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<br />H~'ards of Creat rtoods
<br />fhe amO<Jnt and extunt ~f U~"'~"~ c~u5~d by ~ny flood
<br />de~end3 in g8rL"r~1 "pon ho~ mud, ar~~ is flooded, the hsight Qf
<br />flQoding, the v"locity of no"" tho r~ta of r1SE, <Ir.~ tilE, wc,>tio"
<br />"fflouuing.
<br />
<br />I\c~a" rt"o<.lcd ",,<.I Helqhts of Floodinq
<br />The ~"6a~ along '~i1d Hor~e_Dry CreBk, Dry Cru<!k, ~rLd
<br />CO<ldnlght Arroyo flood ad by the St~nd~rd Project Flood and the
<br />tnhrrnedi~te Regional flood ~r" shown m' Pl"te~ 3 thr<lugh I.
<br />D>Jpths of flow ~~n 00 estimated fr[)oll th.. '.uGlter sl.rfacG profilec
<br />shn~rL on P1atcs 8 through 11.
<br />Ths profiles for the stre~s wer~ computed by using
<br />stream chara"t~rislics, tapo~r"phic m~ps, ~nd vall"y cross s<<dio....s
<br />which were surv8YAd in fll"y 1968. The o~erflow ~,~ml ""0 ehv~tlQl\u
<br />3ho~n On th~ ~bov~ r~fer~ncBd plates have been cot~r~in~d ~it~ 3~
<br />~cc<Jr~cy cone.iatomt with the purposes "f this Bbdy dnd th~ ~"c<Jr,,,,y
<br />of the ba5ic d~t~.
<br />
<br />for sstim~tin~ the floOd potential of ~t~ea~$. Th~sa procedu.ss
<br />are used in detarminin9 the S~~nd~rd Project Flocd PD, a p~rticu-
<br />l~r strsam. The Stand~rd Project Flo~d is deflnsc ~s the flood
<br />th~t Can be expscted from the most 5evsrs ~o~bination of metsor_
<br />ologi~al ~nd hydrolcgic~l condition$ that is considered reaeonably
<br />characterietic of the g~ogr~phical ~rea i~ whiGh tha drai~age
<br />ba"inislocat"d,exclLldingextremelyrarscombinations.
<br />On Wild Hors8-Dry Creek, the estirnBtad Standard
<br />ProJ"c~ flood r~infall IOes dste~,"insd to be: 0.62 rnchas sfter
<br />e houu;9.32 inches after 14 hours; and 10.60 inchse aftar 23
<br />hOUfe. Dry Creek and Goodnight I\,royo Stand~rd Project flo<ld
<br />rainfall ~a~ e~tirnat6d to be: 1.03 inches in 9 hou,s; 9.05 in~hes
<br />in 12 hours; ~nd 11.20 inches in 20 ho~rs.
<br />At tha mouth ~nd upper limit of the st~dy reach,
<br />reepectively, on each streBm, the Stand~rd Project Flood p~~k
<br />discharg~ voty f~~ 49,450 to 2U,4CO c~bic feet per 5econc on
<br />~11d Korse-Dry Cr"8k; from 3,740 to 3,200 cubic feet per second
<br />on Dry Cr~ek; ~nd from 4,C7C to 3,7DC cubic feet pe, ~econd on
<br />
<br />TABLE 9
<br />
<br />STA~OARO PROJECT FLOOD
<br />
<br />PEAK DlSCKARGES
<br />
<br />Sh~~",
<br />
<br />Lor-~Uo"
<br />
<br />,~ile
<br />A""ve
<br />r~ou th
<br />
<br />Wildrlors,,_Cry
<br />Creek
<br />
<br />D. & R.C.W. brid~e
<br />0.75 mile9 below
<br />U.S. HighlllaySO
<br />
<br />0.33
<br />2.SS
<br />
<br />Dry Creek
<br />
<br />fl\outh
<br />About 0.10 mils
<br />upst,eam of U.S.
<br />Hwy.50Bypass
<br />
<br />0.07
<br />1.63
<br />
<br />Goodnight
<br />Anoyo
<br />
<br />Mouth
<br />0.40 miles up_
<br />5tream of Red
<br />Cr"ekRoa<.l
<br />
<br />0.00
<br />2.07
<br />
<br />GoOdnight Ar~oyo.
<br />on Wild Korse-Dry
<br />
<br />Peak cisch~,r,"s uf the St~nd~,d P:oj..ct flood"
<br />Cresk, Dry Creek, ~nd Goodnight Arroyo 3t SPQC-
<br />
<br />iried riv,,: rnile lon"Uon5 are ~ho.m in Table 9.
<br />
<br />Frscr,'3nc'i
<br />
<br />It ie lmpractica: to u~si9n tl frs~u..ncy to th.. St~n-
<br />d~rd Project flood. The OCCClrrence of such a naod ,"ould be a
<br />r~re avent; ho~ever, it could occur in any year.
<br />
<br />POoAible L~rq~: floooe
<br />"oDds larg8r than the Standard Projsct Flou<.l ar..
<br />possibl~; ho~aver, tha ~ombin~tion of f~ctors nsc65sary to ~rc-
<br />d~ce such floode would 5eldo~ occur. The consider~tion of flood5
<br />or this magnitude is ~Ore import~nt in so~e ara~" th~n in oth~rs.
<br />b"t thoy "hould be consi<!e,ed in a"y 5t~dy.
<br />
<br />"
<br />
<br />4~
<br />
<br />Df"in,,~a
<br />Are"
<br />~~.miles
<br />
<br />Di~ch~rQ~
<br />L.f.s.
<br />
<br />82.8 4g,450
<br />69.6 43.650
<br />,.. 3,740
<br />,l,l 3,22D
<br />
<br />5.9
<br />".1
<br />
<br />4,07D
<br />3,75C
<br />
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