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<br />The quantity (1.49/n)AR2/3 in the Manning equation is called the <br /> <br />conveyance, K, and is computed for each cross section. The mean con- <br /> <br />veyance in the reach between any two sections is computed as the geo- <br /> <br />metric mean of the conveyance of the two sections. The discharge <br /> <br />equation in terms of conveyance is: <br /> <br />Q = K{2S <br />where S is the friction slope as previously defined. <br /> <br />(8) <br /> <br />In this investigation the average value of the Manning n was com- <br />~ <br />puted for each reach from the known discharge, the water-surface profile, <br /> <br />and the hydraulic properties of the reach as defined by the cross sections. <br /> <br />The equation applicable to a multisection reach of M cross sections <br /> <br />which are designated 1, 2, 3,...M--1, Mis: <br />1.486 J(h+hV)1 (h+hv)", [(k ~hvb+(k ~hV)2.3+' . .+ <br />n=Q Lt.2 L2.3 + +L(.\f-1J..>f / CJ) <br />--=+ '7 ... '7 '7 l. <br /><,..(2 <''''' ",(M-')"'''' <br />(k ~V)(M-ll.M] <br />where = AR2/3 and other quantities are as previously deFined (Barnes, <br /> <br />.2.L <br /> <br /> <br />1967). A computer program was developed to compute Manning's n using <br /> <br />equation 9 and the cross-section data, slopes defined by the water- <br /> <br />surface profiles, and discharge values For each measurement. Although <br /> <br />Manning's n was computed for each subsection or combination of cross <br /> <br />sections within the reach, an average value of n for each reach was <br /> <br />adopted. The average hydraulic properties for the reach and computed <br /> <br />values of the Manning coefficient n are given in table 1 For these 21 <br /> <br />sites. Occasional inconsistencies in the data are due to difficulties <br /> <br />. in data collection as a result of the extremely turbulent flow con- <br /> <br />ditions. The minimum and maximum values of each variable are given at <br /> <br />the end of table 1. <br />