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% ;; Reach'" Alternative ...2 for Reach A of the Lola Park Tributary (figure 22) ell~l- nates flooding in the central part of Milliken by intercepting runoff 1n a diversion channel routed to the ~9tern Flow Path. The channel would skirt the Bouth ed~ of town e~tendlng from just weat of Joeephine Avenue to just west of Dorothy Avenue where runoff would be diBcharged into the Eastern flow Path detention pond. The pond would be enlarged to Ilcaomod4te the additional flood water from Lola Park. ReachB The downstream reach of th" IJ:>h P'Irk Tributary include" the High""y 60 and Great Western Railroad ~",bankment9. Adequate space for detention pending Alternative A3 WOuld involve transmitting runoff from Lola park to the tire atation pond beneath Josephine Avenue in a storm sewer (Figure 23). Lola park would be recontoured into a detention/sedimentation pond which would drain through a 48-inch reinforced concrete pipe to join the 54-inch reinforced ooncrete sto~ sewer enroute to the fire station pond. Alternative A4 would route the design discharge down Irene and Josephine Avenues as designed in the street improvement plan (Figure 24). A diversion at the eouth end of Lola p,.rkwould divide flow between Josephine Avenu.. a nd Lola park as part of the street Lnprov<llll.entplan toaccomodate the 10-year discharge. The e~isting syetem of culverts and open chennels running from the park to the fire station pond bet~een Irene and Josephine Avenues would be improved to eccomodate the 2-year diScharge. The intersection of Irene Avenue and rorest Street would be lowered as part of the ~treet plan eo that Lola park flow in excess of the 2-year diecharge would cpill onto Irene Avenue. BoUl streets would be lowered to safely pass the design discharge below adja- cent house levels. Forest and Eim Streets just east of Josephine Avenue would he qraded to an elevation Ailch that if oonsiderably more th8n h8lf of the rleeign_di~charge ~ts onto Josephine Avenue, the excess can divert to .rene Ave"ue and thereby _i..t..in roughly a 50-50 loadtng of floo~ waters down M_ch street. I I , , , I , is not available south of Highway 60 so the d1scharge must he rol1tedthro ugh this barrier unrestricted. All structural alternatives require modification of the fire station pond. velocities for all of the Reach A alternatives would be sufficient to keep sediment from entering town in suspension. Since adequ8te space is not available for sediment storage in the fire station pond, velocities in the pondlllUst be kept ahove twofps. Alllocollll'llOntothelltruc - tural alternatives is the detention pond hetwe..n the Thompeon and Platte Oitch and the Great Westarn Railroad embankment, two 54-inch reinforced concrete culverts through the embankment, and improvement of the drainaqe channel north of the ealbankment to the Little Thompson ltiv'sr. Alternative a2 would route the water west from the fire station pond along Highway 60 to the Laura Avenue right-of_ay, then north to the Great Western Railroad pOnd (Figure 22). Four 42-inch reinforced ooncrete culverts would tr8nsmit flow under Josephine Avenue and Broad Street from the fire sta- tion pon~ to an improved ditch along the south edge of the High~ay 60 right- of-way. At the Laura Avenue right-of-way, three 48-inch reinforced concrete culverts would direct the flow north under Highway 60 and into a shallow swale whichW<,luld carry the discharge on to Th<>mpson and Platte Ditch within th e Laura Av~n~ ri4ht-~f-w..y. i\lte>::native a3 \fOuld route the Uow from the fire station pond to the Gre"t Western Railroad pOnd under the North Josephine Avenue right-of-~ay in a closed conduit the entire length (Figure 23). The 72-inch reinforced concrete pipe (Rep) would be designed as an inverted siphon. dropping from the fire staticn pond to pess completely under the Thompson and Platte Ditch and rising- :::n Ir~u" ;'''''''''''' bLu>::.. "..L"r "",uld drain to a low spot t>etw..en Ule new fire station and old fire station where it woul~ spill into a swale lesding west to the fire st,.tion pond. The low point of Josephine Avenue would be located just southwest of the pond wher.. ~ater would b@ directed into the pOnd. o..t&1h of t~e street de_qtqns are given in plates 5. 1~. ..n<! 13 of Chspter n entitled ~Str"et Improvement Pl"n". to th" surfdcs dg'l1n within the Gre"tw.."tern Railr<><ldpond. Alternative B4 would direct the design discharg.. straight down t~.. ~nrth Josephine Avenue ri1ht-of-way to the Great Western Railroad pond (Figurs 24). Two 43-inch by 6a-inch horizontal elliptical >::einforced concrete culverts would lead north out of the firs station pond under Highway 60 to the North Josephtne Avenuo right-of-way. ~orth Josephine Avenue would become a cul-de- sac unrl..,. this plan ~ith ,"ccess tc Highway 60 from the south, built at ~orth Kathleen Avenue. The cul-de-sac would be -v" shaped in cross section and