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- [Narrator] How do you bring the stream back into balance?
How do you restore its biological health?
- By using natural stream design
were actually assisting the stream
to heal itself when it's sick and not feeling well,
restoring some of the natural biological processes,
such as increasing the number of different kinds
of fish that you see in the stream,
the number of different kinds of bugs,
a sick stream won't have a ton of them,
but a healthy stream will.
- [Narrator] The more you can mimic nature
the more successful you'll be.
- The concept we're applying here
is very simply applying natural materials,
understanding natural processes,
letting nature do its part to protect streams,
and managing the energy of the river
in a way that works with nature,
instead of trying to armor the banks and resist nature.
- [Narrator] Stream restoration is a process.
First, define the objectives for the stream.
Is it flood control?
Stream bank stability?
Improving access to the stream?
Improving habitat?
You need to understand what you hope to accomplish.
It is often possible to achieve multiple objectives
with your restoration project.
Next, assess the stream.
Take a close look at what's going on
at that particular site.
Is there down cutting or widening,
is the stream bank vegetation healthy and plentiful,
has something changed in the watershed upstream,
or is something constricting the flow downstream?
Once you've determined your objective
and assess the stream, you have to decide
what is your best course of action?
In some cases removing local stressors
such as cattle grazing, storm water pipes or culverts
and replacing mow turf grasses
with native deep-rooted plants
may sufficiently improve the quality
of the stream channel.
However, if you decide that removing local stressors
and revegetation is not enough,
then you must work with qualified professionals
and appropriate regulators, such as
the U.S. Army Corps of Engineers,
to design and later construct the restored stream channel.
No matter which choice you make you still need
to monitor the stream and maintain it in a form
that meets your objectives.
Natural stream restoration includes three parts.
Reshaping the channel and floodplain.
Building in-stream structures.
And, protecting the banks.
To begin restoring a stream, first you have to reshape it.
Moving dirt and rocks to establish
a more natural stream channel and floodplain.
Reshaping can start with grading banks,
creating benches and more gentle slopes.
This will reconnect the stream to its floodplain
and help slow the water during rain events.
The redesign of the stream may mean adding meanders
to a straight stream or creating riffles and pools.
For some streams regrading is not enough.
Vanes are structures built into the channel
to control the flow and redirect the water.
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This configuration of rocks or other materials
helps lessen the slope of the stream
and moves water away from the banks.
The first type of vane we'll look at
is called a cross vane.
So we can utilize our vane technology
to keep water in the middle of the channel
in areas where both banks are vulnerable,
whether we have infrastructure or other things
on the sides of the bank that we
don't wanna have erosion at.
The cross vane uses our large rocks
that are large enough to not be washed away
by the energy of our high flows,
and we create a V-structure that's
at a 20 to 30 degree angle from the banks,
and they are tied into the banks perpendicular,
here underneath ground.
You can see these footer boulders
that are utilized to keep the bottom structure
of our cross vanes stable.
We have our two to five degree elevation change,
here where the waters higher it moves up
and moves over back towards the middle,
and then as we move to the upstream end of our cross vane,
we have what's called the invert,
this is the lowest elevation of our cross vane,
it moves into a pool, this is an area
that's deeper, there's really great habitat
and you get a lot of turbulence,
a lot of energy dissipation, especially
during your high flows.
This one is a double step cross vane,
so as we move into our second step
it allows us once again to have that turbulence,
that energy dissipation, that great habitat
in the second pool, and then from that second pool
it will move up and out into a riffle.
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So another in-stream structure that's similar
to our cross vane, is our J-hook,
that once again has two different functions.
It's gonna service grade control to lower our slope
and it's also gonna help us to deflect water
from a vulnerable bank.
Our J-hook is utilized to move water away
from only one bank, as opposed to the cross vane
that moves water away from two banks.
So what we wanna do once again is we're gonna
have our slight slope here on our vulnerable bank side,
and this right here is a log J-hook,
it could be also constructed of rocks,
it's gonna be tied in up there at the downstream end
of the J-hook, and then tied in back into the stream bank.
So as the water moves up this vulnerable side
it goes up the slope, up the log,
and then it's moved back into the center
of the stream where it creates this pool.
This pool is once again great habitat
for lots of little critters, macro vertebrates,
that type of thing.
We're installing this with rocks so
that we have little areas in between here
that the fish and critters can still
get upstream during baseflow.
This is especially important in some other parts
of the country where you have critters that go upstream
for spawning and that type of thing.
And then on the side away from the critical bank,
we have our lower part of the J that's made
of rocks here, and it's actually tied way back
into the bank, all the way to the trees,
so that during high flow, when there's a lot
of energy on the bed and on this point bar,
it's not going to get washed away.
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In larger rivers such as this,
a J-hook may not be practical or even beneficial,
because of the large amount of energy that is involved
with this amount of water, if we install the J-hook
in this area we would have the hook part
of the J-hook out in the middle
of the river where the highest energy is,
and the size of boulders required for that type
of installation would be impractical and very expensive.
So instead of that, we utilize something called
a barb, like we have here, and what the barb does
is use the same type of technology as the J-hook
to move the water slightly up slope
and dump it back away from the vulnerable bank
and to the middle of the stream,
thereby protecting that bank from
the high shear stress that would be involved
with the higher flow.
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So a different type of in-stream structure
is known as, toe wood.
