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
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