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<br />
<br />Standard project cloudburst f;ton:l ;LJounts (3 hOtH.- du.(at~~")I1) f~qil!.':,11cnt
<br />to 40 percent of P~W were adopted for Fortification Creek, Pi~c RidEe
<br />Gulch, Cedar Mountain Gulch, and tile other s,":111 triDU t;uIe:. .1l'o\:lld
<br />Craig. PHP ~ounts were dcterl.liil(;d froTJ reference 5. A cO:-ilparlson of
<br />point SPS at Craig with a precipitation freVlency analysis of historical
<br />3-hour May to OctGber amounts at Craig (chart 7) indicates SPS dC.ounts
<br />are reasonable.
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<br />
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<br />
<br />Three cloudburst storm centerings ;;"re used. Oile stann t.;as centered
<br />over 5ubarea I to deter",ine peak flolOs for Fortific"tion Creek. A ,;(,cond
<br />stO:rill "~3S centered over subare2s 2.-5 to dc.tennint:: peak flor,.:s: for these ;',rC'dS~
<br />A third storm W.:JS centered over ~ub3.re2.s 6-10 to detcn:d.,1c peak flo\..'s for
<br />these i9rC2S. Sub2rea 1 is quite large in c:o;~1p2.rj:son to the si;:::e of r'he
<br />cloudburst storm. Accordingly, flood .cO::1pUL~tio;::_s for this <?~~ea wcre. '").,'l.2c
<br />assumIng o!11y a porlion of the btisin 1,.,'aS contributing.. Contr:t:;uti~g .;!.[C2S
<br />are listed on table 2.
<br />
<br />-
<br />
<br />,-.
<br />
<br />Cloudburst storm 2.L-:ounts for the !'Jore frequent events 1-.~ere b;J~-;cd .", "
<br />on ratios to the SPS detec::.dncd frGill Ch"lI:t 7. NC)Ap. At:L~s a::,c',Jnts '...'ere
<br />not use::! since they a.re h3sed on 311 2.L1;Jly~;is of f:n;n~al C)2.x:tr;:l~:n data
<br />"Whereas cloudbursts usually occur in the :31.'_-,~::ilertir::c. Hourly distribut ion
<br />of storm 2:wunts W2re pC1lterned 2fi::er the ?:;..rp di~t:ri.bt:tlon.
<br />
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<br />c. ~!_i!}'_~___l~Ld_!'--.9_g~_~~l~~~_.~_~i__~g_~~_~_ r~~~_<;_~~" -< Since there is a Jilek of
<br />reproducible rai.nfloods in the Y2r;~pa R:Lv(~r b;:~sin unit hy(~t'ogr;.:.phg <1nd.
<br />lc~s rztes ,.;ere es~i::i3.t2d. U~~it ~-:.y,~:<ogI.-.:::q:"hs "":-LTC pr<2p:::re:d for the.
<br />SUb.1rC3[; shown on Cnarts 1 2nd ,2. U~-rit h)-dro[,r.:.:;.pns \--,-'ere COL!p~t:c:d uslng
<br />the modified Los A:lgelcs District S'.1,T:i".-:ltion hydl'O.s~~z.;,h (S.-Ct:;:-vc)
<br />pr0cedur~ as outlined in RefeTCl!Ce 6. Unit hydr02Y.::iph c:;::J."C3cteristj'.cs
<br />arc t<>.bul.s.tcd on Table. 2. The seller"a1 L:WUnL1in 3ild F;:n:f;li:lgtCI1, ?\~(:W )f:-'
<br />Hcxico S--curves 'Were used a.nd arc ~;11oT...'T~ on C1131:"t: 11. The .::dcpted
<br />S-CU1"VCS C1nd n valu2s are consistent with tnose. used for sD:Jili_ar
<br />areas in the FPI studies for Steamboat SpJ:in[;s, 2nd RaI1[;cly, Colorado
<br />and Rock Springs, Hyoming.
<br />
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<br />
<br />Losses "cre coraputed using the initial. ""d co"stanl: lo';s co,~c"pt.
<br />Adopted losses are tabulated below.
<br />
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<br />
<br />Basin
<br />
<br />I"iti:11
<br />_ ..J_:::~~: s_ <_j _I~)
<br />
<br />Cor;st;lnt
<br />Lo"" (in/"c).
<br />--- --- _.--- . -------.-
<br />
<br />Fortification Creek
<br />Pille nnd C0J~r }fcn. Cll]cllCS ~nd otl1cr
<br />&""::.3)1 stl"C.:!i;;S dround CI:dig
<br />Yc,opa Rivc-r above Fortification Cr,
<br />
<br />0.75 " 15
<br />0,5 ,.15
<br />Varies
<br />0.1,.-1.6 ,J5
<br />
<br />l11c losses used for the s:;1..]11 Stl-C;l;:lS ;_~".i.-OU1"'irl. C-:::J:tt; ;1i-C ~;iFJI.l.idC ~o
<br />tl:osc used for sj;~iltar ax-ens .J.t R~:ngc-ly. llicll(~r :1011:1<1.1 .1o:~'s:!~; t..-,:rl_~ lJ;:{'d
<br />for Fortification Crcck 2nd the ...")th(~r h1.ghc~l: elevation ~:uh;)rc.:-!s i.n the
<br />
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<br />1-;./'0U' (lrA'~k~ :V-'1", :,,,,
<br />;, {V-.. r ~_'l/:.. \ ....____-__,--t."--____ J lJ 0...~.-.
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<br />C(' ., J ,- I . / .
<br />1'-C:'f_.,~--0 __ '-~rr;".//
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<br />v.:: .~J..: '..1 -I , 8 '- II i ,.. /
<br />'- " , , -, , , .'- .- /. c. ' .'_,of " ----"~~-,1_A //, '----r , ,. '- ~-...- J ~<
<br /> ';/L_ " . , ,;
<br />iJ " #(f') 'j I~ 11.1 V/, , I , ,J (,
<br /> /- " ~(; ,_. "
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