Revision as of 16:36, 12 December 2017 view source Mitch3007 (talk \| contribs) Bureaucrats, Administrators 1,585 edits →Sensitivity Creek Manning's n Test (Scenario 100ft n0.1) ← Older edit		Revision as of 16:37, 12 December 2017 view source Mitch3007 (talk \| contribs) Bureaucrats, Administrators 1,585 edits →Sensitivity Creek Manning's n Test (Scenario 100ft n0.1) Newer edit →
Line 89: As discussed in the Manning’s n table above, the main creek n value of 0.20 is considered very high, especially in the lower reaches of the study area. A sensitivity analysis was carried out by lowering all the Manning’s n values in the main channel (modeled as 1D cross-sections) to 0.10. The image below shows the flood depths and extent of this sensitivity case. The image below shows the flood depths and extent of this sensitivity case. Of particular interest is that reducing the n value to 0.1 has a significant effect on the arrival time of the flood waters at the model outlet (much earlier), and reduces the volume of water flowing onto the floodplain by around 20% due to the higher conveyance of the creek. Also of interest is that for the n=0.2 scenario, some overbank floodwaters return to the main creek near the model outlet causing a delayed second rise in the outlet flow hydrographs as illustrated in the chart further below. This effect does not occur for the n=0.1 scenario, with all overbank floodwaters remaining on the floodplain.▼ [[File:FMA3_4.jpg\|600px]]<br>▼ ▲~~The image below shows the flood depths and extent of this sensitivity case.~~ Of particular interest is that reducing the n value to 0.1 has a significant effect on the arrival time of the flood waters at the model outlet (much earlier), and reduces the volume of water flowing onto the floodplain by around 20% due to the higher conveyance of the creek. Also of interest is that for the n=0.2 scenario, some overbank floodwaters return to the main creek near the model outlet causing a delayed second rise in the outlet flow hydrographs as illustrated in the chart further below. This effect does not occur for the n=0.1 scenario, with all overbank floodwaters remaining on the floodplain.<br> ▲[[File:FMA3_4.jpg\|600px]]

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