
that their lake levels
28:28.366 --> 28:30.566 align:left position:25%,start line:83% size:65%
still have never
recovered totally
28:30.666 --> 28:32.866 align:left position:15%,start line:89% size:75%
since the '88, '89 drought.
28:32.966 --> 28:35.233 align:left position:12.5%,start line:89% size:77.5%
So we're that many decades out.
28:35.333 --> 28:37.700 align:left position:22.5%,start line:83% size:67.5%
And as you move down
through the system,
28:37.800 --> 28:40.066 align:left position:22.5%,start line:83% size:67.5%
you're accumulating
more water all the time
28:40.166 --> 28:42.366 align:left position:22.5%,start line:83% size:67.5%
and you have higher
groundwater inputs
28:42.466 --> 28:43.866 align:left position:20%,start line:89% size:70%
and surface water input.
28:43.966 --> 28:46.800 align:left position:10%,start line:83% size:80%
So those ones higher up, smaller
watersheds,
28:46.900 --> 28:49.533 align:left position:25%,start line:83% size:65%
less runoff, tend to
be where you find your
28:49.633 --> 28:51.900 align:left position:12.5%,start line:89% size:77.5%
higher quality lake ecosystems.
28:52.000 --> 28:53.900 align:left position:22.5%,start line:83% size:67.5%
The Sand Lake I showed
you, the Long Lake,
28:54.000 --> 28:56.500 align:left position:22.5%,start line:83% size:67.5%
both very, very high
quality systems.
28:56.600 --> 28:58.433 align:left position:25%,start line:83% size:65%
They're very high
on the landscape.
28:58.533 --> 29:01.633 align:left position:35%,start line:83% size:55%
Lake Altoona,
very low on the landscape.
29:01.733 --> 29:03.066 align:left position:12.5%,start line:89% size:77.5%
It's right near almost where
29:03.166 --> 29:05.833 align:left position:22.5%,start line:83% size:67.5%
the Elk River dumps
into the Chippewa.
29:05.933 --> 29:08.866 align:left position:25%,start line:5% size:65%
Large land mass
that drains to it,
29:08.966 --> 29:13.733 align:left position:10%,start line:5% size:80%
has a much poorer water quality
and sedimentation issues.
29:13.833 --> 29:16.366 align:left position:20%,start line:5% size:70%
So let's switch over now
a little bit to think about,
29:16.466 --> 29:19.566 align:left position:12.5%,start line:5% size:77.5%
so that's kind of the
physical nature of this lake
29:19.666 --> 29:22.633 align:left position:12.5%,start line:5% size:77.5%
and how their function, it's
mass of water coming in,
29:22.733 --> 29:25.600 align:left position:12.5%,start line:5% size:77.5%
mass of water in the basin,
those types of things.
29:25.700 --> 29:27.966 align:left position:12.5%,start line:5% size:77.5%
But what are the
characteristics of that water?
29:28.066 --> 29:29.200 align:left position:25%,start line:5% size:65%
How is it influenced?
29:29.300 --> 29:30.900 align:left position:12.5%,start line:5% size:77.5%
That ultimately will influence
29:31.000 --> 29:34.566 align:left position:12.5%,start line:5% size:77.5%
the biological
characteristics of the lake.
29:37.866 --> 29:41.000 align:left position:12.5%,start line:83% size:77.5%
So if we had just distilled
water in our lakes,
29:41.100 --> 29:43.700 align:left position:15%,start line:83% size:75%
we wouldn't have any
life in our lakes, right?
29:43.800 --> 29:47.000 align:left position:22.5%,start line:83% size:67.5%
So we all need a mix of
nutrients in our life.
29:47.100 --> 29:49.533 align:left position:15%,start line:83% size:75%
We have micronutrients, which
are made of the elements
29:49.633 --> 29:52.433 align:left position:25%,start line:83% size:65%
on the side of
the lower graphic.
29:52.533 --> 29:54.733 align:left position:12.5%,start line:89% size:77.5%
Some lakes are harder, softer.
29:54.833 --> 29:56.933 align:left position:20%,start line:83% size:70%
That's simply the
amount of dissolved ions
29:57.033 --> 29:58.700 align:left position:22.5%,start line:89% size:67.5%
in the lake ecosystem.
29:58.800 --> 30:00.433 align:left position:22.5%,start line:83% size:67.5%
And dissolved
oxygen is obviously
30:00.533 --> 30:02.600 align:left position:22.5%,start line:83% size:67.5%
incredibly important
in our lakes.
30:02.700 --> 30:04.033 align:left position:25%,start line:83% size:65%
I talked a bit
about winter-kill.
30:04.133 --> 30:07.000 align:left position:22.5%,start line:83% size:67.5%
To maintain a viable
warm water fishery,
30:07.100 --> 30:10.600 align:left position:15%,start line:83% size:75%
our dissolved oxygen
concentration needs to be
30:10.700 --> 30:13.633 align:left position:17.5%,start line:83% size:72.5%
5 or above
to sustain all life stages
30:13.733 --> 30:15.666 align:left position:10%,start line:89% size:80%
of that fishery and that system,
30:15.766 --> 30:17.333 align:left position:25%,start line:83% size:65%
that is our water
quality standard
30:17.433 --> 30:19.000 align:left position:15%,start line:89% size:75%
for a warm water fishery.
30:19.100 --> 30:21.300 align:left position:15%,start line:83% size:75%
What I really wanna focus
on are nutrients a bit,
30:21.400 --> 30:23.566 align:left position:22.5%,start line:83% size:67.5%
especially the
ones we can manage.
30:23.666 --> 30:27.600 align:left position:15%,start line:83% size:75%
So when we really think about
the primary nutrients in
30:27.700 --> 30:31.333 align:left position:10%,start line:83% size:80%
lake ecosystems, there's carbon,
nitrogen, and phosphorus.
30:31.433 --> 30:32.733 align:left position:15%,start line:89% size:75%
It's that ratio especially
30:32.833 --> 30:35.433 align:left position:25%,start line:5% size:65%
of how they relate
to one another.
30:35.533 --> 30:37.300 align:left position:22.5%,start line:5% size:67.5%
But when we think
about the nutrients
30:37.400 --> 30:39.700 align:left position:25%,start line:5% size:65%
we may have some
ability to impact.
30:39.800 --> 30:40.800 align:left position:12.5%,start line:5% size:77.5%
We really can't impact carbon,
30:40.900 --> 30:42.766 align:left position:10%,start line:5% size:80%
we really can't impact nitrogen,
30:42.866 --> 30:45.366 align:left position:15%,start line:5% size:75%
that much of the
atmosphere is full of it.
30:45.466 --> 30:49.966 align:left position:15%,start line:5% size:75%
But we can impact this
element called phosphorus.
30:50.066 --> 30:52.666 align:left position:22.5%,start line:5% size:67.5%
So phosphorus really
is a major driving
30:52.766 --> 30:56.600 align:left position:12.5%,start line:5% size:77.5%
in ecosystem health in most
of our lakes in Wisconsin.
30:56.700 --> 30:58.700 align:left position:25%,start line:83% size:65%
We need phosphorus
in these systems.
30:58.800 --> 31:01.300 align:left position:15%,start line:83% size:75%
It's a critical component
in all forms of life.
31:01.400 --> 31:03.266 align:left position:12.5%,start line:89% size:77.5%
It's part of our DNA, our RNA,
31:03.366 --> 31:06.600 align:left position:15%,start line:83% size:75%
our energy metabolism
for us to sustain ourselves
31:06.700 --> 31:08.566 align:left position:15%,start line:89% size:75%
or any other living thing.
31:08.666 --> 31:11.333 align:left position:12.5%,start line:83% size:77.5%
But a little bit of
phosphorus can go a long way
31:11.433 --> 31:14.233 align:left position:22.5%,start line:83% size:67.5%
at producing algae in
a freshwater ecosystem.
31:14.333 --> 31:17.233 align:left position:25%,start line:83% size:65%
1 pound of phosphorus
can magnify itself
31:17.333 --> 31:19.033 align:left position:15%,start line:89% size:75%
into 500 pounds of algae.
