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<br />"""""'i9""'I~~~I;;.^"".....~,,",,,,j;,,"" } I
<br />
<br />MAR-28-2000 TUE 10:46 AM
<br />
<br />FAX NO.
<br />
<br />p, 07
<br />~
<br />
<br />g'Limntion of the llf,C L I",.. Pilr"lnet.ors for llo11ting the Probable Maximum Flood
<br />
<br />~, The ilSSl1nlption thnt the errors in F.qunlion (4)
<br />.11''' ,,,Idit.ivc is 0.1.<0 qm,slionable. Kllczel'a (HJ82b)
<br />,,",,11'" thnt the spati~l av('ruging lends to non-add 1-
<br />II\'U ~wcha"Lic errors, which also indllce bia~ in
<br />l':II'i\Jl\eler estimato.~.
<br />N ,'vorlh~lcss, the ro!:re~~ion m.,thod is the only
<br />\'''11 rnr ""Lim:1ting Lho loss ...arnmcter~, Its ultimato
<br />jll,-lil1caLioll is thut it provides more "realistic" 10HH
<br />I ,:i","nelers th:m !:o:1l-oriunL"d moLhod" ."ch as the
<br />"JIl, "",,,1 \,y ODNR to ",i1ximi1.o "urfaco runofr at the
<br />I.:,.!:l"woud Wntcr~lll,d,
<br />
<br />I
<br />j
<br />,
<br />I
<br />,
<br />i
<br />
<br />'<;""','r;l)/1 of v.",;gll Val",,,
<br />
<br />;
<br />I
<br />,
<br />'1
<br />
<br />'I'he dt'sit:!\ value or STltTl, (tn routll the PMF) wa~
<br />""1 ill Ih" average valuo (1,0 inch) reported in Tnble 8,
<br />,\ILllllll!:h the slimdard error is also report~d in th,\t
<br />l<1ill", its sigllillctU\cu is [llIrely mathematic.al becallse
<br />the pnramdcr 8TH,'!'!' is CXjJcctell to vary between
<br />"("nus. The vnrinbility nf tho parameter CNS1'L
<br />(J..,;"r"e~ rurlher study.
<br />A J1reliminnry taslc is to inve.tigate the existence of
<br />IrL'n<ls !inltin!: the estimat.t,cl CNSTL to other 'Iuallti-
<br />1 "'S, The exist,'nce of 0. Sl,rong correlation would break
<br />,1"Wll the assumpt.ion of invariance of CNSTl, and
<br />pmhil,;L simple nvernl,.;n!: (Uates and Townley, ]988).
<br />'r!.C!',,j'ore, plots of eNS'!'l. verSllS total minfall.
<br />t:N:-;'J'(. vcrsus t.ot.al loss, and CNSTI, vefl;US duratiou
<br />wLro obtained in r'il:l1res 5a. 5b, ami 50, respectively,
<br />h ....11 n be seon thut thoro Wll"; 11 trond of' incroursiJ:lK
<br />t:II:-JT1. wiLh an Inor"".o of Lotal rainfall anti total
<br />)''';5, but not with ineronso in duration, The fact t.hnt
<br />CNSTL inrreasns wit.h lotal rainfall and/or total loss
<br />s\lould not como as a sllrpris" because for long dura-
<br />tion storms such as the ones used in this study,
<br />eN !iTI, effects are amplified by the long dur..tinn of
<br />.11 l'I'II('e f\l1lnff, Unwover, a strong linear correlation
<br />li",'" "ot exist between CNS1'L and any of Ihe men-
<br />I i;lllcd vJ\l'hlbles, as supported by the low r2 values,
<br />AI"o. a plut of opthuUln CNS'rf. vnluos vOrYWO the oor-
<br />J"''i'''lI,lol1t II. (Jlo~ tihown) I'ovenled that these two
<br />1''''',\l11''ICr" nl'e independent; the r2 vallie oHhe corre-
<br />Lotiun was 0,008, 'l'hereforc, CNSTL values can bo
<br />;\s,;t1llleu indepcndently identically distriblltcd and
<br />IIIL' aY'tl'''!-tll CNR1'1, vn]u" reported in Table 3 Is reI'-
<br />J'li:,oulillive of tho distribution (hence the subbasin),
<br />'1'1,,, ,'(mliliencc interval is (,'llmpnted next,
<br />Tile optiill\101 CNSTJ, vnlues passed tho l1ol'1lll11ity
<br />h','l l.y the Kolmogrov-Smlrnev teslnt the 95 perc<.'nt
<br />,,".lid~f1CIJ lewd. Thoy an~ plotted in F'jJ,::UfO 6. which
<br />"1,,,\\'." thnt lfJ nf thom fnll within the 95 porcent conli.
