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<br />The program automatically tests the first and last points in the <br />movable bed to ascertain if natural levees are forming during the <br />computations. If so, these override ineffective area elevations <br />specified by input data. In fact, natural levees formed by the <br />movable bed are always considered to establish ineffective areas <br />even if that option was not selected by input data. <br /> <br />'13. $EDI~1ENT DATA <br /> <br />The inflowing sediment load, transport capacity relationship, depth <br />of sediment material in the bed, gradation of material in the bed, <br />armor layer, and unit weight of suspended material as well as fully <br />consolidated deposits form the sediment data. <br /> <br />The grain size of sediment particles commonly transported by rivers <br />ranges over 7 log cycles. Small sizes behave considerably different <br />from large sizes. Therefore, it is necessa~y to classify sediment <br />material into groups for application of different transport theory. <br />The three basic groups considered by this computer program are clay, <br />silt and sand (and larger). The groups are identified and subdivided <br />based on the American Geophysical Union classification scale as shown <br />in table 2. <br /> <br />a. Inflowing Sediment Load. The aegradation or deoradation of a <br />stream bed profile depends upon the amount of sediment inflow and <br />its size relative to the transport capacity of the stream. The <br />sediment load entering the upstream end of the geometric model is <br />called the inflowing load and is expressed in tons/day. An inflowing <br />sediment load is needed for each inflowing water discharge. It <br />should include both bed load and suspended load and can be expressed <br />as a log-log function of water discharge in cfs vs. sediment load in <br />tons/day as shown in figure 2. <br /> <br />\01 <br /> <br /> <br />// <br />I I <br />., I / <br />}~ I ",/" <br />1 > <br />I / <br /> <br />10" <br /> <br />Ul <br />... <br />'-' <br />E 10' <br /> <br />o <br /> <br />\0 <br /> <br />10 \0' 10 10. 10. <br />os In TlIn./Day <br /> <br />Water-sediment inflow relationship <br /> <br />Fig. 2. <br /> <br />12 <br />