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<br />Ill. RESEARCH AND HISTORY OF FLOOCING
<br />
<br />the City bec.1II;c .1 ".1st lake" (Reference 6), and thilt runoff flowed do~'n
<br />several streets at one to foor foot depths. Road and bridue da'_1.1ge WJS
<br />sustalned.asl.iell a, considerable danaue to privote hOllles and I'roo
<br />perty.
<br />
<br />The base data utilired for tile study included local rainfall
<br />records, the Soil Conservation Service (SCS) Soil Survey, as well ver-
<br />b~l and newspaper accounts of si unificant storr,1 events. Rai nfall
<br />rccordsI1avebeenmaint.1irredfor54yearsbytheUnCOlllpahureValley
<br />Water Users Associ.1tion (UVWUA) at North 6th Street and Park Avenue.
<br />Records dt the Montrose r,i rport Iidv~ been IIlaintdirreu for 27 years by
<br />the Nation.1l Weather Service (NWS). These two records provided
<br />excel lent 10C.1l rai nfill 1 base d~ta. Table 111-1 presents d tabul ation
<br />of the major storms of record.
<br />The National Oceanic and Atmospheric Administration Precipit ation-
<br />Frequency Atlas (Rderence 1) proviued regional rainfall inforl,ation
<br />for tile State of Colorado. and provided data for the upper ba,in a rea5.
<br />Theses "Soil Survey of theOe1ta Montrose Mea." (Reference 2)
<br />provides a detailed soil s report for most of tlie st~dy area. Al so con-
<br />sideredweretliesoi1sdatilmadedvailablethrou,;hthellpril,1976
<br />"Geologic Hazards, S~bsurface Soil-Groundwater lnvest i gat iOrl arid
<br />General FoundationOesignCriteria" report prepared for the Mont rose
<br />Co~nty Co,,,aiss ioners by Geotechnic~l Engi neers, Inc. (Reference 27.).
<br />Hydrology dnd flooding reports addressing several nearbyand/or
<br />hydrologically sil<lilarbasins havebuefl studied as pdrt of this
<br />andlysi s. The st~dies reviewed included tlm Ridgeway Dam hydrology and
<br />several srllaller basin studies for wl1i~h 5trealn flow records were
<br />available.
<br />
<br />InFebrUdr)',1963,Chinoo.. winds c.1lised snoWf"elt which res,l1ced in
<br />f1 ood i flg when ~he Md inS t reet \;ro SS i n U of I~orlt ro se A no)' 0 bee cl IIIe
<br />bl{)c,ed witll debris. Thio flo(,d event, however. was not lhe di r~ct
<br />res~lt of precipitation.
<br />
<br />A thunderstorm on June 27,1%1, durrlped over an inch of rain ana
<br />hail on the city causin9 floodinu on [;O)ny stnets, notably Uneom~ilhgre
<br />fl,venue imd ~1din Street. Trl~ Loulsenllizer Canal [Jredched Cdusing
<br />floodi ny of a fi e 1 d and SOllil' crop dcllli~~e.
<br />
<br />The lOore recent de9n:c of urb.1njz~tior\ and !jrowth within the city
<br />and its environs IIIdkes the ,;re,cnt day potential hazarde'lenl;lOre
<br />significant thiln these reports in~icate.
<br />
<br />Figure 111-1 presents summ.ries of available newspaper articles
<br />relating to past floodin~.
<br />
<br />The above data was forther supplemented by local fieldrecon-
<br />rldissanee by flydro-Tri ad, Ltll. stdff. Ddtd gather~d included j!hoto-
<br />graphs of basin con(jitions. strea'nandCandl flow characteristics
<br />,
<br />survey of the str~",;, cros,.inys, ~nd infor',,:ation on the urban dra i na!j€
<br />situation. Since no strearr. flow n::cords were aHilable in the stuuy
<br />bas in, field observat ions W8rc IlJade Jnd verb~l Jccounts of flooding
<br />recorded to aid In corroborating hydrologic analysis resu1ts.
<br />The OHlce of the State Engineer. Oi vision 4; U.S. Borea~ ef
<br />Reclamation (Grand Junction office); UVIIUA; Montrose Corrwnuni ty
<br />Devel o~ment Dept.; S.C.5. (Montro,;e fielrl offi~e); Montros!' County
<br />Pl anning Depdrhlent; Colorado \.later Conservati on lloard; ~nd vari ous
<br />City and County stdff were solicite<l fo,' infor',lation concern ing
<br />fl ""rlin~. (;ef\"r~l COrm1"nt~ were nht"in~d nn th" flnnding inlOJact on the
<br />City and its environs,specificallYds it affectectthe respective are,lS
<br />of inter('st or responsibility.
<br />There are few for'~a 1 ly doculllented records of past fl oodi ny in
<br />~ontrose. f,n event in tile late SUmller of 1933 is indiCilt ive of the
<br />;Jo:ential danger,however. t-leaqrainontl,Qconsl:cutivedays In
<br />Sl:pte'lber, 1938 CdUSe-d flcoding frOJII Ory C~dar Crel'~, as well oS
<br />v,ontrose Arr'oyo. A.vailable infunrlalion hdiCcltes tllat "a por'tirm of
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