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<br />WORKSHEET 4: Graphical Peak Discharge Method
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<br />. Projec1: Cottage Villas Calculated By: CNC
<br />Project No. 92-111 Date: 10-22-92
<br />Location: Arden Hills Checked By:
<br />File: TR-55,WR1 Date:
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<br />Drainage Basin:
<br />Developed Condition
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<br />Peak Discharge Calculations
<br />1, Data:
<br />Drainage Area, Aa 2,50 acre
<br />Drainage Area, Am 0,0039 sq, mile
<br />Runoff Curve Number, Cn 90
<br />Time of Concentration, To 0,35 hr,
<br />Rainfall Distribution Type II (I, lA, II, III)
<br />Pond and swamp areas spread
<br />throughout watershed 0,(1(1 (percent of Am)
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<br />Storm *1 I Stonn *2 I Storm *3 I
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<br />. 2. Frequency, year :::;:;:::::::::;:;:::;:;:\L:::::::::::::::;:::~:~:: <:::::;:::;:::;:;:;~;:~~d
<br />3. Rainfall, P (24-hour), inches 2,4 ! 4,2 5,9 I
<br />;:;:;:;:::;:::;::::::::::::::c:::::;::::::::::::::;:;:::{:;::::::;::::::::::;:::;:;::1
<br />4. Initial Abstraction, la, inches 0,222 ! 0,"2" I 0.222l
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<br />(Losses prior to runoff) ::::m:::::::::m:::um~:::u:::::?:::::::W:::{::::::m:::um::::::::::1
<br />,. Compw. ,.,., 1."'~:~"~J".'.""~:~;~I",,~,:~~,;,i
<br />6, ~::;:~ ~~~~~e~;~4~1~;nn ::,::,::::::::,:,::'~:i~J',::,::"::',::.:.:~f~j.::''::.::":'.::':~~~j
<br /><<<<<<:>C:<<<<<<f>>>>>>>l
<br />7, Runoff, Q, inch I Q".44!" 3:ii i "'4.75!
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<br />8, Pond and swamp adjustment faclor, Fp
<br />(Use percent pond &swamp area
<br />with table 4-2. Factor is 1,0 for
<br />zero percent pond and swamp area,)
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<br />9, P...ak discharge, qp = 'lu*Am*Q*Fp I 3,6 I 8.1 i 12.8 I
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<br />. TR-55
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