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<br />IIYI)l(Alll.ll'I:N(i1NEEKIN(j ''14
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<br />rab!..:: I Ila!loicsdlarat:lcrislit:s
<br />N, I{l\'cr Walcrshl.'lI riverbed 1};1r (;lillfOlIll:har:ach.:rislic Jailll;lllpwll;lllllil\
<br /> me;1 lcnghl slope a 1'1"'_1 I' '( flU AlllOiul W,llcr
<br /> kill' kill Ullll kill! 111111 shed
<br /> I Vlasin;t 17K.8 ." 2.27% 0.7 2M (1f)1I It-ll. 121 11.01% U.75%
<br />1---= III/nK.'" 2lJK.K J.l 178% 0,7 2(,5 ... n.l1 101.4 11.111% 2.10%
<br />f-- 0,7 265 1,579 0.-12 112.1 11.111% 1.2()'}~
<br /> 1 Vla..ina 677 h ." 2.21";',
<br /> . ~::IIl;1 87" Sl.h H'J'Y.. 0.7 26~ 1.582 II. ' 105 0.111%, 1.70%
<br />..-C (}58.8 (1.1 111% "7 2M 1582 0..14 91.1) ll.tll% S.CII)':..
<br /> 5 Vlasm:1
<br />f:ablc2. I-'Ioud W<lWCS Ch:U<lClcrislk-s
<br />N, Ri\'cr W:l- Modifkd synthetic lIuilllidrol-\raph CI:lsics rcculIslrm.:lion
<br /> h':ll.hd.t I>is.;h:ugc Willie lilr Ihlllulf IlisdUlr~..: Wave Ell Illlllull
<br /> an:.. (}ttIiIX \'lIhuuc Il'h.-cill. (t~n' (Jill:'" !,'uluult.! pfcdp L"ud}'
<br /> klll1 m'/s Utili' I'll' 112- m'/s lU'm' ~ 'lit
<br /> I Vlasin:i 118.8 H2. 28S! 72.') UJ, 58:' Itl.K2 1n 'J 0.2;
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<br /> 21.IIJ.nica 2')8.8 4UK 1-1.78 47.S U.H ..'n 10.-11 _.'J lI.l!)
<br /> \ Vlasilla (~77.(1 I.U17 ~J.7J 60.7 u.54 1.11111 21.2. 11.8 0.2(1
<br /> -I Vlilsill:1 81') '12 SU.1{, SU uil 1.2uu 22.2 H2 un
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<br /> 5 Vlm.iuiI ')588 59'.) -11.12 .. un 81U 22.2 25.2 n:n
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<br />It is inleresting 10 poinl out thallhc observed maximum nuntilll (220 lIun, IS of
<br />lhe 10000 relurn period order ofmagnilude (taken in Ihe puim), while Ihe occurrence
<br />plolmbilily for p,ulicular watershells and the entire watershed ranges belween 0,30/11
<br />;.ud 5%1_ Similar maximum discharge relurn periods analysis shows thill the range is
<br />1% to 5%.
<br />
<br />J. CONCLUSIONS:
<br />The i.Plllied melhodology lor comlHlling prccillitatinn, IltlOds and Houd Wilves
<br />reconslruclion guve the results which, un the given example, have proved Ihal il is ac-
<br />ceplable for the use when Ihe data are very pour. The earlier theoretic..1 ilSSUlUplil)IJ
<br />thai the precipilation distribution and the cloud movemenl dircdiun could c;mlsc , I'm
<br />tile same rain, several dillcrenl maximum disclmrge Vlllllcs The l:urrcl:1 lIJlllm"ch 1(1
<br />the turrentiill nows phenomenon comhined with the (;UflCt.:1 Imil hydmgritllh IUclhot.l
<br />chuicc could be used for the computation of Ilood walers ulsn lor the wall"rshcds larg-
<br />er then F-'-JnOkm~. The practice has checked the compulalions thr the w.llcrshcd si:tes
<br />or severnltlu)usands kll1~.
<br />4. Rrn:IlENCt;S:
<br />I Z_(j,;. .i.,vie, Z.Malovit ltc.:wlcw Of DisolSlliIlh TonclIl Flood 011 I he Vlasill:l Riwf or 26 Juue
<br />I'JKK. Indudillg AII:d}MS Of H...I And The Uhtaill,,:d RcsultS.I'lt lIS. .~in, Sprllll-\....r.Ve.lilg 1.....1.:-
<br />lure Notes ill 1~1I111 Sciences V.I: ; /. Flu\'illlll}'dl.llllicsofMollluaill Rq;mlls 1')')(.
