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<br />. <br /> <br />. <br /> <br />. <br /> <br />Appendix B contains the HEC-2 printouts for the existing conditions <br />model run. <br /> <br />It is important to note that the flow regime of the north channel <br />at County Road 21 was determined by HEC-2 to be super-critical - M3 <br />water surface profile - due to the steep slope of the channel <br />invert. Under actual flow conditions the flow regime at this <br />location would most likely be sub-critical due to trash collecting <br />on the up-stream side of the county bridge. The actual flow regime <br />was estimated from high water elevations from the 1989 flood. <br /> <br />III. Alternatives <br /> <br />In order to reduce the impact of flooding on the town of Paoli, <br />three alternatives were modelled. Alternative #1 consists of the <br />construction of a new Highway 6 bridge, B&N R.R. trestle and County <br />Road 21 bridge. Alternative #2 consists of the existing Highway 6 <br />bridge and R.R. trestle but with increased water way flow areas <br />under these structures resulting from excavation under each <br />structure. Alternative #2 also consists of a new bridge on County <br />Road 21. Both alternatives include major channel excavation from <br />County Road 19 to County Road 23 in the main channel (the Upper and <br />Northern channels). Alternative #2 also consists of major <br />excavation south of the rail road tracks on County Road 21 (cross <br />sections 5 and 6) to provide a spillway to divert flood flows to <br />the south of the town. Alternative #3 was essentially modelled <br />identical to Alternative #2 with the exception of the reach between <br />cross sections 3 and 4 was not excavated. <br /> <br />A. Alternative #1 <br /> <br />In order to model this alternative, ground surface profiles were <br /> <br />Paoli Flood study <br />September 29, 1991 <br /> <br />Hydraulic Analysis Report <br /> <br />-7- <br />