Embed Size (px)
Citation preview
Mapping Future Hazards in South East London
Interpreting climate change modelsand predicting the impact of EWE’s
Dr Stephen [email protected]
SWERVE (Severe Weather Events Risk and Vulnerability Estimator)
SWERVE
UKCP09data
Pluvial flooding
Fluvial flooding
Tidal flooding
Heat wavesSubsidence
Water resources
Wind
• Aim to assess current and future hazards by looking at the baseline (1961-90) and the 2020s and 2050s.
• SWERVE only considered the medium emissions scenario.
The South East London Resilience Zone (SELRZ)
The challenge:
• Climate model output is provided at 25 km grid squares.
• UKCP09 weather generator provides outputs at 5km.
The challenge:
• UKCP09 provides many representations of future climate.
• This raises issues of:– Practicality– Usability
Probabilistic climate change scenarios
Risk of damage to buildings and pedestrians
Critical depth thresholds and a new hazard number index
Disruption to water supply
A 9-point vulnerability score
Photo copyright Kenneth Allen
Photo copyright Martin Speck
Photo copyright John Lindsay
Photo copyright Stephen Craven
Health related heat thresholds
Subsidence9 classes of combined vulnerability
10th percentile
90th percentile
50th percentile
2020s
BSL
VERY UNLIKELY TO BE LESS THAN
CENTRAL ESTIMATE VERY UNLIKELY TO
BE MORE THAN
Heat wavesHeat wave (5km) hazard
(32°C - 18°C - 32°C)
Vulnerability information
Risk maps
Hourly, 5km
15minute, 2km
Flooding
High
Low
Medium
UKCP09 sample applied to rainfall model and Urban Inundation Model
Max HN Baseline
9
Max HN 2050s
Water Resources
Rainfall series : baseline, 2020s and 2050s
Associated river flows
Environment Agency’s London Water Resource Zone model (AQUATOR).
Level of service
Action
1(1 in 5 y)
Media campaigns, additional water efficiency activities
2(1 in 10y)
Enhanced media campaign, customer choice/voluntary constraint, sprinkler ban
3(1 in 20y)
Hosepipe ban, non-essential use ban, drought order
4(never)
Severe water rationing e.g. rota cuts, stand pipes
Future demand saving day levels(climate change only)
Total demand saving days: 2050s(climate change & demand)
BASELINE LOW CENTRAL HIGH0
0.4
0.8
1.2
1.6
2
Num
ber o
f pot
entia
lly d
amag
ing
even
ts p
er y
ear
Damaging winds
Baseline
‘Low’ climate projection
‘High’ climate projection
‘Central estimate’ climate projection
• Future heat wave risk is greatest in high-density residential areas in the centre and the east of London.
• 2020s and 2050s see localised increased flooding hazard when compared with the baseline.
• Increased subsidence vulnerability in Croydon and North Downs.
• A combination of demand management and new water supply options need to be considered for the Thames.
Headlines
