08/05/2008

New Approaches for Flood Risk Management in the Netherlands 4th International Symposium on Flood DefenceToronto, Canada

2

Outline

Background on Flood Safety in the Netherlands

Policy DevelopmentsCausesDevelopmentsProcess

3

Flood protection is crucial for the Netherlands• 60% of the country is threatened

by floods

• 70% of the GNP (600 billion US$) is threatened by floods

• Large cities like Amsterdam and Rotterdam are below sea level

4

Defence system developed after disastersAfsluitdijk (1932)

5

The 1953 storm surge disaster

6

The 1953 storm surge disaster

The 1953 storm surge disaster (1800 casualties, 1800 sq. kms flooded) led to the Deltaplan, including:

Closure of estuaries

Safety standards onan economic basis

National dikeimprovement scheme

7

Present flood defence systemDunes

Levees and space for rivers

Dams and barriers

8

The Flood Protection Act (1996)

The Flood protection act dictates:

The safety standards per ‘dike ring’ area (freq. of exceeding of design water level)

The responsibilities of the parties involved

A 5-yearly safety assessment of all primary flood defences

Safety assessment & Design of flood is prescribed in guidelines

9

Causes for New Policy

2005: Policy EvaluationRisk of flooding has grownStandards are not up-to-dateSafety Standards are never fully compliedSafety Chain / Emergency Management Cycle is not used

Attention for Climate Change, urge to be prepared for future New Orleans was a eye-openerDevelopment of Risk-based techniques (FLORIS project)

10

Present Discussion about Flooding Risk in the NL

1950197020052010 (est.)

11

Process

“From the outside inwards”

In 2006 several meetings were organizedTechnical meetings about prevention, spatial measures, safety chain and cost-benefit analysis“Dike-Ring Meetings”, with cross section of stakeholders (not only water professionals)

Gathering of ideas for new policyIn 2007, the most promising ideas were further investigatedSpring 2008: concept of new policy is discussed with stakeholdersFall 2008: policy document

12

Main Elements in Future Policy

General:Risk Based Policy, meaning

Multi-layer safety principleStandards based on risk assessment

Robust, future based

Improvements for prevention systemRobustness in the 5-yearly safety assessment, take into account reinforcement period (20 year)Robustness in designing new flood defencesStep forward to safety standards in terms of probability of floodingReconsider safety standards based on CBA and acceptability of casualties (Individual Risk, Group Risk)

13

Main Elements in Future Policy (2)

Overflow-proof dikes or “superlevees”?Compartmentalization of larger dike-rings?

Improvements for “Reducing Consequences”Incorporate flood risk in “Water Test”Framework for climate-proof spatial planningProtect Vital functions (electricity, water supply etc.)note: still under debate…

Emergency ManagementTask Force Management of Flooding (TMO), improve emergency organization, exercise “Waterproof” end of 2008Keep emergency management organization Raise awareness of public and politicians for flood risk management

14

Challenges

Make probability of flooding work in practice: Guidelines for assessment and design based on probability, applicable for waterboardsDiscussion about height of safety standards

Requires lot of data (FLORIS, cost estimates, future scenario’sCombining economical, personal and group riskDifferentation of safety standards

Communicate change from old to new safety standards

Role of Water in Spatial planning

Balance between preventive and other measures

15

Timeline2008 Flood Safety policy document

fundamental changescomponents of new policyCourse CBA, financial impact, paper 105, session D

2009-2013 ImplementationNew standards based on CBA, estimates of casualties, societal discussionResults of VNK/FLORISInstrument for safety assessmentAdjustment Flood Protection ActSynchronisation with EU Guideline for Flood Risk Management

2013 Safety assessment according to new policy

16

Questions ??