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<br />. <br /> <br />33 <br /> <br />. <br /> <br />2.5 Sediment Transport <br /> <br />2.5.1 General <br />The amount of material transported or deposited in a channel reach is <br /> <br />the result of the interaction of two processes. The first is the transport <br /> <br /> <br />capacity of the reach. This is determined in part by the hydraulic conditions <br /> <br /> <br />which are a direct result of the water discharge, channel configuration, and <br /> <br /> <br />channel resistance. The other major factor is the sediment size present. <br /> <br />The second process is the supply of sediment entering a channel reach. This <br /> <br />is determined by the nature of the channel and watershed above the reach and <br /> <br />development that it may be subject to. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />2.5.2 Type of Sediment Movement <br />Sediment particles are transported by flow in one or a combination of <br />the following ways: (1) rolling or sliding on the bed, surface creep; (2) <br />jumping into the flow and then resting on the bed, saltation; and (3) sup- <br />ported by the surrounding fluid during its entire motion, suspension. <br />There is no sharp line between saltation and suspension. However, this <br /> <br /> <br />distinction is important as it serves to delimit two methods of hydraulic <br /> <br /> <br />transportation which follow different laws (i.e., traction and suspension). <br /> <br /> <br />Of course, sediment may be transported partially as saltation and then sud- <br /> <br />denly be caught by the flow turbulence and transported in suspension. Sediments <br />which move as surface creep or saltation and are supported by the bed are called <br />bed load. Sediments which are suspended and supported by flow are called <br />suspended load. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />2.5.3 Sediment Transport Capacity <br />Many equations have been developed to predict the sediment transport <br />rate under certain hydraulic conditions with certain sediment sizes. Among <br /> <br />. <br />