The diversity of pool-riffle morphologies

Pool-riffle sediment and flow dynamics have been studied for many years, but relatively little work has investigated how variations in flow and sediment regimes might lead to a diversity of pool-riffle morphologies. In this letter we analyze a database of quantitative and qualitative measurements from sites where pool-riffle morphologies have been studied and assess the sites relative to morphologic transitions and mobility thresholds. Results show that pool-riffle sites are stretched over a morphologic gradient of predicted bar types from scrolls to chutes and a modelled mobility gradient from threshold to low transport channels. Flow- and sediment-driven phenomenon that are relevant for pool-riffle mechanics are discussed in this context.