31:19.133 --> 31:20.900 align:left position:22.5%,start line:89% size:67.5%
That's a huge ratio.
31:21.000 --> 31:23.000 align:left position:12.5%,start line:89% size:77.5%
It, naturally, in Wisconsin,
31:23.100 --> 31:26.133 align:left position:25%,start line:83% size:65%
because of our parent
soil materials,
31:26.233 --> 31:29.100 align:left position:25%,start line:83% size:65%
we did not have a lot
of natural phosphorus.
31:29.200 --> 31:32.066 align:left position:15%,start line:83% size:75%
Our lakes in a
pre-settlement condition were
31:32.166 --> 31:36.033 align:left position:20%,start line:83% size:70%
very, very low for the
most part in phosphorus.
31:36.133 --> 31:40.200 align:left position:12.5%,start line:83% size:77.5%
It leads us to this concept of
limiting nutrient principle.
31:40.300 --> 31:43.400 align:left position:22.5%,start line:83% size:67.5%
That simply is that the
nutrient in least supply
31:43.500 --> 31:46.466 align:left position:22.5%,start line:83% size:67.5%
in that lake ecosystem
or freshwater system,
31:46.566 --> 31:49.800 align:left position:15%,start line:83% size:75%
will control the amount
of plant or algae growth,
31:49.900 --> 31:52.566 align:left position:22.5%,start line:83% size:67.5%
and we often relate
this just to algae.
31:52.666 --> 31:57.533 align:left position:15%,start line:83% size:75%
So if we only have about
10 times as much nitrogen
31:57.633 --> 32:00.133 align:left position:10%,start line:89% size:80%
as we do phosphorus in the lake,
32:00.233 --> 32:03.066 align:left position:22.5%,start line:83% size:67.5%
then we say the lake
is nitrogen limited,
32:03.166 --> 32:07.200 align:left position:12.5%,start line:83% size:77.5%
but when we're in 15 times
more nitrogen than phosphorus,
32:07.300 --> 32:08.833 align:left position:10%,start line:89% size:80%
then really phosphorus is doing,
32:08.933 --> 32:11.266 align:left position:12.5%,start line:5% size:77.5%
it's that gray area in between.
32:11.366 --> 32:15.533 align:left position:12.5%,start line:5% size:77.5%
But this was really not
well understood really until
32:16.733 --> 32:19.566 align:left position:22.5%,start line:5% size:67.5%
the 1970s and there
was great debate.
32:19.666 --> 32:21.533 align:left position:10%,start line:5% size:80%
You think back 40, 50 years ago,
32:21.633 --> 32:23.066 align:left position:22.5%,start line:5% size:67.5%
why was that important
because we just
32:23.166 --> 32:27.033 align:left position:25%,start line:5% size:65%
take for granted that
we can deal with this.
32:27.133 --> 32:29.400 align:left position:12.5%,start line:5% size:77.5%
Back in those days, all of our
32:29.500 --> 32:31.733 align:left position:25%,start line:5% size:65%
cleaning solutions
across the world,
32:31.833 --> 32:34.866 align:left position:22.5%,start line:5% size:67.5%
phosphorus was a major
constituent in them.
32:34.966 --> 32:37.333 align:left position:25%,start line:83% size:65%
And the soap and
detergent industry
32:37.433 --> 32:41.466 align:left position:15%,start line:5% size:75%
really wanted to protect that
ability to maintain phosphorus
32:41.566 --> 32:44.333 align:left position:12.5%,start line:5% size:77.5%
and we hadn't really gotten
into this understanding of
32:44.433 --> 32:46.800 align:left position:25%,start line:5% size:65%
well, we should be
morphing our products
32:46.900 --> 32:51.066 align:left position:12.5%,start line:5% size:77.5%
into more healthy things
that help us live our lives.
32:52.733 --> 32:55.333 align:left position:10%,start line:5% size:80%
So there was great debate going
on all across the country.
32:55.433 --> 32:57.200 align:left position:25%,start line:83% size:65%
There was a camp
saying it was carbon,
32:57.300 --> 32:59.333 align:left position:15%,start line:83% size:75%
another camp of scientists
saying it was nitrogen,
32:59.433 --> 33:02.266 align:left position:15%,start line:83% size:75%
and then there was a group
talking about phosphorus,
33:02.366 --> 33:06.200 align:left position:15%,start line:83% size:75%
so this was really put to
rest in the early 1970s
33:06.300 --> 33:09.033 align:left position:20%,start line:83% size:70%
by a Canadian researcher
named Dave Schindler
33:09.133 --> 33:11.466 align:left position:12.5%,start line:83% size:77.5%
as a young graduate
student or young professor,
33:11.566 --> 33:15.533 align:left position:12.5%,start line:83% size:77.5%
up doing his work in
Laurentian Shield in Canada,
33:15.633 --> 33:17.466 align:left position:22.5%,start line:83% size:67.5%
and with lakes,
they simply did was
33:17.566 --> 33:20.366 align:left position:10%,start line:89% size:80%
took this lake, it was Lake 227,
33:20.466 --> 33:24.433 align:left position:15%,start line:83% size:75%
put a plastic curtain there
across the middle of the lake
33:24.533 --> 33:26.033 align:left position:27.5%,start line:83% size:62.5%
that goes all the
way to the bottom,
33:26.133 --> 33:28.633 align:left position:22.5%,start line:83% size:67.5%
and he fertilized
both sides of the lake
33:28.733 --> 33:32.000 align:left position:22.5%,start line:83% size:67.5%
with nitrogen and
carbon, so there was
33:32.100 --> 33:34.233 align:left position:12.5%,start line:89% size:77.5%
plenty there to sustain algae.
33:34.333 --> 33:37.233 align:left position:15%,start line:83% size:75%
And so then what he simply
did is then augmented
33:37.333 --> 33:40.033 align:left position:22.5%,start line:83% size:67.5%
one side of the lake
with phosphorus,
33:40.133 --> 33:42.433 align:left position:25%,start line:83% size:65%
and that was the
response Dave got
33:42.533 --> 33:45.166 align:left position:22.5%,start line:83% size:67.5%
and it got kinda put
the whole issue to bed.
33:45.266 --> 33:47.233 align:left position:25%,start line:83% size:65%
It is, most of our
lakes, phosphorus
33:47.333 --> 33:49.800 align:left position:15%,start line:83% size:75%
does control algal growth
in most of our lakes
33:49.900 --> 33:51.833 align:left position:12.5%,start line:89% size:77.5%
and we feel that in Wisconsin,
33:51.933 --> 33:54.900 align:left position:22.5%,start line:5% size:67.5%
over 90% of our lakes
are phosphorus limited.
33:55.000 --> 33:56.933 align:left position:22.5%,start line:5% size:67.5%
So it's the one we're
really concerned about.
33:57.033 --> 33:59.866 align:left position:20%,start line:5% size:70%
How we manage that on
the land and in the lake
33:59.966 --> 34:03.200 align:left position:12.5%,start line:5% size:77.5%
will control the amount of
algae and the type of algae
34:03.300 --> 34:05.166 align:left position:15%,start line:5% size:75%
you'll get in your lakes.
34:05.266 --> 34:09.466 align:left position:15%,start line:5% size:75%
So soon after that, there
was many, many people
34:09.566 --> 34:11.766 align:left position:30%,start line:83% size:60%
across the world
and the country,
34:11.866 --> 34:15.066 align:left position:15%,start line:83% size:75%
started trying to figure more
of these relationships out,
34:15.166 --> 34:17.533 align:left position:25%,start line:83% size:65%
and this is a very
basic relationship
34:17.633 --> 34:20.266 align:left position:22.5%,start line:83% size:67.5%
and it simply is, as
you put more phosphorus
34:20.366 --> 34:24.100 align:left position:12.5%,start line:83% size:77.5%
into a lake ecosystem, you
will drive more algae growth
34:24.200 --> 34:26.400 align:left position:12.5%,start line:89% size:77.5%
and this is a log-log scale,
34:26.500 --> 34:28.033 align:left position:12.5%,start line:89% size:77.5%
so people that understand math,
34:28.133 --> 34:29.800 align:left position:25%,start line:83% size:65%
this is a lot of
noise around here.
