According to Geyer, the only surprise in the team's study was how strongly the new findings confirmed what foresters have long believed. In average floods, water tends to eat away the soil on the outside of curves, sometimes to the extent of carving out a new channel. In the 1993 flood, however, Geyer found that there had been no tie whatsoever as to whether the water course had been straight or curved. If the river was next to grassland, a swath of pasture 78 feet wide washed away. If the waterway flowed through land that was at least 51 percent covered by trees for a distance of at least 100 feet from shore, the flood deposited enough soil to make the bank 10 feet wider.
Trees slow down water as it surges both to and from land and dwellings.
They also seine debris, ranging from flood-floated buildings to weed seeds. A woody buffer strip 66 feet wide can protect waterways from 90 percent of the yard and farm pesticides and fertilizers that rain tends to carry into streams and rivers. It can also help protect lands from the next flood. Contact Steve Rasmussen, District Extension Forester at 370-4024 for more information on the benefits of riparian forests. Changes from the original CRP have been made that make this one of the best opportunities ever given farmers for incentives to plant trees and shrubs.