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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 a lake ?

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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

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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.

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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.

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Water is 
a pretty unique substance.

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It is a universal solvent,

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so lots of stuff will 
dissolve into water,

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but its physical properties 
are most unique because

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water actually weighs the most 
at 4° Centigrade.

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And that's like many other 
chemical constituents,

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when you heat them 
up they get lighter.

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Well, not so much with water.

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So as you cool water 
down, it gets lighter,

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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.

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So and we don't have a 
lot of this fresh water

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on the earth's surface either,

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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

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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,

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you have to 
understand a bit about

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how does that water 
get to the lake

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and why does that 
lake have water in it?

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So we think about 
the hydrologic cycle.

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So in Wisconsin, we get about 
30+ inches of rain a year.

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As that falls to the earth, 
some of that

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is intercepted by vegetation 
and evaporates right back up.

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Some of it falls on 
our lakes and streams

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and evaporates back up,

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and some of it that 
seeps into the earth,

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is taken up by the plants,

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and then evapotranspired back 
by plant growth.

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But when we think about 
these lake basins out there,

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as the glaciers did gouge these 
holes in the earth's surface

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they simply filled 
with groundwater.

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So when you see a lake, 
what you're really looking at

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is the interception of that 
lake surface representing

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00:08:52,300 --> 00:08:55,300
the ground water 
table in that area.

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00:08:56,866 --> 00:08:59,100
So as far as lake 
types in Wisconsin,

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we really can classify them 
often by their water source,

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00:09:03,666 --> 00:09:06,500
and so we have seepage lakes, 
groundwater drainage lakes,

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00:09:06,600 --> 00:09:10,833
drainage lakes, impoundments, 
and then oxbow lakes.

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A seepage lake is 
where an ice block

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00:09:13,433 --> 00:09:15,933
was gouged into the 
earth's surface,

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00:09:16,033 --> 00:09:18,666
created this depression 
in the earth's surface,

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00:09:18,766 --> 00:09:20,566
and then as the 
glaciers receded,

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00:09:20,666 --> 00:09:22,866
it simply filled 
with groundwater.

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00:09:22,966 --> 00:09:25,700
And the major source of 
water to our seepage lakes

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00:09:25,800 --> 00:09:28,400
is groundwater, we have no 
streams coming in or out,

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00:09:28,500 --> 00:09:30,966
generally have 
groundwater coming in

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00:09:31,066 --> 00:09:33,933
one side of the lake 
and going out the other.

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00:09:34,033 --> 00:09:36,400
And so some of these lakes 
are some of our lakes

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00:09:36,500 --> 00:09:40,066
that are most susceptible 
to water level fluctuations

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00:09:40,166 --> 00:09:44,300
during periods of 
drought, because if 
we aren't getting that

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00:09:44,400 --> 00:09:46,366
rainfall on the earth's surface,

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00:09:46,466 --> 00:09:49,033
then those groundwater 
levels go down

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00:09:49,133 --> 00:09:52,000
and that's characterized 
in our lake levels.

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00:09:52,100 --> 00:09:54,333
The other thing that 
happens on these systems too

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00:09:54,433 --> 00:09:56,200
when we're in 
drought-ier periods,

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the evaporation actually 
from the lake's surface

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00:09:59,366 --> 00:10:01,466
exceeds the amount of rainfall.

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00:10:01,566 --> 00:10:05,366
So if we're in a 20 inch, 
20-some inch rainfall year, and

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00:10:05,466 --> 00:10:08,800
our normal is like 34 inches, 
32 inches, something like 
that,

218
00:10:08,900 --> 00:10:11,933
in a warm summer we 
might have an evaporation

219
00:10:12,033 --> 00:10:14,933
that exceeds 30 inches 
on that lake's surface.

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00:10:15,033 --> 00:10:17,433
So the water budget 
becomes out of balance

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00:10:17,533 --> 00:10:19,533
and then our lake 
levels go down.

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00:10:19,633 --> 00:10:22,000
This is just a shot of 
a piece of landscape

223
00:10:22,100 --> 00:10:24,166
up in Chippewa County, 
where I work,

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00:10:24,266 --> 00:10:26,433
where the glacier left 
many of these small ponds

225
00:10:26,533 --> 00:10:29,833
and lakes across the landscape.

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00:10:29,933 --> 00:10:32,833
The lake in the central 
portion of the photo

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00:10:32,933 --> 00:10:34,166
there is Round Lake.

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00:10:34,266 --> 00:10:36,933
Has no inlet or out, Round Lake,

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00:10:38,833 --> 00:10:41,033
and really it's just 
groundwater coming in

230
00:10:41,133 --> 00:10:43,666
largely from the north, 
the top of the photo

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00:10:43,766 --> 00:10:45,166
and out the side,

232
00:10:45,266 --> 00:10:49,633
and it just represents that 
groundwater level in the area.

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00:10:49,733 --> 00:10:51,233
Groundwater drainage lakes,

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00:10:51,333 --> 00:10:54,533
these are lakes that are 
placed high up in the landscape

235
00:10:54,633 --> 00:10:57,866
but there's enough water coming 
to them from the groundwater

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00:10:57,966 --> 00:11:00,300
that they've created an outlet.

237
00:11:00,400 --> 00:11:04,066
And so they definitely are 
dominated by groundwater

238
00:11:04,166 --> 00:11:06,066
coming through the 
system, but they also

239
00:11:06,166 --> 00:11:08,766
have a stream leaving them.

240
00:11:08,866 --> 00:11:10,666
A good example of 
that is Sand Lake,

241
00:11:10,766 --> 00:11:13,933
up on the Rusk/ 
Chippewa County border.

242
00:11:15,100 --> 00:11:17,000
This lake gathers 
the groundwater

243
00:11:17,100 --> 00:11:19,233
from the groundwater 
shed around it

244
00:11:19,333 --> 00:11:23,633
and then flows out to the 
Chippewa River to the north.

245
00:11:23,733 --> 00:11:26,900
Drainage lakes, now we're 
changing things up a bit.

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00:11:27,000 --> 00:11:29,366
These types of lakes, where 
they're more dominated,

247
00:11:29,466 --> 00:11:31,566
their water source, 
by surface water,

248
00:11:31,666 --> 00:11:33,700
and groundwater's 
less influential

249
00:11:33,800 --> 00:11:36,333
on the characteristics 
of the lake.

250
00:11:36,433 --> 00:11:38,633
So we got a stream coming 
in, stream going out,

251
00:11:38,733 --> 00:11:41,033
and because of that we 
have a larger catchment,

252
00:11:41,133 --> 00:11:43,800
a larger watershed that's 
bringing water to the lake,

253
00:11:43,900 --> 00:11:45,100
and I'll talk more about that.

254
00:11:45,200 --> 00:11:46,833
And as you think about this,

255
00:11:46,933 --> 00:11:49,866
a seepage lake often has 
a very small catchment,

256
00:11:49,966 --> 00:11:52,233
and they tend to be our 
higher quality lakes.

257
00:11:52,333 --> 00:11:54,766
Those are most of our 
clear water lake systems

258
00:11:54,866 --> 00:11:56,866
across Wisconsin.

259
00:11:56,966 --> 00:11:58,500
And we get into 
our drainage lakes.

260
00:11:58,600 --> 00:12:00,166
These are a bit more productive,

261
00:12:00,266 --> 00:12:02,933
and often water quality 
is a little bit less

262
00:12:03,033 --> 00:12:05,400
than what we see in 
our seepage lakes.

263
00:12:05,500 --> 00:12:09,266
This lake is Long Lake 
up in Chippewa County.

264
00:12:10,400 --> 00:12:12,166
It's a pretty unique 
lake ecosystem,

265
00:12:12,266 --> 00:12:15,433
and I'll talk more about 
it's physical nature,

266
00:12:15,533 --> 00:12:18,933
but it drains a stream in from 
the bottom of the photograph,

267
00:12:19,033 --> 00:12:20,900
up into the shore of the lake,

268
00:12:21,000 --> 00:12:23,666
and then it goes out 
through another lake chain

269
00:12:23,766 --> 00:12:26,166
over to the Chippewa River also.

270
00:12:26,266 --> 00:12:28,200
It'd be a surface flow.

271
00:12:29,700 --> 00:12:33,300
Alright, impoundments are what 
we have lots of in Wisconsin,

272
00:12:33,400 --> 00:12:35,200
or reservoirs, 
they are referred to.

273
00:12:35,300 --> 00:12:37,233
And they're not really lakes-- 
they're dammed up rivers.

274
00:12:37,333 --> 00:12:40,233
These are often some 
of our more significant

275
00:12:40,333 --> 00:12:42,933
management challenges, 
because we're really

276
00:12:43,033 --> 00:12:45,466
taking an ecosystem 
function of the river,

277
00:12:45,566 --> 00:12:48,600
which is to transport 
material out of a watershed,

278
00:12:48,700 --> 00:12:50,266
and we're stopping that function

279
00:12:50,366 --> 00:12:53,233
and creating the 
surface water body.

280
00:12:53,333 --> 00:12:55,900
This is Lake Altoona 
on the east side

281
00:12:56,000 --> 00:12:58,200
of Eau Claire, Wisconsin,

282
00:12:58,300 --> 00:13:00,933
and it's a lake that I've 
been engaged with management

283
00:13:01,033 --> 00:13:04,200
over the last 30 years 
of my career.

284
00:13:04,300 --> 00:13:08,300
The Eau Claire River 
is a very high sand port,

285
00:13:08,400 --> 00:13:10,933
sand transport system.

286
00:13:11,033 --> 00:13:13,966
When we first started 
looking at this lake

287
00:13:14,066 --> 00:13:18,000
back in the early '80s, 
the delta had moved

288
00:13:18,100 --> 00:13:20,533
about a third of the way 
down the lake.

289
00:13:20,633 --> 00:13:23,266
The lake had filled 
about a third full with sand.

290
00:13:23,366 --> 00:13:25,000
Its sedimentation rate

291
00:13:25,100 --> 00:13:28,066
was tens of thousands of yards 
of sand every year.

292
00:13:28,166 --> 00:13:31,366
We estimated that as high 
as 70,000 yards of sand a year

293
00:13:31,466 --> 00:13:34,133
were being deposited 
in this system.

294
00:13:34,233 --> 00:13:36,100
It's a huge 
management challenge.

295
00:13:36,200 --> 00:13:39,766
It comes down to, how much 
does society value this lake?

296
00:13:39,866 --> 00:13:42,333
Is this lake going 
to be sustained

297
00:13:42,433 --> 00:13:45,066
as part of the greater 
Eau Claire community?

298
00:13:45,166 --> 00:13:47,033
And the people that 
lived around the lake

299
00:13:47,133 --> 00:13:48,766
have a lake management district,

300
00:13:48,866 --> 00:13:50,766
and in concert with 
Eau Claire County

301
00:13:50,866 --> 00:13:52,166
have found the resources.