34:29.900 --> 34:33.600 align:left position:20%,start line:83% size:70%
We have many, many
mathematical simulations
34:33.700 --> 34:36.033 align:left position:22.5%,start line:83% size:67.5%
and variations of that,
that really help us
34:36.133 --> 34:38.466 align:left position:12.5%,start line:89% size:77.5%
determine how far do we need
34:39.766 --> 34:41.966 align:left position:15%,start line:83% size:75%
to reduce those
phosphorus levels in lakes
34:42.066 --> 34:43.833 align:left position:12.5%,start line:5% size:77.5%
to restore ecosystem health.
34:43.933 --> 34:46.566 align:left position:25%,start line:5% size:65%
So we spent a lot
of time on this.
34:46.666 --> 34:48.066 align:left position:25%,start line:5% size:65%
When I was originally
hired to work
34:48.166 --> 34:50.133 align:left position:27.5%,start line:5% size:62.5%
for the DNR, back
in the early '80s,
34:50.233 --> 34:51.633 align:left position:25%,start line:5% size:65%
it was one of my jobs
34:51.733 --> 34:54.233 align:left position:27.5%,start line:5% size:62.5%
to understand these
relationships in streams
34:54.333 --> 34:56.533 align:left position:22.5%,start line:5% size:67.5%
and people were working
on this in lakes.
34:56.633 --> 35:00.733 align:left position:10%,start line:5% size:80%
So, we finally got to developing
water quality criteria
35:00.833 --> 35:04.966 align:left position:22.5%,start line:83% size:67.5%
for lakes in Wisconsin,
30 years later in 2011.
35:05.066 --> 35:07.866 align:left position:12.5%,start line:89% size:77.5%
So why do we develop criteria?
35:07.966 --> 35:11.133 align:left position:12.5%,start line:83% size:77.5%
Well, it's when we have
obvious water quality problems
35:11.233 --> 35:14.766 align:left position:12.5%,start line:83% size:77.5%
and we know they're caused
by excess nutrient loading,
35:14.866 --> 35:16.433 align:left position:22.5%,start line:83% size:67.5%
we need to know
how clean is clean,
35:16.533 --> 35:18.666 align:left position:15%,start line:83% size:75%
where do we need to manage
that system back to,
35:18.766 --> 35:21.966 align:left position:15%,start line:83% size:75%
and those goals that then
directly relate to them.
35:22.066 --> 35:25.500 align:left position:22.5%,start line:83% size:67.5%
We have numbers that
we know can protect
35:25.600 --> 35:29.300 align:left position:15%,start line:83% size:75%
recreational fish and aquatic
life uses and those things,
35:29.400 --> 35:31.733 align:left position:22.5%,start line:83% size:67.5%
and also EPA said this
would be a good thing
35:31.833 --> 35:33.933 align:left position:15%,start line:89% size:75%
for all the states to do.
35:35.366 --> 35:38.466 align:left position:15%,start line:5% size:75%
And these are our criteria
for lakes in Wisconsin.
35:38.566 --> 35:40.566 align:left position:10%,start line:89% size:80%
So those two-story fishery lakes
35:40.666 --> 35:42.933 align:left position:22.5%,start line:83% size:67.5%
where we wanna
maintain the integrity
35:43.033 --> 35:44.833 align:left position:15%,start line:89% size:75%
of that dissolved oxygen,
35:44.933 --> 35:47.233 align:left position:22.5%,start line:83% size:67.5%
and those deep lakes
below that thermocline,
35:47.333 --> 35:49.266 align:left position:22.5%,start line:89% size:67.5%
that stratified layer,
35:49.366 --> 35:51.066 align:left position:22.5%,start line:83% size:67.5%
they are very sensitive
to phosphorus.
35:51.166 --> 35:54.900 align:left position:10%,start line:83% size:80%
We'll give them a very low
number, 15 micrograms per liter.
35:55.000 --> 35:56.933 align:left position:25%,start line:83% size:65%
To maintain those
stratified lakes,
35:57.033 --> 35:59.366 align:left position:17.5%,start line:83% size:72.5%
those deeper ones,
those higher quality lakes
35:59.466 --> 36:00.766 align:left position:22.5%,start line:89% size:67.5%
that I talked about,
36:00.866 --> 36:02.766 align:left position:12.5%,start line:89% size:77.5%
that's 20 micrograms per liter.
36:02.866 --> 36:04.566 align:left position:25%,start line:83% size:65%
These are very,
very low numbers.
36:04.666 --> 36:06.466 align:left position:12.5%,start line:89% size:77.5%
These are parts per billion,
36:06.566 --> 36:10.633 align:left position:12.5%,start line:83% size:77.5%
so if we had a billion ping
pong balls in this room,
36:10.733 --> 36:13.233 align:left position:25%,start line:83% size:65%
to maintain integrity
of a stratified lake,
36:13.333 --> 36:15.933 align:left position:22.5%,start line:83% size:67.5%
only 20 of them
could be represented
36:16.033 --> 36:17.633 align:left position:20%,start line:89% size:70%
as phosphorus molecules,
36:17.733 --> 36:19.933 align:left position:25%,start line:83% size:65%
so these are very,
very low numbers.
36:20.033 --> 36:24.433 align:left position:15%,start line:83% size:75%
And so, as the lakes become
less sensitive to phosphorus,
36:24.533 --> 36:27.200 align:left position:22.5%,start line:83% size:67.5%
as we get up into those
reservoir systems,
36:27.300 --> 36:29.033 align:left position:12.5%,start line:89% size:77.5%
those numbers we have developed
36:29.133 --> 36:31.833 align:left position:12.5%,start line:5% size:77.5%
are 40 micrograms per liter
which is twice as much
36:31.933 --> 36:34.500 align:left position:25%,start line:5% size:65%
as what would be
in a seepage lake.
36:34.600 --> 36:36.833 align:left position:15%,start line:5% size:75%
So let's think about now,
how does this impact
36:36.933 --> 36:38.666 align:left position:15%,start line:5% size:75%
the biology of the system,
right?
36:38.766 --> 36:41.800 align:left position:12.5%,start line:5% size:77.5%
So what we really want to have,
36:41.900 --> 36:44.500 align:left position:15%,start line:5% size:75%
we gotta create this food
web through the system.
36:44.600 --> 36:46.866 align:left position:22.5%,start line:5% size:67.5%
And so what we want are
36:46.966 --> 36:49.666 align:left position:22.5%,start line:83% size:67.5%
the high quality algae
species in the system
36:49.766 --> 36:52.866 align:left position:22.5%,start line:83% size:67.5%
that can go up into our
invertebrate population,
36:52.966 --> 36:56.033 align:left position:15%,start line:83% size:75%
that little guy in the middle
there is called a zooplankton.
36:56.133 --> 36:58.266 align:left position:15%,start line:83% size:75%
We have many, many species
of those in our lakes,
36:58.366 --> 37:01.766 align:left position:12.5%,start line:83% size:77.5%
and they're the guys that
are the energy transformers.
37:01.866 --> 37:03.933 align:left position:25%,start line:83% size:65%
They're taking
those algae cells,
37:04.033 --> 37:05.866 align:left position:12.5%,start line:89% size:77.5%
turning them into meat protein,
37:05.966 --> 37:09.533 align:left position:10%,start line:83% size:80%
and then they will be harvested
by fish that eat them,
37:09.633 --> 37:11.333 align:left position:12.5%,start line:89% size:77.5%
often our panfish or some of
37:11.433 --> 37:14.133 align:left position:25%,start line:83% size:65%
our minnow species
is a good example.
37:14.233 --> 37:18.700 align:left position:10%,start line:5% size:80%
So we have all this biology
going on in our lake ecosystems.
37:18.800 --> 37:22.400 align:left position:15%,start line:5% size:75%
So what does that primary
function of that algae?
37:22.500 --> 37:24.033 align:left position:22.5%,start line:5% size:67.5%
Well one of the
first things it is,
37:24.133 --> 37:27.733 align:left position:12.5%,start line:5% size:77.5%
is that energy source for
our invertebrate community,
37:27.833 --> 37:30.533 align:left position:25%,start line:83% size:65%
those filter feeders,
we call them.
