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<br />these culverts to convey these flows without increasing <br />upstream water surface elevations more than half a foot <br />along the 100-year st.orm event are presented as ):ollows: <br /> <br />Planned 11 -14-11 X 6 -180 LF Concrete Box Culvert <br />l.!nQe.LLuj,me..L~QYnt:i__EQ~HL5.Q_~mbankm~nt_ <br /> <br />o Assume entrance control <br />Assume headwater elevation = 4996 U.S.G.S. Datum <br /> <br />Invert elevation = ji9U <br /> <br />Headwater depth, HW = 6 feet <br /> <br />fiN = 1. 0 <br />D <br /> <br /> q entrance -- 42 cfs per foot <br /> control <br /> Q = 42 X 36 = 1512 cfs <br />0 Assume full flow <br /> A = 216 Sq. Ft. <br /> P = 108 Ft. <br /> Rn = A = 2.0 Ft. <br /> P <br /> <br />Se required = 0.15% <br /> <br />Q = 1515 cfs <br /> <br />Assume culvert slope, So = 0.5% <br /> <br />Outlet invert elevation = 4990 - (0.005 X 180) <br />= 4989.1 U.SuG.S. Datum <br /> <br />Outlet Channel <br /> <br />b = 37 feet <br /> <br />5.5. = 4:1 <br />Q = 1434 C~'S <br />n = 0.045 <br /> <br />AJLU:i = 0.040 <br />b 8/3 <br /> <br />16 <br />