Dr. ir. Frans H.M. van de VenTU Delft / Deltares
Water robust urban development
Contents
• “Houston, we have a problem…”• Scope• Three-steps approach• Who is to take action• When to select measures• Conclusions
Our delta shows ongoing urbanization
200519701900
in particular in the lowest parts…
> 4 m - MSL
2 to 4 m - MSL
0 to 2 m - MSL
0 to 5 m+MSL
5 to 10 m+MSL
> 10 m+MSL
Rotterdam
Amsterdam
while the landsubsides,the sea level rises…
and climate is changing.Climate scenario’s (KNMI, 2006)
+10% +27% +5% +13% daily rainfall (T=10 yr)
+15% +7% +8% +3% evapotranspiration
-19% +6% -10% +3% average precipitation
Summer
+14% +7% +7% +4% average precipitation
Winter
NoYesYesNoChanging West circulation
W+ W G+ G 2050
Our responses
• [Reduce climate change]• [Improve predictions]• Strengthen our protection• Adapt our living environment• …
Water robust cities
Water robust cities (WRC):Urban areas (re)developed in such a way, that they are able to cope with a more extreme - water surplus or - shortage of water and - heat
Scope of WRC
• All water stresses: Flooding, drought & heat• New developments and existing urban areas• Buildings and public space• Technology, process, legislation and practiceTo identify appropriate measures, taking into
account– Types of water stress …– Types of vulnerability …
Measures we could take
> 100 measures identified…..• Collective ‘soft’ measures
e.g. contingency plans, building legislation
• Collective ‘hard’ measurese.g. dikes, drainage systems
• Individual ‘soft’ measurese.g. increasing water risk consciousness, insurances
• Individual ‘hard’ measurese.g. building without crawl space, wet or dry proofing
Our problem: how to select?
Our solution:
Three-step approach • Step 1: Completing a vulnerability-analysis• Step 2: Strategy to reduce vulnerability• Step 3: Selecting
appropriate measures
1. Vulnerability-analysis
Type of water stress
subsoil
network
occupation
Analysis of the subsoil / soil / water / urban design systemunder the influence of climate change
Based on the 3-layer approach to spatial planning
2. Strategy to reduce vulnerability
Four capacities to reduce vulnerability1:
• Damage prevention = threshold capacity• Damage reduction = coping capacity• Damage reaction = recovery capacity• Damage anticipation = adaptive capacity
1 Graaf, R. de, N. van de Giesen and F. van de Ven, 2007, Alternative water management options to reduce vulnerability for climate change in the Netherlands, Natural Hazards nov.
3. Selecting appropriate measures
Selection depends on:
• Results vulnerability analysis• Strategy to reduce this vulnerability• Available ‘hard’ and ‘soft’ measures
3. WRD measures selection
3. Recovery capacityExtra pumping capacityCleaning & drying capacityWater supplying capacity in extremely dry periods
Et cetera
4. Adaptive capacityTemporary houses & buildingsAdaptive management Water-based spatial planningRegular updates water & spacepolicies
2. Coping capacityMajor drainage sytem; adapted streetprofileWet proofingWarm grass instead cold grasses
Et cetera
1. Threshold capacityWaterrobust infrastructureEnlarged seasonal storagecapacityHigh floor level vs street levelFloating housing
Et cetera
Measures to strengthen …
3. Selecting appropriate measures
Selection depends on:
• Results vulnerability analysis• Strategy to reduce this vulnerability• Available ‘hard’ and ‘soft’ measures• The stakeholders (!!)
Who are the stakeholders?
Public• State • Province• Municipality• Water board
Private• Owner-occupier• Real estate developers
• Housing associations• Waterworks
• Electricity companies• Telecom companies
• Insurance companies• Mortgage banks
Note: Different parties involved in each phase of a (re)development process !
When to select measures
Depends on the phase of development: • Planning • Design• Building• Maintenance
When to select ?= when to apply this three-step approach
1. Spatial planning phase : Select strategy and principal WRD solutions in spat ial plans
2. Spatial developmenta. Initiative: embracing the idea of a WRDb. Draft designs: select water robust measures (spatial water strategy)
3. Feasibility study : market analysis
4. Design, planning, preparation, costs, permits .a. Developing the plan
1. Contracts2. Commitment
b. Urban design: final selection of measures
5. Building processa. Engineering/preparation technical design of selected measuresb. Building site preparation: realization of water robust solutionsc. Constructiond. Completion
6. Maintenancea. Property-, asset- en portfolio management Select water robust maintenance measuresb. Keep up operational rescue capacity, …
Spatial planning phase
Planning & design phase
- At transfer- Corrective measures
In conclusion
• No best, no most robust solution; • Selection of appropriate measures is a
negotiation process– Vulnerability analysis– Strategy to reduce vulnerability
Making water robust cities is challenge,but it is
feasible and affordable
Steering committee:
-consortium thanks
+ Advisory board WRC:
More informationMore information:
www.bouwrijp.nlwww.wrm.tudelft.nl
> Research > Transitions SUW