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<br />,.r <br /> <br />~ <br /> <br />Evaluation of EXistin9 MathemAtical Fluvial Models <br />for National Flood In.u~ance Studies <br /> <br />/ <br /> <br />by <br /> <br />John LiOO' <br /> <br />The prilMry objective of this inve.tiqation was to deteraine whether <br />river-bed degradation durin9 flood pa.sa~ has &n effeCt on flood stage <br />that should be incorpOrated into the calculation of flood-zone H_its. <br />The anci111ary quutiOft is whether flood-zoning studies should ...ke use <br />of flood-.ta~ pre41ctioo ~la vhich in.corporau river-bed. -.obilJ.t:y and <br />degradation/.gqradaUOIl, inat.ead ot utUbug tu.d-bed .-0481..8, which <br />bav. been ~10ye4 heretofore.. ~e nud)' Lftvolved application of dx <br />flow-- and H41.eDt.-roatiDy ao&ala for dludd .ue... to study reachea <br />ot the san Lonuo, Sd O1..,dto, and Sdt Ri"n, tor 'lhich ...lAU"ly <br />co.plet.e uput 4au wen &.aUable. fte develapen: oL the individual <br />-=>4els vere c~u.dCQed to perto~ 'the DWNIdod aJAW,aUQM udnq their <br />.....10. <br /> <br />Fr'*' the reaulu of tbot .~"r it va. coacluded that the etf-=t of <br />river-bed e5ecp'&4at1oa 4IDd &'1'P"adaUoa oa vater-8urfaoe elevation durlnq <br />floo4 pu...ge 1a IaCb ..uler than the effecta of t:he uncertainties of <br />cbannel rouqhheu or' flow trict101l ractDr, ~Dt input, and 1n1t.Ul <br />charuMl geoMItry. ~, t:he a.,..aJ.1ablct J.npu.t data en c:hI.~1 <br />~try. bed-w.atertd c:baracteriat1~. etc., gellenlly .are l....~te to <br />pet'tit full uUllutiOll of the cqabiUti.. of erodible-bed ~b. <br />'l'herefore, e.x~ 1.- cuea of Mftrely dbturbed. riven whld1 ....ft <br />expedetlloed ~ 1Dcal de9radaUon or aqgradat10a through ...n'. inter- <br />VeJ:ltioa., uti.l1ut.1oa ~ erodible-bed IIOdelA in.ete.d of fbed-bed a)dels <br />c:.annat be ju$tit1ed 1J1 tloo4-a.uranC(t nuefi". <br /> <br />BACXCROUMD OE NATIONAL n..ooo INSURANCE PROGRAM <br /> <br />For ekeAdeS. the a.at.1onal response to flood diSASters vas generally <br />liaited to bu.11ding flood (:OCItrol woru (4uI8. lev~. Maw.lls. <<c.) and <br />prorldiD9 disaster relief to flood dctiall. 'l'his "Pproach did not redllc:e <br />losses or discourage GllWiu dnel~t a.nd in .ocw 1nstan~ aC1::U<ally <br />encouraged _dd1tioo.a1 deftJ.ot-etllt.. 1'0 COIIpOW1d the probl~ the public could <br />not buy flood cover.a.ge fr~ iJl.su.ralKle c:o.patllies. ~d building techniques: to <br />reduce flood daaag"! to ON coostructiOll were ofteo overlooked. In the hoe of <br />-.ounting flood los~ .and esealaUbg costa to the general taxpayers. Congress <br />created the Rational Flood Insurance PrQ9rAa (NFIP) in order to iUt1gAte <br />tQture 4aJu.qe and ,proYide protection for property ownen against potential <br />-lossea. Coagreu establi.hed the NFIP with the passa9fl: of the National Flood <br /> <br />1Pederal ElDergeney Ka.n.l.9fl:MDt A~cy Region VIII. Denver. <br />Colorado. <br /> <br />3.29 <br />