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Worksheet 4: Graphical Peak Discharge method <br />.Project SDH#4 AR EA "B" By DGA Date 7/1/93 <br /> <br />Location <br />Circle one: Present Developed <br />mil (acres/640) <br />(From worksheet 2) <br />hr (From worksheet 3) <br />(I, IA,. II, III) <br />percent of m (_ acres or mil covered) <br />1. Data: <br />Drainage area .......... Am ' 0.0029 <br />Runoff curve number .... CN = • 89 <br />Time of concentration .. Tc 0.18 <br />Rainfall distribution type II <br />Pond and swamp areas spread <br />throughout watershed ...... 0 <br />2. Frequency ............................... <br />3. Rainfall, P (24-hour) ................... <br />.. Initial abstraction, Ia ................. <br />(Use CN with table 4-1.) , <br />5. Compute Ia/P ............................ <br />6. Unit peak discharge, qu ................. <br />(Use Tc and Ia/P with exhibit 4-_) <br />7. Runoff, Q ... ............................ <br />(From worksheet 2). <br />8. Pond and swamp adjustment factor, Fp ,,,, <br />(Use percent pond and swamp area <br />with table 4-2. Factor is 1.0 for <br />zero percent pond and swamp area.) <br />9. Peak discharge, qp ...................... <br />(4lhere qp = quAmQFp) <br />• <br />Checked Date <br />yr <br />in <br />Storm 1 Storm 2 Storm 3 <br />lOYR 25YR <br />1.4" 1.8" <br />in 0.247 0.247 <br />0.176 0.137 <br />csm/in 775 795 <br />in 0.55 0.86 <br />1.0 1.0 <br />cfs 1.24 1.98 <br />42-F. <br />D-4 (210-VI-TR-55, Second Ed., June 1986) i <br />