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INTERPOLATING FACTORS FOR VARIOUS SLOPES AND DRAINAGE AREAS <br />Received <br /> <br />°^~ar, a F~Td o1f1q~ ;' <br />~+.ra~ <br />s ~~, <br />;. <br />FIaC Slopes Steep Slopes <br />Round to nearest $ slope shown Roun d to nearest $ slope shown <br />(Use discharge values from (Use discharge values from <br />ES sheets labeled "F lat") ES sheets labeled "Steep") <br />Slope A~c res Slope Acres <br />$ 1-SO St-Soo Sot-zooo $ 1-SO 51-5oa 501-2000 <br />.I .47 .43 .40 8 .92 .88 •83 <br />•2 .58 .55 .53 9 •93 •90 .BS <br />•3 .66 .64 .62 10 .94 .9t ,87 <br />.4 •74 .71 .7o II .95 •93 .89 <br />•'S .79 •77 .76 I2 .96 .94 .9t <br />•7 .89 .88 .87 13 •97 .96 .94 <br />1.0 1.00 1.00 1.00 14 .98 •97 .96 <br />2.0 1.13 1.16 1.18 15 .99 •99 .98 <br /> 16 1.00 1.00 I.00 <br /> 17 1.01 I.02 1.02 <br /> t8 1.02 1.03 1.04 <br /> 19 1.03 1.05 1.06 <br />Modera te Slopes 20 1,04 1.08 1.08 <br />Round to nearest $ slope shown 25 1 <br />08 1 <br />14 1 <br />17 <br />(Use discharge values from 30 . <br />I. 11 . <br />1.20 . <br />1,23 <br />ES sheets labeled "Moderate") 35 1.13 1.24 1.28 <br />Slope Acres 40 1.16 1.29 1.33 <br />X - I-50 51-500 501-2000 45 <br />50 1.18 <br />1 <br />21 1.31 <br />1 <br />34 1.37 <br />1 <br />40 <br /> . . . <br />•3 .96 •95 . •94 55 1.23 I.35 1.43 <br />4 1.00 1.0a t.na 6a 1.26 1.37 1.46 <br />5 <br />` .I-: 04 - - -1.05 i-06 65 1.28 1.39 1.48 <br />b- 1.07 1. r0 l.ll 70 1.30 1.40 I.So <br />7 1.09 l..la 1.11 75 1.32 1.42 1.52 <br />EXAMPLE: Alternate method of determining peak flaw using actual watershed <br />slope. h ~ 2 <br />S .75 <br />Given Solution P~,~, <br /> F <br />1. Orainaga aret ~ 250 ae res_ 1. From ES 10 27, slopes - flat, CN 70 <br /> Readpeak discharge ~ 72 c.f.s . <br />2. Rainfa}1 ~ 4 inches. 2. From flat slopes table above, under <br /> 51-500 acr es and acros s from o. 5$ slope, <br /> read 0.77, <br />3• Curve number ~ 70 3• Peak flow ~ 72 x 0.77 ~ 55 c.f.s. <br />4. Slope ~ 0.5$. <br />VAS+a;,~ ~GlT4 ~~"'~~ <br />2.4~i <br />2~~~i. <br /> ~ 2- iz.S`~ -S tot."? ~ ~'7Z c~ s <br /> <br />ENGINE ERING FlE LO MANUAL NOTICE IN-11 , <br />REFERENCE U.S. DEPARTMENT OF AGRICULTURE <br />Engineering <br />SCS-TP-149 SOIL CONSERVATION SERVICE Fietd Manual <br />RTSC-NE-ENG 2f0 INDIANA Figure 2.18 <br />.w.e.~.e..... ~... <br />S,L-7z. 190 <br />