302
00:13:52,266 --> 00:13:54,700
This has just finished 
another dredging project

303
00:13:54,800 --> 00:13:57,300
literally a couple of weeks ago,

304
00:13:57,400 --> 00:14:01,000
and it was like the third 
time it's been dredged,

305
00:14:01,100 --> 00:14:03,266
so they're dredging 
almost once a decade

306
00:14:03,366 --> 00:14:05,400
and they took 
almost 200,000 yards

307
00:14:05,500 --> 00:14:08,200
of sand out of this system.

308
00:14:08,300 --> 00:14:12,500
And that is just to 
sustain it as a lake basin.

309
00:14:12,600 --> 00:14:14,800
Another interesting 
lake we have in our area

310
00:14:14,900 --> 00:14:17,100
north of Eau Claire, 
this is Lake Hallie

311
00:14:17,200 --> 00:14:19,133
in the village of Hallie.

312
00:14:19,233 --> 00:14:21,633
This lake is an Oxbow Lake,

313
00:14:21,733 --> 00:14:24,000
it was part of the 
Chippewa River one time,

314
00:14:24,100 --> 00:14:27,333
and at the time of the cutover, 
when a lot of the water,

315
00:14:27,433 --> 00:14:31,666
the timber was coming out 
of the Chippewa River basin,

316
00:14:31,766 --> 00:14:34,633
this lake was used 
for log storage.

317
00:14:34,733 --> 00:14:36,500
And so they put a 
dam on this system

318
00:14:36,600 --> 00:14:39,233
and it's what we refer 
to as a raised lake.

319
00:14:39,333 --> 00:14:41,500
So this lake only 
has a mean depth of

320
00:14:41,600 --> 00:14:43,666
about 9 feet 
in average depth.

321
00:14:43,766 --> 00:14:48,200
But the uniqueness about this 
lake, up until the mid-1990s

322
00:14:48,300 --> 00:14:50,933
it had very, very, high levels 
of groundwater flow into it.

323
00:14:51,033 --> 00:14:53,533
So it's a very 
shallow ecosystem,

324
00:14:53,633 --> 00:14:54,966
we would think 
it'd be very warm,

325
00:14:55,066 --> 00:14:57,100
but it had such high 
groundwater inputs,

326
00:14:57,200 --> 00:14:59,866
we could sustain trout 
in this lake year round,

327
00:14:59,966 --> 00:15:02,133
because on the far 
end of the lake

328
00:15:02,233 --> 00:15:03,966
near the bottom 
of the photograph,

329
00:15:04,066 --> 00:15:07,066
we had very high spring 
flow into this system

330
00:15:07,166 --> 00:15:10,166
and it would keep the 
water cool enough where

331
00:15:10,266 --> 00:15:14,033
it would sustain a stocked 
trout fishery for the community.

332
00:15:14,133 --> 00:15:16,733
And the other thing that 
that high groundwater flow

333
00:15:16,833 --> 00:15:20,100
did in to this system, was 
it's warm water in the winter.

334
00:15:20,200 --> 00:15:21,833
Groundwater's about 50 degrees

335
00:15:21,933 --> 00:15:24,066
as it comes in to 
lake ecosystems,

336
00:15:24,166 --> 00:15:27,466
and it kept the upper 20 acres 
of this lake open

337
00:15:27,566 --> 00:15:30,433
all through the winter, 
no matter how cold it got.

338
00:15:30,533 --> 00:15:33,233
Well, as we've developed 
its groundwater shed,

339
00:15:33,333 --> 00:15:36,666
here on the left side 
of the photograph,

340
00:15:37,700 --> 00:15:39,033
a couple of things have gone on.

341
00:15:39,133 --> 00:15:41,066
We've put some high 
capacity wells in

342
00:15:41,166 --> 00:15:43,133
to provide water supply 
for the community.

343
00:15:43,233 --> 00:15:45,666
But we've put a lot of 
impervious surface down,

344
00:15:45,766 --> 00:15:49,200
and that impervious surface 
now is running water off

345
00:15:49,300 --> 00:15:51,033
that used to infiltrate 
into the ground.

346
00:15:51,133 --> 00:15:53,500
And we lost our 
groundwater flow.

347
00:15:53,600 --> 00:15:55,633
And the consequences 
of that have been

348
00:15:55,733 --> 00:15:58,566
we are no longer able to, say, 
net trout,

349
00:15:58,666 --> 00:16:02,933
to keep this lake as a put and 
take trout fishery in the summer

350
00:16:03,033 --> 00:16:05,600
so the lake has lost 
that ecosystem service

351
00:16:05,700 --> 00:16:07,133
to the community.

352
00:16:07,233 --> 00:16:09,333
Because we have less 
groundwater coming in

353
00:16:09,433 --> 00:16:12,166
we don't keep the lake 
open anymore in the winter.

354
00:16:12,266 --> 00:16:15,166
And in the mid-'90s, when 
some fishermen were out there,

355
00:16:15,266 --> 00:16:17,033
we got some calls in the office

356
00:16:17,133 --> 00:16:20,000
and said, "The fish are 
dying in Lake Hallie."

357
00:16:20,100 --> 00:16:21,900
And, sure enough, now this lake,

358
00:16:22,000 --> 00:16:25,000
we have to sustain the fishery 
in the lake

359
00:16:25,100 --> 00:16:26,933
through a winter aeration system

360
00:16:27,033 --> 00:16:29,933
because we don't have that 
open water area out there.

361
00:16:30,033 --> 00:16:34,566
And I'll talk more about why 
that occurs in lakes like this.

362
00:16:34,666 --> 00:16:36,200
So as we think now more about,

363
00:16:36,300 --> 00:16:38,166
that's the lake types we have,

364
00:16:38,266 --> 00:16:41,233
we have these physical 
characteristics 
that impacts lakes,

365
00:16:41,333 --> 00:16:43,466
and we'll talk about 
mixing and stratification,

366
00:16:43,566 --> 00:16:45,466
why lake depth's important,

367
00:16:45,566 --> 00:16:47,933
how long water 
stays in a system,

368
00:16:48,033 --> 00:16:49,633
retention time or flushing rate,

369
00:16:49,733 --> 00:16:53,900
and watershed or drainage 
basin area to lake area ratio,

370
00:16:55,200 --> 00:16:57,500
where this lake is 
positioned in the landscape,

371
00:16:57,600 --> 00:17:00,366
and influences of 
watershed runoff.

372
00:17:00,466 --> 00:17:02,800
So when we think about 
mixing and stratification,

373
00:17:02,900 --> 00:17:06,800
most lakes in Wisconsin, 
we call them dimictic.

374
00:17:06,900 --> 00:17:09,400
That's simply a term 
that means our lakes mix,

375
00:17:09,500 --> 00:17:11,066
top to bottom, twice a year.

376
00:17:11,166 --> 00:17:12,900
So if we think why 
does this happen,

377
00:17:13,000 --> 00:17:15,200
as I was talking about earlier,

378
00:17:15,300 --> 00:17:18,633
water is most dense 
at four degrees,

379
00:17:18,733 --> 00:17:21,500
so in the spring 
where the ice is off,

380
00:17:21,600 --> 00:17:24,333
what we see when we're--let's 
start with winter.

381
00:17:24,433 --> 00:17:26,500
As we're coming out of winter,

382
00:17:26,600 --> 00:17:30,066
and we have zero degree water 
virtually on the surface.

383
00:17:30,166 --> 00:17:32,733
So that's the lightest water 
in the lake at that time,

384
00:17:32,833 --> 00:17:34,900
that's why that ice is floating.

385
00:17:35,000 --> 00:17:36,833
And then as that ice melts,

386
00:17:36,933 --> 00:17:39,800
that lake water warms 
to about four degrees,

387
00:17:39,900 --> 00:17:42,533
and once it's the same 
temperature top to bottom,

388
00:17:42,633 --> 00:17:44,266
or what we call isothermal,

389
00:17:44,366 --> 00:17:46,900
that lake easily is mixed.

390
00:17:47,000 --> 00:17:50,100
So if we put wind energy 
with our spring wind events

391
00:17:50,200 --> 00:17:53,700
onto a lake's surface, then we 
get the spring mixing event.

392
00:17:53,800 --> 00:17:55,766
And we call that 
spring turnover.

393
00:17:55,866 --> 00:17:58,000
And that really 
rejuvenates the lake,

394
00:17:58,100 --> 00:18:00,666
so then our water 
chemistry in this system

395
00:18:00,766 --> 00:18:02,766
is the same top to bottom.

396
00:18:02,866 --> 00:18:05,300
It's just like kinda putting 
a blender into the lake,

397
00:18:05,400 --> 00:18:07,133
it mixes top to bottom.

398
00:18:07,233 --> 00:18:08,966
So as we come out 
of spring here,

399
00:18:09,066 --> 00:18:11,933
as we approach that time period 
in a month or so from now,

400
00:18:12,033 --> 00:18:14,933
that summer condition 
begins to set up.

401
00:18:15,033 --> 00:18:19,166
As that surface water warms, 
as that lake temperature warms,

402
00:18:19,266 --> 00:18:21,833
that water now 
becomes lighter water,

403
00:18:21,933 --> 00:18:25,066
and it sets up a stratification 
is what we call it.

404
00:18:25,166 --> 00:18:27,900
The lake actually layers 
into three distinct layers

405
00:18:28,000 --> 00:18:30,100
as we go into the summer.

406
00:18:31,266 --> 00:18:33,966
So that top layer 
over there on summer

407
00:18:34,066 --> 00:18:36,600
is called a epilimnion,

408
00:18:36,700 --> 00:18:39,533
and it's a fancy term for 
the top layer of the lake,

409
00:18:39,633 --> 00:18:41,600
and that layer is 
really dependent

410
00:18:41,700 --> 00:18:43,500
somewhat on the depth of lake,

411
00:18:43,600 --> 00:18:45,966
but how warm or 
cool the summer is.

412
00:18:46,066 --> 00:18:47,900
So in most lakes in the summer,

413
00:18:48,000 --> 00:18:50,333
that top layer is anywhere from,

414
00:18:50,433 --> 00:18:54,633
it could be as little as 
six feet, or two meters,

415
00:18:54,733 --> 00:18:56,700
on some lakes that 
are very protected

416
00:18:56,800 --> 00:18:59,266
that do not get much 
wind energy on them,

417
00:18:59,366 --> 00:19:03,166
to up to ten meters or 
approximately 30 feet.

418
00:19:03,266 --> 00:19:06,266
And then below that is 
the transitional layer,

419
00:19:06,366 --> 00:19:08,100
we call that the thermocline,

420
00:19:08,200 --> 00:19:10,166
and any people who 
love to swim or dive,

421
00:19:10,266 --> 00:19:12,633
when you swim down into the lake

422
00:19:12,733 --> 00:19:14,833
you'll feel that great 
temperature change,

423
00:19:14,933 --> 00:19:16,800
and that happens 
very, very quickly.

424
00:19:16,900 --> 00:19:19,733
Then our coolest water, 
our most dense water,

425
00:19:19,833 --> 00:19:21,566
stays on the bottom of the lake.

