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<br />To compute the K and m fitting coefficients for the X-section at the <br /> <br /> <br />downstream face of the dam, the X-sectional data at mile 0.0 is reduced by <br /> <br /> <br />subtracting the channel invert elevation from the elevation associated with <br /> <br /> <br />each topwidth, producing table 2. <br /> <br />Table 2 -- TOPWIDTH VS. DEPTH AT DAM FOR EXAMPLE PROBLEM <br /> <br />Depth Topwidth <br />0 0 <br />8 480 <br />18 900 <br />28 1300 <br />38 1350 <br /> <br />Examination of this reduced data indicates that, because the topwidths <br /> <br /> <br />increase very slowly above a depth of approximately 30 feet, a reasonable <br /> <br />value for hv is 30. <br /> <br />This reduced data is used in Eqs. (5)-(6a) to determine the K and m <br />coefficients of the equation B = Khm. <br /> <br />Table 3 -- VALUES USED IN LEAST SQUARES COMPUTATION <br />OF K AND M COEFFICIENTS AT DAM <br /> <br />i hi log hi (log hi)2 Bi log Bi (log hi)(log Bi) <br />1 8 0.90 0.82 480 2.68 2.42 <br />2 '18 1.26 1.58 900 2.95 3.71 <br />3 28 1.45 2.09 1300 3.11 4.51 <br /> hv <br />4 30 1.48 2.18 1310* 3.12 4.60 <br /> = 5.08 6.67 11.87 15.24 <br />*Linearly interpolated. <br /> <br />1-10 <br />