Human-induced subsidence
in urbanizing deltas and coastal zones
Policy brief and Sinking Cities II brochure
Cees van de Guchte & Kim van Nieuwaal

Workshop Japan and the Netherlands
Climate Adaptation and Resilience
Tokyo, Japan - 31 October 2019

Nikkei Shimbun, 22 October 2019

Johannis de Rijke, Colijnsplaat

Tokyo Metropolitan Government delegation in Dordrecht (NL), Sept. 2019

Delta Alliance Countries

Delta Alliance & Delta Coalition

Bridging the gap for deltas
Policy network

Knowledge network

Delta Alliance is active participating organization of the Global Center on Adaptation

Available in december 2019 also: Assessment reporton Ouémé Delta (Benin) and Volta Delta (Ghana)Collaboration on subsidence between Coalition and AllianceHuman-induced land subsidence is a big challenge worldwide
especially in low-laying urbanizing deltas and coastal zones•••

6-100 mm/year, while global
mean SLR is around 3 mm/yrDamage is totalling billions ofdollars per year
Impacts are further exacerbatedby climate change (extreme
events + SLR)
Policy brief• Describes the challenges and the actionable approaches to counteract
human-induced land subsidence• Recommendations are made on policy and governance, technology,
capacity building and financing aspects
Sinking Cities II brochure (supporting the policy brief)• Step-by-step approach illustrated by real life example cases

Policy brief
Policy and governance aspects of subsidence••••

Subsidence is not mentioned in the global agendas and often also notaddressed in national or local policy agendas
Subsidence is often a ‘hidden’ policy issue, not fully recognized oracknowledged
In many subsidence prone areas there is no comprehensive subsidence
strategy and approach, no multi-sectoral cooperation, no legal framework nor
specific instruments, which hampers setting of clear policy targets andimplementation of measures to mitigate subsidence
An organisational structure with clear roles and responsibilities regarding
subsidence issues is often non-existent or not sufficient, thus undermining
planning and action

Policy brief
Comprehensive approach towards solutions
Integrated framework and stepwise approach (6 steps) addressing most relevant
aspects of subsidence, incorporating technical as well as governance aspects

Policy brief
Recommendations
Technology•••

Knowledge agendas and collaborative research on subsidence
Systematic monitoring
Artificial groundwater recharge

Policy and governance•••

Clear policy framework and appropriate legislation on subsidence
Multi-sectoral cooperation, joint policy development, coordination and participation
Future proof decisions enabled by evidence-based decision support models and tools

Capacity building•••

Awareness raising and need assessments on subsidence knowledge
Training programs, workshops, seminars and conferences
Community of practice on subsidence mitigation (from planning to implementation)

Finance•••

Assessments of main financial risks and costs/benefits
Financing mechanisms and innovative financial instruments
Integrated economic assessment framework for land subsidenceSinking Cities II brochure
A step-by-step approach to address land subsidence in urbanisingdeltas••

Illustrated by real life example cases
Lessons learned and recommendations for each step

Step 1. Measuring subsidence (example case Ganges–Brahmaputra–Meghna delta andDhaka, Bangladesh)
Step 2. Understanding subsidence Mechanisms (example case Jakarta, Indonesia)
Step 3. Modelling land subsidence (example case the Mekong Delta, Vietnam)
Step 4. Measures - Cost-benefit analysis and decision support (example case Gouda, TheNetherlands)
Step 5 Implementation of measures (example case Bangkok)
Step 6. Monitoring and evaluation of land subsidence (example case Shanghai, PRC)

Subsidence in Dutch national Climate Effect Atlas

Two dominant frames (cf. De Boer & Wardekker, 2010)

Risk Avoidance“To prevent damage and climate
risks to society”

Opportunity“To realize resilient, sustainable
and innovative businesses andcities”

Two dominant frames
Risk Avoidance

Opportunities

Reductionistic

Integrated holistic

Technical engineering (controllingthe water)

Systems approach (using nature,living with water)

Quantification of risks anduncertainties

Creating support through designand visualization

Are measures cost effective?

Is there support for measures? Can
they be financed?

Minimizing risks

Maximizing opportunities,
value creation

Delta Commisson 2008

“The threat is not acute, but measures toimprove flood risk management and fresh
water supply should be prepared urgently.”

Delta Programme

One Aim:• Keeping NL a good, safe and attractive place to live and workfor present and future generations ( 2100, long termperspective)
Two Goals:• Safe, now and in the future (2050-2100)• Fresh water supply guaranteed, also in dry periods
Three Basic values:• Solidarity, Flexibility and Sustainability
Not in answer to a disaster, but in advance, to be prepared or
avoid itSome lessons learned• Establish the network on the ground, with those that do theactual work. Make them feel part of the family• Make the connection with identity and let others shine• A frontperson that is both powerful (stay in control) andaccessible (make connections)• Secure the funds• It’s not just threats, it’s above all about opportunities• Secure the knowledge base and work interdisciplinary• Be innovative / flexible in organizing (e.g. collaboration with NAS)

National Adaptation Strategyof The Netherlands

NAS NL: effects sea level riseNAS NL: effects wetter

NAS NL: effects warmer

NAS NL: effects drier

The Dutch delta

The Dutch delta works

Paradigm shift: room for the river

The DutchWadden Sea
Western part of theUNESCO World
Heritage Site, withAfsluitdijk visible atthe bottom

The Dutch
Wadden Sea
Fish Migration River

Building theclimate
adaptation
services chain
in Bangladesh(CAS work inprogress)

Thank you. Let’s work on our
beautiful deltas together!
www.delta-alliance.org