426
00:19:21,666 --> 00:19:23,933
So then as we move into fall,

427
00:19:24,033 --> 00:19:26,500
as that top layer then 
begins to cool again,

428
00:19:26,600 --> 00:19:29,033
once it reaches four 
degrees centigrade

429
00:19:29,133 --> 00:19:32,533
or 39 degrees Fahrenheit, it 
becomes the most dense water

430
00:19:32,633 --> 00:19:34,400
in the lake so what's it do?

431
00:19:34,500 --> 00:19:35,833
It simply sinks.

432
00:19:35,933 --> 00:19:38,033
And then causes this 
fall mixing period

433
00:19:38,133 --> 00:19:40,666
that will continue on 
until ice up.

434
00:19:40,766 --> 00:19:45,133
And then again we rejuvenate 
that whole lake ecosystem.

435
00:19:45,233 --> 00:19:49,400
So let's go into, you know, 
why does lake depth matter?

436
00:19:51,166 --> 00:19:53,233
Deep lakes, definitely 
we'd use this term,

437
00:19:53,333 --> 00:19:55,266
they layer up, they stratify,

438
00:19:55,366 --> 00:19:57,733
and shallow lakes stay 
continuously mixed

439
00:19:57,833 --> 00:19:59,800
so there's a couple of 
things going on here

440
00:19:59,900 --> 00:20:03,300
that really can influence 
lake characteristics,

441
00:20:03,400 --> 00:20:05,766
especially in the summer 
and in the winter.

442
00:20:05,866 --> 00:20:07,566
In our deep lakes, 
what's going on,

443
00:20:07,666 --> 00:20:09,266
and in our shallow lakes,

444
00:20:09,366 --> 00:20:11,200
you think of our lakes again,

445
00:20:11,300 --> 00:20:13,033
they're 10,000 years old, right?

446
00:20:13,133 --> 00:20:15,400
So we've been growing plants 
and algae in these systems

447
00:20:15,500 --> 00:20:18,466
for 10,000 years, 
and we've accumulated

448
00:20:18,566 --> 00:20:20,700
all this really rich, 
organic sediment

449
00:20:20,800 --> 00:20:22,233
on the bottom of these lakes.

450
00:20:22,333 --> 00:20:24,366
Well what happens when you put

451
00:20:24,466 --> 00:20:27,766
organic matter and oxygen 
together, you grow bacteria.

452
00:20:27,866 --> 00:20:30,800
Same thing happens in your 
compost pile in your yard,

453
00:20:30,900 --> 00:20:32,733
you're decomposing that, well,

454
00:20:32,833 --> 00:20:34,400
that same process is 
virtually occurring

455
00:20:34,500 --> 00:20:37,000
on the bottom of every 
lake in the state

456
00:20:37,100 --> 00:20:39,800
and it goes on 24/7, 365.

457
00:20:39,900 --> 00:20:43,066
Well, now does that 
bottom portion of the lake

458
00:20:43,166 --> 00:20:45,466
maintained as habitat or not?

459
00:20:45,566 --> 00:20:47,000
Well it may or may not,

460
00:20:47,100 --> 00:20:48,733
it depends upon the volume of it

461
00:20:48,833 --> 00:20:50,633
and the rate at 
which those bacteria

462
00:20:50,733 --> 00:20:53,266
are consuming that oxygen out 
of the bottom of the lake.

463
00:20:53,366 --> 00:20:55,966
So in our state we only 
have a handful of lakes

464
00:20:56,066 --> 00:20:59,333
where the oxygen concentration 
remains high enough

465
00:20:59,433 --> 00:21:01,600
to sustain a fishery 
in that portion

466
00:21:01,700 --> 00:21:03,300
of the lake as a trout fishery.

467
00:21:03,400 --> 00:21:05,466
So that's why we have 
Trout Lake, Green Lake,

468
00:21:05,566 --> 00:21:07,433
are a couple of the 
more common lakes,

469
00:21:07,533 --> 00:21:10,733
that still have 
lake trout in them.

470
00:21:10,833 --> 00:21:13,300
But we also need that 
oxygen down there

471
00:21:13,400 --> 00:21:15,633
for many of our 
cool water species,

472
00:21:15,733 --> 00:21:17,933
especially our walleye 
fisheries because

473
00:21:18,033 --> 00:21:21,766
there's a fish species named 
cisco that lives down there

474
00:21:21,866 --> 00:21:25,066
and they need that cool water 
place for the cisco to live.

475
00:21:25,166 --> 00:21:26,933
That is a very 
important resource

476
00:21:27,033 --> 00:21:30,000
for sustaining many of 
our walleye fisheries.

477
00:21:30,100 --> 00:21:32,633
It doesn't need it in all 
lakes, but some lakes.

478
00:21:32,733 --> 00:21:35,700
So if we've changed the 
characteristics of the lake,

479
00:21:35,800 --> 00:21:37,100
where we've increased the rate

480
00:21:37,200 --> 00:21:39,166
of that organic 
material being produced

481
00:21:39,266 --> 00:21:41,900
by putting more nutrients 
into that system,

482
00:21:42,000 --> 00:21:45,366
we increase the rate at 
what oxygen depletes.

483
00:21:45,466 --> 00:21:48,366
If we don't have enough oxygen

484
00:21:48,466 --> 00:21:50,366
stored in that 
portion of the lake

485
00:21:50,466 --> 00:21:53,000
because of this high rate 
of sediment decomposition,

486
00:21:53,100 --> 00:21:57,133
that area goes without 
oxygen, we call that anoxia,

487
00:21:57,233 --> 00:22:00,400
and then fish species 
and other aquatic life

488
00:22:00,500 --> 00:22:01,966
can't really live down there.

489
00:22:02,066 --> 00:22:03,600
Some invertebrate species can,

490
00:22:03,700 --> 00:22:06,333
that can sustain really 
low oxygen levels,

491
00:22:06,433 --> 00:22:07,966
but the things we 
might relate to

492
00:22:08,066 --> 00:22:09,866
can't live in that 
portion of the lake.

493
00:22:09,966 --> 00:22:12,466
So conversely, in 
a shallow lake,

494
00:22:12,566 --> 00:22:14,966
that same process is going on.

495
00:22:15,066 --> 00:22:17,666
And as long as that lake 
stays continually mixed

496
00:22:17,766 --> 00:22:20,466
we're fine, but the 
whole chemistry changes

497
00:22:20,566 --> 00:22:23,100
when we go without 
oxygen in the bottom

498
00:22:23,200 --> 00:22:25,466
of the lakes down 
there and lakes start

499
00:22:25,566 --> 00:22:28,600
to release nutrients back 
into the water column.

500
00:22:28,700 --> 00:22:31,033
Well, that's not a problem 
up in our deep lake,

501
00:22:31,133 --> 00:22:33,000
where those nutrients 
stay down there

502
00:22:33,100 --> 00:22:34,966
on the bottom of the 
lake and aren't available

503
00:22:35,066 --> 00:22:38,200
for algal production 
through the growing season,

504
00:22:38,300 --> 00:22:39,933
but in some of 
our shallow lakes,

505
00:22:40,033 --> 00:22:41,633
which one I'm gonna 
show you shortly,

506
00:22:41,733 --> 00:22:43,966
that can be extremely 
problematic,

507
00:22:44,066 --> 00:22:46,266
cause we call that 
internal loading,

508
00:22:46,366 --> 00:22:48,500
or the ability of the 
lake to self-fertilize

509
00:22:48,600 --> 00:22:50,600
itself from its lake sediments.

510
00:22:50,700 --> 00:22:52,900
And in some of those 
lake ecosystems,

511
00:22:53,000 --> 00:22:55,400
we have approximately 
200 of these lakes,

512
00:22:55,500 --> 00:22:59,600
we call them polymictic, or 
they mix many times per summer,

513
00:22:59,700 --> 00:23:02,733
and every time they mix 
after a period of anoxia

514
00:23:02,833 --> 00:23:05,333
or when that sediment 
water interface

515
00:23:05,433 --> 00:23:07,966
has gone without oxygen 
for several days,

516
00:23:08,066 --> 00:23:10,433
you get a pulse of 
nutrients buildup there,

517
00:23:10,533 --> 00:23:13,100
boom, the lake mixes, where 
does that nutrients go,

518
00:23:13,200 --> 00:23:15,766
it goes up in the water 
column, it becomes available.

519
00:23:15,866 --> 00:23:18,466
The other issue 
with shallow lakes,

520
00:23:18,566 --> 00:23:21,266
especially lakes, 
let's say, shallower

521
00:23:21,366 --> 00:23:24,233
than maybe 12, 13 
feet and shallower,

522
00:23:24,333 --> 00:23:27,033
when that ice layer goes 
on in the winter time

523
00:23:27,133 --> 00:23:28,633
that creates a barrier now

524
00:23:28,733 --> 00:23:30,633
between the atmosphere 
and the lake.

525
00:23:30,733 --> 00:23:33,766
Well, as long as sunlight is 
getting through that ice layer

526
00:23:33,866 --> 00:23:36,800
the lake still sustains 
a relatively high amount

527
00:23:36,900 --> 00:23:39,900
of dissolved oxygen to 
sustain a fishery in there.

528
00:23:40,000 --> 00:23:42,433
But when we put the 
snow on that ice,

529
00:23:42,533 --> 00:23:44,700
we turn the lights out, 
when we turn the lights out,

530
00:23:44,800 --> 00:23:46,400
we turn off the 
algal production,

531
00:23:46,500 --> 00:23:49,200
the ability of that lake 
to produce its own oxygen.

532
00:23:49,300 --> 00:23:51,600
Then that fishery becomes 
at the mercy

533
00:23:51,700 --> 00:23:54,700
of the amount of oxygen 
that's stored in that water.

534
00:23:54,800 --> 00:23:57,200
And so, if you hear the 
term "winter-kill lakes,"

535
00:23:57,300 --> 00:24:01,066
well, what's really gone on 
in that system is the lake,

536
00:24:01,166 --> 00:24:04,866
simply because of the bacterial 
decomposition in the sediments,

537
00:24:04,966 --> 00:24:08,266
has used up all the oxygen 
in the lake, and the fish die.

538
00:24:08,366 --> 00:24:12,033
So lake depth definitely 
does matter and impact.

539
00:24:12,133 --> 00:24:14,866
This is a lake that I've 
worked on for many years now.

540
00:24:14,966 --> 00:24:18,700
Now, folks, if you 
have your own lakes,

541
00:24:18,800 --> 00:24:22,000
and you want to get like an 
average depth of your lake,

542
00:24:22,100 --> 00:24:25,733
this is Cedar Lake, it's up in 
Polk and St. Croix Counties.

543
00:24:25,833 --> 00:24:28,100
This is a polymictic lake.

544
00:24:28,200 --> 00:24:31,066
Well, if you look at 
that darker gray center

545
00:24:31,166 --> 00:24:33,000
where the words Cedar Lake are,

546
00:24:33,100 --> 00:24:35,266
that's the only 
portion of the lake

547
00:24:35,366 --> 00:24:37,433
that's about 25 
feet or different.