<br />2. S.JUViuwvit, M.llrajkovit M.ltkcUlitlu:al model fur the Ooud \\-:IWC!l sUllulalioll using silllh~'lic
<br />millf;llt doll" for a \'L'Sl walershed Inlerll:ltion:d s)'mposiullI UlllllillhclIl;llic:d moods illll)"dwloC)
<br />.W:us;m'ltJ11.
<br />3 M Ihajkuvit. AII:llyscs of daily Raillf:.11 mad Their Use ill Floods cakulalicms fOf Wall..'f fCS{mrl.:~'l>
<br />M:lllagclIlcllll)csclglI NL'L'tIS. Yugoslav SymposiulII 011 L~uGillecfjllg Ilydwlugy Sphl I'J85.
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<br />Factors Affecting Accuracy of
<br />Slope-Area Discharge Determination of
<br />the September 1992 Flood In Raven Fork,
<br />Western North Carolina
<br />
<br />W.llamld Eddinsl and ThumasJ. Zcmbnuski,.Ir.1
<br />
<br />Abstract
<br />
<br />For the floud of September 10. 19Y2, in Raven Fork. Swain ('uunty. Norlh
<br />('arolina, a peak diSt.:harge of 46U t:ubil; meters per sct:und was computed by using Ihc
<br />slope-area melhoil. Accuracy of this detcmlinalion depends on suimhility of the
<br />sdl.~t.:tl'd rcat.:h and, in particular, sela:tion of Manning's roughness coeftkients,
<br />inlCrprClaliulI of lhe high-WOller marks, number and placemenl of t:ross S\."1.'liuns,
<br />prescllt:t.' of hUl!C cxpansions or t:omraelions. slale~of-now tr.ansilions, and magnitude
<br />of Ihe change in waler-surface elevalion. Some of these factors t.:an contrihutc to
<br />l!ft'ater uncertainties fur lIll"asurcment!oi in steep mountain streams Ihan fur
<br />IIk'usmellll'nlS in strcilllt~ with OUller grudienls.
<br />
<br />Introduction
<br />
<br />A severe fliI."ih fluod swept through Raven Fork ncar Smokemonl, Swuin Counly,
<br />Nunh Carolina, on Scplcmber 10, 1992, hetwl>en IYCHI and 22UO hours easlern
<br />dilyliglu lime (clll), t.."uusing serious diUOOgC to hridges, homes, camp~ruutuls,
<br />t.tlllllllCn:i<lllroUI ponds, and mainlcnance fm:ilities (fig. 1)_ The flood was tlit.." result
<br />III' ahollt .l hours l)f ilUt'nse rain from a small hUI slrong thunderslormcelll'cnlen."d over
<br />Ihe hip.hcr elcv<ltions of Mt. Guyot (2,0IM m) .lnd Mt. liardisnn (J ,M7U Ill). at Ih~
<br />hCiUlwalers of RitVcn Fork. The Nalion,,1 Weather .scrvit.:e dCIt."nuined from hUl'kel
<br />survl.'Ys ltnd rmlllrdula Ihalthe storm resultt.'d in <Ipproximalely 131022 cm of minrall
<br />1R.( '. jUlies, N:'lIiun:tl WCilther .service. oral t.:onunun., Mar{;h 11)94), Linle r.tin fell in
<br />.he luwer, pUJlUlilll"d jl<lrl of the Raven fork drainage basin (below MUU 111) where
<br />l}fupcny t1il1l1agcs were sustained from lhe flood walers,
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<br />As pan nf il cuntilluing crfon to document IIl1lahle floods. Ihe U.S. GClllllgit.:al
<br />Survcy (IJS<lS) reconnuilered the flooded urca along Ruvcn Fork un Seplcmhcr II,
<br />I ()tJ2, sclt.'f..letl U sHuly re:.tdl, anti flagged hil!h.wuler marks fm subSCt.IUenl surveying
<br />for .t sloik'..trt'u diSt.:haf}.:c measun'menl. The slope-area mcthod (Dalrymple and
<br />Bl'IIS111l, 19(7) W4lS t:hoscn ::IS the 1U1lsI suil<lhle llne for indirct.:t di:iChllr~l'
<br />t!t.-Il'nuinalion for Ihis 1100d; no dams arc prCM'ut, anll Ihe few hridges wherc il
<br />t'tIIUfaCll.'tt- lllll'uing measurcmenl could have heen made were pilnly plugged wilh
<br />llehris :uul(llr) WCTC OVl'rHlpped.
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<br />IlIy(hulu~ist. u.s. (iculll~k:al Survey, R II) Tyvnlil Rund, (1lilfIIlUC. N(' 2X211
<br />!IIYtlrulu~ist, U.S. GCUlugk:lll Survey, Wit, SUll'iCl Rid~c Rtl:nl.l(illci~h. N.l', 2'1W1
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