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<br />cent to the stre""I. Once thesVeec is extend0d, the 5-yeor fre<juer.cy
<br />storm flow will Jmountto42cfs. This f10wIHilY be arained to Cedar
<br />Creek cithlJrthrough inlets (threedoub1einletsl.then;;ipedt()the
<br />stream (30" RCr ~t O.8:t) (all new instdll<lt ion). or throu~h a curb cu~
<br />(dpproximately 10 feet IQng) ~ith d surface swo1e d:rectifl~ the nnoff
<br />to the rlYer. The surface swale cOflfiguration\lOuld hov€to lncor-
<br />porateerosioncontrol Il€asures to ovoid futllreproblems.
<br />
<br />ProbleITI Areas 2 a~d 3
<br />
<br />U~eolll;Jahgre I\~enue to Montrose I\rroyo. The ca~<lC Hy of :Ids pi pe is
<br />estimatedd:only5cfs. The 5-year storll1 flow qu<<ntity <<t Meau and
<br />7 (combined) is approxilliately 25 cfs. ThuS, to ;Jro~;~e the 5-yClar
<br />I e~el of protection, a Il€W storm sewer in :~orth 4tn StreH is re"wi r~d.
<br />A combined totdl of 4 ~e.... inlets are rlicolf."endlid for locations G and 7:
<br />one edcll at tile sOIJth and east corners of So~th 4th d~d U'lcol";;alo~re
<br />^vl!~ue and SOljth 4th d~d Park A~enue. The fl ow i nterce~ted 1.>; tile
<br />,
<br />inlets would be drained by a ne'~ 27 j~ch diiH"eter Rep at 0.5% slope to
<br />Montrose Arroyo. Add it iond! in1 ets could be provided at other S~IIIJ.!S or
<br />10.... sJ.!ots between these prob1e~ \Otdt ions, if dl!s ired.
<br />Prob1emAreds8,9,10
<br />
<br />Problem Areas 2 and 3 (Lot AVe~ue at South 2nd Street, and NeVdd<l
<br />A ~enue at South I st Street, respect i ve ly) ore caused by I oca 1 i zed SIJlllpS
<br />Ilnicll no not drai n. The sol uti o~ is to place inl e:s at each low spot,
<br />connectedto15"RCP'sleadingtoMontrosel\rroyo (all nellinstal-
<br />latio1}. The 5-yeilrflow at Are<l2 is 7cfs, thus onlyooe inle:'....ou1d
<br />be required. More could be pro~ided if Imre than one spot does not
<br />drain. The 5-yeor runoff villueilt Area 3 is 12cfs, r.ecessitatingtllO
<br />inlets. If there are "l.Iltiple low spots, one inlet could be i)ldCed ilt
<br />each.
<br />
<br />Problem Area 5
<br />
<br />Problelni\reds8,9, and 10 all share d tQII,non tributary Jreil dna,
<br />because of existing local stormsewering,clrebest handled as o unit.
<br />Problell<dreas8and9are locdted on Main Street at TOIIllsenoAvenu eand
<br />Sel i 9 Avenue, respect i ~e 1y; whil e problem area 10 is located at Ri 0
<br />GrJnde A~enue at South 1st Street. The totd1 flow quantity for these
<br />three areas is90cfs (approxilnately 75 cfs tributary ilt Areas 3 a nd9
<br />andanadditiona120cfsatArealO). The present prob1eln is in,de-
<br />quate inlet C<lpacity into the existing large storrn SCller syste,n '_ "
<br />COlllpounding this problt~n is the lar~e <lccur.lulilted storm flow, r'"€dcl11 n-g
<br />Main Street duri n<J e~ell a minor storm, such that add1tl ona I lnlets
<br />along Milin Street would be inJde~ijate to intercept the flow at this
<br />location. Thernagnituaeoftheflowfora5-ycarstornllSUlfflcultto
<br />In"~age and dffects traffic at that ~ey locat ion.