And toe wood is really great for stabilizing
the outer edge of meander, where you have
that vulnerable area where the stream bottom joins the bank.
So what were doing on this is utilizing logs
and sticks and different brush
from around this restoration site,
that we buried six to eight feet within the bank,
and it provides all these little crevices
for the little critters and fish
and things like that to live.
It also provides structure and things
that disrupt the flow at the bottom
of the stream, in the deep part
of the stream where the most energy is.
Over time these sticks are gonna degrade,
but we also utilize live plants
to create this toe wood, so they are going
to sprout and create a treeline along
the bottom of our stream bank that
will stabilize it over the long-term.
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After reshaping the stream channel
there will be a period of time
when extra stream bank protection is needed.
Think about bank protection in three steps.
Temporary measures such as matting,
that hold the freshly restored bank in place.
Then, some quick, short-term plantings.
And finally, the vegetation that's going
to be there over the long-term.
One of the first things we wanna do
on a new stream bank stabilization is
to protect the bank from erosion.
Here we do that with straw.
The straw is going to reduce the impact
of the raindrops as it hits the surface,
and also as the soil gets wet that straw
will incorporate into the soil and hold it in place.
Down here, within the channel where the water
will be flowing, this coir matting,
which is made of coconut fiber,
helps us to reduce the amount of stress
that hits the bank, and holds that soil
in place, underneath the matting.
The matting will also give us some structure
for vegetation to grow through as the site matures.
- If you have done a stream bank stabilization project,
and you have essentially bare soil banks,
the first thing you need to do is put
a quick growing grass on those banks
to protect it from any water fall,
any rain events that come through.
Then you need to begin to think about
what plants you wanna put into those areas
to further stabilize them, to really get
the root systems going.
Plants that are adapted to aquatic systems typically
have extensive root systems for that very fact.
- That vegetation, over time, puts in roots
that acts as rebar, it holds soil in place,
it helps bind that soil to resist erosion.
- [Narrator] You want a mix of vegetation along
the bank, grasses, shrubs and trees.
- Things like Bermuda and fescue,
which are great for pasture, are not good
for stream banks, because they
have little short root systems.
So what we like to see planted right along
the bank are things like big
and little bluestem, Indiangrasses.
Bluestem can have a root structure eight feet tall.
So it's really going down and holding all of that in place.
- And those roots will help lock
that soil and gravel in place so
that during future floods the roots
are helping hold the soil, and the plants
that are growing above ground help slow
the water down, taking away some of the energy
that would be causing erosion,
leaving most of the flow energy out in the main channel.
- There are plants that thrive exceptionally well
with their feet wet.
So we look to put things like willows
and other wetland type plants right up
at the toe of the stream so that they can sprout
and really vigorously grow to start holding
the soil in place.
We're talking about trees that prefer being
in close proximity to water, that during times
of flood when the waters come up,
instead of washing out around root holes,
the plants themselves will actually bend
with the floodwaters, and then when
the floodwaters recede they'll pop back up.
- [Narrator] Trees also provide a number
of other benefits for a stream,
including things you might not think about.
For example, trees cool down the water.
Why is that important?
- Trees themselves will shade the stream,
lowering the water temperature.
Many fish species are dependent upon
a certain range of temperatures before they
can reproduce, and so it's important
that they have those conditions so
that you can have a growing population.
They also allow for the water itself told more oxygen,
which once again if you are a fish, or a bug,
or as scientist will call them, macro invertebrates,
living inside the stream, that's important too.
You need something to breed.
- Leaves also, as they fall into a stream,
serve as the very base of the food web.
So that we get that carbon input
that we need for a healthy ecosystem
to support the aquatic insects in a healthy fisheries.
- There are certain aquatic insects called, shredders,
that begin to cut up those leaves and chew on them
and eat them, and then there are another two
or three suites of different insects
that will continue to break those leaves down.
- [Narrator] Native plants can give you a head start
on revegetating the banks.
- And another key in selecting those plants is
to simply look around and see what already grows there,
in areas up and down that stream.
- Those native plants we know are supposed
to be here because they're all around us,
they will get established and grow quickly,
plus they serve as that critical wildlife habitat,
an important habitat, even leaf quality
for streams, for the insects in the streams
and decomposition rates.
- [Narrator] Some non-native plants can be invasive
and outcompete the beneficial plants
that are vital for a healthy riparian ecosystem.
- What we want to fight against strongly
are the invasive exotics that move in quickly
when we have disturbed areas.
So managing for native species and actively trying
to remove and slow down the spread
of invasive exotics is a critical element of these projects.
- [Narrator] All this work can be done
to restore a stream, but it will take
the continuing growth of plant life
to make it a success.
- Plants, above ground and below ground,
help serve important processes for stream restoration.
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- [Narrator] Restoring stream stability
and function requires working
with qualified professionals in a multi-step process
of assessment, design, proper construction,
and long-term monitoring and maintenance.
This design may include, grading to reconnect
the floodplain, in-stream structures for stabilization,
and to decrease the slope of the stream bottom
and lots of vegetation.
To achieve success this type of restoration
requires vigilance to ensure plant establishment,
especially during the first few years after construction.
Additionally, these methods need to be integrated
with watershed base plans and storm water management
on the landscape.
Major changes to the watershed
can impact your stream restoration.
By working together we can ensure
that the natural beauty and function
of our streams can be enjoyed for generations to come.
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