HUMAN IMPACTS ON WISCONSIN STREAM CHANNELS∗

摘要: ABSTRACT The conversion of natural land cover to agricultural uses in the Platte watershed southwestern Wisconsin caused a three fivefold increase magnitudes floods that recur more frequently than once five years small headwater and tributary watersheds. impact settlement on is less for larger watersheds, but general has major channel metamorphosis throughout River system. Most channels have modern cross sections are relatively wide shallow when compared their presettlement counterparts. along downstream main channel, beyond reaches where bedload sediments dominant factor determining shape, narrow deep relative Much sediment related man-induced accelerated surface runoff been transported only short distances presently deposited al...