CONTROL Stream Erosion

Article Tools

Image Gallery

Print

E-mail

Comments

RSS

UP ON THE BANK

For the purposes of erosion control, a stream bank above the waterline can be looked at as a piece of steep agricultural land. As on "dry" land, the most versatile tool for erosion control is vegetation. But there are a few other tactics that may be appropriate (such as the use of riprap).

However, perhaps the most important erosion-control tool on many stream banks is the barbed-wire fence. Livestock in general, and cattle in particular, are virtual bankwrecking machines. They break down vertical banks, loosen soft soil, make paths that become gulleys, trample and overgraze protective vegetation, and stir up streambottom sediments. If at all possible, livestock should be completely fenced out of streams and off their immediate banks. If no other provision can be made for watering, or if the animals must cross the waterway, give them limited access, only at a gently sloping, erosionresistant site.

Human beings need "fencing," too. Try to limit your own access to a few carefully selected points. And, if necessary, construct steps to avoid beating a path into a steep bank.

PROPER VEGETATION

The proper planting of stream banks involves matching the vegetation to the habitat. As a general rule, the wider the stream, the taller the vegetation can be. A bank totally lined with large, mature trees may be quite appropriate on large rivers, while tiny brooks may do better with nothing more than a good grass cover. (I'm speaking solely in terms of flood and erosion control. Choosing a strategy becomes much more complex when one considers the water temperature requirements of fish, the potential for loss of water by evaporation and transpiration, the value of the bank as a wildlife habitat, the available fishfood supply, the nutrient contribution made by fallen tree leaves, and the demands of personal aesthetics. In most cases, some combination of trees and low-growing vegetation will be called for.)

Even where the use of trees is strongly indicated, the first step may be to establish a good ground cover. The procedures for doing so are no different from those employed in ordinary agriculture. (But do be cautious with fertilizers; there's no point in trading erosion for pollution.) Among the many grasses appropriate for stream-bank planting, my personal favorite is reed canary grass, which holds soil well, tolerates occasional flooding, provides food for wildlife, and looks beautiful. Its only real drawback is that when grown alongside very small streams, it may extend out into the water. Narrow waterways may thus be temporarily choked in late summer.

RSS | Comments | E-mail | Print