USGS Multimedia Gallery: (Video)--Design considerations for more natural channel reconstructions, Villa Mann Creek, Wisconsin freeway reconstruction project

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Faith: What about some of the design

challenges to a project like this?

Tom: Some of the design challenges as

part of this whole project were, in

particular, as you saw downstream it

was nothing but a concrete line channel

that was an extreme elevation and with

a width of about three feet and depth

of about three inches. So that's not

the kind of channel we were trying to

restore. So there were some remnant

channels that we could use as a

template full of concrete rubble and

such, but trying to estimate that

channel bank flow, which was what we

designed here at the top of the bank,

and then we knew our slope, so we had

to tie into this concrete lining.

We knew our upstream elevation from the

pipes, so we were able to incorporate

the top – the lower end of the riffle

and the top end of the riffle

elevations. These as you can see the

outside meanders are a little more

armored but the inside have those point

bar areas, so they don't require the

heavy rock. But we're trying to

incorporate those as well as the pools

around the bends which are deeper. So

as you know the grade is controlled

through these riffles, and it's two

kinds of channel types that we had as

cross-sections are a typical riffle and

typical pool. And then you kind of fill

in the excavation as the outside

meanders in the pool.

So the contractors did a fantastic job

as well as the team in general in

assisting them and laying out this

channel and getting it constructed as

was designed on the plant. One of the

things too that I think is so important

as part of our projects is that this

overall stream design and the overall

staging is all thought of together

integrated with the roadway

construction, everything from the

timing of the wetland plants, as well

as the dewatering, and the timing of

moving equipment and roadways. So

that's the real advantage with our

whole team effort with this project.

That includes DOT, DNR, myself, and the

consultant engineers, so it's what

makes these projects far more

successful than they would be without

everyone talking together.

Faith: Yeah. And then you get to link

all these different parts together as well.

Tom: Right. Right. So what we're trying

to do is just trying to get it to

function properly, and then we know

there's gonna be adjustments over time.

But this whole area is designed to

overbank and reduce erosion on the

banks, and it will come up slowly as we

get on the upland side. But that was

all part of the modeling, and so the

height of this elevation was

approximately adjusted for a two-year

event, but since most of this area is

fed by storm water pipes, you can see

water flowing out through there now.

And you can see the pipes of the

headwater, you can't get much more

unnatural, but we're trying to recreate

a more natural stream given the

flashiness and through here.

And we're trying to recreate not just

improved water quality, and the

potential for fisheries is limited

right now given we have several miles

of concrete lining. But from a wildlife

perspective and from an infiltration of

stormwater and reducing the total

suspended solids, and recreation of the

diverse wetland and upland areas for

migratory birds and even aesthetics and

recreation, we're trying to accomplish

all those things. As well as of course

flood mitigation and trying to tie in

and not flood any homes and to try to

accomplish both these things at the same time.

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