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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 f10wrHilY be arJined to Cedar
<br />Creek cithlJrthrough inlets (three double inlets),then;;iped t()the
<br />stream (30" RCr ~t O.8:t) (Jl1 new install<lt ion), or throu~h J curb cu~
<br />(approximJtely 10 feet IQng) ~ith d surface swo1e d:rectifl~ the r,moff
<br />to the rlYer. ThesurfJceswalecQflfiguration\IOUldhov€tQlnCQr-
<br />porateerosioncontrol ll€dSUreS to ovoid futllreproblems.
<br />
<br />ProbleITI Areas 2 a~d 3
<br />
<br />Uneolll;)ahgre I\~enue to Montrose I\rroyo, The Cd~<lC Hy of :Ids pi pe is
<br />estimJtedd: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 4th StreH is re"wi r~d.
<br />A combined totdl of 4 ~e.... inlets are rlicolf."endli<i for locations G and 7:
<br />one edcll at tile SOIJth and east corners of So~th 4th d~d U'lcol";;ah~re
<br />^vl!~ue a~d SOljth 4th d~d Park A~enue. The flow interte~ted 1.>; tile
<br />,
<br />inlets would be drained by a ne'~ 27 irTch diiH"cter 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" s~uts between these prob1e~ \OCdt ions, if dl!s ired.
<br />Prob1emAreds8,9,10
<br />
<br />ProblemAreas2and3(LotAverTueatSouth2ndStreet, dndNeVdd<l
<br />A ~enue at South I st Street, res~ect i ve ly) ore caused by I oca 1 i zed SIJlllpS
<br />Ilhicll no not drai n. The sol uti O~ is to place inl e:s at each low spot,
<br />connectedto15"RCP'sleadingtoMontrosel\rroyo (all ne'linstal-
<br />latio1;-. The 5-yearflow 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)ldce<i ilt
<br />eJch,
<br />
<br />Problem Area 5
<br />
<br />Problelni\reds8,9, and 10 all share dCOII,nontributarjdreil and,
<br />because of existing local storm sewering, are best handled JS 0 ~nit.
<br />Problemdreas8and9are located on Mair. Street at Townsend Avenu eand
<br />Sel i g 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 quantitj for these
<br />three areas is90cfs (approxirnately 75 cfs tributuj at Areas 3 a n<i9
<br />andanadditiona120cfSJtArealO). 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, reacl11n-g
<br />Main Street duri ny e~ell a minor storm, such that add1t1 ana 1 1nlets
<br />along Milin Street would be inJde~ijate to intercept the floll at this
<br />location. Thernagnituaeoftheflowfora5-jcarstornllSUlfflcultto
<br />In"~age and dffects traffic at that ~ey locat ion.
<br />Several alternatives were exalllined for these drainaje iwoble::;
<br />areas. The reCO"lllended solution is as follo....s: The e~hting stor'"
<br />sewer syste,n in:.1ainStreet is a co",bination of 36 ir.chdlar;>eterJnd42
<br />inchdialileterpipe, with a capacitj far in exci'SS Oflihdt thesyste 'II'S
<br />inlets wi 11 ir.tercept. The reco"me~deo sol utio'l invul v'"s install at10n
<br />of a storm sewer along South 3rd $treet, trOlll Cascaoe r\ve~ue to k io
<br />Grande thence north to joi n the existing syste", at :1di n Street. Aloll~
<br />South 3rd Street, fruIII Cascade to Townsend, the sewer should b~ 27 inch
<br />dialTIetcrRCPandthe"":IlJinderbeing36inchdiallleterRCP, olllaida
<br />rr,inirllU~1 of 0.7% slupe, ~e\i double inlets should ~e provided Jt the
<br />sout I, ar.d east corners of South 3rd Street and Cascade I\~erl~c, a.,ie 11
<br />as South 3rd Street and Townsemi. II lIe~' double inlet sho,jld dts~ be
<br />provided at the NeSt COrner of Sel j ~ Aven~e a~d South 3rd Streel, . with
<br />a new s i ng1 e in 1 et bei n-g pro~ I <ied at the south corner. Tlw sue.,p areJ
<br /><It Rio Grande Avenue and South 3rd Street should Iwve 4 nCII 1~le,s iJro-
<br />vided along wittl 0 trashrJd, <lnd two f1eli inlets are 'lCede<l "t the
<br />South'lst Street, Rio Gra~de i\~e~ue intersection. Monhules .ho~td ~
<br />pro~ided at Nch street i~ter5ection, i~to whiCh the 1111 ets shOlJld
<br />dra I 11 ~; J a nell ,"i ni rlt(.'m size 15 i ncl1 d i d'netp.r RCP.
