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<br />Cross sections were renumbered to be consistent with the revised <br />stationing. The left bank, right bank and channel distance between <br />sections were adjusted. <br /> <br />For the 1989 SFH study three separate HEX:-2 lIDdels were used in <br />the lower reach below the Timnath Reservoir Inlet ditch diversion. <br />For this study, these models were combined into a single file named <br />LCWER for the l~-, 5lil- and l~~-year events. A separate file, <br />LOWER5~~, was created to model the 5~~-year event. <br /> <br />D::>wnstream fran Fort Collins' Waste Water Treatment plant Number <br />2, the flood plain was divided by the Burlington Northern Railroad <br />embankment. For the l~-, 5lil- and l~~-year flood events, only the area <br />of the right bank north and east of the railroad embankment was <br />considered effective for flow, although both sides of the embankment <br />were subject to inundation. To develop flood water surface elevations <br />on the landward side of the embankment a file, LOWFAIL, was developed <br />that considered the embankment failed and the full area of the flood <br />plain available for flow. This condition was the "worst case" for the <br />flood hazard on the south side of the embankment. <br /> <br />For the 5~~-year event, the split flow option was used to <br />calculate the flows overtopping the embankment. The split flow <br />routine from the 1989 study was modified to assume that the proposed <br />dike protecting Treatment Plant Number 2 was in place with no flow <br />through that area. The LOWFAIL file was used to develop the 5~~-year <br />flood elevations to the south of the railroad, assuming embankment <br />failure. <br /> <br />Two major flow divisions were retained in the lower reach of the <br />Cache La Poudre River model. Between cross sections 2~98~~ and 2lll~0 <br /> <br />6 <br /> <br />I . <br />