On 26 May, 2021 an international symposium on Living Polder Strategies for Living Deltas was organized by Frank van Laerhoven and Martijn van Staveren. The event was funded by the Water, Climate and Future Deltas Hub (part of Utrecht University’s Pathways to Sustainability strategic theme). The objective was to build an international community of practice and facilitate knowledge exchange.
During the symposium the practices and potential of hybrid polder management strategies and (temporary) restoration of flood dynamics on delta lands based in 4 case studies in the Netherlands, the USA, Vietnam and Bangladesh, where presented and discussed. The full recording of the symposium as well as the PowerPoint presentations can be accessed here.
The four case studies tabled many points for further discussion, including the following:
- As indicated by the varied type of cases, projects and geographical distribution of the symposium contributions, controlled flooding can be seen as a topic that can be approached from various sectoral angles and scientific disciplines. In terms of policy sectors, controlled flooding is relevant for flood risk management, agriculture, nature restoration and sedimentation control. In scientific terms, both the natural and social sciences can provide interesting analyses on the potential effects of such projects. In particular the social sciences can reflect on institutional frameworks and community engagement as important conditions for successful implementation of controlled flooding initiatives.
- The contributions supported the statement that controlled flooding is a promising concept, but whether it is also proven varies very much on the project objective and specific environmental conditions. In the USA case, controlled flooding takes place relatively frequently and as expected, while in the Bangladesh case, sediment increasing land height was not anticipated but is now seen as a more-than-welcome side effect. It was suggested to keep conducting research, reflect on the (unexpected) impacts and pay attention to monitoring & evaluation, in order to build the scientific knowledge base of controlled flooding.
- Attention to governance and societal impacts is important. Some participants referred to ‘winners and losers’. In the Dutch case, for example, the studied case contributes to regional flood safety, but at the expense of dozens of farmers who had to relocate and move elsewhere. Restoring flood dynamics in certain areas might reduce land value.
- Various implementation projects, supported by the ADB, show the range of controlled flooding principles, from flood retarding basins in the Philippines, to seasonally flooded parks along the Bagmati river in Nepal. It is important to conduct social and environmental impact analysis upfront, to be aware of the effects of such projects.
- Related, a local perspective benefits more abstract policy deliberations and plans about how to deal with delta dynamics. Local communities can support or oppose projects, but can also suggest feasible interventions and can act as local ‘monitors’ to reflect on project impacts (citizen science?). In Vietnam, regulations to allow one flood period after 8 rice periods, is in place but farmer communities do not always implement this. A good understanding of local governance arrangements and individual’s motivations are important to take into account when considering engineered interventions or changes in water management practices.
- It is important to consider the financial possibilities and limitations when it comes to implementing controlled flooding projects. In some cases, lack of funds limits the scale or compensation of interventions. Financial blending of various (inter)national sources and sectors alike, could be an option to overcome this obstacle.
Follow-ups of the symposium:
- Bilateral discussions will be scheduled between participants who expressed an interest to do so;
- Recording, presentations and a summary report will be distributed;
- Participants represent a Community of Practice of those conducting research about, implementing projects on, or being generally interested in, the topic of controlled flooding. As such this Community is warmly invited to participate in future activities;
- A structured approach to collect and present relevant information, stimulate knowledge exchange between international stakeholders, helps to build the scientific knowledge base of controlled flooding;
- A website will be set up to provide various sources of information about controlled flooding cases, as well as to facilitate continued interaction between the Community of Practice.