A
field day sponsored recently by the Logan County Soil and Water
Conservation District and the Land of Lincoln Soil Savers gave area
farmers a look at a new stream stabilization technique, one way to
control soil erosion. These two groups, along with the U.S.
Department of Agriculture Natural Resources Conservation Service and
the Illinois Department of Agriculture are working on projects to
prevent Logan County’s waterways from carrying away its farmland.
"With
three good-sized creeks in the county —
Salt, Kickapoo and Sugar Creeks —
it’s a never-ending job," Dickerson says. As
a district conservationist for the NRCS, Dickerson works closely
with Logan County’s Soil and Water Conservation District.
On
Thursday he took a group of area farmers to a Kickapoo Creek site
southeast of Atlanta, on farm ground owned by Dave Evans and Dan
Koons, to explain a new technique called the stream barb system.
[These
three rock projections are a new stream stabilization technique
called barbs. Pointing
upstream, they work together to redirect the water in Kickapoo Creek
toward the middle of the creek and keep it from undercutting the
stream bank.]
What
the farmers saw were three projections of large stone riprap jutting
out into the creek, angling upstream, at a point where the creek had
been cutting away the bank. The barb-shaped stone projections work
together to catch the current and redirect it to the middle of the
stream, away from the bank which is being eroded.
The
project was completed in December of last year, and, according to
the landowners, is working just as predicted.
"A
few weeks ago, when the water was higher, I could see it working. I
could actually see water turn and go back into the channel,"
Koons said.
Before
the barbs were put in, he added, the bank went straight down,
because it was being undercut by the creek at the rate of at least a
foot a year. Now the stream bank slopes, maintaining the angle it
was given by the construction crew that put in the new stabilization
system. The bank is also being held in place by the natural
vegetation that is beginning to grow there.
The
new stream barb system is protecting about 600 feet of the bank of
Kickapoo Creek, Dickerson says, preventing the loss of about
one-half ton of soil per foot per year. That means 300 tons of prime
topsoil is no longer washing down the creek, eventually ending up
somewhere in the Gulf of Mexico.
It is
the nature of streams and rivers to meander, traveling in a series
of S-curves, as they slow down and broaden out their flood plains,
Dickerson explains. Formerly, engineers tried to keep streams from
eroding the land around them by straightening them out, a process
called channelizing. Kickapoo Creek was channelized on the Koons-Evans
farm in the mid-1970s, when the land belonged to a different owner.
But
the channelizing couldn’t prevent the creek from reverting to its
natural tendency to meander, and it soon began cutting into the land
again. (It’s now against federal law to straighten a stream.)
Today
the idea is to work with nature, allowing the stream to meander but
preventing it from meandering too much, Dickerson explains.
"Moving water is one of the strongest forces on earth. We are
now going with the natural force of the stream, rather than fighting
it."
