Channel changes

Environmental impacts may alter the quantities of water and sediment carried in a stream and thus may increase or diminish naturally occurring rates of channel changes and the pre-impact frequency of flows. Repetitive cross-channel surveys to determine changes in channel size or location are a measure of the response of stream to environmental impact and may provide data necessary before corrective measures can be taken to minimize the effects of the impact. One effect on stream channels from the impact of urbanization can be shown, by example from one stream, to be a loss in channel size due to deposition of sediment. After 17 years of urbanization encroaching on the area, the channel was only 66 percent of the size it was at the beginning of that period.