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<br />Su~~
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<br />flo~ (gene~al1y 100-year frequency) wi~h a specified increase in water
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<br />Englneertng field surveys for "..,,"tleat .1nd horhont"l (_ontr01 '...ere
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<br />surface elevations. The procedun~ is based on the equal conveyance
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<br />condu<:ted by Davis EngineeringSer"lces, [nc., 517 Spru"-e St,eet, Box 130,
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<br />reduction concept; however, the program does not allow encroach~ent or
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<br />Del None, Colorado. Held surveys ""re ","cdcd for additional "",pplng and
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<br />narro"ingof the channel. Input data to this program Include: cross-
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<br />crO$S eeetlon data preparedesl'ecially fOI" the hydraullr studies t nthis
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<br />section information in the sa~e format as water surface profile program
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<br />report. funds for the f1eldsll(veys, addttlo=l mapping and crOS$ sections
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<br />WSP-2 and elevations of the selected flow at each cross-section ~tthout a
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<br />~"re provIded by, and contra~.ted through the Colorado Water Conservat1on
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<br />floodway (from WSP-2 analysis). A basic assumption in thIs analysis Is that
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<br />Board. This work Was cOlllpleted in the faU<>f 19711 and ""l'pl......ntedw1th
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<br />changes in velocHy head resulting frornmodifiedwatersurface elevations is
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<br />additional infot'Olat1on by Davis Engineering Services, Inc. in 1979. The
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<br />negligible, or in other words, the friction slope re~ins essentially the
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<br />surveys were tied into the original mapping and the ~sis for verticsl and
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<br />BlllQe.
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<br />horhontal control are described in the legend of "Flood Hazard Area Maps",
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<br />A table of floodway ~idths vs changes tn 8trea~ stage 1s included in
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<br />sheets 1 through 12.
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<br />AppendixlI,separatetothe"",inreport."
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<br />flood Plain Values
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<br />Maps
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<br />The assessOlenrsof natural and flood plaIn values ""re "",de as
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<br />Watershed and dr"in"e~ or,," maps were developed from U.S. Geologlc..1
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<br />follows:
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<br />topographic maps (scale 1:62,500). Flood hazard areas arc plotted on
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<br />1. O"-~Lte investigation by Mdie W. !1ustard. State B!oLog1st. sou
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<br />I'hotogra""""tticmaps. Topographyandl'lani<netrywerccollll'lledbYl'horogralll_
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<br />Conservation S"rviee. Denver. Colorado.
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<br />"'etric lIlethods fr= low level aerial photography taken June 18. 1975. The
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<br />2. Farml.andsinthestudyareaareiml'ortant. h.ololever,tr.cyarenot
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<br />photograo,,"etry ia by l1errick and Co., Engine<!rsandArchitects,lOIl55E.
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<br />classified as "PrIme". Info.m.~tion regardl~ I'd"", Fan.lands WaS
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<br />Beth.anyDrive, Denver, Colorado 80232. funds for themapping1o'ere provided
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<br />obtained from the mal': "IlIlportant Fannlandsof RioGrandeConnty,
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<br />by Rio Grande Connty tlnd thcColor:ldo WaterConservat1on BOilrd. Theorig-
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<br />('-:-lorcb" ~re.."rc:! h;'
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<br />ucn'_CA" ('~~e"~',".'~"
<br />___.. y~.. ~w..v_. .__.w..
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<br />SCt.~tC "n:! Col"r~o State
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<br />inal.,"pping1o'as ona scale of 1"-lOO'andrcducedtoa acaleof I". 200'
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<br />University Experiment ~tatton, 1979.
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<br />forworklllllps. The workm"ps '"'ere reduced to 1". 400' for report purposes.
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<br />5pec.ific criteria used ro idencify Prime Farmlands can be found in
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<br />Contour interval is 2 feet and thcdatUl:lisl:lcansea level. Thelllaptopo-
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<br />Public Law 95-97 Section 657.5; publlshed in the Federal Register On
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<br />grilphytomplie8101ith Mtional rnapaccuracystandarda. l1"pmylarsonnscale
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<br />Jan<".ry31,1978.
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<br />cf 1" - ~C:C:', "".: ;;...-.""y l"r,,,,"d,,,, ."" <H' ille ac Lhe lA>lorano ,."ter
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<br />Elcvatlon Reference Marks
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<br />Conservat10n 80ard, 823 State Cent~nnial Bldg., 1313 She~l:l~~ St., Ocnva~,
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<br />Th" "rlglMI b.,." ""pping uMd for this Elnnd h",.~,d study ""~ "dapl,'d
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<br />Colorado 80203, teleph"nc (3a3) 839-3441.
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<br />from topo;;r"pbic: ""'PS ",ade csp"cial1y tot dcvdop"ent plannilll\ in 1975.
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<br />AP-6
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<br />AP-S
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