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This alternative differs with Alternate 2 in that all :[lows north of the Hydraulic Ditch will be intercepted by a concrete open channel which would be constructed in the current canal location. The existing canal flows would be enclosed within a 72" RCP. This concrete ch.mnel would vary in size from 8 feet to 15 feet and transport this flow dircetly to the Abbey Channel. Tllis increase in flow in the Abbey Channel would need to be dctained within a new detcntion basin within the Abbey Channel. Since all flows north of the existing Hydraulic Ditch would be intcrcepted, only the area south of the canal would flow to SH 50. This flow could be intercepted by a 66" RCP stmm sewer and transported to the Arkansas River. The cost for this Alternate 3 is $4,695,000.00 E. Alternate 4 This alternative is also the same as Alternate 2 for the western draninage basin north of Pear Street. Once the flow reachcs Pear Street from tlle western and central portion of the drainage basin, a 60" RCP storm sewer will transport flows to Diamond A vcnue. For the central basin the proposed storm sewer along Central Avenue will continue west past Stage Coach A venue and then turn south through an easement witl1in an undevdoped area until it reaches a jum;don box at Pear Street. From Pear Street south to SH 50 a 72" RCP stonn sewer would be built to intercept about 60% of the flow. The remainder of the lOO-year flow would be contained within improved street sections down Orchard Avenue, Diamond Avenue and Cottonwood Avenue to SH 50. The total lOO-year flow would be intercepted by a 10 x 5 foot box culvert and transported to Ihe Arkansas rivcr. The flow from the eastern portion of the basin would continue flowing toward the Abbey Drainage Basin. The estimated cost for Alternate 4 is $2,918,000.00. F. Alternate 5 The improvements in this alternative are the same as those outlined in Alternate :3 eKcept that the flow would be intereepted by a system along Central A venue instead of the Hydraulic Ditch. The ncw Central Avenue trunk sewer would begin as a 60" RCP and increase in size to a 12 x :; foot box culvert when it outfalls into the Abbey Channel. The cost for this Alternate 5 is $3,281,000.00. G. Summary of Alternatives Several factors were used to evaluate the alternatives, these included: Cost, constructability, citizen feedback, and city input. As a result of tlle numerous meetings held with public and private individuals Alternate 4 was selected as the preferred alternative. It was .11:;0 recommendcd that Alternate 4 be modified to include the 16 acre - iCet detention basin along Field Drive to reduce flows into the Abbey Channel. Alternate 4 will require the disruption to only one residential street for construction. It also erosses SH 50 and the railroad in one location. A further reason for choosing this alternative is that the Fremont County Sanitary District can coordinate the construction of a new trunk sewer such that the new sanitary laterals would be placed. below the proposed 72" RCP :>Ioml sewer invert.