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<br />e <br /> <br />- <br /> <br />e <br /> <br />J <br /> <br />r. Plate 6. GeneraUn4 o.pth-Area-CIU'ft., 24-BDur Ra1nt'all. <br />COlI.8idering all etonu tabulated 1D Plat. 5, tile 24-hCIIlr values ot Il:ldex <br />!la.1D1'all Ratios (Le. Percent ot IDdex Ra1nt'all) "'1"8 &n'UlJed 1D order ot <br />iI.... n'sh1Ilg magn1 tude tor each ot the areaa .ses1&Date4 1D tbe eolUltlll bead- <br />1IIgs ot PlAte 5. Tbe DUII1ber ot Index !la.1D1'all Ratio. exc..d1Jl& various valuee <br />vas detenl1ned and eouverted to perceot or tbe total ~r ot stonu etudi.. <br />(&p'pl'OX. 4(0). The e\U'T8 00 Plate 6 d..~ted u "........._- ObHZ"'IlId" val <br />obta:lned by plott1Jl& the highest value ot Index Ra1AhJ.l !laUo tor each <br />area and dI'v1Il6 a lCllOotb e~ to eovelope tbe plotted po:lnt.. The set ot <br />c:urves n\llllber !E, 5E, and lOE vas o'bta1Ded 'by plott1JlC tor each seleeted <br />area the valuee ot Index Ra1n1'ooll Ratio eqll&l.led. Dr ezcee4ed 'by 1 pereeat I <br />5 perc:ent,' and 10 perc:ent, reepectivel;y, ot tbe total ~r ot value.. <br />For purpoe8 or cOlllp&risoo, tbe S8t ot c:ur'nlS de.1pated u lA, 5.\, lOA, <br />25A and 50A 'lIere o'bta1Juld by plott1Jl& the _U ot the ~st 1 pereeot, <br />5 percent, 10 percsnt, etc., ot tile IDdex !l&1Iltall Rat1011 tor the ..lecM4 <br />are.... <br /> <br />g. Plates 7 and 8. These Plates vere p1"8plU'8d :In the _ <br />lIl&Imer sa Plate 6, us1Jl& data applicable to 48-hlNr UIll 96-hour stora per- <br />iods, respectively. <br /> <br />h. Plates 9. 51'S Depth-Area-Duratiou RelatiOll.8hips by 2"- <br />llaur Ston:! Increments. Folioving a general review ot tile pro'bl_ and <br />data analyzed, Curves Nos. 25A on PlAtes 6, 7, and 8 were selected sa <br />1lld1ces to the volume ot precipitation tbat should be u_d u occur1JlS <br />:In 2", 48, and 96-bour periods ot 5tAnrla?d Pro.l~t Bt01'll8. Plate 9 <br />represents a replott1Jl& ot Curves 25A trom Plates 6, 7, and 8, Y1th lII1 <br />:Interpolated curve tor the 72-bour duration, tor coaftll1l1Z1Ce 1D use. <br />Applications ot the eures :In prepa:r1lla BPS ..t1-.te. tor 'buiDa ot va:r1~ <br />sizes are discussed hereiDatter. <br /> <br />1. Plate 10. l'1JDe-DUtrib1nton ot 2"-Hour 51'S Ra1nt'all. <br />In develoP1JI& Plate 10, charts s1Jll11ar to Plate 2 were prepared rrom data <br />recorded :In actual. stonu to represent the ............ raWall ill 6 and 12 <br />hours, respectively, over seleeted areu ot less than lOCO sq.m1les <br />Correlat1011.8 ot 1II&X1lIIuIII 6-bour lII1d 12-hour ra1IIrallvalues Y1th the BPS <br />Index Rainfall values tor various geographical locat1DD.1 resulted ill ClU'ft. <br />substantially u :Indicated in Fig (a) ot Plate 10. B\1pplementary studies <br />us1Jl& different lIlethods ot approach substazlt1ated the results obt&iJled by <br />the first method Y1thill acceptBble l.1III1tB ot var1at.1cm. A relatively <br />e:rtensi VB study ot b;ydrographs ot actual stonu shoved that the IIIlIXi=a <br />6-hour ra:lnf'all _,. occur near the begiftfti'lg, III1ddle or eDd ot the 1IIIIoX1InlII <br />24-hour ra:lnf'all period ot a stom. Accordi 'lg'7, the ~. ot 6-hlNr <br />ra1nt'all increments 1Ild1cated ill Fig (b) at Pla1;& 10 ".. selected tor 8PS <br />estimates applicable to drai.IIage areas ot app~~ lOCO sq.lII1. and leu, <br />on tbe basis that such a sequeJlCe vov.ld produee critical runott troIII IIIOs1; <br />bae1J1s. Procedures tor e.tiDat1Jl& t1llle-41s1;ributioa 0'1 ra1l:Itall 111. SPS <br />estimates tor d_'n'lge basiDa larser tbaIl appron.ate~ lOCO sq.lII1. are <br />outlined here1Dat'ter. <br /> <br />9 <br />