548
00:24:37,533 --> 00:24:39,766
The wind fetch on this 
lake is north to south,

549
00:24:39,866 --> 00:24:42,066
it's almost two miles long,

550
00:24:43,233 --> 00:24:44,600
and what happens 
with Cedar Lake is

551
00:24:44,700 --> 00:24:49,333
that 25 foot from really 
about 18 feet and shallower,

552
00:24:49,433 --> 00:24:51,266
when we go to quiescent periods,

553
00:24:51,366 --> 00:24:53,500
not much wind during the summer,

554
00:24:53,600 --> 00:24:55,600
Cedar Lake will set 
up and stratify,

555
00:24:55,700 --> 00:24:58,900
but has very enriched 
bottom sediments.

556
00:24:59,000 --> 00:25:02,366
Those bottom sediments 
are releasing phosphorus

557
00:25:02,466 --> 00:25:05,900
into that lake water and then 
when we get a thunder storm

558
00:25:06,000 --> 00:25:08,033
or a large wind event 
that comes through,

559
00:25:08,133 --> 00:25:10,033
the lake will mix top to bottom

560
00:25:10,133 --> 00:25:12,133
and we'll end up 
with an algal bloom.

561
00:25:12,233 --> 00:25:14,300
But one of the things 
I wanted to show you

562
00:25:14,400 --> 00:25:15,733
here with this slide was,

563
00:25:15,833 --> 00:25:18,266
you can simply calculate 
your mean depth

564
00:25:18,366 --> 00:25:20,000
of your lake very easily,

565
00:25:20,100 --> 00:25:22,966
and it's simply the volume 
of water in the lake,

566
00:25:23,066 --> 00:25:27,200
which in this lake it's 
about 20,000 plus acre feet,

567
00:25:27,300 --> 00:25:29,533
divided by the number of acres,

568
00:25:29,633 --> 00:25:32,533
and that gives us 
your mean depth of 18.

569
00:25:32,633 --> 00:25:34,233
So you can do this 
in cubic meters,

570
00:25:34,333 --> 00:25:36,800
and square meters on top,

571
00:25:36,900 --> 00:25:39,066
but this information is 
usually available to you

572
00:25:39,166 --> 00:25:41,533
on any of your lake maps.

573
00:25:41,633 --> 00:25:44,033
Retention time 
and flushing rate,

574
00:25:44,133 --> 00:25:45,533
this is very important.

575
00:25:45,633 --> 00:25:50,200
Algae need times to get off 
many generations to live,

576
00:25:50,300 --> 00:25:53,200
and pollutant flushing is 
also dependent on this.

577
00:25:53,300 --> 00:25:56,266
So when we use the 
term retention time,

578
00:25:56,366 --> 00:25:59,400
that is simply, if you 
drained your lake down,

579
00:25:59,500 --> 00:26:02,533
how long would it 
take it to refill?

580
00:26:02,633 --> 00:26:05,233
The inverse of that 
is flushing rate,

581
00:26:05,333 --> 00:26:07,433
and that would 
give you, in time,

582
00:26:07,533 --> 00:26:11,433
how many times per year 
your lake would flush.

583
00:26:11,533 --> 00:26:13,766
So when we think about 
a lake like Long Lake,

584
00:26:13,866 --> 00:26:16,600
that is relatively high 
up in the landscape,

585
00:26:16,700 --> 00:26:18,866
it's a deep lake, 
it's a large lake,

586
00:26:18,966 --> 00:26:21,300
without a lot of 
water coming into it.

587
00:26:21,400 --> 00:26:24,400
If we drained Long 
Lake out totally

588
00:26:24,500 --> 00:26:27,333
it would take seven years 
for that lake to fill up.

589
00:26:27,433 --> 00:26:30,466
So water stays in that 
lake at least seven,

590
00:26:30,566 --> 00:26:32,066
but when we think about a mass

591
00:26:32,166 --> 00:26:34,233
of pollutants coming 
in to a system,

592
00:26:34,333 --> 00:26:37,866
it takes about three of 
these flushing times,

593
00:26:37,966 --> 00:26:40,333
or the lake has to fill, 
empty, fill, empty,

594
00:26:40,433 --> 00:26:42,400
three times before we 
move the pollutant on.

595
00:26:42,500 --> 00:26:45,033
So it can have an 
impact for a long time,

596
00:26:45,133 --> 00:26:46,733
so if we get a big storm event,

597
00:26:46,833 --> 00:26:49,033
would bring a lot 
of pollutant loading

598
00:26:49,133 --> 00:26:51,300
or phosphorus into Long Lake,

599
00:26:51,400 --> 00:26:53,133
it would be potentially

600
00:26:53,233 --> 00:26:55,933
impacting water quality 
for a couple of decades.

601
00:26:56,033 --> 00:26:58,933
That's opposed to Lake Altoona 
which I showed you earlier,

602
00:26:59,033 --> 00:27:02,000
where they have a large river 
coming into that system,

603
00:27:02,100 --> 00:27:04,300
it's a relatively shallow basin.

604
00:27:04,400 --> 00:27:08,200
The average time water stays 
in Lake Altoona is 22 days,

605
00:27:08,300 --> 00:27:11,433
but when we get into 
a high flow event,

606
00:27:11,533 --> 00:27:13,833
it may be only in 
there less than a day,

607
00:27:13,933 --> 00:27:16,000
a few hours, during 
a flood event.

608
00:27:16,100 --> 00:27:18,733
So we can take a lot 
of pollutant loading

609
00:27:18,833 --> 00:27:21,233
and flush it through 
a system like that.

610
00:27:21,333 --> 00:27:23,866
The other impact on lakes 
when we think about that is

611
00:27:23,966 --> 00:27:28,166
how much land physically 
drains to each acre of lake.

612
00:27:28,266 --> 00:27:32,266
When we have lakes that have 
less than ten acres of land,

613
00:27:32,366 --> 00:27:35,433
ten acres of watershed 
to each acre of lake,

614
00:27:35,533 --> 00:27:38,200
those tend to be our higher 
water quality systems.

615
00:27:38,300 --> 00:27:40,433
There just isn't enough 
land mass out there

616
00:27:40,533 --> 00:27:42,933
to produce enough inputs 
of sediments and nutrients

617
00:27:43,033 --> 00:27:45,633
to impact water 
chemistry that much.

618
00:27:45,733 --> 00:27:49,366
And that's opposed to some 
of our lake ecosystems,

619
00:27:49,466 --> 00:27:52,133
and I'll talk about 
that, or reservoirs,

620
00:27:52,233 --> 00:27:55,166
where we may often have 
two, three thousand acres

621
00:27:55,266 --> 00:27:57,466
of land draining to 
every surface acre

622
00:27:57,566 --> 00:28:00,133
in a reservoir ecosystem.

623
00:28:00,233 --> 00:28:03,033
So landscape 
position, simply think

624
00:28:03,133 --> 00:28:04,833
about the land of 
Wisconsin on a tilt,

625
00:28:04,933 --> 00:28:07,133
or your watershed 
a bit on a tilt.

626
00:28:07,233 --> 00:28:10,533
Those lakes high up in the 
system near the top of the hill,

627
00:28:10,633 --> 00:28:13,133
so to speak, those 
are our seepage lakes.

628
00:28:13,233 --> 00:28:16,400
The ones highest up, 
often don't even have

629
00:28:16,500 --> 00:28:19,300
a lot of groundwater 
in flow to them

630
00:28:19,400 --> 00:28:23,033
so drought can produce 
extreme effects on them.

631
00:28:23,133 --> 00:28:25,500
We have lakes up in the 
Chippewa County forest

632
00:28:25,600 --> 00:28:28,266
and the Chippewa marine 
that their lake levels

633
00:28:28,366 --> 00:28:30,566
still have never 
recovered totally

634
00:28:30,666 --> 00:28:32,866
since the '88, '89 drought.

635
00:28:32,966 --> 00:28:35,233
So we're that many decades out.

636
00:28:35,333 --> 00:28:37,700
And as you move down 
through the system,

637
00:28:37,800 --> 00:28:40,066
you're accumulating 
more water all the time

638
00:28:40,166 --> 00:28:42,366
and you have higher 
groundwater inputs

639
00:28:42,466 --> 00:28:43,866
and surface water input.

640
00:28:43,966 --> 00:28:46,800
So those ones higher up, smaller 
watersheds,

641
00:28:46,900 --> 00:28:49,533
less runoff, tend to 
be where you find your

642
00:28:49,633 --> 00:28:51,900
higher quality lake ecosystems.

643
00:28:52,000 --> 00:28:53,900
The Sand Lake I showed 
you, the Long Lake,

644
00:28:54,000 --> 00:28:56,500
both very, very high 
quality systems.

645
00:28:56,600 --> 00:28:58,433
They're very high 
on the landscape.

646
00:28:58,533 --> 00:29:01,633
Lake Altoona, 
very low on the landscape.

647
00:29:01,733 --> 00:29:03,066
It's right near almost where

648
00:29:03,166 --> 00:29:05,833
the Elk River dumps 
into the Chippewa.

649
00:29:05,933 --> 00:29:08,866
Large land mass 
that drains to it,

650
00:29:08,966 --> 00:29:13,733
has a much poorer water quality 
and sedimentation issues.

651
00:29:13,833 --> 00:29:16,366
So let's switch over now 
a little bit to think about,

652
00:29:16,466 --> 00:29:19,566
so that's kind of the 
physical nature of this lake

653
00:29:19,666 --> 00:29:22,633
and how their function, it's 
mass of water coming in,

654
00:29:22,733 --> 00:29:25,600
mass of water in the basin, 
those types of things.

655
00:29:25,700 --> 00:29:27,966
But what are the 
characteristics of that water?

656
00:29:28,066 --> 00:29:29,200
How is it influenced?

657
00:29:29,300 --> 00:29:30,900
That ultimately will influence

658
00:29:31,000 --> 00:29:34,566
the biological 
characteristics of the lake.

659
00:29:37,866 --> 00:29:41,000
So if we had just distilled 
water in our lakes,

660
00:29:41,100 --> 00:29:43,700
we wouldn't have any 
life in our lakes, right?

661
00:29:43,800 --> 00:29:47,000
So we all need a mix of 
nutrients in our life.

662
00:29:47,100 --> 00:29:49,533
We have micronutrients, which 
are made of the elements

663
00:29:49,633 --> 00:29:52,433
on the side of 
the lower graphic.

664
00:29:52,533 --> 00:29:54,733
Some lakes are harder, softer.

665
00:29:54,833 --> 00:29:56,933
That's simply the 
amount of dissolved ions

666
00:29:57,033 --> 00:29:58,700
in the lake ecosystem.

667
00:29:58,800 --> 00:30:00,433
And dissolved 
oxygen is obviously

668
00:30:00,533 --> 00:30:02,600
incredibly important 
in our lakes.

669
00:30:02,700 --> 00:30:04,033
I talked a bit 
about winter-kill.

