City of Dordrecht and Water Board Hollandse Delta
Province South Holland; Safety Region South Holland South; Ministry of Infrastructure and Environment (incl. Rijkswaterstaat)
The decision problem is whether to adopt a resilient strategy or a resistant strategy for the management of flood risk on the Island of Dordrecht.
The Island of Dordrecht is a pilot study of the Dutch Delta Programme on resilient flood risk governance, with a specific focus on ‘smart combinations’ of measures. The concept of a smart combination has been introduced in the Delta Decision on Flood Risk Management to provide for the possibility, in specific cases, to replace flood protection measures with measures involving prevention and preparedness (see Figure). Prevention can be realised through e.g. spatial planning and adaptation of buildings, while preparedness can be improved by e.g. developing emergency plans and setting-up insurance schemes.
The regional authorities (of the Island) and central government have jointly commissioned the pilot study to gain practical experience with the application of smart combinations. This pilot study involved concrete elaborations of spatial and non-structural flood risk measures, as part of a comprehensive resilient strategy. It also examined how these measures could be safeguarded, both legally and administratively speaking.
This case study presents emerging practices in the Netherlands on the development of a resilient flood risk strategy (for the Island of Dordrecht) that builds system robustness.
The resilient flood risk strategy for the Island of Dordrecht involves: improving preparedness for vertical evacuation; restoring, and partly removing, the regional flood defences; and adjusting (i.e. lowering) the legal standard pertaining to the primary flood defences. The adoption of this strategy has several positive effects for the Island.
It fulfils the requirements of the flood risk standards until 2050, which implies that the local individual risk should not exceed the value of 10-5 per year. The local individual risk describes the probability of dying of an individual, present or not, at a certain location per year. Besides that, it decreases the probability of a large number of fatalities per year (that is, the societal risk) more effectively than the resistant strategy.
System robustness is enhanced by the resilient strategy, because it substantially reduces the economic damage for the more extreme flood scenarios (compared with a resistant strategy). As a result, the resilient strategy is not dependent on financial support from other countries to recover the Island.
The resilient strategy also creates added value within the social and ecological domain. With this strategy, a couple of co-benefits can be realized that include: the preservation of monumental buildings on top of the Voorstraat dike and the (further) restoration of the Biesbosch ecosystem, which is Europe’s largest fresh water tidal area.
On the other hand the resilient strategy is more difficult to implement than the resistant strategy. Its implementation is difficult for three reasons in particular.
It is difficult to find a suitable legal arrangement that gives the competent water authorities enough confidence in the long-term viability of the spatial and non-structural flood risk measures. Safeguarding that these measures will remain effective until (and beyond) 2050 and will not fail in case of an actual flood event is seen as conditional for approving the adjustment of the legal standard for the primary flood defences.
Moreover, it is difficult to organize the financial resources that are required for its implementation. Contrary to a resistant strategy, resources have to be reallocated before the strategy can be implemented—and in some instances (as for the regional flood defences), they should be brought forward in time. Also, the regional authorities, like the municipality and safety region, have to make additional resources available (e.g. to improve preparedness for vertical evacuation). These resources are not automatically available, as flood risk management is not a formal task of these authorities.
A third difficulty is the effort that is required to organize and safeguard sufficient commitment of all stakeholders who have to contribute to the realization of the resilient strategy. This critically depends on the sustained collaboration between and continuous effort of many stakeholders, who all have their own agendas and dynamics. It is difficult to find a sufficiently binding and flexible governance arrangement that enables a durable implementation pathway and gives the water board enough confidence in the ultimate realisation.
PROJECT WEBSITE OR RESOURCES
Gersonius, B., A. van Buuren, M. Zethof, and E. Kelder. 2016. Resilient flood risk strategies: institutional preconditions for implementation. Ecology and Society 21(4):28. https://doi.org/10.5751/ES-08752-210428
Flood risk, institutional feasibility, resilience, system robustness
COUNTRIES OR REGIONS INVOLVED
City of Dordrecht, Water Board Hollandse Delta; Province South Holland; Safety Region South Holland South; Ministry of Infrastructure and Environment (incl. Rijkswaterstaat); local residents
The Knowledge Platform is designed to promote and showcase an emerging set of approaches to water resources management that address climate change and other uncertainties — increasing the use of "bottom-up approaches" through building capacity towards implementation, informing relevant parties, engaging in discussion, and creating new networks. This is an ongoing project of the Alliance for Global Water Adaptation (AGWA) funded by the World Bank Group.