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Subsection Area and Wetted Perimeter <br />_ D <br />_1 DD P- <br />A' 2 tan 0 ' Cos 0 <br />A Z = D P 2 s =D-b <br />1' <br />Cos <br />A 3 = (D - a )P3 <br />A4 =(D-b)P4 <br />A5 _1(D-b) D b <br />2 tan 0 <br />P2.4 are measured values from the river cross section at the dike repair area. Figure C5 in <br />Appendix C shows all of the measured values. The Figure C3 in Appendix C shows the <br />breakdown of each subsection geometrically. <br />Table 3 - Subsection Values <br />Subsection River Sloe Area ft Wetted Perimeter ft Mannin 's n Flow cfs <br />1 1.3% 11.85 6.90 0.03 96.23 <br />2 1.3% 513.74 111.20 0.025 9,684.10 <br />3 1.3% 53.15 12.90 0.03 773.49 <br />4 1.3% 111.03 26.95 0.03 1,615.94 <br />5 1.3% 16.15 12.60 0.06 53.94 <br />Total 705.93 170.56 12,223.70 <br />D = 4.62 ft. <br />The correct river depth was determined via iterative inputting of various depths until the total <br />flow was approximately 12,200 cfs. The river depth is approximately 4.62 feet during the 100 <br />year event. With this depth, the velocity along the dike slope (subsection 5) can be determined. <br />) 3/3 V <br />V _ 1.49 (A5 <br />S 12 <br />s n PS <br />VS = 3.34 feet per second <br />Tri County Dike Slope Stability Jan 08 11