670
00:30:04,133 --> 00:30:07,000
To maintain a viable 
warm water fishery,

671
00:30:07,100 --> 00:30:10,600
our dissolved oxygen 
concentration needs to be

672
00:30:10,700 --> 00:30:13,633
5 or above 
to sustain all life stages

673
00:30:13,733 --> 00:30:15,666
of that fishery and that system,

674
00:30:15,766 --> 00:30:17,333
that is our water 
quality standard

675
00:30:17,433 --> 00:30:19,000
for a warm water fishery.

676
00:30:19,100 --> 00:30:21,300
What I really wanna focus 
on are nutrients a bit,

677
00:30:21,400 --> 00:30:23,566
especially the 
ones we can manage.

678
00:30:23,666 --> 00:30:27,600
So when we really think about 
the primary nutrients in

679
00:30:27,700 --> 00:30:31,333
lake ecosystems, there's carbon, 
nitrogen, and phosphorus.

680
00:30:31,433 --> 00:30:32,733
It's that ratio especially

681
00:30:32,833 --> 00:30:35,433
of how they relate 
to one another.

682
00:30:35,533 --> 00:30:37,300
But when we think 
about the nutrients

683
00:30:37,400 --> 00:30:39,700
we may have some 
ability to impact.

684
00:30:39,800 --> 00:30:40,800
We really can't impact carbon,

685
00:30:40,900 --> 00:30:42,766
we really can't impact nitrogen,

686
00:30:42,866 --> 00:30:45,366
that much of the 
atmosphere is full of it.

687
00:30:45,466 --> 00:30:49,966
But we can impact this 
element called phosphorus.

688
00:30:50,066 --> 00:30:52,666
So phosphorus really 
is a major driving

689
00:30:52,766 --> 00:30:56,600
in ecosystem health in most 
of our lakes in Wisconsin.

690
00:30:56,700 --> 00:30:58,700
We need phosphorus 
in these systems.

691
00:30:58,800 --> 00:31:01,300
It's a critical component 
in all forms of life.

692
00:31:01,400 --> 00:31:03,266
It's part of our DNA, our RNA,

693
00:31:03,366 --> 00:31:06,600
our energy metabolism 
for us to sustain ourselves

694
00:31:06,700 --> 00:31:08,566
or any other living thing.

695
00:31:08,666 --> 00:31:11,333
But a little bit of 
phosphorus can go a long way

696
00:31:11,433 --> 00:31:14,233
at producing algae in 
a freshwater ecosystem.

697
00:31:14,333 --> 00:31:17,233
1 pound of phosphorus 
can magnify itself

698
00:31:17,333 --> 00:31:19,033
into 500 pounds of algae.

699
00:31:19,133 --> 00:31:20,900
That's a huge ratio.

700
00:31:21,000 --> 00:31:23,000
It, naturally, in Wisconsin,

701
00:31:23,100 --> 00:31:26,133
because of our parent 
soil materials,

702
00:31:26,233 --> 00:31:29,100
we did not have a lot 
of natural phosphorus.

703
00:31:29,200 --> 00:31:32,066
Our lakes in a 
pre-settlement condition were

704
00:31:32,166 --> 00:31:36,033
very, very low for the 
most part in phosphorus.

705
00:31:36,133 --> 00:31:40,200
It leads us to this concept of 
limiting nutrient principle.

706
00:31:40,300 --> 00:31:43,400
That simply is that the 
nutrient in least supply

707
00:31:43,500 --> 00:31:46,466
in that lake ecosystem 
or freshwater system,

708
00:31:46,566 --> 00:31:49,800
will control the amount 
of plant or algae growth,

709
00:31:49,900 --> 00:31:52,566
and we often relate 
this just to algae.

710
00:31:52,666 --> 00:31:57,533
So if we only have about 
10 times as much nitrogen

711
00:31:57,633 --> 00:32:00,133
as we do phosphorus in the lake,

712
00:32:00,233 --> 00:32:03,066
then we say the lake 
is nitrogen limited,

713
00:32:03,166 --> 00:32:07,200
but when we're in 15 times 
more nitrogen than phosphorus,

714
00:32:07,300 --> 00:32:08,833
then really phosphorus is doing,

715
00:32:08,933 --> 00:32:11,266
it's that gray area in between.

716
00:32:11,366 --> 00:32:15,533
But this was really not 
well understood really until

717
00:32:16,733 --> 00:32:19,566
the 1970s and there 
was great debate.

718
00:32:19,666 --> 00:32:21,533
You think back 40, 50 years ago,

719
00:32:21,633 --> 00:32:23,066
why was that important 
because we just

720
00:32:23,166 --> 00:32:27,033
take for granted that 
we can deal with this.

721
00:32:27,133 --> 00:32:29,400
Back in those days, all of our

722
00:32:29,500 --> 00:32:31,733
cleaning solutions 
across the world,

723
00:32:31,833 --> 00:32:34,866
phosphorus was a major 
constituent in them.

724
00:32:34,966 --> 00:32:37,333
And the soap and 
detergent industry

725
00:32:37,433 --> 00:32:41,466
really wanted to protect that 
ability to maintain phosphorus

726
00:32:41,566 --> 00:32:44,333
and we hadn't really gotten 
into this understanding of

727
00:32:44,433 --> 00:32:46,800
well, we should be 
morphing our products

728
00:32:46,900 --> 00:32:51,066
into more healthy things 
that help us live our lives.

729
00:32:52,733 --> 00:32:55,333
So there was great debate going 
on all across the country.

730
00:32:55,433 --> 00:32:57,200
There was a camp 
saying it was carbon,

731
00:32:57,300 --> 00:32:59,333
another camp of scientists 
saying it was nitrogen,

732
00:32:59,433 --> 00:33:02,266
and then there was a group 
talking about phosphorus,

733
00:33:02,366 --> 00:33:06,200
so this was really put to 
rest in the early 1970s

734
00:33:06,300 --> 00:33:09,033
by a Canadian researcher 
named Dave Schindler

735
00:33:09,133 --> 00:33:11,466
as a young graduate 
student or young professor,

736
00:33:11,566 --> 00:33:15,533
up doing his work in 
Laurentian Shield in Canada,

737
00:33:15,633 --> 00:33:17,466
and with lakes, 
they simply did was

738
00:33:17,566 --> 00:33:20,366
took this lake, it was Lake 227,

739
00:33:20,466 --> 00:33:24,433
put a plastic curtain there 
across the middle of the lake

740
00:33:24,533 --> 00:33:26,033
that goes all the 
way to the bottom,

741
00:33:26,133 --> 00:33:28,633
and he fertilized 
both sides of the lake

742
00:33:28,733 --> 00:33:32,000
with nitrogen and 
carbon, so there was

743
00:33:32,100 --> 00:33:34,233
plenty there to sustain algae.

744
00:33:34,333 --> 00:33:37,233
And so then what he simply 
did is then augmented

745
00:33:37,333 --> 00:33:40,033
one side of the lake 
with phosphorus,

746
00:33:40,133 --> 00:33:42,433
and that was the 
response Dave got

747
00:33:42,533 --> 00:33:45,166
and it got kinda put 
the whole issue to bed.

748
00:33:45,266 --> 00:33:47,233
It is, most of our 
lakes, phosphorus

749
00:33:47,333 --> 00:33:49,800
does control algal growth 
in most of our lakes

750
00:33:49,900 --> 00:33:51,833
and we feel that in Wisconsin,

751
00:33:51,933 --> 00:33:54,900
over 90% of our lakes 
are phosphorus limited.

752
00:33:55,000 --> 00:33:56,933
So it's the one we're 
really concerned about.

753
00:33:57,033 --> 00:33:59,866
How we manage that on 
the land and in the lake

754
00:33:59,966 --> 00:34:03,200
will control the amount of 
algae and the type of algae

755
00:34:03,300 --> 00:34:05,166
you'll get in your lakes.

756
00:34:05,266 --> 00:34:09,466
So soon after that, there 
was many, many people

757
00:34:09,566 --> 00:34:11,766
across the world 
and the country,

758
00:34:11,866 --> 00:34:15,066
started trying to figure more 
of these relationships out,

759
00:34:15,166 --> 00:34:17,533
and this is a very 
basic relationship

760
00:34:17,633 --> 00:34:20,266
and it simply is, as 
you put more phosphorus

761
00:34:20,366 --> 00:34:24,100
into a lake ecosystem, you 
will drive more algae growth

762
00:34:24,200 --> 00:34:26,400
and this is a log-log scale,

763
00:34:26,500 --> 00:34:28,033
so people that understand math,

764
00:34:28,133 --> 00:34:29,800
this is a lot of 
noise around here.

765
00:34:29,900 --> 00:34:33,600
We have many, many 
mathematical simulations

766
00:34:33,700 --> 00:34:36,033
and variations of that, 
that really help us

767
00:34:36,133 --> 00:34:38,466
determine how far do we need

768
00:34:39,766 --> 00:34:41,966
to reduce those 
phosphorus levels in lakes

769
00:34:42,066 --> 00:34:43,833
to restore ecosystem health.

770
00:34:43,933 --> 00:34:46,566
So we spent a lot 
of time on this.

771
00:34:46,666 --> 00:34:48,066
When I was originally 
hired to work

772
00:34:48,166 --> 00:34:50,133
for the DNR, back 
in the early '80s,

773
00:34:50,233 --> 00:34:51,633
it was one of my jobs

774
00:34:51,733 --> 00:34:54,233
to understand these 
relationships in streams

775
00:34:54,333 --> 00:34:56,533
and people were working 
on this in lakes.

776
00:34:56,633 --> 00:35:00,733
So, we finally got to developing 
water quality criteria

777
00:35:00,833 --> 00:35:04,966
for lakes in Wisconsin, 
30 years later in 2011.

778
00:35:05,066 --> 00:35:07,866
So why do we develop criteria?

779
00:35:07,966 --> 00:35:11,133
Well, it's when we have 
obvious water quality problems

780
00:35:11,233 --> 00:35:14,766
and we know they're caused 
by excess nutrient loading,

781
00:35:14,866 --> 00:35:16,433
we need to know 
how clean is clean,

782
00:35:16,533 --> 00:35:18,666
where do we need to manage 
that system back to,

783
00:35:18,766 --> 00:35:21,966
and those goals that then 
directly relate to them.

784
00:35:22,066 --> 00:35:25,500
We have numbers that 
we know can protect

785
00:35:25,600 --> 00:35:29,300
recreational fish and aquatic 
life uses and those things,

786
00:35:29,400 --> 00:35:31,733
and also EPA said this 
would be a good thing

787
00:35:31,833 --> 00:35:33,933
for all the states to do.

788
00:35:35,366 --> 00:35:38,466
And these are our criteria 
for lakes in Wisconsin.

789
00:35:38,566 --> 00:35:40,566
So those two-story fishery lakes

790
00:35:40,666 --> 00:35:42,933
where we wanna 
maintain the integrity

791
00:35:43,033 --> 00:35:44,833
of that dissolved oxygen,

792
00:35:44,933 --> 00:35:47,233
and those deep lakes 
below that thermocline,

793
00:35:47,333 --> 00:35:49,266
that stratified layer,

794
00:35:49,366 --> 00:35:51,066
they are very sensitive 
to phosphorus.

