OUTDOOR CORNER: WHEN CONCERN ERODES, EROSION CAN BECOME A BIG PROBLEM IN STREAMS

Sand and gravel in streams can be good or bad news for Missouri landowners.

Some use it to pave farm roads; others curse it for causing stream channel problems. However, we haven't always had large amounts of sand and gravel in our streams. Over the last century deep pools, stable streambanks and narrow stream channels slowly changed to shallow wide, eroding streams; the "old swimming hole" was often buried under sand and gravel. Through it all, landowners tried to deal with these changes, many of which have caused problems.

What cause sand and gravel problems?

Much of the sand and gravel in Missouri streams came from changes that occurred on the Missouri landscape over a century ago. History reveals the dramatic watershed changes began to occur in the 1800's, as large tracts of Ozark hardwood timber were harvested for lumber and railroad ties. In northern and western Missouri, prairie sod was plowed to feed a growing nation.

Farming efforts that followed these changes were characterized by poor soil conservation which left the ground unprotected. Burning, plowing and overgrazing of hillsides removed vegetation which held soil in place. Trees along streambanks were frequently cleared for more farmland. As these trees were removed, roots which formerly held streambanks in place decayed. Stream banks eroded faster and channel changes occurred more rapidly. Sand and gravel washed into Missouri streams.

What can landowners do?

Today, we are still facing problems that began over a century ago. As landowners, you must work with unstable streams that erode streambanks and deposit sand and gravel on fields during floods. Some actions landowners can take to save their valuable soil and farmlands:

* Practice good soil conservation. Most of the problems that we have with sand and gravel in our streams was caused by poor watershed management in the past and also today If people become good stewards of the land, then these problems can be reduced. Good soil conservation not only keeps topsoil on agricultural fields where it belongs, but it also keeps it from being washed into streams and adding to the sand and gravel already there.

* Don't push gravel against streambanks. Some landowners believe that using gravel against streambanks will control erosion. In reality, gravel will only remain against the streambank until the next flood, and then it will be washed downstream where it may cause problems for your neighbors. Eroding streambanks should be fixed using approved stabilization structures. The Missouri Department of Conservation can assist you with many common streambank erosion problems.

* Maintain trees along the streams. A dense stand of trees along the stream is the best long-term solution to bank erosion. The tree roots hold soil in place, and during floods, the vegetation causes sand and gravel to settle out before washing into nearby field or pastures. A single or double row of mature trees along a stream does not adequately protect the streambank or adjacent fields.

Sand and gravel can be removed from streams for personal use (e.g. roads), but this does not address the problems of erosion in streams. By following a few guidelines sand and gravel can be removed with minimal harm to the stream.

-- Restrict removal activities to grave bars that are loosely packed and without trees.

-- Avoid excavating gravel below the elevation of the water line.

-- Maintain an undisturbed buffer of 20 feet between the removal area and the stream and between the removal area and the bank.

-- Do not relocate, straighten, or modify the stream channel.

-- Do not remove gravel from riffles. Don not wash gravel in the stream channel.

Most gravel removal operations require a permit from the U.S. Army Corps of Engineers. It is also important to remember that sand and gravel removal can create physical and economic problems for landowners above and below the removal area if it is not done correctly.

So remember that a stream is a product of its watershed, and everyone lives in a watershed. If we manage the watershed properly, then sand and gravel will be less of a problem in our streams.

More information can be found in the brochure "Sand and Gravel Removal and Stream Health: A Landowner's Brochure." For a copy of this brochure and more information on stream management, contact the Department of Conservation, Fisheries Division, in Cape Girardeau at (573)290-5730.

~Brad Pobst is an aquatic services biologist with the Missouri Department of Conservation.