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<br />the j.iro~osed systelll, as well dS f10ws 'Jener.>ted by the "red bet\'een tile
<br />prOlJo,ed,tor",se\ler,ewersystelllolndtheproulerlloredS.
<br />.Also.reco"lllendedforinstdllatioIl1Sdne"singleinletdndne"
<br />15- 1 ne h d 1 dlllet er ReI' to dra i II th e 1 Ow spot at tile "out iI co rller of r~d i n
<br />Street and Townsend Avenue. This would dNin to the existin~ mdnhole
<br />at that corner.
<br />
<br />dnd the drdinage be carried in a new ditch to the Uncompahgre River.
<br />The ldrge pipe under the rdilway is reconTnen<le<l to accorror.odate le ss
<br />frequent storrll f1OVIS, as'o'/ell as runoff generated by future develop-
<br />ment.
<br />
<br />Problem Area 16
<br />
<br />Problemf,rN 11
<br />
<br />Problen) Arei; 16 (Highl and Street i;t Ridge Street) rC'l~ires provi-
<br />sion of proper urdinage to allevi~te the present sump condi~ ion. The
<br />5-year frequency runoff 'luant lty at thl s point is 4 cfs. It is recorn~
<br />",ended that ~ new single inlet be installed on tile south si de .of tILe
<br />street at the 10wspot,connectingtoa ncw15 inchdiarlleterRCP which
<br />woulddayl1ght in the alleysoutllwest of the problern area. The;lley
<br />would convey the flow to Montrose Arroyo. Alternately, ifease'.l€nt is
<br />a~~i1able,. a 3-foot curb cut and surface swale to the all ey would pro-
<br />vlde positlve dralnage. A crosspan from tile north to till! south side of
<br />the street at this problernarea would alleviate any sunpconditio nor.
<br />the north side of the street caused by the street crown.
<br />F. Recommendations - Preventative Measures
<br />The most important measure whiCh can be taken by the City and
<br />Cour"ltytopreventtheproliferationofdrainageproblernsthroughthe
<br />urban area is adoption and use of a cons istent integrated draina~e
<br />planandprogral",anddraillagestandards. '
<br />,it is recllIiTolended Uldt .a11 new developr,lent which is proposed be
<br />re'lulred to submlt to the Clty or County a drainage study fortileslt e
<br />which addresses rnanagement, consistent wi:h ~dopted standards of Roth
<br />runoff gener~ted within the site as well as th~l '~hidl cOII.es frOl" the
<br />~urrounding areas which impact the si te. 6uth tile 5~yedr dnd 10::J-year
<br />frE''1'H!ncy stornlS sho~ld be CXd,..ined., The study should be revie'"ed by
<br />the CIty or County am! appronl ncqulred prlor to issuance of building
<br />perlllits, sub<li vi sian pI at appro~a I, or a llowi ng connect i on to water
<br />and sewer ~ti 1 ities. Authority for such act ion is grdnted to co~nt ies
<br />by 1973 C.R.S. 30-28-133.
<br />
<br />Problem Area 11 is_located at Gr~nd rwenue near '~i 11 erup Avenue,
<br />and needs to have pOSIt lYe draJ nage provided. The 5~year rec~rrencc
<br />Interval rUlIoffquantityat this point is 7cfs. DrainClr.e<::ouldbe
<br />accol~lished either.bY a curb cut (approximately 5 feet iong), with d
<br />s~rface.swale drainlng Vlest to the Uncompahgre River, or by providhu a
<br />sln~le lnlet at the low poi nt cOllneoti ng to a 15 inch didJlleter RC~
<br />draining west to the river (all new installation).
<br />Problem Are~ 12, 13, 14, 15
<br />The recOllTllended solut ion for Probl ern Areas 12 13 14 and 1~
<br />involves handl ing all four ~reas as a unit. It is' rec~"lIlc~ded that the
<br />curb ~nd gutter be repl aced dt Problem dreCl 14 (Col ur.IDla <.ay at Brown
<br />Road) to assure pas it 1 ve dra 1 n~ge. The result I, dral nage rou~ed north
<br />and westward, transferring the draindge to Problem Areo 12 (Columbia
<br />WdYat SpruceOrive). The resu1tant 5-year flow at Area 12 then uould
<br />be 16 cfs. ~ recomllended double inlet at the 10" spot of An~a 12 woulO::
<br />1 ntercept thlS runoff dnd convey 1t in d new 21 inch di~,;;eter RCP to dn
<br />existing open ditch ~Iong Rio Grande Avenue.
<br />ProblerrrArea15 (Montrose Drive <lt Montrose Court) invol',cs inadc-
<br />q~ate sum~ lirai nage. The 5-year flow at this j.lOlnt is 11 cis, '~rlicll
<br />Wlll requlreanewdoubleinlet (orsingleoncaChSidC()tthc>treet\
<br />connecti ng to d ';ell 18 i nch di~meter RCP urai ni ng ..est to the ditch .
<br />a lon~ Ri 0 Grande A~enue. A1tern~tely, a curb cot (approximately b feet
<br />long) and surface swa I e to the R 1 0 Grande r\venue ~itch caul d pro~ i de
<br />posit i ve dr~indge frolli th~ low spot.
<br />
<br />Problem Area 13 is loc~ted at the lower end of Troy Court. The
<br />solution to tlw draindge problem recorif-If'mled for Pr<llller;j Area 13
<br />requires that anewcrosspanbc installed across Troy Court at South
<br />9th Street to dll o~' flows in that street to bypass Troy Court. At the
<br />10" end of Troy Court, a ~w single inlet connected to a nc..15 inch
<br />dlaoleterRCPor, if easement is available. d3-footcurbtutdnd sur-
<br />face swal e 1I0uld dra in the 5-y~ar frequency floll of 4 cf<;. Thi s flow
<br />would be carried west to the existin~ ditch alonS Rio Grande Aveoue.
<br />ThcexistingopenditchdlongRioGrdllueAvellueintowhichPrObl"l,I
<br />Arc~s 12, 13, 14. dM 15 are recomf,;endeu t~ dra; n should be c1 eJ"cu dnd
<br />shalled to carry the flow oorthwest to the jog ill tire rOddway ~t SOuth
<br />9~h Street. At ~his ;'>01 nt, it is recolllnended that a IlI<W larye pipe
<br />(I.e., 6Q !nth dlallleter RCP) l)e 1llst~l1ed untler the ,.J; 1 road trac.s
<br />,
<br />
<br />The City and County should adopt standards so thdt a conshtent
<br />level of protection is rrovided throughout the area. Hlese standar<ls
<br />5houl d consi der the numerous economic, regul ~tory and soci al im"dct
<br />type factors (see "Floodplain Del ineation~Recor""enJoltions~Preve~tdt i ve
<br />Meas,-,r".~ Flf)(}r1pl ai n ~.ano~pr;lentn, below).
<br />ReCOllTl1ende~ standards inc1uoe use of the street system to convey
<br />s torlll dr~ i nage, to the extent per~liss i b 1 e, accord i ng to T db 1 e V -6.
<br />~hen the indicated allowances Jre exceeded, storlll seweri ng, or cttler
<br />conveyancelfleans, should be provided for tlie exce,s.
<br />
<br />Where runoff 1s conveyed by gutter flows ~tn.l"S ~ street (1 .e., at
<br />an interscctlon, ?r in a cross pan). recomended all(}'Mole flow de,lths
<br />are "s ~et fo,.th 1 n T ~b 1 e '1.7.
<br />
<br />~2R-
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