<br />
<br />ProblernArea4
<br />
<br />The prob 1 em of Area 4 is a sump condi t i O~, at the end of North ~ lid
<br />Street cul-dc-sac. The S.yeJr flow ~ellerated by the tributary atea is
<br />approx lJllate ly 1 cfs. Glle means of hand1 i ng the s i tuat i o~ i s ~rov~<1 i n~
<br />oClJrbcut (approxilnately 1-2 feet long) at the lo....sput, with as<Jr-
<br />face Sl/ale to carry drai na~e to Montrose ArTOYO. ,\1terndtel;" a ~in"l e
<br />i nll.'t could be placed at th~ 10" point, connect in~ to a 15. i rich
<br />dia<"eter RCP draining to the strealn (all new ;nsLlllalior,).
<br />
<br />Proolelll Areo 5 is a cul-oe-sac o~ 110rth Bln SLr'eeL ae l'iuIIL,'u,,,
<br />I\rroyo which does ~ot drain proller1y. The 5-year flo,,' generated by tile
<br />tributJrYdrea is5cfs and could be picked up by a ne"single inlel
<br />placed at the low point of the North 8tl1 Street cul-de-sac, AnelilS
<br />inclidiameterRCPwoIJldthencarrjthedrainJgeta:'.ontrase,\rroyo.
<br />"not her IlJea~s of h<lnd1 ing the I,robl em would be to pl del' new double or
<br />triple inlets at North 8th Street and Nevada Avenue, These inlets
<br />would intercept signifiCdnt runoff drilining norUllldrd on Ne~Jda, part
<br />of which present ly (lrains into the ,unp area 011 the ~ortiL Jtn Street
<br />cul~de-sac. These inlets would require <l new 24 indi djarilet'1r RCP, ilt
<br />O.:,~ slope, to drain to the Arroyo, A new SIngle lnlet at the 10", spot
<br />of the cul-de-~dc cunlled~d dh'ectly to this 24 inch pipe would J$SJre
<br />dra i l1a ~e of the SUint'.
<br />
<br />Problem Areas 6 and 7
<br />
<br />The proposed sys ~e," Wl 11 I nte< ~!:'pt the . odJor1tj of th~ 5.jCJr
<br />starlll r'ulloff quallt j tj, ,0 that tt,e IIIlpact of sucn fl u,,~ olt ' r[iu llll"
<br />ared, BoliO q 1S .redtly r'educ~d. .11e ~e"la'nll1~ "ul1off ~hic~ >io;j!d
<br />reach tl'Ese two proble" dn'Jas, th,,~, wQul d c()~5i st of J.'Ij llypaS~ fr();"
<br />
<br />?roulQH' drQaS 6 drTd 7 Jre locatell nn :,urth 4LI, Strellt, at P~r'~ ,md
<br />Ull~ol.,..ah!jre Avenues. respecti ve)y. There i, Jr. exis: ing storr;1 se,,~r
<br />(l~ 11Ch d'JI"eter dt 0.5\ s lope est.) d1 on!> ~Qrth 5th Stl"<,et. frOll'
<br />
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