Don't Go With the Flow

Most rural landowners, and many urban landowners, have some form of stream running across or adjacent to their property. It may be as big as the Missouri River, or small enough to step over. In any case, water flowing through a channel will always cause some erosion. In healthy stream conditions this isn’t a problem, but in other cases erosion may become excessive and cause serious damage in a short period of time.

Slow the flow

Stream banks with minimal erosion are considered stable. Unstable banks are those eroding at an excessive rate.

Flowing water has the power to pick up and move soil, sand, gravel and, sometimes, large rocks. The more powerful the flow, the more erosion it is likely to cause. In most cases, the faster and deeper the water flows, the more power it has to erode. So it makes sense that reducing the power of flowing water reduces stream bank erosion.

Stable stream banks in Missouri are usually covered with deep-rooted plants. This coverage continues onto nearby land, or stream corridors. Plants minimize erosion because they slow down the flow of water and their roots hold the soil in place. Streams that meander, rather than flow in straight lines, also slow water flow and keep erosion in check.

People often increase the power of streams inadvertently. For example, they convert a portion of a stream’s watershed from a healthy forest to an urban setting with many roads, parking lots and driveways. Rainwater that was once held by the forest floor and slowly released to the stream now runs off rapidly. The stream receives faster and deeper flows more often than in the past. This results in unstable stream banks and excessive erosion. It is also common for stream banks to become unstable when their vegetation is removed with heavy equipment or significantly reduced by livestock.

Treat the cause

Rather than simply treating the symptoms, it is important to diagnose the cause of unstable stream banks. This often requires the assistance of trained professionals. The Department of Conservation has helped landowners correct stream bank erosion for more than 15 years. Specially trained employees assist hundreds of landowners each year.

The Department has worked to develop practical stream bank erosion-control practices. These methods have high success rates and low maintenance requirements. They include cedar tree revetments and bendway weirs.

A cedar tree revetment involves anchoring a series of cedar trees at the base of a stream bank. This technique slows water flow against the bank to prevent erosion. A bendway weir is a structure made from large rocks that protrude into the flowing water at an upstream angle. This design directs flow away from the eroding bank. And finally, establishing a vegetated stream corridor is always recommended. A good corridor of soil-holding vegetation along streams is a key component of all practices.

Landowner success stories

Over the years, the Department’s work with landowners has led to a number of success stories. One such story occurred on Little Maries Creek in Osage County.

The Luebbert family has owned their property since 1851, and Chris Luebbert is the sixth generation to live on the farm. In the mid-1990s, an erosion problem developed on his property. “Over a five- to seven-year period, I lost about 2 acres of a 30-acre bottom to erosion at this site,” said Luebbert.

In 2000, he contacted the Department for assistance. Luebbert worked with Rob Pulliam, a fisheries management biologist out of the Sullivan office, as well as the U.S. Fish and Wildlife Service and the Natural Resources Conservation Service to develop a solution.

In the summer of 2001, a bendway weir project consisting of three weirs was installed to protect the eroding bank. Trees were planted the following spring to reestablish the stream corridor. Within two years, Luebbert could see a difference. “It’s remarkable how quickly it started to heal,” he said. “You wouldn’t even be able to tell the first two weirs are there if you didn’t know.”

When asked if he would do it again, Luebbert said, “Without question. In fact, we are already talking about working on another bank on my property.”

Another project was completed on C. Dale Murphy’s property along the Little Bourbeuse River in Crawford County.

Like the Luebbert place, the Murphy farm has been in the family for generations. “My family homesteaded this land in 1865 and has been grazing cattle ever since,” said Murphy. “We have been dealing with erosion problems along the Little Bourbeuse since I was a kid.”

In 1996, Murphy contacted Kenda Flores, a fisheries management biologist out of the Sullivan office. In 1998, he fenced his cattle from the stream and started planting trees in the corridor. He, too, started seeing results within two years.

“We moved the cattle out, planted trees and let nature take the lead,” said Murphy. “We just followed. The difference is amazing. I am convinced that the cows kept the banks beat down and caused our problems.”

Murphy is also convinced of the value of vegetated stream corridors. “The riparian [or vegetated] corridor protects your banks not just from channel erosion, but also from water coming across your field,” he said.“That corridor stops a lot of erosion. I am the fourth generation of Murphys to own this land, but I don’t really own it—I am just the steward until I pass it on to my kids. By doing this, I can really see that stewardship becoming a reality.”

Conservation area projects

In addition to working with private landowners, Department employees have also stabilized eroding stream banks on conservation areas across the state. These projects improved the areas for all citizens that use and visit them, and they provided a proving ground for trying new techniques prior to suggesting them to landowners. Almost every technique recommended to landowners is first attempted on a conservation area.

Some of the first tree revetments that the Department constructed were built on Otter Creek, which runs through the Lamine River Conservation Area in Cooper County.

Beginning in 1989, Kent Korthas, area manager, and the Department’s Stream Unit put in five cedar tree revetments. The project helped stabilize a large segment of the creek, and information collected by the Stream Unit over the years was used at other sites.

The Department has also learned a lot about what doesn’t work. Some past attempts to control eroding stream banks have failed, and we have learned from those experiences. One important lesson learned is that every stream bank is influenced by the conditions of the watershed—both upstream and downstream. No part is isolated. Another is that erosion control is almost always costly. Preventing problems is far less expensive than repairing them.

The research continues

Despite many successes, the Department and private landowners are still looking for more options to stabilize eroding banks. There are limitations to the current techniques, and some only work on streams up to a certain size. Others can be cost-prohibitive for many landowners. In response, the Department is researching alternative techniques that are more universal and cost-effective.

The techniques being evaluated reduce costs by using more readily available materials and by changing designs to use less materials overall. Because we are using unproven materials in limited quantities, we are increasing the risk of failure compared to traditional techniques. The objective is to determine if significant cost and manpower savings can be achieved with an acceptable level of risk.

Due to the higher level of risk involved, the initial trials of these techniques will be conducted on Department lands rather than private properties.

Over the next two years, projects testing six different techniques will be installed at sites across Missouri. These projects will be monitored for several years across multiple high-flow events to learn as much as possible. The results will be used to improve our recommendations to landowners dealing with erosion problems.

Erosion-control myths

Some erosion-control practices just don’t work. For example:

• Dumping junked cars, refrigerators, washing machines and other refuse into streams is not only unsightly and polluting, it does not stop erosion.
• Using heavy equipment to push gravel onto eroding stream banks does not work well because the flowing water easily washes the gravel-sized rocks away. The heavy equipment also disrupts the streambed, causing turbidity problems and destroying habitat.

For more information

If you are facing erosion problems on your property, contact your local Missouri Department of Conservation office for assistance (see a list of regional phone numbers).