Expected impact of Climate Change on flooding in the Dender Basin. Results MSc thesis: Adaptive...
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Transcript of Expected impact of Climate Change on flooding in the Dender Basin. Results MSc thesis: Adaptive...
Expected impact of Climate Change on flooding in the Dender Basin.
Results MSc thesis: Adaptive measures to reduce climate change impacts on flood
probabilities.
Niels Van Steenbergen & Jeroen Verbelen
Expected impact of CC in Dender Basin
• 3 climate scenarios• CCI-HYDR Perturbation Tool• Perturbation factors • Composite hydrograms (T= 5, 10, 25, 100, 250)
Expected impact of CC in Dender Basin
• Conceptual model– Linear reservoir
– Calculation time 10² s
– Simplification
– Calibration
– Measures
• Hydrodyn. model– Saint Venant
– Calculation time 104 s
– Accurate
– Detailed
Expected impact of CC in Dender Basin
• Conceptual model of the upstream Dender basin
Expected impact of CC in Dender Basin
• Floodmapping of conceptual model– Method of fictive floodbranches
– Floodbranch in the lowest point
– Water height as boundary of the floodbranch
– Extrapolation of water height in polygon
Hw
d
HW
H (DEM)
Expected impact of CC in Dender Basin
• Simulation results (climate scenarios: red = low, orange = mean, green = high, blue = normal) (T=10)
Expected impact of CC in Dender Basin
• Simulation results (climate scenarios: red = low, orange = mean, green = high, blue = normal) (T=10)
Expected impact of CC in Dender Basin
• Simulation results (climate scenarios: red = low, orange = mean, green = high, blue = normal) (T=10)
Adaptation scenarios considered and the expected impact on flooding in the Dender basin.
Results MSc thesis: Adaptive measures to reduce climate change impacts on flood
probabilities.
Niels Van Steenbergen & Jeroen Verbelen
Adaptation Scenarios in Dender Basin
• Adaptation scenarios– Baseline scenario = Situation before the flood 2002-
2003
– Scenario 1 = dikes built in 2003
– Scenario 2 = scenario 1 + adapted weirs
– Scenario 3 = scenario 2 + flood control reservoirs• Marke + Molenbeek Zandbergen• Spatially concentrated• Assumption on filling and emptying
Adaptation Scenarios in Dender Basin
• Scenario 1: dikes– T = 25 year
– Climate Scenario = Mean
– Blue = Baseline
– Red = Scenario 1
Adaptation Scenarios in Dender Basin
• Scenario 2: weirs– T = 25 year
– Climate Scenario = Mean
– Red + Green = Scenario 1
– Green = Scenario 2
Adaptation Scenarios in Dender Basin
• Scenario 3: flood control reservoir– T = 25 year
– Climate Scenario = Mean
– Green + Orange = Scenario 2
– Orange = Scenario 3
Adaptation Scenarios in Dender Basin
• Other inundation parameters– Water rise rate
– Water velocity in floodplains Historical events
Adaptation Scenarios in Dender Basin
• Other inundation parameters– Rise rate (1995)
Adaptation Scenarios in Dender Basin
• Other inundation parameters– Water velocity in floodplains (2002-2003)
• Criterion : < 2 m/s
Adaptation Scenarios in Dender Basin
• Conclusions– Calculation time
– Measures• Dikes: most positive influence, but can cause
problems upstream• Weirs: positive influence, but can cause problems
downstream• Flood control reservoirs: small influence, but most
desirable measure Improvement of efficiency
- Other possible measure:- Lowering dikes in non-built area’s