37:30.633 --> 37:32.600 align:left position:15%,start line:89% size:75%
But they also produce oxygen.
37:32.700 --> 37:35.766 align:left position:15%,start line:83% size:75%
We surely need oxygen
in our systems to sustain us.
37:35.866 --> 37:38.266 align:left position:25%,start line:83% size:65%
But it's the type
of algae we have.
37:38.366 --> 37:40.600 align:left position:22.5%,start line:83% size:67.5%
As long as we stay with
these types of algae
37:40.700 --> 37:44.033 align:left position:15%,start line:83% size:75%
over in the lower type, these
are smaller-celled algae,
37:44.133 --> 37:47.900 align:left position:10%,start line:83% size:80%
our lakes' ecosystem health
remains in a high quality state.
37:48.000 --> 37:50.733 align:left position:12.5%,start line:83% size:77.5%
But when we put too many
nutrients into this system,
37:50.833 --> 37:54.633 align:left position:20%,start line:83% size:70%
we shift from this algae
population dominated to
37:54.733 --> 37:58.866 align:left position:25%,start line:83% size:65%
a blue-green algae
population,
37:58.966 --> 38:02.233 align:left position:10%,start line:83% size:80%
so we call those cyanobacteria,
blue-green algae.
38:02.333 --> 38:06.000 align:left position:12.5%,start line:83% size:77.5%
As you increase the phosphorus
concentration in our lakes,
38:06.100 --> 38:08.500 align:left position:25%,start line:83% size:65%
we increase that
lake's capability,
38:08.600 --> 38:10.966 align:left position:25%,start line:83% size:65%
we make that nutrient
more available,
38:11.066 --> 38:15.233 align:left position:12.5%,start line:83% size:77.5%
we want all those other algae,
different genera of algae
38:16.866 --> 38:19.666 align:left position:12.5%,start line:83% size:77.5%
to be in our lakes that
are smaller cellular algae.
38:19.766 --> 38:22.200 align:left position:25%,start line:83% size:65%
They don't create the
nuisance algal blooms.
38:22.300 --> 38:24.800 align:left position:22.5%,start line:83% size:67.5%
But you can see there's
a transition right there
38:24.900 --> 38:28.566 align:left position:20%,start line:83% size:70%
in many lakes around that
20 microgram per liter number.
38:28.666 --> 38:31.800 align:left position:20%,start line:83% size:70%
Soon as you get above
20 micrograms per liter,
38:31.900 --> 38:33.966 align:left position:12.5%,start line:89% size:77.5%
you start to create a situation
38:34.066 --> 38:37.166 align:left position:10%,start line:83% size:80%
where blue-green algae dominate
in our lake ecosystems.
38:37.266 --> 38:40.600 align:left position:22.5%,start line:83% size:67.5%
These are both pictures
that have come from--
38:40.700 --> 38:44.400 align:left position:10%,start line:83% size:80%
Picture on the left is an
algae bloom on peat oil flowage.
38:44.500 --> 38:47.066 align:left position:20%,start line:83% size:70%
That's one of my
co-workers on the right,
38:47.166 --> 38:51.433 align:left position:12.5%,start line:77% size:77.5%
that is in Tainter Lake,
over near the city of
Menomonie.
38:51.533 --> 38:54.066 align:left position:22.5%,start line:83% size:67.5%
These lakes have the
ability to produce
38:54.166 --> 38:58.033 align:left position:22.5%,start line:5% size:67.5%
very, very high levels
of blue-green algae.
38:58.133 --> 39:00.300 align:left position:22.5%,start line:5% size:67.5%
And what blue-green algae,
some species
39:00.400 --> 39:03.733 align:left position:22.5%,start line:5% size:67.5%
at some times during
their life stage,
39:03.833 --> 39:05.733 align:left position:22.5%,start line:5% size:67.5%
we're trying to figure
out what trips us,
39:05.833 --> 39:07.966 align:left position:15%,start line:5% size:75%
they can produce toxicity.
39:08.066 --> 39:10.500 align:left position:12.5%,start line:5% size:77.5%
That's what probably killed
that goose in the left.
39:10.600 --> 39:13.900 align:left position:22.5%,start line:5% size:67.5%
But these toxins can be
harmful to us, our pets,
39:14.000 --> 39:16.033 align:left position:12.5%,start line:89% size:77.5%
if we get to these high levels.
39:16.133 --> 39:19.400 align:left position:25%,start line:83% size:65%
When these cells die,
they release
39:19.500 --> 39:21.400 align:left position:15%,start line:89% size:75%
the toxins into the water.
39:21.500 --> 39:24.633 align:left position:22.5%,start line:83% size:67.5%
These are just some
of the characteristics
39:24.733 --> 39:27.666 align:left position:22.5%,start line:83% size:67.5%
associated that can
be how they impact us.
39:27.766 --> 39:29.166 align:left position:12.5%,start line:89% size:77.5%
We can get dermal reactions.
39:29.266 --> 39:31.866 align:left position:12.5%,start line:83% size:77.5%
We have had many folks over
in the Tainter Lake system
39:31.966 --> 39:34.366 align:left position:17.5%,start line:83% size:72.5%
that are very prone to it,
that'll get rashes.
39:34.466 --> 39:37.000 align:left position:12.5%,start line:83% size:77.5%
One of our staff people was
loading a boat one time,
39:37.100 --> 39:39.766 align:left position:22.5%,start line:83% size:67.5%
by the time
she got back to the lab,
39:39.866 --> 39:42.000 align:left position:17.5%,start line:83% size:72.5%
showered up and everything,
she got home
39:42.100 --> 39:43.766 align:left position:10%,start line:89% size:80%
and she had this incredible rash
39:43.866 --> 39:45.800 align:left position:10%,start line:89% size:80%
on the lower portion of her leg,
39:45.900 --> 39:48.866 align:left position:17.5%,start line:83% size:72.5%
where she had been
in contact with that water.
39:48.966 --> 39:52.633 align:left position:15%,start line:83% size:75%
Neurotoxins, when you hear
of dog deaths sometimes,
39:52.733 --> 39:57.300 align:left position:10%,start line:83% size:80%
or cattle deaths in farm ponds,
they ingest that water.
39:57.400 --> 40:00.200 align:left position:20%,start line:83% size:70%
It can be a very rapid
death for some of those,
40:00.300 --> 40:05.033 align:left position:12.5%,start line:83% size:77.5%
and then we also have
hepatotoxins, blood impacts,
40:05.133 --> 40:06.966 align:left position:10%,start line:89% size:80%
where it impacts liver function,
40:07.066 --> 40:09.300 align:left position:22.5%,start line:5% size:67.5%
so if you see water
quality characteristics
40:09.400 --> 40:11.533 align:left position:15%,start line:5% size:75%
that look bad, just stay out,
40:11.633 --> 40:15.533 align:left position:15%,start line:5% size:75%
cause there could be
blue-green algal toxicity.
40:17.833 --> 40:20.933 align:left position:15%,start line:5% size:75%
So let's switch here, I mean,
I guess, just again show
40:21.033 --> 40:22.866 align:left position:12.5%,start line:5% size:77.5%
this invertebrate communities,
40:22.966 --> 40:25.500 align:left position:22.5%,start line:83% size:67.5%
an important part of
our lake ecosystem,
40:25.600 --> 40:27.933 align:left position:22.5%,start line:83% size:67.5%
and it is one of those
that energy transfer.
40:28.033 --> 40:31.000 align:left position:20%,start line:83% size:70%
This is the zooplankton,
the daphnia on the left.
40:31.100 --> 40:33.833 align:left position:15%,start line:83% size:75%
That is lunch for
"young-of-the-year" fishes,
40:33.933 --> 40:35.666 align:left position:15%,start line:89% size:75%
that's what they're after.
40:35.766 --> 40:38.533 align:left position:15%,start line:83% size:75%
And if we have a high
quality algae population,
40:38.633 --> 40:41.466 align:left position:15%,start line:83% size:75%
high quality zooplankton,
there's a lot of energy there
40:41.566 --> 40:44.600 align:left position:15%,start line:83% size:75%
to produce a lot of fish
biomass up the food chain.
