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<br />Firruref!
<br />James Street during theAl'r;] 1974 flood.
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<br />FigureS
<br />A "p><idencPonOakSlrcct,Aprill!!71.
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<br />FLOOD DAMAGE PREVENTION
<br />The,"c arc no flood control projects that
<br />have an l'ffe~t in the study area and flood
<br />damng-,. prevention eompri'e, emergency
<br />operation" dur;no: floods. The Steamboat
<br />Springs 7,onin~ ordinance does tlot provide
<br />for flood zone,. but it dots require that ~hp
<br />lol1owin~ be submitted to the Planning
<br />Commt.s;on for consideration if property
<br />proposed for conditional uses is located in
<br />wholeor;n part within a IOO.yearfloodplain.
<br />a. A flood plain report inc1uding n plot of
<br />thelOO-}"earfloodp\ain.
<br />b. Cro". sections of the stream channel.
<br />c. Flow projections,
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<br />d. The site reJ;rading plan.
<br />e. An evaluation of flooding effects on
<br />other property.
<br />f. The speeifieations for building coo-
<br />struetion and materials for nO<J(I proofing.
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<br />For Planning Commission eonsidc,'ation of
<br />petitions for rezoning propertyd~med sub.
<br />jecttoflood hazard. the ordinance reqllires
<br />the petitioner to submit the above informa-
<br />tionplustbcspedficationsforfilling.droog-
<br />ing. grading, channel improvement. storage
<br />of materials, water storage. and sanitary
<br />facilities.
<br />
<br />FUTURE FLOODS
<br />
<br />100- AND SOO-YEAR FLOODS
<br />The lOO-year flood is one with a peak flow
<br />ma"nitllde that has a 1 percent chance of
<br />being equalleci or e:<ceeded in any given year.
<br />and a freqllency ofo<:currenceo[aboutoncl'
<br />In 100 y'ears on the long-term avcrage.
<br />Similarl;'. the "OO':rear flood nas a O.~ JICr-
<br />cent chance of being equalled ore:<ce<>ded in
<br />an:r.':iven;'ear. and a frequency of Ol'cur.
<br />renceof about once in 500 years on the long-
<br />IOrrr, "-verage. As indicated earlier, the most
<br />se\'",',' floods in the stud;' area would re<lllt
<br />fro'n general rain on the tributary drainage
<br />ofthc Yampa River and froll1 convective type
<br />cloudburst storms on the drainage basins of
<br />the tributary creeks.
<br />TI..' unit hydroj('raph for the YampaHiver
<br />\\'asderivedbytheS-l\"raphmcthod.utilizing
<br />~n S-j('raph used to produ~~ a unit
<br />hydrograph for the Animas Rive" and
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<br />tribul.arie. at Dumngo. The j('enera\ moun.
<br />taio S-llTaph for Arizona. Colorado. Utah,
<br />aod Wyoming was used to produce unit
<br />hydrographsforthetribularyer<:<'ks,
<br />As previously noted. general rainstorms
<br />that generate mllJor floods in western
<br />Colorado usually occur during Sepl<lmber
<br />and Ootoner. On the basis of available
<br />pre<:ipitation records. a standard project
<br />storm' for the Yampa River Basin was
<br />dovcloped using a rlood-producing storm that
<br />occurred inSeptembcr 1970 in tho Four Cor-
<br />nero Area as a model. The Stt'amboat
<br />Springs 24-hour probable ma:<imum
<br />preeipitation is very similar to tnatofthe San
<br />Juan Mountains and tho Gnmd IIIesa area.
<br />Thorefore. a standard pI -ectstormcentered
<br />over the Grand Mesa locea cast of Grand
<br />Junction was developed "nd transp<l,ed to
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<br />'The "'''"' r..ulli"~ from tho '""'1..",.. ""mbin.lio" or,"e',,,,,,,I<>uioal<""dition, l"".ree,,",jd.,,,,d r....<onal,~
<br />,h.ra<t",;,,"< oftn'~",,~r.poio.l.re. i" "'oi," ..1".", b..i, i, 1"".,<'<1
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