 The sequence within a stream bed commonly occurs at intervals of from 5 to 7 stream widths.Meandering streams with relatively coarse bed load tend to develop a riffle-pool sequence with pools in the outsides of the bends and riffles in the "crossovers" between one meander to the next on the opposite margin of the stream.The pools are areas of active erosion and the material eroded tends to be deposited in the riffle areas between them.