Rolf Kellerhals's research while affiliated with University of British Columbia - Vancouver and other places

... Most authors investigating the sizes and shapes of coarse-grained material have focused on modern J o u r n a l P r e -p r o o f Journal Pre-proof 4 systems where individual grains are lying flat on gravel bars and where the a-/b-axes plane can be viewed from above (Johansson, 1976;Brayshaw, 1984;Strom et al., 2010). However, the partial hiding of clasts due to imbrication or burial of individual grains poses major challenges when collecting grain size data from photos (e.g., Kellerhals and Bray, 1971;Adams, 1979;Graham et al., 2010). Furthermore, since photos display the grains as projections in 2D, they cannot resolve the full 3D-view of a single grain, which introduces an additional bias during the collection of such grain size datasets (e.g., Warrick et al., 2009;Stähly et al., 2017). ...

... Of course, some scholars believe that the scope of application of Shen and Lu's model has certain limitations. For example, some scholars assert that this method has poor accuracy for beds that include fine sand Kellerhals and Church, (1977) ;Ettema, (1984); Odgaard (1984) discussed and analyzed the above-mentioned problems. He chose a normal curve to describe the size distribution of the static armor layer, and the results were supported by both theory and experiment. ...

... Open-water floods occur when the river flow exceeds the bankfull discharge, which also represents the channel-forming discharge (Leopold 1994), and spills river water onto the adjacent floodplains . For North American rivers, the bankfull discharge commonly approximates the maximum flow that is reached on average every 2 years (Leopold 1994), and possibly up to 5 years for some channels that are widened by ice scour (Kellerhals and Church 1980;Polzin and Rood 2006). The magnitude, frequency, duration, and timing of floods are of particular importance in river ecosystems (e.g., productivity, response to habitat availability, etc.) (Poff et al. 1997). ...

... Enfin, il a été constaté que le bon mélange était beaucoup plus difficilement atteint si la surface de la rivière est recouverte de glace (Engman & Kellerhals, 1974). ...

... The lithology of each pebble was recorded every 0.5 m (Attal and Lavé, 2006;Dingle et al., 2017). The lithological proportions based on the relative number of pebbles derived from the transects are directly comparable to volumetric proportions, with previous studies suggesting surface and subsurface samples yield comparable results (Kellerhals and Bray, 1971;Attal and Lavé, 2006). Identifying the provenance of gravel bar pebbles is enabled by the contrasting lithologies found in each of the four major structural units of the Himalayan mountain range (Fig. 1). ...

... En cambio, los ríos con lechos de grava y pedrones, que generalmente se encuentran en zonas montañosas, son más complejos de caracterizar por la amplia gama de tamaños de partículas que presentan, en este caso los métodos más utilizados son denominados como clásicos y corresponden a: recuento de guijarros de Wolman (1954), recuento de guijarros con estructura de muestreo de Bunte & Abt (2001), recuento de cuadrícula de Kellerhals & Bray (1971). ...

... width, depths, bed slope, grain size, bedforms, pattern), physical processes (e.g. degrading headwater channels that are primary source of sediment and water input, stable mid channels with roughly balanced inputs and outputs, and aggrading channels characterised by depositional floodplain), and climatic and ecological response (Dietrich et al., 1989;Dietrich and Dunne, 1978;Gilbert, 1914Gilbert, , 1887Gomi et al., 2003;Helley and LaMarche, 1973;Kellerhals et al., 1976;Buffington, 1998, 1997;Powell, 1875;Schumm, 1977;Williams, 1978). The three torrent reaches were identified by analysing the longitudinal profile of the case study: both main stream length and elevation values have been normalised within a specific range to allow a better representation. ...