• journal_title：Geological Society of America Bulletin
• Contributor：EDWARD A KELLER
• Publisher：Geological Society of America
• Date：1971-
• Format：text/html
• Language：en
• Identifier：10.1130/0016-7606(1971)82[753:ASOBMT]2.0.CO;2
• journal_abbrev：Geological Society of America Bulletin
• issn：0016-7606
• volume：82
• issue：3
• firstpage：753

The hypothesis of velocity reversal seems adequate to explain the areal sorting of channel material, that is, relatively large material in riffles and finer material in pools. The hypothesis is based primarily on the measured observations that, with increasing discharge, the average bottom velocity of a pool increases faster than that of a riffle until at relatively high flow the average bottom velocity of the pool exceeds that of a riffle. The areal sorting produced by the velocity reversal occurs at flows of moderate frequency.