<br />Several alternatives were exalllined for these drainaje iwoble::;
<br />Jreos. The reCO"lllended solution is dS follows: The existing stor'"
<br />sewer syste,n in Main Street is a cO"Ibination of 36 inchdlal;>et!.!rJnd42
<br />inchdialileterpipe, with a capacity far in exci'SS of Ii hat thesyste 'II'S
<br />inlets will intercept. The reco"mendeo solutio'l invulves installatl0n
<br />of a storm sewer along South 3rd $treet, trOlll Cascaoe r\ve~ue to k io
<br />Granoe thence north to joi n the existing syste", Jt :1ai n Street. Aloll~
<br />South 3rd Street, fruIII Cascade to Townsend, the sewer should b~ 27 inch
<br />diametcrRCPandther<':llainderbeing36inchdiallleterRCP, olllaida
<br />rr.inilllu~1 of 0.7% slul!~' ~e\i oouble inlet, shQulo ~e provided at the
<br />sout II ar.d east corners of South 3rd Street and Cascdde I\~ell~c, a.,ie 11
<br />as South 3rd Street ana Townsemi. II lIe~' double inlet sho,jlo also be
<br />provided at the east corner of Sel j ~ Aven~e a~d South 3rd Streel, . with
<br />a new single inlet bein-g prOVided at the south corner. Tlwsuc',pdroa
<br /><It Rio Grande Avenue dnd South 3ro Street should Iwve 4 nCII l~le,s iJro-
<br />vided along wiUI 0 trashrJd, <lnd two f1eli inlets are 'lCede<l "t the
<br />South'lst Street, Rio Gra~de i\ve~ue intersect ion. Monhules .ho~ld ~
<br />pro~ided at eilch street i~tersectioo, i~to whiCh the 101 ets shOlJld
<br />dra I 11 ~i J a nell ,"i oi IIt(."m size 15 i ncl1 d i a.netp.r RCP.
<br />
<br />ProblelnArea4
<br />
<br />The prob 1 em of Area 4 is a sump condi t i o~" at tho enO of North ~ lid
<br />Street cul-dc-sac. The S.year flow ~ellerated by tho tributdry ated is
<br />approx lJllate ly 1 cfs. Glle means of hand1 i ng tho s i tUJt i o~ i s ~rov~(! i n~
<br />oClJrbcut (approxilnately 1-2 feet lang) at the lo"sput, with as<Jr-
<br />fdCO Sllale to carry drai na~e to Montrose ArTOYO. "\1terndtel;" a ~in"l e
<br />i nl et could be p1<1ceo at the 10" point, connect in~ to a 15. i Ilcb
<br />dia<'Ieter RCP draining to the strealn (all new insLlllaliol').
<br />
<br />Proolelll Areo 5 is a cul-oe-sac o~ 110rth Bln SLr"eeL de foiuIlL,'u,,,
<br />I\rroyo which does ~ot drain proller1y. The 5-ycar flo,,' generated by tile
<br />tributary <lrea is5cfs and coultl be picked up by a ne"single inlel
<br />placedilttne low point of the North 8th Street cul-de-sac, AnelilS
<br />incl1diameterRCPwoIJlothencarrjthedrainJgeta:'.ontrasc.\rroyo.
<br />.,nother IllE'a~s of h<lnd1 ing the I,robl em would b~ to pl ace new double or
<br />triple inlets at North 8th Street and Nevada Avenue. These inlets
<br />wou1 d interce~t signifiCdnt runoff or. ining norUI\lilrd on Ne~Jda, part
<br />of which present Iy (lrdins into the ,unp dred on th~ ~ortiL Jtn Street
<br />cul~de-silc. These inlets would require <l new 24 indi djalilet'1r RCP, ilt
<br />O.:'~ slope, to drain to the Arroyo. A new SIngle lnlet at the le'" spot
<br />of the cul-de-~dc cunllect~d dj,"ectly to thi s 24 i nclo ~ipe would a$SJre
<br />dra i l1a ~e of the SUint'.
<br />
<br />Problem Areas 6 and 7
<br />
<br />The proposed syste,owl1l lnteoCt:'pt the>>dJor1tj of the S.jcar
<br />starlll r"ulloff "udllt j tj, so that tt.e llllpact of sucn fl u,,~ olt ' rou lei"
<br />d red, B 0'1(1 0 1 S .red t Iy .'educ..d. .Ile re"la' II 111~ ,'unoff ~hi c ~ .,O;I! d
<br />reach tl'ese two prob Ie" on'!as. tl1,,~. wou 1 d C()~S i s t of J.'Ij llypaS~ f r():"
<br />
<br />?rouleH' areilS 6 a~d 7 Jre 10Cdt~1l nn :,urth 4111 Street, dt P~I'~ ,md
<br />UnClll...'dhijreAvenues, respectively. There i, ar.cxis:ingstorr;lse"er
<br />(l~ lnch dlJI"eter Jt 0.5\ s lo~e est.) a1 on!> ~Qrth 5th Street, frOll'
<br />
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<br />
<br />-27-
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