795
00:35:51,166 --> 00:35:54,900
We'll give them a very low 
number, 15 micrograms per liter.

796
00:35:55,000 --> 00:35:56,933
To maintain those 
stratified lakes,

797
00:35:57,033 --> 00:35:59,366
those deeper ones, 
those higher quality lakes

798
00:35:59,466 --> 00:36:00,766
that I talked about,

799
00:36:00,866 --> 00:36:02,766
that's 20 micrograms per liter.

800
00:36:02,866 --> 00:36:04,566
These are very, 
very low numbers.

801
00:36:04,666 --> 00:36:06,466
These are parts per billion,

802
00:36:06,566 --> 00:36:10,633
so if we had a billion ping 
pong balls in this room,

803
00:36:10,733 --> 00:36:13,233
to maintain integrity 
of a stratified lake,

804
00:36:13,333 --> 00:36:15,933
only 20 of them 
could be represented

805
00:36:16,033 --> 00:36:17,633
as phosphorus molecules,

806
00:36:17,733 --> 00:36:19,933
so these are very, 
very low numbers.

807
00:36:20,033 --> 00:36:24,433
And so, as the lakes become 
less sensitive to phosphorus,

808
00:36:24,533 --> 00:36:27,200
as we get up into those 
reservoir systems,

809
00:36:27,300 --> 00:36:29,033
those numbers we have developed

810
00:36:29,133 --> 00:36:31,833
are 40 micrograms per liter 
which is twice as much

811
00:36:31,933 --> 00:36:34,500
as what would be 
in a seepage lake.

812
00:36:34,600 --> 00:36:36,833
So let's think about now, 
how does this impact

813
00:36:36,933 --> 00:36:38,666
the biology of the system, 
right?

814
00:36:38,766 --> 00:36:41,800
So what we really want to have,

815
00:36:41,900 --> 00:36:44,500
we gotta create this food 
web through the system.

816
00:36:44,600 --> 00:36:46,866
And so what we want are

817
00:36:46,966 --> 00:36:49,666
the high quality algae 
species in the system

818
00:36:49,766 --> 00:36:52,866
that can go up into our 
invertebrate population,

819
00:36:52,966 --> 00:36:56,033
that little guy in the middle 
there is called a zooplankton.

820
00:36:56,133 --> 00:36:58,266
We have many, many species 
of those in our lakes,

821
00:36:58,366 --> 00:37:01,766
and they're the guys that 
are the energy transformers.

822
00:37:01,866 --> 00:37:03,933
They're taking 
those algae cells,

823
00:37:04,033 --> 00:37:05,866
turning them into meat protein,

824
00:37:05,966 --> 00:37:09,533
and then they will be harvested 
by fish that eat them,

825
00:37:09,633 --> 00:37:11,333
often our panfish or some of

826
00:37:11,433 --> 00:37:14,133
our minnow species 
is a good example.

827
00:37:14,233 --> 00:37:18,700
So we have all this biology 
going on in our lake ecosystems.

828
00:37:18,800 --> 00:37:22,400
So what does that primary 
function of that algae?

829
00:37:22,500 --> 00:37:24,033
Well one of the 
first things it is,

830
00:37:24,133 --> 00:37:27,733
is that energy source for 
our invertebrate community,

831
00:37:27,833 --> 00:37:30,533
those filter feeders, 
we call them.

832
00:37:30,633 --> 00:37:32,600
But they also produce oxygen.

833
00:37:32,700 --> 00:37:35,766
We surely need oxygen 
in our systems to sustain us.

834
00:37:35,866 --> 00:37:38,266
But it's the type 
of algae we have.

835
00:37:38,366 --> 00:37:40,600
As long as we stay with 
these types of algae

836
00:37:40,700 --> 00:37:44,033
over in the lower type, these 
are smaller-celled algae,

837
00:37:44,133 --> 00:37:47,900
our lakes' ecosystem health 
remains in a high quality state.

838
00:37:48,000 --> 00:37:50,733
But when we put too many 
nutrients into this system,

839
00:37:50,833 --> 00:37:54,633
we shift from this algae 
population dominated to

840
00:37:54,733 --> 00:37:58,866
a blue-green algae 
population,

841
00:37:58,966 --> 00:38:02,233
so we call those cyanobacteria, 
blue-green algae.

842
00:38:02,333 --> 00:38:06,000
As you increase the phosphorus 
concentration in our lakes,

843
00:38:06,100 --> 00:38:08,500
we increase that 
lake's capability,

844
00:38:08,600 --> 00:38:10,966
we make that nutrient 
more available,

845
00:38:11,066 --> 00:38:15,233
we want all those other algae, 
different genera of algae

846
00:38:16,866 --> 00:38:19,666
to be in our lakes that 
are smaller cellular algae.

847
00:38:19,766 --> 00:38:22,200
They don't create the 
nuisance algal blooms.

848
00:38:22,300 --> 00:38:24,800
But you can see there's 
a transition right there

849
00:38:24,900 --> 00:38:28,566
in many lakes around that 
20 microgram per liter number.

850
00:38:28,666 --> 00:38:31,800
Soon as you get above 
20 micrograms per liter,

851
00:38:31,900 --> 00:38:33,966
you start to create a situation

852
00:38:34,066 --> 00:38:37,166
where blue-green algae dominate 
in our lake ecosystems.

853
00:38:37,266 --> 00:38:40,600
These are both pictures 
that have come from--

854
00:38:40,700 --> 00:38:44,400
Picture on the left is an 
algae bloom on peat oil flowage.

855
00:38:44,500 --> 00:38:47,066
That's one of my 
co-workers on the right,

856
00:38:47,166 --> 00:38:51,433
that is in Tainter Lake, 
over near the city of 
Menomonie.

857
00:38:51,533 --> 00:38:54,066
These lakes have the 
ability to produce

858
00:38:54,166 --> 00:38:58,033
very, very high levels 
of blue-green algae.

859
00:38:58,133 --> 00:39:00,300
And what blue-green algae, 
some species

860
00:39:00,400 --> 00:39:03,733
at some times during 
their life stage,

861
00:39:03,833 --> 00:39:05,733
we're trying to figure 
out what trips us,

862
00:39:05,833 --> 00:39:07,966
they can produce toxicity.

863
00:39:08,066 --> 00:39:10,500
That's what probably killed 
that goose in the left.

864
00:39:10,600 --> 00:39:13,900
But these toxins can be 
harmful to us, our pets,

865
00:39:14,000 --> 00:39:16,033
if we get to these high levels.

866
00:39:16,133 --> 00:39:19,400
When these cells die, 
they release

867
00:39:19,500 --> 00:39:21,400
the toxins into the water.

868
00:39:21,500 --> 00:39:24,633
These are just some 
of the characteristics

869
00:39:24,733 --> 00:39:27,666
associated that can 
be how they impact us.

870
00:39:27,766 --> 00:39:29,166
We can get dermal reactions.

871
00:39:29,266 --> 00:39:31,866
We have had many folks over 
in the Tainter Lake system

872
00:39:31,966 --> 00:39:34,366
that are very prone to it, 
that'll get rashes.

873
00:39:34,466 --> 00:39:37,000
One of our staff people was 
loading a boat one time,

874
00:39:37,100 --> 00:39:39,766
by the time 
she got back to the lab,

875
00:39:39,866 --> 00:39:42,000
showered up and everything, 
she got home

876
00:39:42,100 --> 00:39:43,766
and she had this incredible rash

877
00:39:43,866 --> 00:39:45,800
on the lower portion of her leg,

878
00:39:45,900 --> 00:39:48,866
where she had been 
in contact with that water.

879
00:39:48,966 --> 00:39:52,633
Neurotoxins, when you hear 
of dog deaths sometimes,

880
00:39:52,733 --> 00:39:57,300
or cattle deaths in farm ponds, 
they ingest that water.

881
00:39:57,400 --> 00:40:00,200
It can be a very rapid 
death for some of those,

882
00:40:00,300 --> 00:40:05,033
and then we also have 
hepatotoxins, blood impacts,

883
00:40:05,133 --> 00:40:06,966
where it impacts liver function,

884
00:40:07,066 --> 00:40:09,300
so if you see water 
quality characteristics

885
00:40:09,400 --> 00:40:11,533
that look bad, just stay out,

886
00:40:11,633 --> 00:40:15,533
cause there could be 
blue-green algal toxicity.

887
00:40:17,833 --> 00:40:20,933
So let's switch here, I mean, 
I guess, just again show

888
00:40:21,033 --> 00:40:22,866
this invertebrate communities,

889
00:40:22,966 --> 00:40:25,500
an important part of 
our lake ecosystem,

890
00:40:25,600 --> 00:40:27,933
and it is one of those 
that energy transfer.

891
00:40:28,033 --> 00:40:31,000
This is the zooplankton, 
the daphnia on the left.

892
00:40:31,100 --> 00:40:33,833
That is lunch for 
"young-of-the-year" fishes,

893
00:40:33,933 --> 00:40:35,666
that's what they're after.

894
00:40:35,766 --> 00:40:38,533
And if we have a high 
quality algae population,

895
00:40:38,633 --> 00:40:41,466
high quality zooplankton, 
there's a lot of energy there

896
00:40:41,566 --> 00:40:44,600
to produce a lot of fish 
biomass up the food chain.

897
00:40:44,700 --> 00:40:48,500
Aquatic plants, incredibly 
valued in our lake ecosystem,

898
00:40:48,600 --> 00:40:51,000
as long as, again, that 
system is in balance.

899
00:40:51,100 --> 00:40:53,566
They are absolutely 
critical habitat

900
00:40:53,666 --> 00:40:57,233
for many of our aquatic 
species that live in lakes.

901
00:40:57,333 --> 00:40:59,333
They are great 
physical structure

902
00:40:59,433 --> 00:41:03,666
and are energy dissipaters 
and they produce oxygen.

903
00:41:06,333 --> 00:41:08,766
Fish, I think this is what 
we all kind of relate to

904
00:41:08,866 --> 00:41:10,333
when we think about this.

905
00:41:10,433 --> 00:41:13,733
As long as we have good 
habitat, good water quality,

906
00:41:13,833 --> 00:41:15,766
we tend to have 
high quality fisheries,

907
00:41:15,866 --> 00:41:18,200
and some of those 
highly impacted lakes,

908
00:41:18,300 --> 00:41:20,400
that Cedar Lake that 
I was talking about,

909
00:41:20,500 --> 00:41:24,466
we went through a period of 
time there where the fishery,

910
00:41:24,566 --> 00:41:27,366
probably 95% of the fish biomass

911
00:41:27,466 --> 00:41:29,766
in the lake was tied up in carp.

912
00:41:29,866 --> 00:41:32,833
It was also a huge 
impact on water quality.

913
00:41:32,933 --> 00:41:35,333
Our rough fish 
have very short gut tracts.

