Rapid erosion of stream banks and down-cutting of stream beds occurs. When the existing stream beds cannot handle the increased flow, they flood the surrounding urban area, particularly development within adjacent floodplains. Flooding can be a major problem as cities grow and stream channels attempt to keep up with these changes. Click here to see examples of flood damage in Austin. Often humans intervene to speed the flow of water through stream channels and to control erosion.
Many different methods exist to control flooding and the flow of streams.
Banks may be reinforced with plants, rock, or concrete retaining walls. Such channelization turns the stream into a very efficient culvert. Unfortunately, such channelization has the disadvantage of simply shifting the burden of the extra water flow downstream to other communities. Click here to see examples of flood control measures in Austin. As they grow, cities also tend to encroach on flood plains.