Estimate the channel roughness n value based on the Cowan method using the supplied worksheet and the channel picture in the back of the test. Values should be within plus or minus 0.010 of the answer. Shown your approach and return your worksheet showing how you arrived at your answer.

a. Estimate the channel roughness using only table supplied. and compare your answers. Be sure to document the section and letter and subsection. of the table on how you estimated the n value. b. Determine the channel roughness Mannings n value for the channel picture if the channel is estimate to be an approximate trapezoidal channel with a average slope, So = 0.0045; bottom width, B = 5.0 ft; left side slope 3 horizontal to 1 vertical; right side slope of 4 horizontal to 1 vertical and a uniform flow depth of 5.00 ft with discharge of 600 cfs. c. Using Flowmaster or Auburn University calculator and information in (b) above provide a chart showing for the trapezoidal channel how the roughness coefficient, n varies with discharge and provide the range of n values from 200 cfs to 1000 cfs below and plot the chart.

Estimate the channel roughness n value based on the Cowan method using the supplied worksheet and the channel picture in the back of the test. Values should be within plus or minus 0.010 of the answer. Shown your approach and return your worksheet showing how you arrived at your answer. a. Estimate the channel roughness using only the table supplied. Be sure to document the section and letter and subsection of the table on how you estimated the n value. b. Determine the channel roughness Manning's " n " value for the channel picture if the channel is estimated to be an approximate trapezoidal channel with an average slope, So =0.0045; bottom width, B =5.0ft; left side slope 3 horizontal to 1 vertical; right sideslope of 4 horizontal to 1 vertical and a uniform flow depth of 5.00ft with discharge of 600cfs. c. Using Flowmaster or Auburn University calculator and information in (b) above provide a chart showing for the trapezoidal channel how the roughness coefficient, " n " varies with discharge and provide the range of " n " values from 200 cfs to 1000 cfs below and plot the chart. BY E4. \{5-12\} 12 UNIFORM PLOW DEVELOPARENT OF UNIFORM FLOW AND ITS FORMULAS 113 Table 5-6. Valueg or thn Rovghness Conpficient n (continued) Tarle 5-6. Valves of the Rotghness Coefrecent n (confinued) The yellow dashes represent the assumed normal water depth for determining the Manning' " " " value