This presentation is made possible in part
by Missouri Department of Agriculture, the
Environmental Protection Agency, and University
of Missouri Extension.
The goal of this program is to Improve Water
Quality through education and the proper use
of pesticides, and through the Identification
of Vulnerable Areas in the Environment.
We will provide a definition of watersheds
and potentially vulnerable watershed areas,
and examine the criteria used to identify
them.
We'll review the use of pesticides in potentially
vulnerable watersheds and the best management
practices to protect water quality.
We'll discuss the potential for off-target
movement of pesticides through surface and
groundwater and through spray drift, as well
as other problem areas.
And, of course, we'll consider the significance
of regulations in the effort to protect water
quality.
In developing best management practices for
your farming operation it's necessary to understand
what a watershed is.
A watershed is the area of land that drains
to a particular point along a stream, a lake
or other bodies of water.
As you consider how water might flow across
a landscape, it becomes clear that determining
the boundaries for watersheds can be a significant
challenge.
Watersheds or basin drainage areas play a
significant part in the management of an area
with the protection of water quality in mind.
In the year 1803, President Thomas Jefferson
used watersheds as a means of determining
boundaries.
BOB BROZ: When we looked at the Louisiana
purchase, we didn't have what was called the
Continental Divide at that time.
What they did was define the watershed as
the boundary for the Louisiana purchase.
All the land where the water falls and runs
to the Mississippi River to what we now call
the Continental Divide, is part of the Louisiana
Purchase.
Watersheds are as varied as the landscape
and include basins, sub-watersheds or sub-basins.
BOB BROZ: We are fortunate in some ways to
live in the single largest watershed in the
continental United States that's the Mississippi
River basin.
This goes all the way from the Appalachian
Mountains all the way to the Rockies.
It contains more than a million square miles.
Now within the Mississippi River basin we
then have six major watershed areas that we
look at.
Where we're at here in Missouri, we live in
the Missouri River basin.
Now within that larger watershed and we divide
watersheds into what we call Hydrologic unit
areas and we give them a number.
The smaller that number the larger the watershed.
In the state of Missouri we have 66 x 8 digit
Hydrologic units or what we call Huc's H-U-C's.
We have one big number which says this is
the bigger area and we had more numbers to
specify a much smaller address or area we're
looking at.
Serious efforts to protect water quality and
the environment require that pesticides be
used in adherence to the directions on the
product label.
According to the Federal Insecticide, Fungicide,
and Rodenticide Act or FIFRA:
THE LABEL IS THE LAW .
Remember the label is designed for normal
or average conditions.
Keep in mind that actual conditions in the
"Real World" may not be described on the label.
In such circumstances, there is an increased
potential for runoff and leaching.
BOB LERCH: There's often been the misconception
that if I apply according to the label rate,
I'm going to protect the environment.
The label rates are designed and the rates
that there are designed for your soil type
and designed for weed control.
The company that makes that chemical designed
that rate to maximize the chance that you're
going to get weed control, not protect the
environment.
So, a label rate like atrazine has some other
specific requirements, so you have to pay
attention to some of these other things that
are on the label for setback requirements.
But also consider some the other management
practices, especially if you're on one of
these high runoff potential soils.
Just following the label is not enough, is
the bottom line.
Various criteria are used to estimate the
how vulnerable a watershed may be to pesticide
contamination.
These may limit the effectiveness of a pesticide
label to protect human and environmental health.
For example, the natural features of a watershed,
and the activities that occur there can impact
its vulnerability to pesticide contamination.
Hydrology and soils are important factors
in the movement of pesticides within the watershed.
They affect the potential for pesticides to
move from the application area to creeks,
streams, lakes, rivers and groundwater.
The Center for Applied Research and Environmental
Systems website is an excellent source of
information on watersheds.
Every two years the Missouri Department of
Natural Resources identifies those bodies
of water in the state considered to be impaired,
and lists them in the Missouri 303 D list
of impaired waters.
BOB BROZ: So, as we have more and more data
from different water bodies, we start identifying
those that don't meet the criteria that it's
been set for, whether it's for drinking whether
it's for fishing, whether it's for whole body
contact.
So every two years they develop a new three-oh-three
D list that has to be approved by the Environmental
Protection Agency and for each state we have
one of those lists.
The particular geology of a region, along
with the physical properties of a watershed
can help identify areas with the potential
for runoff or leaching problems.
BOB BROZ: Missouri has a large amount of karst
geology, or fractured limestone.
One of the things that makes this so important
to the state of Missouri is that it allows
a lot of our water, surface water to get into
those cracks and move down into the lower
groundwater aquifers very very quickly.
Those are the things that feed our stream
in many cases, it causes a lot of the beautiful
springs we have in the state of Missouri,
and as that water runs though that karst,
many times it goes ahead and start dissolving
that rock.
So it creates sinkholes, it can create caves.
Missouri's official nickname is the cave state.
We have over five thousand registered caves
in this state.
A lot of it because of that underlying karst
topography that we have.
One of the problems we have with that is that
it can move a lot of contaminants from the
surface down through that karst.
Because it moves so quickly it doesn't get
much treatment and it comes out somewhere
else.
The timeframe that the water is within the
soil, within the rock all help to determine
how pure it's going to be or how much it's
going to be cleaned by the natural environment.
The landscape doesn't always reveal underlying
areas such as sinkholes or high claypan soils,
conditions that can have a significant impact
on the effectiveness of various farming practices.
BOB LERCH: Yeah, one of the things that we've
developed over the years, soil scientists
and soil water conservationist is this concept
of no till.
Where you don't till the soil at all, you
leave the maximum amount of crop residue on
the surface and that was designed to control
soil erosion which is a major problem.
It's just that it doesn't work the same on
all soils.
In some soils if you use no till for a long
period of time you get better infiltration
of rainwater and less runoff, but on these
high runoff potential clay pan soils we actually
see the opposite.
We control the erosion but we actually have
more runoff loss, the volume of runoff is
greater under no till.
It doesn't soak into the soil as well and
if your chemicals are sitting there on top
of the soil and easily washed off because
you haven't mixed them into the soil, then
that's why no till doesn't work well on our
claypan soils.
BOB BROZ: One of the big areas we get to talking
about, we talk a lot about the soil and the
importance of the soil when we look at water
quality.
And the ability to either hold water or to
allow water to runoff.
When we look of sediment pesticide nutrient
runoff, a lot of that that we talk about deals
with the soil.
Sometimes in different parts of the state
what's even more important is what's that
underlying parent material.
Sandy soils, on the other hand, can allow
pollutants to leach into ground water at a
rate faster rate than label regulations recommend.
Depth to groundwater is an important criterion
affecting watershed vulnerability.
In summary :
Consider the significance of watersheds in
the management of an area with the protection
of water quality in mind.
Remember how a watershed is defined and the
characteristics that identify it as vulnerable.
Every two years the Missouri Department of
Natural Resources identifies those bodies
of water in the state considered to be impaired,
and lists them in the Missouri 303 D list
of impaired waters.
The particular geology of a region, along
with the physical properties of a watershed
can help identify areas with the potential
for runoff or leaching problems.
Depth to groundwater, Hydrology and Soil Type
are important factors in the movement of pesticides
within the watershed.
When it comes to pesticides
The Label is the Law.
However, keep in mind the pesticide label
is designed for normal or average conditions
which may differ from your "Real World" circumstances.
These differences can impact the effectiveness
of best management practices is pesticide
application and should be considered prior
to any pesticide purchase and application.
For more information contact these resources:
