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" " ~d into the Great ~stern Railroad pond. Water Is released through the railroad embankment to the Little Thompson River. Stage construction to accomodate financing is possible. The rn~te Is In~lrect though and esdiment- laden water allowed to pond in several placee will settle out. Also, the available head between the fire etation pond and the Thompson and Platte Ditch ie limited eo that lengthening the path between the two complicates the hydraulics by decreasing the available elope along each esqment of the route. Alternative 83 would route the flow from the fire statIon pond to the Greet Western Railroad pond under the North Josephine Avenue right-ot-way In a closed conduit the entIre length. The 72-inoh ~inforced concrete pipe would be designed as an inverted siphon, droppin~ from the fire station pond to ~ss completely under the Thompson and ~latte Ditch and ri8in~ to the surface again within the Great Western Railroad pond. Ths pond would drain through the railroad embankment to the Little Thompson River. The d1sadvantagen of Alternative B3 include the maintenance inherent to inverted siphons I 20,000 cubic feet of water will be trapped in the pipeline when the flow stopa. Public health and safety would necessitate the pumping of this water following a rainfall resulting in any significant runoff. Also, if the flow velocity in the conduit drops below two ips, s~diment will aettle out in the bottom of the pipeline. Significant accumulatione of eediment would have tabe re!ll<>ved to Mintain the design capacity of theoonduit. Il.lt..rn..Uv.. 84 ~'O"V"'r" flow wld..r~r<Hlnd llorthw....t out of th.. fin. at..tion pQnd under Hi~hway 60 to North Josephine Avenue aoross the Thompson and Platte Ditch and into the Great Western Railroad pond. The pond would drain through the railroad embank_nt to the Littl.. 'J;'hompeon Riv..r. This is th.....,atdirect overland route and the most hydraulically trouble free. This fourth option is slightly more expensive than Alternative 82 or 83, but ~s tn previously discus~~d redGh~a, the cost inoludes pdvin~ d stre~tl an expense that can be ,ustifiably removed from the drainage improvement economic analyeis if the town intends to pave all streets. North Josephine ~venue would need to be paved in order to reduoe flow resistance and oedimentation problero.e. The ....in acceSa to the ""bili! t\ome park fro", Kighway 60 via Josephine Avenu," would be eliminated, The cost to build the new one at North ~thleen Avenue is elso inclu~Ad in the coot estimate. Alternative BS wouid follow the same path out of the fire etation pond a8 Alternative 82. The flow would be directed west along the south aide of Highway 60 to the Thompson dnd Platte Ditoh then down the ditch to the Great Western Railroad pond. This final alternative provides a relatively simple and very inexpensive Dolution to the Highway 60 barrier. This oonoept as well as others, is contingent upon the cooperation of the Thompson and Platte Ditch Company. Adhadvantage of Alternative B5 is that a permanent pond as pre- sentlyexistswillbelocatedatthed1tcheouthofrlighway60. Alao,the hydra.ulice involved in draining the d1tch south of Highway 60 intoth.. Thompson and ~latte Ditch are critical and somewhat uncertain. Eastern Flow Path Both of the atructural alternatives for the Eastern Flow Path employ a detention pond south",eat of the Union pacific Ral1road8lnbankrnent. Botha.lso follow the same route north of Highway 60. The difference lies in the con_ nection bet",een the pond and the ditCh north of Highway 60. Alternative 2 routea the flow overland through a aeries of culverts and roadside ditches. Alternative 3 transmits the detention pond discharge underg]:'Qund in a storm sewsr. Both require raising the road surface of County ROad 23 to cover underlying culverts or storm sewers. Ditchee On both sides wouldbe...intaine,l. Alternative2i....lightlylessexpen..i"ethan Alternative 3. Recommended ~lternatives Based on previous discussion, the recommended ~lternativ"~ are as tallows. ~estern Plow Path - Alternative 4 Lola?arkTributary Reach A I\lternativeA4 l,ol..P..rkTribut..ry n"ach8 I\1ternative54 ~astern flow Path - Alternative 2 The alternatives involving paved streets were chosen because of the wide- ranging benefits they offer. Alternative 55 was e11minated becauee .. per- ~..n"nt pond w111 ~ createa and the hydraulics involvea are uncertain. The decision in the ~..stern Flow path was based strictly On eoonomics.