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I I I I I I I I I I I I I I I I I I I V. IIYDRA[;L1C ~101)ELI:'iG RESULTS As discussed in Chapter 4. the methodology selected for the hydraulic modeling of the South Plane River included the use of the U.S. Anny Corps of Engineers' River Analysis System computer model (HEC.RAS Version 3.1.2). The two plans defined in the HEC-RAS model were used to evaluate hydraulic conditions associated with IOO-year (I-percent annual chance) flood and the I-foot rise tloodway. Summary output for both analyses is included in Appendix F.l. The CD enclosed with this report includes model input and complete output for both the floodplain and tloadway analyses. Results of the unencroached (i.e.. floodplain) analyses are summarized in the form of a tabular water surface profile provided in Table 5.1. The correlation of numbered cross sections in the hydraulic model to lettered cross sections sho\\TI on the graphical water surface profiles and in the tloodway data tables is included in Table 5.1. Graphical water surface profiles for the 100.year event. prepared in FIS fonnat. are included in Appendix G. Results of the I.foot tloodv..;ay analysis are summarized in Table 5.2, which provides a water surface profile comparison between the unencroached (i.e.. floodplain) and encroached (i.e.. floodway) conditions associated \\ith the 100.year event. Floodway results are also reHected in the Hoodway data tables. prepared in FIS fonnat. which arc included in Appendix F.2. Digital copies of the graphical flood profiles (in AutoCAD 2004 format). floodway data tables (in WORD format). and hydraulic model (HEC.RAS files) are provided on the CD included with this report. COCWCB03_Soulh Planc_repon.doc 17 A...dER'<'C" eo""dlhG E'Gi'HRSo, he.