914
00:41:35,433 --> 00:41:38,633
They eat the benthos, 
the bottom invertebrates

915
00:41:38,733 --> 00:41:41,066
off the lake, and 
what they can do is

916
00:41:41,166 --> 00:41:43,066
they actually take 
those invertebrates

917
00:41:43,166 --> 00:41:44,800
and sediments from the bottom,

918
00:41:44,900 --> 00:41:46,300
put them through the gut tract,

919
00:41:46,400 --> 00:41:48,266
make many nutrients available,

920
00:41:48,366 --> 00:41:50,100
and they can be a 
source of nutrients,

921
00:41:50,200 --> 00:41:52,900
posing a poor water 
quality problem.

922
00:41:53,000 --> 00:41:55,000
When we looked at 
Cedar Lake back then,

923
00:41:55,100 --> 00:41:58,233
we thought about 30% of 
the water quality problem

924
00:41:58,333 --> 00:42:01,400
in the lake was simply 
due to the mass of carp

925
00:42:01,500 --> 00:42:03,000
that was in that system.

926
00:42:03,100 --> 00:42:05,866
They were putting thousands 
of pounds of phosphorus a year

927
00:42:05,966 --> 00:42:09,566
into the photic zone, the area 
where light is in the lake,

928
00:42:09,666 --> 00:42:11,366
to create the algal blooms.

929
00:42:11,466 --> 00:42:13,433
They were a big 
factor in that issue.

930
00:42:13,533 --> 00:42:17,700
So, again, all these critters 
need high quality habitat.

931
00:42:17,800 --> 00:42:20,800
These are the views and 
those characteristics,

932
00:42:20,900 --> 00:42:23,233
those services we want to 
maintain in those lakes.

933
00:42:23,333 --> 00:42:25,100
We'll talk a bit about habitat.

934
00:42:25,200 --> 00:42:29,400
That near shore habitat, 
we call the "littoral zone"

935
00:42:29,500 --> 00:42:33,100
is where the light penetrates 
deep enough into the water

936
00:42:33,200 --> 00:42:35,233
to allow aquatic plants to grow

937
00:42:35,333 --> 00:42:40,100
shoreward from that, and 
then up onto the lake shore.

938
00:42:40,200 --> 00:42:42,833
So when we just think 
about that littoral zone,

939
00:42:42,933 --> 00:42:45,100
or the area where light 
penetrates deep enough

940
00:42:45,200 --> 00:42:47,266
to stimulate the growth 
of aquatic plants,

941
00:42:47,366 --> 00:42:50,933
over 90% of the species 
in any given lake

942
00:42:51,033 --> 00:42:54,666
are dependent on that 
critical habitat component

943
00:42:54,766 --> 00:42:57,566
for at least some component 
of their life history.

944
00:42:57,666 --> 00:43:00,033
So if we can maintain 
the integrity of that,

945
00:43:00,133 --> 00:43:03,400
we often maintain the 
integrity of the system.

946
00:43:03,500 --> 00:43:05,733
And then shoreward from that,

947
00:43:05,833 --> 00:43:10,066
that shoreland buffer zone 
area is absolutely incredibly

948
00:43:10,166 --> 00:43:13,966
valuable for aquatic 
life near shore,

949
00:43:14,066 --> 00:43:18,300
water-dependent wildlife 
and water quality of the lake.

950
00:43:18,400 --> 00:43:20,066
So how have we 
developed our lakes?

951
00:43:20,166 --> 00:43:23,400
And how have these impacts 
impacted our lake ecosystems?

952
00:43:23,500 --> 00:43:25,833
I'll try and finish up here.

953
00:43:26,833 --> 00:43:28,500
Oh, sorry.

954
00:43:29,500 --> 00:43:31,333
As we think about 
this, we look at,

955
00:43:31,433 --> 00:43:33,633
this is what our lake 
shores often looked like

956
00:43:33,733 --> 00:43:35,200
in an undeveloped state.

957
00:43:35,300 --> 00:43:38,733
We had emergent vegetation 
out the submergent.

958
00:43:38,833 --> 00:43:40,400
Natural woody vegetation 
on the shore.

959
00:43:40,500 --> 00:43:43,100
As we have brought 
our societal values

960
00:43:43,200 --> 00:43:44,866
and how we live 
in our communities,

961
00:43:44,966 --> 00:43:47,466
you know, this is what 
we've often brought to these,

962
00:43:47,566 --> 00:43:50,566
and so, when we bring that 
type of pattern of development,

963
00:43:50,666 --> 00:43:53,833
we lose these natural ecosystem 
functions to our lakes.

964
00:43:53,933 --> 00:43:56,266
So how does that 
impact our lakes?

965
00:43:56,366 --> 00:43:58,166
So one of the things 
we've looked at,

966
00:43:58,266 --> 00:44:00,733
we have a compendium of 
literature that's been developed

967
00:44:00,833 --> 00:44:04,233
in the '90s and through the 
early 2000s in Wisconsin,

968
00:44:04,333 --> 00:44:06,600
but they all kind of 
show the same thing.

969
00:44:06,700 --> 00:44:08,800
With the way we develop 
our lake shores,

970
00:44:08,900 --> 00:44:11,833
once we get to about 
30 homes per mile,

971
00:44:11,933 --> 00:44:15,500
we have lost many of 
the ecosystem services that

972
00:44:15,600 --> 00:44:19,300
that nearshore and that shallow 
water area provides.

973
00:44:20,500 --> 00:44:23,533
And this happens to be 
a green frog study.

974
00:44:23,633 --> 00:44:26,400
Once you get about to 
that level, there is no 
longer

975
00:44:26,500 --> 00:44:29,000
the characteristics there 
at a high enough level,

976
00:44:29,100 --> 00:44:30,900
and our green frogs are gone,

977
00:44:31,000 --> 00:44:33,700
but it also shows up 
in other areas.

978
00:44:34,900 --> 00:44:37,100
This is coarse woody 
habitat, we call it.

979
00:44:37,200 --> 00:44:38,500
It's wood in the lake.

980
00:44:38,600 --> 00:44:41,866
And this is a very valuable 
ecosystem function,

981
00:44:41,966 --> 00:44:45,600
providing diversity of 
habitat, diversity of refuge

982
00:44:45,700 --> 00:44:47,766
on that wood that's growing,

983
00:44:47,866 --> 00:44:49,400
and there is a 
thin layer of algae

984
00:44:49,500 --> 00:44:51,800
which has a lot of 
inverts growing on it

985
00:44:51,900 --> 00:44:54,433
which a lot of small fish 
come in and pick off.

986
00:44:54,533 --> 00:44:56,300
Big fish come in 
there to the prey,

987
00:44:56,400 --> 00:45:00,266
little fish come in there 
to get away from big fish.

988
00:45:00,366 --> 00:45:04,066
But again, when we get out 
around that 30 homes per mile,

989
00:45:04,166 --> 00:45:07,833
we lose this ecosystem 
service in our lakes.

990
00:45:08,866 --> 00:45:10,100
This is Dan Schindler's work,

991
00:45:10,200 --> 00:45:12,533
he happens to be the 
son of Dave Schindler.

992
00:45:12,633 --> 00:45:14,066
He was one of our grad students

993
00:45:14,166 --> 00:45:17,200
at the Center for Limnology 
back in the late '90s.

994
00:45:17,300 --> 00:45:20,100
And what Dan started looking at,

995
00:45:20,200 --> 00:45:22,400
so how does this 
impact fish growth

996
00:45:22,500 --> 00:45:26,100
if we don't have that 
high quality habitat

997
00:45:26,200 --> 00:45:28,633
in our lake ecosystems 
in the north?

998
00:45:28,733 --> 00:45:31,166
And what he really showed was

999
00:45:32,366 --> 00:45:35,166
fish in lakes with 
good woody habitat

1000
00:45:37,200 --> 00:45:40,133
have growth rates 
of three times more

1001
00:45:40,233 --> 00:45:41,666
than lakes where 
we've lost that.

1002
00:45:41,766 --> 00:45:44,033
So if you turn that 
around, you could say

1003
00:45:44,133 --> 00:45:45,833
one way we've 
developed our lakes,

1004
00:45:45,933 --> 00:45:49,200
we've lost about 
a factor of three,

1005
00:45:49,300 --> 00:45:52,933
or if we had that high quality 
habitat in our systems,

1006
00:45:53,033 --> 00:45:55,300
our fisheries' production 
would be improved

1007
00:45:55,400 --> 00:45:57,300
by as much as 300%.

1008
00:45:57,400 --> 00:45:59,000
It's a huge number.

1009
00:46:00,333 --> 00:46:02,466
So, finishing up 
with talking a bit

1010
00:46:02,566 --> 00:46:04,200
about how land use impacts

1011
00:46:04,300 --> 00:46:07,533
and watershed 
impacts water quality.

1012
00:46:07,633 --> 00:46:10,800
We think about that and 
natural lake ecosystem,

1013
00:46:10,900 --> 00:46:15,066
when that water falls on back 
to the hydrologic cycle slide,

1014
00:46:16,533 --> 00:46:19,600
only about 10% 
of that water would runoff.

1015
00:46:19,700 --> 00:46:21,166
50% of it would go in

1016
00:46:21,266 --> 00:46:23,633
and contribute to 
sustaining 
ground water levels.

1017
00:46:23,733 --> 00:46:26,800
So when we urbanize 
an area, especially,

1018
00:46:26,900 --> 00:46:29,133
we flip that totally around.

1019
00:46:29,233 --> 00:46:31,766
In an urban area, we 
only maybe infiltrate

1020
00:46:31,866 --> 00:46:35,266
15% of the rainfall 
and we runoff 55%.

1021
00:46:35,366 --> 00:46:38,566
That 55% running off is a 
huge transport mechanism

1022
00:46:38,666 --> 00:46:41,700
for phosphorus sediment 
and other pollutants.

1023
00:46:41,800 --> 00:46:43,966
So our challenge as managers is

1024
00:46:44,066 --> 00:46:48,000
how do we take a system like 
the picture up on the left,

1025
00:46:48,100 --> 00:46:51,433
but make it function 
like one on the right?

1026
00:46:51,533 --> 00:46:54,100
And we can do this, 
it's not that big a deal.

1027
00:46:54,200 --> 00:46:57,666
But we have to value 
that function, as a society,

1028
00:46:57,766 --> 00:46:59,466
before we can do that.

1029
00:46:59,566 --> 00:47:01,033
So when we think about this,

1030
00:47:01,133 --> 00:47:02,433
we have a variety of models,

1031
00:47:02,533 --> 00:47:06,366
but when we as scientists 
talk about runoff

1032
00:47:06,466 --> 00:47:10,733
or how much pollutant loading 
comes from a given land type,

1033
00:47:10,833 --> 00:47:12,966
in a natural state, 
our landscape,

1034
00:47:13,066 --> 00:47:14,666
that one on the lower right,

1035
00:47:14,766 --> 00:47:17,833
that forested area 
or low density urban,

1036
00:47:17,933 --> 00:47:21,000
that only loads pollutant 
phosphorus to a water body

1037
00:47:21,100 --> 00:47:22,433
at about

1038
00:47:22,533 --> 00:47:26,366
0.1 kilograms 
per hectare per year.

