Faculty of Geosciences

River and delta morphodynamics

Land-level rise

in the Flemish-Dutch waterscape

Maarten G. Kleinhans

et al.

2

nu

Sea level

m +NAP

Holocene (10.000 yr)

Sea level rise

+land level fall

(and subsidence)

Slangen

3

NL Delta committee 2018

€

Main questionCan land level rise be as fast as sea level rise?

Reduce flood risk

Mariculture

Nature

4

DYNAMIC NATURAL SYSTEM

SUSTAINABLEECONOMICSFLOOD

PROTECTION

DELTA 3.0

5

peat

dikes→ingressions

Maps: Peter Vos

dikes→ingressions

But the Dutch made Holland

6(and did an Orwellian revision of history)

Land level rise in the Holocene

7

The land rosewaves+M4

mud+plants

peat

The land

drowned

dijk

hoog

Laag

heel laag

‘Verdronken’

Land van

Saeftinghe

1585 dikes breached

3 m in >300 yr

www.uu.nl/metronome

9

10

11

Water, sand, mud and plantsTbd this winter: 1000 yrs of sea level rise

The trick:

• Mud + multispecies

• M4 → net sand import

Steven Weisscher

Where?

12

WS

ED

OS

Walsoorden

talk by

Addink

To be tested in Groningen:

13

Pilots: Dubbele Dijk,

Polder Breebaart,

plan Groote Polder

Hedwige

First conclusionLand level rise may keep up with ≈1 cm / year

in double dikes, exchange polders

■ Nature

■ Saline agriculture, mariculture

Mud from sea, sand due to M4

Count your blessings: only in the Scheldt and the Ems

14

15

Effects of 5 m sea level rise in 2150?Sup€r dik€s

Salinity intrusion2

Tidal amplification @ Antwerp…

+ rising fast and furious!

16

no Paris.

Note: the Paris treaty is a compromise

17

18

Societal and governance challenge

Whose backyard is it anyway?

19

Good leaders plant trees for next generations

Awkward questions Iff Paris, then land level rise ≈ as fast as sea level rise

Plan B?

Plan C?

20

21

Plan C

evacuation Biesbosch (near Dordrecht) 1424

Dare to nightmare: plan BExpand Zeebrugge seawards?

Barrier before Antwerp?

Transition to live with/in water?

22

wet

ConclusionsLand level rise may keep up with 1 cm / year

in double dikes, exchange polders

■ Nature

■ Saline agriculture, mariculture

Count your blessings: only in the Scheldt and the Ems

Also needed:

Crystal ball watching & plans A+

■ Keep eye on sea level rise

■ Energy transition

■ Innovations in food production & other economic changes

■ Delta plan for biodiversity23

24

25

If we stick our heads in the sand

then our grand-children will need to get their heads out of the water

26©Carof-Beeldleveranciers in opdracht van Deltares

B) Beschermen openA) Beschermen gesloten

D) MeebewegenC) Zeewaarts

27

Netherlands science

Dollard history:

1100 dikes built

1277 ingressions

1509 green=estuary

1545-1900 re-embanked when +2m