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<br />\ <br />----l: <br />, <br />~-f <br />----', <br />--; <br />~ <br /> <br />where <br /> <br />Kt=emo <br /> <br />I <br />1: <br />i=l <br /> <br />Ai R/13 <br /> <br />(5-14) <br /> <br />n. <br />1 <br /> <br /> Q = total water discharge in ft3/sec or m3/sec <br />, <br />, em = units conversion coefficient and is 1.486 for English <br />, units or 1.0 for metric units <br />I <br />'. Manning's hydraulic roughness value <br /> n = <br /> A = cross sectional area in ft2 or m2 <br /> R = hydraul i c radius in ft or m <br /> Sf = total friction slope <br /> Kt = total conveyance as defined by equation (5-14) <br /> I = total number of subsections <br /> i = an individual subsection such as left overbank, channel <br /> etc. <br /> <br />When using manual computations. curves of conveyance are often <br /> <br />plotted for each subsection and used in the place of area and hydraulic <br />radius curves. This decreases the amount of computations required <br />for the water surface profile. The disadvantage of this technique <br />is that n-values are often changed during a study which introduces <br /> <br />a correction factor for the conveyance curves. Tile factor can vary <br /> <br />from section to section, and with elevation or discharge, which makes <br />application of the factor somewhat awkward. <br /> <br />5.11 <br />