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)

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• 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 + +

Discussion

Transition will be supported by:

1. Stakeholders with benefits (agriculture and real estate developers) paying the costs of subsidence

2. Carbon Credits can be used to pay transition

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