1039
00:47:26,466 --> 00:47:29,333
You can flip that right into 
pounds per acre per year,

1040
00:47:29,433 --> 00:47:31,200
if that's easier 
to think about it.

1041
00:47:31,300 --> 00:47:34,333
But by the time we 
get to mixed ag,

1042
00:47:34,433 --> 00:47:37,266
or high density urban, 
we've increased that

1043
00:47:37,366 --> 00:47:40,866
by an order of magnitude, 
by about ten-fold.

1044
00:47:43,300 --> 00:47:46,333
This is a new tool that's out 
there for any of you folks.

1045
00:47:46,433 --> 00:47:50,600
Go see Matt Diebel's talk in 
the next session after plenary,

1046
00:47:51,833 --> 00:47:54,133
but what Matt has put 
together for us now

1047
00:47:54,233 --> 00:47:55,700
for all lakes in Wisconsin--

1048
00:47:55,800 --> 00:47:59,333
That happens to be Cedar Lake 
down there in the bottom.

1049
00:47:59,433 --> 00:48:04,100
And through GIS techniques 
and digital elevation models,

1050
00:48:04,200 --> 00:48:07,466
we can computer generate what 
your water shed looks like now

1051
00:48:07,566 --> 00:48:09,966
and the land use 
characteristics of it.

1052
00:48:10,066 --> 00:48:14,466
And the reason Matt put this 
together for us on Cedar Lake

1053
00:48:14,566 --> 00:48:18,733
is that, I think he's got 
some place here, I thought--

1054
00:48:20,300 --> 00:48:22,800
oh, the phosphorus load, 
most likely

1055
00:48:22,900 --> 00:48:25,833
because of the amount 
of agriculture in there,

1056
00:48:25,933 --> 00:48:29,600
this watershed, 
he estimates to be loading

1057
00:48:29,700 --> 00:48:32,700
about 0.5 pounds 
per acre per year,

1058
00:48:32,800 --> 00:48:34,800
most likely, 
at 13,600 pounds a year.

1059
00:48:35,900 --> 00:48:37,266
Well, because of the farmers

1060
00:48:37,366 --> 00:48:40,666
in this watershed have 
cooperated fantastically

1061
00:48:40,766 --> 00:48:43,000
with their lake shore neighbors,

1062
00:48:43,100 --> 00:48:45,133
this watershed 
only is functioning

1063
00:48:45,233 --> 00:48:48,566
at a factor of about 
0.2 pounds per acre.

1064
00:48:50,300 --> 00:48:52,100
And it shows we can 
manage the runoff

1065
00:48:52,200 --> 00:48:55,866
in these agricultural 
ecosystem watersheds,

1066
00:48:55,966 --> 00:48:59,833
so their amount of phosphorus 
coming off the land

1067
00:48:59,933 --> 00:49:02,533
is only two times 
above background.

1068
00:49:02,633 --> 00:49:05,066
That's a phenomenally low number

1069
00:49:05,166 --> 00:49:08,800
for an agricultural 
dominated watershed.

1070
00:49:08,900 --> 00:49:11,566
And so how does that ag 
source area get on there?

1071
00:49:11,666 --> 00:49:14,100
Well, we put it on there through 
what we've fed our cattle.

1072
00:49:14,200 --> 00:49:17,000
After World War II, we've 
had a lot of our dairy cattle

1073
00:49:17,100 --> 00:49:19,766
on enriched phosphate 
mineral that showed up

1074
00:49:19,866 --> 00:49:21,500
through their 
manure that has been

1075
00:49:21,600 --> 00:49:23,033
on their land for decades.

1076
00:49:23,133 --> 00:49:25,966
Farmers have really since, 
I would say, the late '90s,

1077
00:49:26,066 --> 00:49:28,966
no longer feed, we found 
we don't need to feed that.

1078
00:49:29,066 --> 00:49:31,833
And then of course, 
inorganic fertilizers,

1079
00:49:31,933 --> 00:49:34,566
and farmers are doing a 
tremendously better job

1080
00:49:34,666 --> 00:49:38,333
of really putting on that 
fertilizer based on crop need

1081
00:49:38,433 --> 00:49:40,933
and managing their 
land off in a way

1082
00:49:41,033 --> 00:49:42,800
so it doesn't generate runoff.

1083
00:49:42,900 --> 00:49:45,633
Here's just a fact 
from Lake Mendota.

1084
00:49:45,733 --> 00:49:48,566
This is Elena Bennett's 
master's research

1085
00:49:48,666 --> 00:49:51,733
for Center of Limnology 
back in the mid '90s.

1086
00:49:51,833 --> 00:49:54,700
What Elena did was 
put together a mass balance

1087
00:49:54,800 --> 00:49:57,433
for how much phosphorus 
did we put on the land

1088
00:49:57,533 --> 00:49:59,333
in the Lake Mendota watershed?

1089
00:49:59,433 --> 00:50:02,033
Well, this is 1,300 metric tons,

1090
00:50:03,133 --> 00:50:05,733
so there's 2,200 pounds 
in a metric ton.

1091
00:50:05,833 --> 00:50:09,933
That's a few million pounds 
of phosphorus a year.

1092
00:50:10,033 --> 00:50:13,900
And then, how much really 
do we use of that phosphorus

1093
00:50:14,000 --> 00:50:17,033
to produce the meat commodities?

1094
00:50:17,133 --> 00:50:18,566
A little over half of that.

1095
00:50:18,666 --> 00:50:22,800
So we were storing, 
back in pre-1995 conditions

1096
00:50:22,900 --> 00:50:26,066
of Lake Mendota, we were 
just mass accumulating

1097
00:50:26,166 --> 00:50:27,900
phosphorus on the landscape

1098
00:50:28,000 --> 00:50:32,366
of over a million pounds 
a year, 575 metric tons.

1099
00:50:32,466 --> 00:50:33,600
It's a huge number.

1100
00:50:33,700 --> 00:50:35,500
So we have learned 
from these situations

1101
00:50:35,600 --> 00:50:38,800
and we're doing 
much better today.

1102
00:50:38,900 --> 00:50:42,566
Residential development, boy, 
that has impacted our lakes,

1103
00:50:42,666 --> 00:50:44,200
especially from new channeling.

1104
00:50:44,300 --> 00:50:47,566
How we develop property 
when we develop

1105
00:50:47,666 --> 00:50:52,400
or rebuild a home, we totally 
destroy the soil health,

1106
00:50:52,500 --> 00:50:55,900
the soil structure, by putting 
all this equipment around.

1107
00:50:56,000 --> 00:50:58,933
We virtually eliminate 
often, or severely reduce

1108
00:50:59,033 --> 00:51:01,800
the ability of that soil 
to infiltrate water.

1109
00:51:01,900 --> 00:51:05,266
We fertilize our yards, 
we grade our yards

1110
00:51:05,366 --> 00:51:07,033
to make them highly efficient

1111
00:51:07,133 --> 00:51:09,866
to get that storm water run 
off away from the buildings.

1112
00:51:09,966 --> 00:51:12,600
So we did a little 
work, John Panuska,

1113
00:51:12,700 --> 00:51:15,066
he did this work for us 
when he worked at DNR.

1114
00:51:15,166 --> 00:51:16,900
He's now over at the university.

1115
00:51:17,000 --> 00:51:18,366
John did some modeling for us

1116
00:51:18,466 --> 00:51:20,100
so we took an 
individual lake slot.

1117
00:51:20,200 --> 00:51:22,500
We wanted to simulate a lot up

1118
00:51:22,600 --> 00:51:24,233
on Long Lake in Chippewa County.

1119
00:51:24,333 --> 00:51:26,366
So in a natural condition,

1120
00:51:26,466 --> 00:51:28,066
before we did any development,

1121
00:51:28,166 --> 00:51:30,633
John simulated that 
this slot would generate

1122
00:51:30,733 --> 00:51:33,400
about 1,000 cubic feet 
of runoff of water,

1123
00:51:33,500 --> 00:51:35,733
3 hundredths of a pound 
of phosphorus

1124
00:51:35,833 --> 00:51:37,500
and 5 pounds of sediment.

1125
00:51:37,600 --> 00:51:40,900
So the first property that 
was built on this lake

1126
00:51:41,000 --> 00:51:42,433
was post-World War II, 
where we had,

1127
00:51:42,533 --> 00:51:44,300
this is what we were building.

1128
00:51:44,400 --> 00:51:48,033
This happens to be 
the Laine Cabin, up on a lot.

1129
00:51:48,133 --> 00:51:49,800
And so when Grandpa 
Laine came up

1130
00:51:49,900 --> 00:51:51,700
on the train from Chicago 
in the summer,

1131
00:51:51,800 --> 00:51:53,833
he built a cabin, 
built a cottage,

1132
00:51:53,933 --> 00:51:56,266
and what was that impact?

1133
00:51:56,366 --> 00:51:58,500
Well, that impact, 
he really didn't impact

1134
00:51:58,600 --> 00:52:01,066
cause we weren't putting 
much impervious surface down,

1135
00:52:01,166 --> 00:52:03,433
we weren't disturbing 
much of the lake life,

1136
00:52:03,533 --> 00:52:05,333
so we maintained most

1137
00:52:05,433 --> 00:52:09,500
of those natural 
hydrologic characteristics 
of that landscape.

1138
00:52:09,600 --> 00:52:13,166
So things changed a bit when 
the Laines sold the property

1139
00:52:13,266 --> 00:52:15,533
and the boom in the 
market in the '90s.

1140
00:52:15,633 --> 00:52:18,733
This is a very modest home 
by those standards,

1141
00:52:18,833 --> 00:52:21,400
but it really changed things up 
on that lot.

1142
00:52:21,500 --> 00:52:24,966
So we went almost to 4,000 
square feet of imperviousness.

1143
00:52:25,066 --> 00:52:27,966
We had to get around on that 
lot to build that house,

1144
00:52:28,066 --> 00:52:32,233
and so we impacted runoff, 
we predicted five-fold increase.

1145
00:52:33,433 --> 00:52:36,366
In phosphorus, about 
a seven-fold increase.

1146
00:52:36,466 --> 00:52:39,133
Our lakes cannot 
sustain these types

1147
00:52:39,233 --> 00:52:43,066
of increased inputs 
if we don't manage them.

1148
00:52:43,166 --> 00:52:44,833
Okay, so this is just a shot

1149
00:52:44,933 --> 00:52:47,366
as we increase 
that imperviousness.

1150
00:52:47,466 --> 00:52:50,133
Once we get to even as 
little as

1151
00:52:50,233 --> 00:52:52,133
15% of the lot is covered

1152
00:52:52,233 --> 00:52:55,366
with rooftops, sidewalks, 
walkways, driveways,

1153
00:52:55,466 --> 00:52:58,500
you've increased 
the mass loading of phosphorus

1154
00:52:58,600 --> 00:53:01,733
from that parcel of land 
by a factor of six.

1155
00:53:01,833 --> 00:53:04,233
And so, with that, I'm done.

1156
00:53:04,333 --> 00:53:06,066
Thanks, folks.

1157
00:53:06,166 --> 00:53:09,166
(applause)