40:44.700 --> 40:48.500 align:left position:15%,start line:83% size:75%
Aquatic plants, incredibly
valued in our lake ecosystem,
40:48.600 --> 40:51.000 align:left position:22.5%,start line:83% size:67.5%
as long as, again, that
system is in balance.
40:51.100 --> 40:53.566 align:left position:22.5%,start line:83% size:67.5%
They are absolutely
critical habitat
40:53.666 --> 40:57.233 align:left position:12.5%,start line:83% size:77.5%
for many of our aquatic
species that live in lakes.
40:57.333 --> 40:59.333 align:left position:25%,start line:83% size:65%
They are great
physical structure
40:59.433 --> 41:03.666 align:left position:15%,start line:83% size:75%
and are energy dissipaters
and they produce oxygen.
41:06.333 --> 41:08.766 align:left position:15%,start line:83% size:75%
Fish, I think this is what
we all kind of relate to
41:08.866 --> 41:10.333 align:left position:15%,start line:89% size:75%
when we think about this.
41:10.433 --> 41:13.733 align:left position:12.5%,start line:83% size:77.5%
As long as we have good
habitat, good water quality,
41:13.833 --> 41:15.766 align:left position:22.5%,start line:83% size:67.5%
we tend to have
high quality fisheries,
41:15.866 --> 41:18.200 align:left position:22.5%,start line:83% size:67.5%
and some of those
highly impacted lakes,
41:18.300 --> 41:20.400 align:left position:22.5%,start line:83% size:67.5%
that Cedar Lake that
I was talking about,
41:20.500 --> 41:24.466 align:left position:15%,start line:83% size:75%
we went through a period of
time there where the fishery,
41:24.566 --> 41:27.366 align:left position:10%,start line:89% size:80%
probably 95% of the fish biomass
41:27.466 --> 41:29.766 align:left position:10%,start line:89% size:80%
in the lake was tied up in carp.
41:29.866 --> 41:32.833 align:left position:20%,start line:83% size:70%
It was also a huge
impact on water quality.
41:32.933 --> 41:35.333 align:left position:17.5%,start line:5% size:72.5%
Our rough fish
have very short gut tracts.
41:35.433 --> 41:38.633 align:left position:20%,start line:5% size:70%
They eat the benthos,
the bottom invertebrates
41:38.733 --> 41:41.066 align:left position:22.5%,start line:5% size:67.5%
off the lake, and
what they can do is
41:41.166 --> 41:43.066 align:left position:22.5%,start line:5% size:67.5%
they actually take
those invertebrates
41:43.166 --> 41:44.800 align:left position:12.5%,start line:5% size:77.5%
and sediments from the bottom,
41:44.900 --> 41:46.300 align:left position:12.5%,start line:5% size:77.5%
put them through the gut tract,
41:46.400 --> 41:48.266 align:left position:12.5%,start line:5% size:77.5%
make many nutrients available,
41:48.366 --> 41:50.100 align:left position:22.5%,start line:5% size:67.5%
and they can be a
source of nutrients,
41:50.200 --> 41:52.900 align:left position:22.5%,start line:5% size:67.5%
posing a poor water
quality problem.
41:53.000 --> 41:55.000 align:left position:25%,start line:5% size:65%
When we looked at
Cedar Lake back then,
41:55.100 --> 41:58.233 align:left position:15%,start line:5% size:75%
we thought about 30% of
the water quality problem
41:58.333 --> 42:01.400 align:left position:22.5%,start line:83% size:67.5%
in the lake was simply
due to the mass of carp
42:01.500 --> 42:03.000 align:left position:20%,start line:5% size:70%
that was in that system.
42:03.100 --> 42:05.866 align:left position:12.5%,start line:5% size:77.5%
They were putting thousands
of pounds of phosphorus a year
42:05.966 --> 42:09.566 align:left position:12.5%,start line:5% size:77.5%
into the photic zone, the area
where light is in the lake,
42:09.666 --> 42:11.366 align:left position:12.5%,start line:5% size:77.5%
to create the algal blooms.
42:11.466 --> 42:13.433 align:left position:25%,start line:5% size:65%
They were a big
factor in that issue.
42:13.533 --> 42:17.700 align:left position:15%,start line:83% size:75%
So, again, all these critters
need high quality habitat.
42:17.800 --> 42:20.800 align:left position:22.5%,start line:83% size:67.5%
These are the views and
those characteristics,
42:20.900 --> 42:23.233 align:left position:15%,start line:83% size:75%
those services we want to
maintain in those lakes.
42:23.333 --> 42:25.100 align:left position:12.5%,start line:89% size:77.5%
We'll talk a bit about habitat.
42:25.200 --> 42:29.400 align:left position:17.5%,start line:83% size:72.5%
That near shore habitat,
we call the "littoral zone"
42:29.500 --> 42:33.100 align:left position:15%,start line:83% size:75%
is where the light penetrates
deep enough into the water
42:33.200 --> 42:35.233 align:left position:12.5%,start line:89% size:77.5%
to allow aquatic plants to grow
42:35.333 --> 42:40.100 align:left position:12.5%,start line:83% size:77.5%
shoreward from that, and
then up onto the lake shore.
42:40.200 --> 42:42.833 align:left position:15%,start line:83% size:75%
So when we just think
about that littoral zone,
42:42.933 --> 42:45.100 align:left position:22.5%,start line:83% size:67.5%
or the area where light
penetrates deep enough
42:45.200 --> 42:47.266 align:left position:22.5%,start line:83% size:67.5%
to stimulate the growth
of aquatic plants,
42:47.366 --> 42:50.933 align:left position:22.5%,start line:83% size:67.5%
over 90% of the species
in any given lake
42:51.033 --> 42:54.666 align:left position:15%,start line:83% size:75%
are dependent on that
critical habitat component
42:54.766 --> 42:57.566 align:left position:12.5%,start line:83% size:77.5%
for at least some component
of their life history.
42:57.666 --> 43:00.033 align:left position:25%,start line:83% size:65%
So if we can maintain
the integrity of that,
43:00.133 --> 43:03.400 align:left position:20%,start line:83% size:70%
we often maintain the
integrity of the system.
43:03.500 --> 43:05.733 align:left position:15%,start line:89% size:75%
And then shoreward from that,
43:05.833 --> 43:10.066 align:left position:15%,start line:83% size:75%
that shoreland buffer zone
area is absolutely incredibly
43:10.166 --> 43:13.966 align:left position:22.5%,start line:83% size:67.5%
valuable for aquatic
life near shore,
43:14.066 --> 43:18.300 align:left position:12.5%,start line:83% size:77.5%
water-dependent wildlife
and water quality of the lake.
43:18.400 --> 43:20.066 align:left position:22.5%,start line:83% size:67.5%
So how have we
developed our lakes?
43:20.166 --> 43:23.400 align:left position:15%,start line:83% size:75%
And how have these impacts
impacted our lake ecosystems?
43:23.500 --> 43:25.833 align:left position:12.5%,start line:89% size:77.5%
I'll try and finish up here.
43:26.833 --> 43:28.500 align:left position:35%,start line:5% size:55%
Oh, sorry.
43:29.500 --> 43:31.333 align:left position:25%,start line:5% size:65%
As we think about
this, we look at,
43:31.433 --> 43:33.633 align:left position:20%,start line:5% size:70%
this is what our lake
shores often looked like
43:33.733 --> 43:35.200 align:left position:20%,start line:5% size:70%
in an undeveloped state.
43:35.300 --> 43:38.733 align:left position:15%,start line:83% size:75%
We had emergent vegetation
out the submergent.
43:38.833 --> 43:40.400 align:left position:20%,start line:83% size:70%
Natural woody vegetation
on the shore.
