Water management solutions for land subsidence, consequences for land use and costs Panel session “How to deal with subsidence in deltas”
LANDac’s Annual International Conference 2017, Utrecht
Simon Troost, 29-6-2017
Choices in Holland
• Living with ‘dry feet’ (= subsidence)
• NOT Living in a swamp (= no subsidence)
2/ 20
• Produce milk and cheese (= subsidence)
• NOT wet agriculture in a peat area (= no subsidence)
Why these choices? • We have the technics
• We need the space
• It’s difficult to change
3/ 20
It’s difficult to leave a historical trail
Consequences
1. Technical problems caused by differences in subsidence.
2. Increase of costs
3. Emission of greenhouse gases
4/ 20
Solutions
Subsidence, Let it go Subsidence, Decrease Subsidence, Decrease/stop
Under water drainage High water level and transition land use
Decrease of subsidence
No scenario will stop subsidence
6/ 20
Current policy 50 – 150 cm until 2100
Maximum decrease 20 – 80 cm until 2100
Costs and benefits
7/ 20
Costs Benefits
Cost benefit analysis
Using RE:PEAT for cost benefit analyse
Consequences
8/ 20
Effect relative to current situation
Conclusion: go for a transition
Sub
sid
ence
Let
it g
o
Sub
sid
ence
Dec
reas
e
Sub
sid
ence
Sto
p/
dec
reas
e
Cost watermanagement - 0/+ 0
Cost infrastrucuture 0 + ++
Cost buildings 0 + ++
Effect nature - - ++
Agriculture 0 ++ --
Emission greenhouse gas 0 0/+ ++
Total 0 + +