<br />,1,.',,<,," hllnd of N (0,095 lnch/hollr. 0.016 inch/hour),
<br />ll,,,"~ Ihe l-stnl.istics, Ih" 9" pe'fcellt cantidonc" inter-
<br />\,,,j hII' lhe dc"i~n eNS'!'!. value is thus IO.IlIlS :f; 0,0:33
<br />t,ul./lIIHlrt.
<br />
<br /> CL3Q
<br />" '25
<br />,
<br />"
<br />~ QiQ
<br />~ 0.15
<br />~ 0,'0
<br />'"
<br />'"
<br />'" ...
<br /> o.co.
<br />
<br />'$ ...
<br />"
<br />~
<br />e O,:i
<br />
<br />;: '.1"
<br />~
<br />(:;
<br />
<br />0.30
<br />'C" 0.25'
<br />,
<br />"
<br />..!C D:!O
<br />~
<br />"
<br />:!. 0,15'
<br />....
<br />t; 0,10'
<br />"
<br />(,) 005'
<br />
<br />;t-
<br />v
<br />f ..
<br />
<br />~ 7'
<br />IL
<br />,~ 50
<br />;;
<br />!! 30
<br />a
<br />
<br />:l
<br />
<br />Ob..Md -
<br />-- ~. 0.04. t 0,009
<br />i' = 0,35
<br />
<br />----;.-.
<br />--------
<br />.. : .:--------.
<br />!-'____ to
<br />.
<br />
<br />. ,
<br />
<br />(A)
<br />
<br />--~ ,
<br />
<br />%
<br />
<br />l
<br />Total Rainfall (inch)
<br />
<br />.
<br />
<br />4
<br />
<br />030
<br />
<br />ObOOMld
<br />-- y=O.C15x+O,01
<br />r' = 0.446
<br />
<br />--------
<br />-- -
<br />
<br />0.20
<br />
<br />Q,ClS
<br />
<br />
<br />(S)
<br />
<br />000
<br />o
<br />
<br />.,.
<br />
<br />2 3
<br />Tolal Loss (inch)
<br />
<br />.
<br />
<br />.. Ob&CN13d
<br />__w_ 'i:ll o.Qooe x of' 0,07
<br />~O,02
<br />
<br />.
<br />
<br />.
<br />
<br />.. -.---.-......---
<br />
<br />.
<br />
<br />. .
<br />oC13._-~_.
<br />o 10
<br />
<br />.
<br />..
<br />.
<br />
<br />-
<br />.
<br />
<br />(e)
<br />
<br />. ....-r-.
<br />20 30 IiIQ
<br />Runoff Durition {h01Jr)
<br />
<br />"
<br />
<br />"
<br />
<br />l:'iJ,"Uru 5, StutiGlical CorrC'Illtinn orC::NSTI.. wiLh
<br />(A) Total nainfall, CDl 1"'ta1 Lo",
<br />and (C> Runort'DumWt>n.
<br />
<br />gg
<br />
<br />.._---"",./".,--
<br />----
<br />------
<br />--
<br />--
<br />--
<br />--"
<br />--
<br />--
<br />,/,/
<br />,/
<br />,/
<br />,/ -
<br />,/ .
<br />~..... . "
<br />.
<br />
<br />10
<br />
<br />--'
<br />,/,/
<br />,,--
<br />..............."....
<br />,/,/
<br />,/--
<br />,/,/
<br />,/
<br />--
<br />A -."..'
<br />. --,/
<br />--
<br />
<br />
<br />..... '---'
<br />
<br />, .
<br />
<br />. .....-- ,
<br />
<br />",__'.R"_'_
<br />
<br />0.00
<br />
<br />006
<br />
<br />010 0,15 020
<br />CNSTL Onelllhour)
<br />
<br />0.25
<br />
<br />Q",iQ
<br />
<br />FiC~lrc G, Pcriodogl'1l1n lndiC'ating NonnnHLy of CN~T'...
<br />The dtl:shetllin..:r;: ddimiL Lh. 0.5 j1Grcl1nt conficlc..'l1cc 1.1~llld.
<br />
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