43:40.500 --> 43:43.100 align:left position:22.5%,start line:83% size:67.5%
As we have brought
our societal values
43:43.200 --> 43:44.866 align:left position:25%,start line:83% size:65%
and how we live
in our communities,
43:44.966 --> 43:47.466 align:left position:12.5%,start line:83% size:77.5%
you know, this is what
we've often brought to these,
43:47.566 --> 43:50.566 align:left position:10%,start line:83% size:80%
and so, when we bring that
type of pattern of development,
43:50.666 --> 43:53.833 align:left position:10%,start line:83% size:80%
we lose these natural ecosystem
functions to our lakes.
43:53.933 --> 43:56.266 align:left position:25%,start line:83% size:65%
So how does that
impact our lakes?
43:56.366 --> 43:58.166 align:left position:22.5%,start line:83% size:67.5%
So one of the things
we've looked at,
43:58.266 --> 44:00.733 align:left position:10%,start line:83% size:80%
we have a compendium of
literature that's been developed
44:00.833 --> 44:04.233 align:left position:15%,start line:83% size:75%
in the '90s and through the
early 2000s in Wisconsin,
44:04.333 --> 44:06.600 align:left position:22.5%,start line:83% size:67.5%
but they all kind of
show the same thing.
44:06.700 --> 44:08.800 align:left position:22.5%,start line:83% size:67.5%
With the way we develop
our lake shores,
44:08.900 --> 44:11.833 align:left position:22.5%,start line:83% size:67.5%
once we get to about
30 homes per mile,
44:11.933 --> 44:15.500 align:left position:17.5%,start line:83% size:72.5%
we have lost many of
the ecosystem services that
44:15.600 --> 44:19.300 align:left position:12.5%,start line:83% size:77.5%
that nearshore and that shallow
water area provides.
44:20.500 --> 44:23.533 align:left position:22.5%,start line:83% size:67.5%
And this happens to be
a green frog study.
44:23.633 --> 44:26.400 align:left position:25%,start line:77% size:65%
Once you get about to
that level, there is no
longer
44:26.500 --> 44:29.000 align:left position:20%,start line:83% size:70%
the characteristics there
at a high enough level,
44:29.100 --> 44:30.900 align:left position:15%,start line:89% size:75%
and our green frogs are gone,
44:31.000 --> 44:33.700 align:left position:25%,start line:83% size:65%
but it also shows up
in other areas.
44:34.900 --> 44:37.100 align:left position:22.5%,start line:83% size:67.5%
This is coarse woody
habitat, we call it.
44:37.200 --> 44:38.500 align:left position:22.5%,start line:89% size:67.5%
It's wood in the lake.
44:38.600 --> 44:41.866 align:left position:12.5%,start line:83% size:77.5%
And this is a very valuable
ecosystem function,
44:41.966 --> 44:45.600 align:left position:12.5%,start line:83% size:77.5%
providing diversity of
habitat, diversity of refuge
44:45.700 --> 44:47.766 align:left position:12.5%,start line:89% size:77.5%
on that wood that's growing,
44:47.866 --> 44:49.400 align:left position:22.5%,start line:83% size:67.5%
and there is a
thin layer of algae
44:49.500 --> 44:51.800 align:left position:25%,start line:83% size:65%
which has a lot of
inverts growing on it
44:51.900 --> 44:54.433 align:left position:15%,start line:83% size:75%
which a lot of small fish
come in and pick off.
44:54.533 --> 44:56.300 align:left position:25%,start line:83% size:65%
Big fish come in
there to the prey,
44:56.400 --> 45:00.266 align:left position:17.5%,start line:83% size:72.5%
little fish come in there
to get away from big fish.
45:00.366 --> 45:04.066 align:left position:12.5%,start line:83% size:77.5%
But again, when we get out
around that 30 homes per mile,
45:04.166 --> 45:07.833 align:left position:22.5%,start line:5% size:67.5%
we lose this ecosystem
service in our lakes.
45:08.866 --> 45:10.100 align:left position:15%,start line:5% size:75%
This is Dan Schindler's work,
45:10.200 --> 45:12.533 align:left position:22.5%,start line:5% size:67.5%
he happens to be the
son of Dave Schindler.
45:12.633 --> 45:14.066 align:left position:12.5%,start line:89% size:77.5%
He was one of our grad students
45:14.166 --> 45:17.200 align:left position:12.5%,start line:83% size:77.5%
at the Center for Limnology
back in the late '90s.
45:17.300 --> 45:20.100 align:left position:10%,start line:89% size:80%
And what Dan started looking at,
45:20.200 --> 45:22.400 align:left position:25%,start line:83% size:65%
so how does this
impact fish growth
45:22.500 --> 45:26.100 align:left position:25%,start line:83% size:65%
if we don't have that
high quality habitat
45:26.200 --> 45:28.633 align:left position:22.5%,start line:83% size:67.5%
in our lake ecosystems
in the north?
45:28.733 --> 45:31.166 align:left position:15%,start line:89% size:75%
And what he really showed was
45:32.366 --> 45:35.166 align:left position:25%,start line:83% size:65%
fish in lakes with
good woody habitat
45:37.200 --> 45:40.133 align:left position:22.5%,start line:83% size:67.5%
have growth rates
of three times more
45:40.233 --> 45:41.666 align:left position:30%,start line:83% size:60%
than lakes where
we've lost that.
45:41.766 --> 45:44.033 align:left position:25%,start line:83% size:65%
So if you turn that
around, you could say
45:44.133 --> 45:45.833 align:left position:22.5%,start line:83% size:67.5%
one way we've
developed our lakes,
45:45.933 --> 45:49.200 align:left position:25%,start line:5% size:65%
we've lost about
a factor of three,
45:49.300 --> 45:52.933 align:left position:12.5%,start line:5% size:77.5%
or if we had that high quality
habitat in our systems,
45:53.033 --> 45:55.300 align:left position:15%,start line:5% size:75%
our fisheries' production
would be improved
45:55.400 --> 45:57.300 align:left position:22.5%,start line:5% size:67.5%
by as much as 300%.
45:57.400 --> 45:59.000 align:left position:22.5%,start line:5% size:67.5%
It's a huge number.
46:00.333 --> 46:02.466 align:left position:25%,start line:5% size:65%
So, finishing up
with talking a bit
46:02.566 --> 46:04.200 align:left position:15%,start line:89% size:75%
about how land use impacts
46:04.300 --> 46:07.533 align:left position:22.5%,start line:83% size:67.5%
and watershed
impacts water quality.
46:07.633 --> 46:10.800 align:left position:22.5%,start line:83% size:67.5%
We think about that and
natural lake ecosystem,
46:10.900 --> 46:15.066 align:left position:15%,start line:83% size:75%
when that water falls on back
to the hydrologic cycle slide,
46:16.533 --> 46:19.600 align:left position:32.5%,start line:83% size:57.5%
only about 10%
of that water would runoff.
46:19.700 --> 46:21.166 align:left position:25%,start line:89% size:65%
50% of it would go in
46:21.266 --> 46:23.633 align:left position:22.5%,start line:77% size:67.5%
and contribute to
sustaining
ground water levels.
46:23.733 --> 46:26.800 align:left position:25%,start line:83% size:65%
So when we urbanize
an area, especially,
46:26.900 --> 46:29.133 align:left position:12.5%,start line:89% size:77.5%
we flip that totally around.
46:29.233 --> 46:31.766 align:left position:25%,start line:83% size:65%
In an urban area, we
only maybe infiltrate
46:31.866 --> 46:35.266 align:left position:22.5%,start line:83% size:67.5%
15% of the rainfall
and we runoff 55%.
46:35.366 --> 46:38.566 align:left position:15%,start line:83% size:75%
That 55% running off is a
huge transport mechanism
46:38.666 --> 46:41.700 align:left position:22.5%,start line:83% size:67.5%
for phosphorus sediment
and other pollutants.
46:41.800 --> 46:43.966 align:left position:12.5%,start line:89% size:77.5%
So our challenge as managers is
46:44.066 --> 46:48.000 align:left position:12.5%,start line:83% size:77.5%
how do we take a system like
the picture up on the left,
46:48.100 --> 46:51.433 align:left position:22.5%,start line:83% size:67.5%
but make it function
like one on the right?
46:51.533 --> 46:54.100 align:left position:20%,start line:83% size:70%
And we can do this,
it's not that big a deal.
