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<br />othe, uses.
<br />
<br />AS an altern<ltlllp to the P,l>Sl>nt tlooding sitW<ltion,
<br />
<br />G,ande Canal, The Fa"ne,s Union C..nal, and ethers divert
<br />I ~r I 9at i On "ater t rem the r i vOIr in var i ab I e "want I t i e5 ..<:<:erd i n9
<br />te the river stag.., and the lellel ot demand bv ir~ ig"""s.
<br />It "as determined to, this studv that minimwm diversions,
<br />",hich might retle<::t a ",et Spr,n'3' ",ewld be the safest "ssumptien.
<br />Theretore, di5<:ha''3e-treQUenCY valwe5 at the Monte Vista stream
<br />9"'3" location ,,>+I.."t this "55wmptien and",e sli",htlv hlsh,,"
<br />than it historical aver"9" divllr5ion5 ",.!e" essum..d.
<br />0".. ..~amp I e that Supperts th i!l aSSumpt I On is the !lpr i n9 ot
<br />
<br />Floed"ay
<br />Art..'cl..1 till enc,oach",ent On flood "Iains can redu<:e the
<br />areal IIl1tent of a tlood plain and pro\lid.. additional 5pa<:e for
<br />
<br />D.
<br />
<br />.. possible fleod"ay ..ith tlood plain encroa<:h..""t up to l.O ft.
<br />rise will be studilld tor 5ele.::ted portions ot the study rea"h.
<br />The ~..su 1 t ot th i s ana I yS is", I I I be sho"'n In" document -separate
<br />trom thl5 rllPort.
<br />
<br />Hl'd~.9:-'_Cl9l'
<br />The dischar",e-tre"UenCY Infermation tor this stuc:h.. "as
<br />
<br />1967.
<br />
<br />It "as.. ",et sprln9 and irri",ator9 did not <:al I tor
<br />
<br />developed tram stream ",age data and previous studies.
<br />
<br />T>.
<br />
<br />irri9..tloM "'atEr.
<br />
<br />Theretore, hi 9h t I o,,~ ,"TOa i "ed j n the river
<br />
<br />m"9n i tud" 0 t d i ~charges tor the upper end at thO' study reach "'a~
<br />
<br />Conserv..tion S..rvlce.
<br />
<br />o i ~~har",e-tr ""UenCY va I ues at a secoMd
<br />
<br />produ~ i M'3 .. 9reat'" threat at flood i n9.
<br />A d i ~.::harge-tre"ulln<:y-p'ot i I" "..s plotted uS i n9 the
<br />p,ec::"..din':l data (ti9ure:2) and used as the basis tor this study.
<br />Only th.. r..~ultln9 lDD-year tr.."uen"y discharge at Mont" Vlst..
<br />O:;01Op..r"S closely ",ith the v..lu" published by the FedEral
<br />Emer9pncv Manag..ment A","ncy flood lnsurance Study REPort for Rio
<br />
<br />dEtllr..ined tro.. publ i shed valu&s siven in the October, 196C
<br />
<br />r"port nflood Hazard Study, South For' Rio Grande and Rio Grande
<br />in theVic::inlty 01 South For", COlo'ado", by the Soil
<br />
<br />locat,on ",i t..in tME study area "a~ deveioped he", 70 ye..,r,!; of
<br />str....m ",a9" data (Rio Grand.. n..ar Oel Norte) analys..d accordin",
<br />to proc..dure~ '" I ven In "8u I I et I" 178, Gl..I i de I i n..s for O..t..rm I n i "'"
<br />Flood Flo", Fre"u..n.::l..s."
<br />Dischar'3e-tr"Quency values for th.. lo~er end et the study
<br />.each I~ less straight fe.eward because ot Irri9ation diversion
<br />
<br />G.ande Countv' U"ln<:orporated Areas, Ma~ 1967.
<br />by <:'055 sect'on location ..... ",Iv..n in Table 1.
<br />
<br />Dlsch..rge vlues
<br />
<br />in f I uenc,,~.
<br />
<br />The p. I m"rv d<lt~ r"te'"nCI~ to. th i s I e<:at i On i ~
<br />
<br />streamtlow d..t.. (Rio Grande Riller near Monte Vi st..) and
<br />
<br />hI5tC'.'cal ir"'9ation d,v......;or.s.
<br />
<br />Majo.. c..n..l& such as the Rio
<br />
<br />"
<br />
<br />" -
<br />
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