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<br />[JOF.THERN ND. 1 POND <br />CALCULATIONS <br />Mazimuum Discharge <br />12 inch CMP, 29.5 feet in length <br />Om=CA 2GH <br />Qm=Maximum cfs <br />C=Coeff icent of discharge -C i~1I Eng lneer ing HandboeF., Table 6, page <br />4-40 0.48 <br />G=Gravity <br />H=Head in feet <br />A=Rrea of pipe in feet square <br />Qm=0.48<o.5ft ) 2(32.2ft/sec)1.Ift <br />Om=3.17cfs 3cfs <br />R=VA <br />V=Q/R <br />V=3cfs/0.79ft <br />• V=3.95f t/sec Oft/sec <br />Gate Opening For Average Retention Period Of 24 Hour=_~ <br />10 year, 24 hour event = 0.54 ac *ft <br />R=(0.54 ac-ft * 43560 ft/ac>/C49 hrs#3600 sec/hr) <br />Q=0.14cfs <br />Ht=1.1 feet: Haug=0.55feet <br />c <br />HaVg=Hg=KgCV/2G) <br />Kg=Coeff icent of head loss due to gate salves) Civil Engineering <br />HandbooK, tablel9, page 4-71 <br />Kg=40=17% opening 2 inches <br />V= a~g* * g <br />V= (0. 5* * <br />V=0.94 ft/sec <br />ChecK~ Q=VA: A=0/V=0.14/0.94=0.15it 2lnches of opening <br />. 10year-24hour event 3.35 ac-ft <br />Q=<3.35 ac-ft * 43560 ft/ac)/<46 hrs * 3600 sec/hr> <br />