46:54.200 --> 46:57.666 align:left position:15%,start line:5% size:75%
But we have to value
that function, as a society,
46:57.766 --> 46:59.466 align:left position:22.5%,start line:5% size:67.5%
before we can do that.
46:59.566 --> 47:01.033 align:left position:12.5%,start line:5% size:77.5%
So when we think about this,
47:01.133 --> 47:02.433 align:left position:12.5%,start line:5% size:77.5%
we have a variety of models,
47:02.533 --> 47:06.366 align:left position:15%,start line:5% size:75%
but when we as scientists
talk about runoff
47:06.466 --> 47:10.733 align:left position:15%,start line:5% size:75%
or how much pollutant loading
comes from a given land type,
47:10.833 --> 47:12.966 align:left position:22.5%,start line:83% size:67.5%
in a natural state,
our landscape,
47:13.066 --> 47:14.666 align:left position:12.5%,start line:89% size:77.5%
that one on the lower right,
47:14.766 --> 47:17.833 align:left position:25%,start line:83% size:65%
that forested area
or low density urban,
47:17.933 --> 47:21.000 align:left position:17.5%,start line:83% size:72.5%
that only loads pollutant
phosphorus to a water body
47:21.100 --> 47:22.433 align:left position:40%,start line:89% size:50%
at about
47:22.533 --> 47:26.366 align:left position:35%,start line:83% size:55%
0.1 kilograms
per hectare per year.
47:26.466 --> 47:29.333 align:left position:12.5%,start line:83% size:77.5%
You can flip that right into
pounds per acre per year,
47:29.433 --> 47:31.200 align:left position:25%,start line:83% size:65%
if that's easier
to think about it.
47:31.300 --> 47:34.333 align:left position:25%,start line:83% size:65%
But by the time we
get to mixed ag,
47:34.433 --> 47:37.266 align:left position:22.5%,start line:83% size:67.5%
or high density urban,
we've increased that
47:37.366 --> 47:40.866 align:left position:15%,start line:83% size:75%
by an order of magnitude,
by about ten-fold.
47:43.300 --> 47:46.333 align:left position:15%,start line:83% size:75%
This is a new tool that's out
there for any of you folks.
47:46.433 --> 47:50.600 align:left position:10%,start line:83% size:80%
Go see Matt Diebel's talk in
the next session after plenary,
47:51.833 --> 47:54.133 align:left position:25%,start line:83% size:65%
but what Matt has put
together for us now
47:54.233 --> 47:55.700 align:left position:15%,start line:89% size:75%
for all lakes in Wisconsin--
47:55.800 --> 47:59.333 align:left position:15%,start line:83% size:75%
That happens to be Cedar Lake
down there in the bottom.
47:59.433 --> 48:04.100 align:left position:15%,start line:83% size:75%
And through GIS techniques
and digital elevation models,
48:04.200 --> 48:07.466 align:left position:15%,start line:83% size:75%
we can computer generate what
your water shed looks like now
48:07.566 --> 48:09.966 align:left position:22.5%,start line:83% size:67.5%
and the land use
characteristics of it.
48:10.066 --> 48:14.466 align:left position:15%,start line:83% size:75%
And the reason Matt put this
together for us on Cedar Lake
48:14.566 --> 48:18.733 align:left position:12.5%,start line:5% size:77.5%
is that, I think he's got
some place here, I thought--
48:20.300 --> 48:22.800 align:left position:25%,start line:5% size:65%
oh, the phosphorus load,
most likely
48:22.900 --> 48:25.833 align:left position:20%,start line:5% size:70%
because of the amount
of agriculture in there,
48:25.933 --> 48:29.600 align:left position:17.5%,start line:5% size:72.5%
this watershed,
he estimates to be loading
48:29.700 --> 48:32.700 align:left position:12.5%,start line:5% size:77.5%
about 0.5 pounds
per acre per year,
48:32.800 --> 48:34.800 align:left position:35%,start line:83% size:55%
most likely,
at 13,600 pounds a year.
48:35.900 --> 48:37.266 align:left position:12.5%,start line:89% size:77.5%
Well, because of the farmers
48:37.366 --> 48:40.666 align:left position:20%,start line:83% size:70%
in this watershed have
cooperated fantastically
48:40.766 --> 48:43.000 align:left position:10%,start line:89% size:80%
with their lake shore neighbors,
48:43.100 --> 48:45.133 align:left position:22.5%,start line:83% size:67.5%
this watershed
only is functioning
48:45.233 --> 48:48.566 align:left position:22.5%,start line:83% size:67.5%
at a factor of about
0.2 pounds per acre.
48:50.300 --> 48:52.100 align:left position:22.5%,start line:83% size:67.5%
And it shows we can
manage the runoff
48:52.200 --> 48:55.866 align:left position:25%,start line:83% size:65%
in these agricultural
ecosystem watersheds,
48:55.966 --> 48:59.833 align:left position:15%,start line:5% size:75%
so their amount of phosphorus
coming off the land
48:59.933 --> 49:02.533 align:left position:25%,start line:5% size:65%
is only two times
above background.
49:02.633 --> 49:05.066 align:left position:10%,start line:5% size:80%
That's a phenomenally low number
49:05.166 --> 49:08.800 align:left position:25%,start line:5% size:65%
for an agricultural
dominated watershed.
49:08.900 --> 49:11.566 align:left position:15%,start line:5% size:75%
And so how does that ag
source area get on there?
49:11.666 --> 49:14.100 align:left position:10%,start line:83% size:80%
Well, we put it on there through
what we've fed our cattle.
49:14.200 --> 49:17.000 align:left position:15%,start line:83% size:75%
After World War II, we've
had a lot of our dairy cattle
49:17.100 --> 49:19.766 align:left position:25%,start line:83% size:65%
on enriched phosphate
mineral that showed up
49:19.866 --> 49:21.500 align:left position:22.5%,start line:83% size:67.5%
through their
manure that has been
49:21.600 --> 49:23.033 align:left position:15%,start line:89% size:75%
on their land for decades.
49:23.133 --> 49:25.966 align:left position:15%,start line:83% size:75%
Farmers have really since,
I would say, the late '90s,
49:26.066 --> 49:28.966 align:left position:12.5%,start line:83% size:77.5%
no longer feed, we found
we don't need to feed that.
49:29.066 --> 49:31.833 align:left position:22.5%,start line:83% size:67.5%
And then of course,
inorganic fertilizers,
49:31.933 --> 49:34.566 align:left position:22.5%,start line:83% size:67.5%
and farmers are doing a
tremendously better job
49:34.666 --> 49:38.333 align:left position:15%,start line:83% size:75%
of really putting on that
fertilizer based on crop need
49:38.433 --> 49:40.933 align:left position:25%,start line:5% size:65%
and managing their
land off in a way
49:41.033 --> 49:42.800 align:left position:12.5%,start line:5% size:77.5%
so it doesn't generate runoff.
49:42.900 --> 49:45.633 align:left position:25%,start line:5% size:65%
Here's just a fact
from Lake Mendota.
49:45.733 --> 49:48.566 align:left position:22.5%,start line:83% size:67.5%
This is Elena Bennett's
master's research
49:48.666 --> 49:51.733 align:left position:22.5%,start line:83% size:67.5%
for Center of Limnology
back in the mid '90s.
49:51.833 --> 49:54.700 align:left position:27.5%,start line:83% size:62.5%
What Elena did was
put together a mass balance
49:54.800 --> 49:57.433 align:left position:22.5%,start line:83% size:67.5%
for how much phosphorus
did we put on the land
49:57.533 --> 49:59.333 align:left position:12.5%,start line:89% size:77.5%
in the Lake Mendota watershed?
49:59.433 --> 50:02.033 align:left position:10%,start line:89% size:80%
Well, this is 1,300 metric tons,
50:03.133 --> 50:05.733 align:left position:22.5%,start line:83% size:67.5%
so there's 2,200 pounds
in a metric ton.
50:05.833 --> 50:09.933 align:left position:12.5%,start line:83% size:77.5%
That's a few million pounds
of phosphorus a year.
