This document discusses strategies for adapting the Netherlands' flood protection system to a changing climate. It outlines four climate change scenarios and their potential impacts, such as increased flood risks and saltwater intrusion affecting fresh water supply. Adaptation tipping points are identified, after which certain flood defenses may no longer adequately protect against risks. The document evaluates alternative adaptation strategies and considers flexible, robust, and open system approaches. It stresses the need for adaptive delta management that allows decisions and investments to be tailored based on how climate impacts and other factors actually unfold over time.

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Protecting The
Netherlands against
flooding in the future
Adaptation to a changing
climate
19-01-2011
Cees van de Guchte, Ad Jeuken,
Nadine Slootjes, Frans Klijn
Deltares

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Climate impacts in NL

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The Delta programme
“to protect our country from high water
and secure its freshwater supply,
for today and the future.”

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Characteristics
• Flood risks
highriver

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Deltaprogramma Rijnmond-
Drechtsteden5 24-7-20145
Characteristics: continuing growth of population
Deltaprogramma Rijnmond-Drechtsteden
20201980

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Deltaprogramma Rijnmond-
Drechtsteden6 24-7-20146
Characteristics: large unembanked areas
Deltaprogramma Rijnmond-Drechtsteden

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High potential damage in case of floods

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Kenmerken
• Protection against flooding with stormsurge barriers and dams
Haringvlietsluizen
Hartelkering
Maeslantkering Hollandsche IJsselkering

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Kenmerken
1:4.000
1:4.000
1:4.000 1:4.000
1:10.000
1:4.000
1:4.000
1:2.000
1:2.000
1:2.000
1:2.000
1:2.000
• Current protection standards (Waterwet)

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Salt intrusion
1894
1921
1947 1958 1965

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Deltaprogramma Rijnmond-
Drechtsteden11 24-7-201411
Safe
Delta
Economy
Unique
nature
Attractive to live
Characteristics
Deltaprogramma Rijnmond-Drechtsteden

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Deltaprogramma Rijnmond-
Drechtsteden12 24-7-201412
Relations between water and regional ambitions
Economy and mobility
Deltaprogramma Rijnmond-Drechtsteden
• Harbour and closing frequency of
storm surge barrier
• Greenports, agriculture and fresh
water supply
• Industry => fresh water supply
• Increase in transport volumes =>
over water?

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Deltaprogramma Rijnmond-
Drechtsteden13 24-7-201413
Scenarios
= Conceivable futures, not
≠ predicted
Deltascenarios:
– National-climate: KMNI 2006
– National-socio-economic: WLO
Regional specification
– harbour
– city
– rural areas
Future changes in climate, economy, population?
Deltaprogramma Rijnmond-Drechtsteden

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Four Delta Scenarios
moderate fast
low
high
Stoom
WarmRust
Vol
climate change
socio-economicdevelopment
Quiet
SteamFull
Warm

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Increase of waterlevels (and risks)

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Increase number of days closure fresh water
supply
Fresh water
supply at Gouda
0
20
40
60
80
100
120
140
160
180
Huidig G G+ W W+
= extreem droog jaar (1:100)
= droog jaar (1:10)
= matig droog jaar (1:5)
= gemiddeld jaar
0
20
40
60
80
100
120
140
160
180
0
20
40
60
80
100
120
140
160
180
Huidig G G+ W W+
= extreem droog jaar (1:100)
= droog jaar (1:10)
= matig droog jaar (1:5)
= gemiddeld jaar
= extreem droog jaar (1:100)
= droog jaar (1:10)
= matig droog jaar (1:5)
= gemiddeld jaar
Number of days of closure of
fresh water supply at Gouda
due to climate change
Current

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year with Veermanscenario2130211020902070205020302010
year with G-scenario2470240023202240216020852010
cm sea level rise1801501209060300
Large dike reinforcements necessary
Energy supply starts to fail due to limiting cooling capacity
Sand nourishment can not keep up with coastal erosion
Maeslant barrier is hampering shipping too much
Exceedance design criterium Maeslant barrier
The inlet Gouda too salt
Nature goals can not be met
Adaptation tipping points

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Example: delta program for the rivers

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Building strategies for adaptation
• as an answer to avoid negative impacts
• looking for opportunities
• as an alternative for the current (and past) strategy
• start with a broad view on solutions (possible, favourable, preferable)

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Flexible closure

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Robust closure

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Open system

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Open distributary (WWF)

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24 24 juli 2014
evaluation of alternative strategies
+ meest positieve, - meest negatieve effect
overstromingsrisico
hoekpunt binnend. buitend. zoetwater scheepvaart natuur kosten
verbeterd afsluitbaar
afsluitbaar open zee- en rivierzijde
gesloten zee- en rivierzijde + - -
gesloten zeezijde + +
open - - + -

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Cost benefit analysis
W+/GE (Steam)
W+/RC (Warm)

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timing of decisions and investments:
‘Adaptive delta management’
• design a strategy which is adaptive in itsself and ultimately is able to
meet the goals under a worst-case scenario
• may contain multiple possible pathways starting at one decision at
present
• measures can be accelerated or postponed, different paths can be
chosen depending on:
– the speed and magnitude of change
– other related planned investments / opportunities
• Delta Plan > Delta Decisions 2014
• Delta Act
• Delta Commissioner
• Delta Budget