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<br />Planned 12-12X6 . 120 LF concrete box culvert under <br />tb~_~ast_tQ_nQ~tb_~aID~_ <br /> <br />QDES = QIOO = 550 CFS <br />As~Ym~_~a~L~l_~QntLQl <br />Assume tailwater elevation <br /> <br />4996.22 <br /> <br />Assume outlet invert elevation <br />Depth of flow at culvert outlet <br />A = 5.22X24 = 125 Sq. Ft. <br />V = 4.4 Ft./Sec <br />Assume outlet loss of full velocity head <br />EGL at culvert outlet = <br /> <br />~9.2l.Lll <br />+ !i..22 feet: <br /> <br />+ lL..1.O feet: <br />4996.52 <br /> <br />Se required to convey 550 CFS 0.04% <br />Shear loss 120 X 0.0004 = <br />entrance loss (4.3**2/64.4) = <br /> <br />0,,05 feet: <br />JL..29. feet <br /> <br />6 <br /> <br />AssYme_entLan~e_~QntLQl <br />Assume culvert slope of 0.5% <br />Invert at culvert entrance 4991.0+1201 0.005 <br /> <br />4991.6 <br /> <br />q req = ~5..Q./24 = 22.9 cfs per foot: <br /> <br />HW/D req = 0.64 <br />Required Headwater Depth <br /> <br />Required Headwater Elevation <br /> <br />= 0.64x6 <br />- 3.84 feet <br />- 4991.6 + 3.84 = <br /> <br />4995.44 <br /> <br />CONCLUSION <br /> <br />The planned 12-l2X6 double concrete box culvert under the <br />east to north ramp can be set to convey 550 CFS without <br />increasing upstream water surface elevations more than half <br />a foot. <br /> <br />18 <br />