Factoring Global Warming into Design Flood Estimation · Factoring Global Warming into Design Flood...
Transcript of Factoring Global Warming into Design Flood Estimation · Factoring Global Warming into Design Flood...
Factoring Global Warming into
Design Flood Estimation
Ashish Sharma and Conrad [email protected]
Water Research Centre, Civil and Environmental Engineering
UNSW, Sydney, AUSTRALIA
http://www.civeng.unsw.edu.au/staff/ashish.sharma
with help from Seth Westra, Fiona Johnson, Fitsum Woldemeskel, Raj Mehrotra and many more
AcknowledgementsAustralian Research Council
Australian Bureau of Meteorology
Where I am from
Current Scaling StudiesP
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Inte
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Temperature
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Time (hours)
Our StudyP
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Time (hours)
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Scaling of Fractions
Pre
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Time (1 hour)
Less Uniform Within Storm Patterns
Pre
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Spatial patterns
Spatial patterns
More concentrated with higher temperatures
Pre
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nsity
Flow routing
𝑑𝑆
𝑑𝑡= 𝐼 − 𝑄
With non-linear storage
𝑆 = 𝑘𝑄𝑚
And catchment size governed by
𝑡𝑐 = 0.76𝐴0.38
Impact on Flooding
m = 0.6, 0.7, 0.8, 0.9, 1
tc = 1, 2, 4 hours
A = 2, 12, 80 km2
For 5 degree increase
1 hour (2km2)
Antecedent Conditions
Antecedent Conditions
𝐴𝑃𝐼 = 𝐾𝑃𝑡−1 +⋯+ 𝐾𝑇𝑃𝑡−𝑇
[ K ]
Consistent
increase
Consistent
increase
Consistent
decrease
Antecedent Conditions
𝐴𝑃𝐼 = 𝐾𝑃𝑡−1 +⋯+ 𝐾𝑇𝑃𝑡−𝑇
[ K ]
Consistent
increase
Consistent
increase
Consistent
decrease
• Colder days = more uniform temporal/spatial patterns
• Warmer days = more non-uniform temporal/spatial patterns
• #Cold-days/#Warm days decreasing!
• Patterns becoming overall more non-uniform
Leads to flood increases in urban settings even without changing storm volume (intensity)
Added changes regionally due to changed antecedent conditions
May be countered by evaporation increases in large catchments – but urban floods will continue to increase!
Conclusions
Factoring Global Warming into
Design Flood Estimation
Ashish Sharma and Conrad [email protected]
Water Research Centre, Civil and Environmental Engineering
UNSW, Sydney, AUSTRALIA
http://www.civeng.unsw.edu.au/staff/ashish.sharma
with help from Seth Westra, Fiona Johnson, Fitsum Woldemeskel, Raj Mehrotra and many more
AcknowledgementsAustralian Research Council
Australian Bureau of Meteorology