Controlled flooding in the delta

Martijn van Staveren

PhD candidate @ Environmental Policy Group, Wageningen University

Visiting researcher to Stockholm Environmental Institute, 2015

4-9-2015

Outline

Why are we here & acknowledgements Introduction & objective of the presentation Into deltas – and trends in delta/flood management Topics for discussion Questions/discussion

Introduction: research project

Funding: NWO, carried out by Wageningen UR, UNESCO-IHE and partners working in the deltas Timeframe: 2012 – 2017 (0,8 fte) Domain: Environmental Policy Formal research objective: understanding socio-political

drivers of controlled flooding initiatives, and asses their potential contribution to building delta resilience Personal fascination: the ‘place’ of floods in delta

histories and futures/(un)controlled flooding Approach: STS (Science and Technology Studies)/policy Objective: present work and have a discussion about

three themes

Into deltas: opportunities and challenges

Flood management

Urbanization

Various interests

Climate change

Institutional complexity

(Dutch) hydraulic engineering

Four trends in delta/flood management policy

1. Ecosystem-based approaches to water/floods 2. Interest in ‘long term delta planning’ in delta flood

management 3. Flood dynamics restoration emerges in several deltas 4. New conceptualizations of deltas (topic for discussion)

Diving into controlled flooding: Understanding socio-political drivers of these initiatives, and asses their potential contribution to building delta resilience

Trend #1: Ecosystem-based approaches to water/floods

Concerns about environmental impact of engineering Driven by eco-’inspired’ engineers Mixed responses from ‘traditional’ engineering (+/-) Presented as innovation (but not always that new)

Trend #2: interest in ‘long term delta planning’ in delta flood management

Thinking in longer time scales (i.e. 100 years) To some extent parachuting Dutch delta planning

concepts in other context... Limited historical awareness (existing engineering

works/past plans) Who’s delta? Stakeholders, participation and decision-

making

Trend #3: Flood dynamics restoration emerges in several deltas

Restoring or preserving (tidal) flood dynamics Different drivers (e.g. top down ‘hydrocracy’ vs local

action) Social shaping of technology (design and ‘operations’) Place in and contribution to long term delta survival?

Case study example: de-poldering Noordwaard polder

Formulated under Room for the River project Lowering northern

embankments to take in water at a certain level (ca once per 10 years) Water flows through grass

land towards the estuary Contributing to fresh

water wetlands Some families moved out

(compensated), other stayed (houses on raised mounds)

De-poldering the Noordwaard in the Dutch delta

A large part of the Noordwaard polder will be reconnected to the adjacent river, to facilitate controlled flooding in times of high river discharge, thereby lowering peak water levels. Together with restored tidal dynamics, this contributes to the Biesbosch wetlands. Dikes will be removed or lowered to control flood water entering into the former agricultural area.Innovative hybrid-engineered dikeNear the Steurgat Fortress, a willow forest will be laid out in front of a section of the dike. This reduces flood waves and compensates for required dike reinforcements.

Flow-through zone

Intake

High water level

DORDRECHT

National Park de Biesbosch FIGURES

70km dikes50km new roads29 mounds38 bridges12 pumping stations4 million m3 of earth moving

WERKENDAM

Homes rebuilt on mounds

Flow-through zone

© Infographic: Loek Weijts Text: Martijn van Staveren

Topics for discussion

1. Conceptualizing deltas – as complex social-ecological systems, in which interaction is mediated via hydraulic engineering?

2. Dealing with flood management in deltas – e.g. a new perspective on sedimentation processes?

3. Building long term delta resilience with controlled flooding (and sedimentation)?

Trend #4 and discussion point #1: new attempts to conceptualize/define deltas

Deltas systems/river basins ‘development’ over time

Linear? Trajectories?

T-bana?

One type: deltas as social-ecological systems

Approach seems a good fit to environmental dynamics and social responses (i.e. interaction) to them in deltas, and brings in resilience thinking. But what about

● ... how this interaction actually takes shape in practice?

