Pulsations in Bedload Transport Rates Induced by a Longitudinal Sediment Sorting: A Flume Study using Sand and Gravel Mixtures

Channel responses to varying sediment input: A flume experiment modeled after Redwood Creek, California

“…In our flume experiment, bedload sheets formed in the intense transport zones of the aggrading channel after the bed became finer and output rates were high. Bedload sheets are associated with high mobility of fine as well as coarse particles (Iseya and Ikeda, 1987;Whiting et al, 1988;Seminara et al, 1996), and their presence in both the flume and Redwood Creek is consistent with high transport capacity during phase I conditions. The presence of bedload sheets is apparently an easily identifiable indicator of high sediment loads in gravel-bed channels.…”

Period and amplitude of bedload pulses in a macro-rough channel

“…The wide grain size distribution present on steep slopes has a noticeable impact on bedload, causing its fluctuation even under constant water and sediment feed (Iseya and Ikeda, 1987;Frey et al, 2003). According to Iseya and Ikeda (1987), two main factors cause sediment transport to fluctuate, namely, migration of bedforms and segregation of the surface grain size distribution, which results in the formation of an armor layer.…”

Formation and evacuation of a large gravel-bar deposited during a major flood in a Mediterranean ephemeral stream, Nahal Me'arot, NW Israel

“…Depositions of fine sediment and consequent vertical accretion in natural pools were described by Lisle and Hilton (1999), and following artificial disturbances in low-gradient reaches by Madej and Ozaki (1996) and Wohl and Cenderelli (2000). Bedload waves, sediment pulsation and sediment slugs were described both in laboratory flumes (Iseya and Ikeda, 1987;Lisle et al, 1997;Cui et al, 2003) and in mountainous gravel-bed rivers following extreme precipitation (Maita, 1991;Marutani et al, 1999;Lisle et al, 2001;Sutherland et al, 2002;Kasai et al, 2004), and also in hyperarid desert ephemerals (Lekach and Schick, 1983).…”