CONTROL Stream Erosion

Image Gallery

Last issue we told you how to combat erosion on your land. This sequel shows how you can . . .

Photos Courtesy of the US Soil Conservation Service and the Wisconsin Department of Natural Resources

A "well-behaved" brook can produce energy; water for crops, livestock, or and fish for food and re- creation. people; creation. A degraded one, on the other hand, detracts from the appearance of its surround ings and-during and just after a flood-can endanger life and property, as well as ab sconding with chunks of irreplaceable soil.

Floods and massive soil erosion naturally bring to mind another virtue of a wellmannered stream: its ability to carry excess water off the land in an orderly fashion. A stream, however, isn't the only thing that can perform that function. There's that human invention known as a ditch. Far too often, when a stream fails to dispose of its load of water efficiently, we tend to think of it as a malfunctioning ditch. We even discipline rowdy streams into monotonous canals through the process called channelization: straightening and deepening the streambed and removing all obstructions to flow.

This often "works" in controlling the flooding and erosion-if you don't care about fish, wildlife, aesthetics, or recreation, and if you can justify dumping your problem on people downstream.

You can stop streams from flooding or changing course over the years without resorting to heroic engineering feats. You can also prevent changes in course and water level from occurring so abruptly that the carrying capacity of the land-for everything from wildlife to agriculture to housing-is reduced with each rain.

GREAT OR SMALL?

Whatever the size of your stream-and the scale of your project-the same basic principle applies. The main thing is to understand the interactions between the flowing water and the solid objects it confronts. And so (assuming that your house isn't in danger of washing away after the next rain), the first rule to consider is look before you touch.

Begin by reminding yourself that water flows downhill. Whatever problems are created upstream from you are passed on to you in the forms of turbidity, siltation, flooding, and irregular flow rates. Your job is to mitigate these effects as the water flows through your land, thus passing a better stream on to your neighbors downhill.

Start off by walking your brook in a downstream direction. Do it during low, clear water, when details of the streambed will be most apparent. Then do it again during high water, when you can best observe the erosive force of water in action. Do it all kinds of inbetween times. Walk in the stream when you can, and on the bank when you can't.