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<br />the bed gradation.) From table 1, determine the maximum number of <br />water discharges that can be coded on each Q-card. The absence of <br />a value indicates impossible combinations in which case either the <br />number of cross sections (NR) or the number of grain sizes (NGS) <br />must be decreased. <br /> <br />In no case can NR exceed 150, NGS exceed 15 or MNQ exceed 10. A <br />short test case is recommended before coding an extensive problem. <br /> <br />11. DEVELOPING DATA DECKS THAT MODEL THE PHYSICAL PROBLEM (GENERAL <br />CONCEPTS) <br /> <br />With the study reach located on a topographic map. mark the upstream <br />boundary, the downstream boundary, the lateral limits and the location <br />of each cross section. Assign an identification number to each cross <br />section--miles above the mouth are recommended. Subdivide the flood <br />plain into channel and overbank portions. These can be considered <br />as strips having similar hydraulic properties in the direction of <br />flow. Within a strip, flow conditions (depth, velocity, roughness) <br />are similar and n-values and reach lengths can be assigned. Locations <br />where strip lines intersect cross sections are called subsection <br />stations. <br /> <br />In most cases, three strips will be used--left overbank, main channel <br />and right overbank, but up to seven are permitted. An alternate <br />data format is presented in exhibit 5-2 if more than three strips <br />are required. <br /> <br />Table 1. Maximum Number of Grain Sizes(l) <br /> <br />Cross Number of parallel Discharges Desired (See p. 19) <br />Sec- <br />tions 1 2 3 4 5 6 7 8 9 10 <br />50 15 15 15 15 15 15 15 15 15 12 <br />60 15 15 15 15 15 15 15 10 3 <br />70 15 15 15 15 14 6 <br />80 15 15 15 15 13 5 <br />90 15 15 15 14 6 <br />100 15 15 15 9 1 <br />110 15 15 12 3 <br />120 15 15 8 <br />130 15 13 5 <br />140 15 10 2 <br />150 15 8 <br /> <br />8 <br /> <br />- ;>. <br /> <br />. ,--_:_,>;,.,.;,~*;0;~~!!i0;~-;~;~~ '~',:.-~::>~.",";~-,,~.;.~-.;.,,~, --";"'&~.:~;'i:;;'~';.<,~;-<"4:_' .~t,.,j,._,;;,.'.;it~" -C,' <br /> <br />","""",,' <br />