● ... the role of hydraulic engineering in shaping how deltas evolve towards the future?

(Conceptual) lessons can be learned from socio-technical systems research, which has delivered several studies on the hydraulic engineering works.

Socio-technical research on hydraulic engineering

Provides some ‘new’ concepts e.g. ● technological lock-in ● path dependency ● technological trajectories following technological (in this case

hydraulic) actions -> understanding the development of delta by means of delta trajectories

● (eco-)technological add-ons which offer some flexibility in hydraulic works’ operation or functioning

Existing hydraulic works act as ‘system attractors’ -> needs to be taken into account when talking about delta futures Historically informed analyses of technological systems Provides a basis to identify unsustainable or undesirable

system trajectories (partly a political endeavour)

Path dependency (storm surge barrier)

Oosterschelde storm surge barrier: 2 billion euros Paradigm: promised to provide

flood protection ‘forever’ following a large scale flood disaster in 1953 Lifespan 200 years Despite sluice gates,

environmental consequences, addressed as second order effects since TINA Removal ‘out of the question’

(Province/Ministry/society)

Technological lock-in (embankments)

Low embankments in the past (14th century) More attractive to heighten due to past investments and

earlier efforts, than to chose for other approaches. Also ‘mentally’. Century-long cycles of embankment heightening Difference river/land in some places up to 8 (!) meters

How to approach deltas (proposed)

As social-ecological systems, in which interaction is ‘mediated’ via hydraulic engineering. Social-ecological-technological system? Deltas develop over time dynamically, moving within a

range of relative ‘stability’ unless too little or too much water tips the system towards another regime Flood dynamics and sedimentation processes are

inherent to a ‘stable’ delta system Managing for change via (eco-)technological add-ons Argued in Van Staveren and van Tatenhove (in review

with Ecology&Society, to be resubmitted Sept 2015)

Discussion point #2: a new perspective on sedimentation processes?

In the Netherlands: controlled flooding in the Noordwaard de-poldering indicate tight control of both water flows and sediment processes In Bangladesh, tidal polders are filled up with sediment,

but not primarily to increase land height In other parts of the world (e.g. the Mekong delta coast,

Indonesia) mangroves are specifically planted to catch floating sediment particles for coastal improvement Therefore, some indicative/associated developments, but

not spot-on -> your experiences?

Discussion point #3: flood/delta resilience

Many definitions, etc Rockström et al (2014)’s

interpretation of system’s resilience:

1. Capacity to absorb disturbances/shocks

2. (learning) adaptability to stressors while maintaining a certain system state

3. Transformability after crossing threshold

But...

Discussion point #3: flood/delta resilience

Distinction between water/flood/delta resilience (resilience of delta inhabitants in the face of extreme floods) and delta resilience (resilience of the social-ecological delta in the face environmental (broader than floods!) dynamics) Water resilience (control - state - driving variable) Flood resilience (society resilient in the face of extreme

floods – which doesn’t necessarily preventing all floods). Short term small floods contribute to building long term flood resilience? Delta resilience. Integrity of the social-ecological delta

system, in providing delta/ecosystem services to humans.

Back to topics for discussion

1. Conceptualizing deltas – as complex social-ecological systems, in which interaction is mediated via hydraulic engineering?

2. Dealing with flood management in deltas – a new perspective on sedimentation processes?

3. Building long term delta resilience (for humans and the dynamic environmental of the delta) with controlled flooding (and sedimentation)?

Thank you for your time & attention!

More information:

www.wageningenur.nl/enp

martijnvanstaveren.blogspot.nl

Van Staveren M.F., Warner J.F., van Tatenhove J.P.M., Wester P. 2014. Let’s bring in the floods. Controlled flooding as a strategy for long term delta survival? Water International, http://dx.doi.org/10.1080/02508060.2014.957510.

Van Staveren M.F., van Tatenhove J.P.M. (in review with Ecology&Society, to be resubmitted Sept 2015). Deltas as social-ecological systems and the role of hydraulic engineering in (re-)shaping delta trajectories