Because the water level of the
river varies, farmers along the
Missouri River use floating pumps
like this one to collect irrigation
water without the pump clogging.
Another concern is streambank
stability, which is now more
manageable thanks to an online
guide developed by scientists.
| In the world of finance, bank failures
tend to get press coverage. But there's another kind of bank failure that
affects the American West: Missouri River bank failures in eastern Montana
involve lost soilnot dollarsbut still hurt farmers financially.
Just ask Boone Whitmer, who farms 3,000 acres of wheat and
alfalfa near Wolf Point. Like most farmers bordering the Missouri River
downstream from the Fort Peck dam, he places irrigation pumps along the banks
to get water for his crops. But the shifting sand bed of the river can clog
pumps with sediment and hit growers like him hard.
In the winter, you can have a working pump site, but
by spring it's silted, he says. Replacing a pump site is bad news
for anybody. It cost me $20,000.
Whitmer says many farmers along the Fort Peck reach also
worry about losing farmland to streambank erosion.
It's not that huge amounts of land are being lost.
But if you only own 200 acres and lose 10, that can be quite significant,
says John Remus, a hydraulic engineer with the Water Resource Branch of the
U.S. Army Corps of Engineers in Omaha, Nebraska.
Bank failures happen when a river erodes its bed so
deeply that the water level is too low and the upper banks are exposed,
says ARS geologist Andrew Simon.
It's the weight of the water against the river banks and the stability of
the soils in the banks that hold them up.
Whitmer and other local farmers now have a new resource to
help them prevent these problems, thanks to researchers at the USDA-ARS
National Sedimentation Laboratory (NSL) in Oxford, Mississippi, and their
scientific collaborators throughout the United States.
This team of scientists and engineers has prepared a guide,
Channel Erosion Problems on the Missouri River, Montana, Between Fort
Peck Dam and the North Dakota Border. It is available on line at NSL's
It will help people and agencies manage the river
corridor using scientific evaluation of the river and its relationship to the
dam, says Simon, who is with NSL and is the guide's senior author and
editor. Simon used his knowledge of stream processes and streambank stability
to locate the weakest and most susceptible banks, so Montana farmers can know
where to make improvements along a certain reach of the river.
A river will transport sediment. If you take away the
supply of sediment at one location, the river will find another source of it
further down, says Remus. But that doesn't mean a mile of protected
banks will cause erosion a mile downstream. It has to do with soil properties.
We hope Simon's data will tell us where weak spots are and what effects might
occur when we do stabilize an area.
Simon is also exploring how to reduce the stress on banks
in winter during dam opening.
The channel erosion guide also benefits from research done
by NSL hydraulic engineer Doug Shields, Jr. He worked with soil scientist Lyle
Steffen of USDA's Natural Resources Conservation Service (NRCS) in Lincoln,
Nebraska, to document the average rate of river bank migration for the past
Before Fort Peck dam was built in the 1930s, the
river channel moved across the floodplain about 6.6 meters, or about 22 feet,
per year, says Shields. However, since large floods have been just
about eliminated by the damand since most erosion occurs during
floodscurrent averages of lateral movement have decreased to about 1.8
meters, or 5.9 feet, per year.
Ice Is Not Nice
Simon's publication also reports research on ice effects,
contributed by river ice engineering expert Robert Ettema. He is with the
Institute of Hydraulic Research at the University of Iowa-Iowa City.
Ice is an important factor in the river's overall
behavior, says Ettema. It seems to do something to the river. You
see sediment accumulations and bars appear that can affect pump intake
Scientists and engineers with ARS and NRCS are working with
Ettema and the U.S. Army Corps of Engineers to understand what happens when the
river ices over. The Corps' Cold Regions Research and Engineering Laboratory
will play a role in this effort.
Farmers are also critical partners in this research. Ettema
says he is indebted to local producer Alan Pipal, who alerts him to changing
We want to study how ice forms, how thick it gets,
and how it affects river flow, so we need before-and-after measurements,
says Ettema. The information on ice will also benefit Remus in his work with
the Corps of Engineers.
When considering ways to stabilize banks, we need to
know whether it's most important to measure soil strength, frost penetration,
or depth to groundwater, says Remus. Measurements cost money, and
we don't want to waste funds looking at factors that don't really matter.
Getting the Best Return
Jim Suit, a state engineer with NRCS in Montana, will also
use this channel erosion guide. If tax dollars are going to be spent on
bank stabilization and restoration and you have 10 candidate sites but money
for only 5, you want to do the most with the money you have.
Knowing more about how the dam and river interact will help
residents around Fort Peck share both the benefits and burdens. In 1994, Paul
Johnson, then chief of NRCS, traveled to eastern Montana to help residents form
the Lower Missouri River Coordinated Resource Management Group.
The group includes representatives from six county
conservation districts and the Sioux and Assiniboine tribes living on a
reservation near the dam. They use the group to discuss how to use the river
and protect its banks. It serves as a public forum, to be sure that everyone
benefits from the Missouri River and that the cost of its protection is shared.
Cooperation is critical, says Suit. And
having accurate information is one way to balance everyone's needs. Say
somebody wants to move grain barges below Sioux City, Iowaor say it's a
really cold day and power consumption is upthe U.S. Army Corps of
Engineers will get a request to release water from the dam to increase flow
rates or to generate electricity. Everybody here wants healthy wildlife and
bank stability, but they also want flood control and grain transportand
enough electricity for Monday night football.By Hank Becker
and Jill Lee, both formerly with ARS.
This research is part of Water Quality and Management,
an ARS National Program (#201) described on the World Wide Web at
Simon is in the USDA-ARS
Channel and Watershed
Process Research Unit, and Doug
Shields, Jr., is in the Water Quality and Ecology Research Unit,
Sedimentation Laboratory, P.O. Box 1157, Oxford, MS 38655; phone (662)
232-2918 [Simon], (662) 232-2919 [Shields], fax (662) 232-2920.