Seite - 356 - in Book of Full Papers - Symposium Hydro Engineering

Table 4. Sensitive analysis of height increment of sand bars in the tributaries (unit: m) Influencing factors -20% -10% -5% +5% +10% +20% Outflow discharge -0.107 -0.052 -0.026 0.025 0.049 0.095 Sediment concentration -0.107 -0.052 -0.026 0.025 0.049 0.095 Relative width in the river mouth 0.028 0.013 0.006 -0.006 -0.012 -0.023 Distance from the front of delta -0.252 -0.126 -0.063 0.063 0.126 0.252 Distance from the river mouth 0.315 0.140 0.066 -0.060 -0.114 -0.210 (Note: the mathematic meaning of the sensitive analysis table is: the change for one single factor causes the change of the dependent variable. For example, if the outflow discharge decreases by 20%, then the height of the sand bar will decrease 0.107m). Table 5. Sensitive analysis of annual sedimentation quantity in the tributaries (unit: ×106m3) Influencing factors -20% -10% -5% +5% +10% +20% Outflow discharge -3.334 -1.704 -0.861 0.878 1.774 3.613 Grain size of bed material load 1.467 0.672 0.323 -0.299 -0.578 -1.083 Relative width in the river mouth -0.805 -0.387 -0.190 0.183 0.360 0.699 Distance from the front of delta -1.797 -0.883 -0.438 0.432 0.857 1.692 Distance from the river mouth 2.101 0.951 0.454 -0.417 -0.802 -1.489 Gradient in the main channel -0.805 -0.387 -0.190 0.183 0.360 0.699 Given from Table 4 and Table 5, some conclusions can be obtained: (1) For the height increment of sand bars in the tributaries, the sensitive order is: Distance from the river mouth to the dam> Distance from the front of delta to the dam> Outflow discharge= Sediment concentration> Relative width in the river mouth; (2) For the annual sedimentation quantity in the tributaries, the sensitive order is: Outflow discharge> Distance from the front of delta to the dam>Grain size of bed material load> Gradient in the main channel= Relative width in the river mouth. 356