Initiating sediment movement
Whether sediment will be eroded, transported or deposited is depended on the particle size and the flow rate of the water. Flow (ft 3 /s) =Area (ft 2) * Velocity (ft/s). OR Flow (ft 3 /s) =Volume (ft 3)/ Time (s). The equations describing the relationship of water flow and sediment transport are a bit more complex. Organic sediment transport is will vary by location and season. In one estuarine study, the organic portion of the suspended load fell from 85% to 18% from February to November due to seasonal effects on sediment transport 18. Sediment transport is the movement of organic and inorganic particles by water 10. In general, the greater the flow, the more sediment that will be conveyed. Water flow can be strong enough to suspend particles in the water column as they move downstream, or simply push them along the bottom of a waterway 11. Organic sediment transport is will vary by location and season. In one estuarine study, the organic portion of the suspended load fell from 85% to 18% from February to November due to seasonal effects on sediment transport 18. All the time there are mini-collisions and in this way we can observe the process of attrition at work. It's important that we make the link between the river's ability to transport through traction and saltation and the process of attrition. Abrasion is also at work as bedload collides with the bed of the river.  Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice, and/or by the force of gravity acting on the particles.  Membrane Transport. The transport of water and other types of molecules across membranes is the key to many processes in living organisms. Many of these transport processes proceed by diffusion through membranes which are selectively permeable, allowing small molecules to pass but blocking larger ones. Diffusion refers to the process by which molecules intermingle as a result of their kinetic energy of random motion. Consider two containers of gas A and B separated by a partition. The molecules of both gases are in constant motion and make numerous collisions with the The estimation of suspended load by sampling is relatively simple, but taking a representative sample of bedload is difficult. Both types of sampling are briefly reviewed, also estimation of the total sediment movement, and estimates based on measuring the amount of deposition in ponds or lakes. This is called movement in saltation, and is a very important part of the process of transport by wind, but in liquid flow the height of the bounces is so low that they are not readily distinguished from rolling bedload. The relative quantities moved in suspension and as bedload vary greatly. On Fraser River at Mission, for example, about 1 million tonnes of the total 22 million tonnes of total sediment transport moves as bedload (about 5%). Equation (4.2) and others of its type utilize a critical condition (denoted by the subscript cr) for initiating sediment movement. Bed-material load but also those near the bed transported in saltation or suspension. Bed load, strictly defined, is just that component of the moving sediment that is supported by the bed (and not by the flow). That is, the term “bed load” refers to a mode of transport and not to a source. Sediment transport due to fluid motion occurs in rivers, oceans, lakes, seas, and other bodies of water due to currents and tides. Transport is also caused by glaciers as they flow, and on terrestrial surfaces under the influence of wind. Fluvial sediment transport can result in the formation of ripples and dunes, in fractal-shaped patterns of erosion, in complex patterns of natural river systems, and in the development of floodplains. Rapids are sections of a river where the gradient of the river bed is relatively steep resulting in an increase in the river’s turbulence and velocity. They form where the gradient of the river is steep and the bed is composed mainly of hard rocks. In the upper course of a river, its load is large and mainly transported by traction along the river bed. When flowing water encounters bedload, it is forced over it and downcuts behind the bedload in swirling eddie currents. These currents erode the river’s bed and create small depressions in it. A taxis (plural taxes /ˈtaeksiːz/ , ˈtæksiːz from The Ancient greek, τάξις meaning) arrangement is the movement of an organism in response to a stimulus such as light or the presence of. food 1 Phototaxis is the movement of an organism in response to light: that is, the response to variation in light intensity and direction. 2  Negative phototaxis, or movement away from a light source, is demonstrated in some insects, such as cockroaches.
http://www.fondriest.com/environmental-measurements/parameters/hydrology/sediment-transport-deposition/ http://www.fondriest.com/environmental-measurements/parameters/hydrology/sediment-transport-deposition/ http://thebritishgeographer.weebly.com/river-processes.html https://en.wikipedia.org/wiki/Sediment http://hyperphysics.phy-astr.gsu.edu/%e2%80%8chbase/Kinetic/diffus.html http://www.fao.org/docrep/t0848e/t0848e-10.htm http://www.sfu.ca/~hickin/RIVERS/Rivers4%28Sediment%20transport%29.pdf https://en.wikipedia.org/wiki/Sediment_transport https://geographyas.info/rivers/river-landforms/ https://en.wikipedia.org/wiki/Taxis
what types of movements are observed in transport of bedload