50:10.033 --> 50:13.900 align:left position:12.5%,start line:83% size:77.5%
And then, how much really
do we use of that phosphorus
50:14.000 --> 50:17.033 align:left position:10%,start line:89% size:80%
to produce the meat commodities?
50:17.133 --> 50:18.566 align:left position:12.5%,start line:89% size:77.5%
A little over half of that.
50:18.666 --> 50:22.800 align:left position:17.5%,start line:83% size:72.5%
So we were storing,
back in pre-1995 conditions
50:22.900 --> 50:26.066 align:left position:20%,start line:83% size:70%
of Lake Mendota, we were
just mass accumulating
50:26.166 --> 50:27.900 align:left position:12.5%,start line:89% size:77.5%
phosphorus on the landscape
50:28.000 --> 50:32.366 align:left position:20%,start line:83% size:70%
of over a million pounds
a year, 575 metric tons.
50:32.466 --> 50:33.600 align:left position:22.5%,start line:5% size:67.5%
It's a huge number.
50:33.700 --> 50:35.500 align:left position:25%,start line:5% size:65%
So we have learned
from these situations
50:35.600 --> 50:38.800 align:left position:25%,start line:5% size:65%
and we're doing
much better today.
50:38.900 --> 50:42.566 align:left position:15%,start line:83% size:75%
Residential development, boy,
that has impacted our lakes,
50:42.666 --> 50:44.200 align:left position:12.5%,start line:89% size:77.5%
especially from new channeling.
50:44.300 --> 50:47.566 align:left position:22.5%,start line:83% size:67.5%
How we develop property
when we develop
50:47.666 --> 50:52.400 align:left position:15%,start line:83% size:75%
or rebuild a home, we totally
destroy the soil health,
50:52.500 --> 50:55.900 align:left position:12.5%,start line:83% size:77.5%
the soil structure, by putting
all this equipment around.
50:56.000 --> 50:58.933 align:left position:15%,start line:5% size:75%
We virtually eliminate
often, or severely reduce
50:59.033 --> 51:01.800 align:left position:20%,start line:5% size:70%
the ability of that soil
to infiltrate water.
51:01.900 --> 51:05.266 align:left position:22.5%,start line:5% size:67.5%
We fertilize our yards,
we grade our yards
51:05.366 --> 51:07.033 align:left position:15%,start line:5% size:75%
to make them highly efficient
51:07.133 --> 51:09.866 align:left position:15%,start line:5% size:75%
to get that storm water run
off away from the buildings.
51:09.966 --> 51:12.600 align:left position:22.5%,start line:5% size:67.5%
So we did a little
work, John Panuska,
51:12.700 --> 51:15.066 align:left position:22.5%,start line:5% size:67.5%
he did this work for us
when he worked at DNR.
51:15.166 --> 51:16.900 align:left position:10%,start line:89% size:80%
He's now over at the university.
51:17.000 --> 51:18.366 align:left position:15%,start line:89% size:75%
John did some modeling for us
51:18.466 --> 51:20.100 align:left position:25%,start line:83% size:65%
so we took an
individual lake slot.
51:20.200 --> 51:22.500 align:left position:12.5%,start line:89% size:77.5%
We wanted to simulate a lot up
51:22.600 --> 51:24.233 align:left position:10%,start line:89% size:80%
on Long Lake in Chippewa County.
51:24.333 --> 51:26.366 align:left position:15%,start line:89% size:75%
So in a natural condition,
51:26.466 --> 51:28.066 align:left position:12.5%,start line:89% size:77.5%
before we did any development,
51:28.166 --> 51:30.633 align:left position:20%,start line:83% size:70%
John simulated that
this slot would generate
51:30.733 --> 51:33.400 align:left position:22.5%,start line:83% size:67.5%
about 1,000 cubic feet
of runoff of water,
51:33.500 --> 51:35.733 align:left position:22.5%,start line:83% size:67.5%
3 hundredths of a pound
of phosphorus
51:35.833 --> 51:37.500 align:left position:12.5%,start line:89% size:77.5%
and 5 pounds of sediment.
51:37.600 --> 51:40.900 align:left position:15%,start line:83% size:75%
So the first property that
was built on this lake
51:41.000 --> 51:42.433 align:left position:25%,start line:83% size:65%
was post-World War II,
where we had,
51:42.533 --> 51:44.300 align:left position:12.5%,start line:89% size:77.5%
this is what we were building.
51:44.400 --> 51:48.033 align:left position:15%,start line:83% size:75%
This happens to be
the Laine Cabin, up on a lot.
51:48.133 --> 51:49.800 align:left position:22.5%,start line:83% size:67.5%
And so when Grandpa
Laine came up
51:49.900 --> 51:51.700 align:left position:20%,start line:83% size:70%
on the train from Chicago
in the summer,
51:51.800 --> 51:53.833 align:left position:25%,start line:83% size:65%
he built a cabin,
built a cottage,
51:53.933 --> 51:56.266 align:left position:15%,start line:89% size:75%
and what was that impact?
51:56.366 --> 51:58.500 align:left position:27.5%,start line:83% size:62.5%
Well, that impact,
he really didn't impact
51:58.600 --> 52:01.066 align:left position:15%,start line:83% size:75%
cause we weren't putting
much impervious surface down,
52:01.166 --> 52:03.433 align:left position:25%,start line:83% size:65%
we weren't disturbing
much of the lake life,
52:03.533 --> 52:05.333 align:left position:25%,start line:89% size:65%
so we maintained most
52:05.433 --> 52:09.500 align:left position:17.5%,start line:77% size:72.5%
of those natural
hydrologic characteristics
of that landscape.
52:09.600 --> 52:13.166 align:left position:12.5%,start line:83% size:77.5%
So things changed a bit when
the Laines sold the property
52:13.266 --> 52:15.533 align:left position:22.5%,start line:83% size:67.5%
and the boom in the
market in the '90s.
52:15.633 --> 52:18.733 align:left position:17.5%,start line:83% size:72.5%
This is a very modest home
by those standards,
52:18.833 --> 52:21.400 align:left position:12.5%,start line:83% size:77.5%
but it really changed things up
on that lot.
52:21.500 --> 52:24.966 align:left position:12.5%,start line:83% size:77.5%
So we went almost to 4,000
square feet of imperviousness.
52:25.066 --> 52:27.966 align:left position:12.5%,start line:83% size:77.5%
We had to get around on that
lot to build that house,
52:28.066 --> 52:32.233 align:left position:17.5%,start line:83% size:72.5%
and so we impacted runoff,
we predicted five-fold increase.
52:33.433 --> 52:36.366 align:left position:22.5%,start line:83% size:67.5%
In phosphorus, about
a seven-fold increase.
52:36.466 --> 52:39.133 align:left position:22.5%,start line:83% size:67.5%
Our lakes cannot
sustain these types
52:39.233 --> 52:43.066 align:left position:27.5%,start line:5% size:62.5%
of increased inputs
if we don't manage them.
52:43.166 --> 52:44.833 align:left position:12.5%,start line:5% size:77.5%
Okay, so this is just a shot
52:44.933 --> 52:47.366 align:left position:22.5%,start line:5% size:67.5%
as we increase
that imperviousness.
52:47.466 --> 52:50.133 align:left position:22.5%,start line:83% size:67.5%
Once we get to even as
little as
52:50.233 --> 52:52.133 align:left position:20%,start line:89% size:70%
15% of the lot is covered
52:52.233 --> 52:55.366 align:left position:15%,start line:83% size:75%
with rooftops, sidewalks,
walkways, driveways,
52:55.466 --> 52:58.500 align:left position:15%,start line:83% size:75%
you've increased
the mass loading of phosphorus
52:58.600 --> 53:01.733 align:left position:20%,start line:83% size:70%
from that parcel of land
by a factor of six.
53:01.833 --> 53:04.233 align:left position:12.5%,start line:5% size:77.5%
And so, with that, I'm done.
53:04.333 --> 53:06.066 align:left position:32.5%,start line:5% size:57.5%
Thanks, folks.
53:06.166 --> 53:09.166 align:left position:22.5%,start line:5% size:67.5%
(applause)