Nature-based flood management
Natural water retention measures are a key example of how green infrastructure can work alongside traditional grey infrastructure (e.g. flood gates). However, there are barriers to widespread uptake of natural water retention measures which need a joined-up policy approach in order to manage benefits and trade-offs.
Natural water retention measures take many forms – from small green roofs to large forests – and bring multiple benefits: as well as reducing flood risk, they can be valuable for biodiversity, recreation and water quality. However, this multi-functionality leads to barriers to the widespread uptake of natural water retention measures, as identified by Swedish researchers.
1. Spread benefits and costs
Benefits and costs fall under different policy areas and in different (geographic) places. This makes it difficult to distribute the (financial) costs fairly. The researchers suggest that a payment for ecosystem services (PES) model could be used to finance natural water retention measures. Research from the USA has indicated that it is less costly to pay farmers to flood their land upstream temporarily, than it is to pay for urban damage downstream.
There is a lack of distinction between jurisdictions. Measures are taken locally, without taking account of needs and effects on larger scales.
3. Specific knowledge gaps
There is also a lack of real world studies which show how to incorporate measures into flood risk management plans and their likely impact on downstream urban flood risk.
What needs to be done?
The authors recommend that institutional structures and mechanisms are created or enhanced:
- to oversee the urban/rural trade-offs that natural water retention measures may bring,
- to match potential costs with benefits and
- to ensure an appropriate compensation scheme is put in place, for example one which links payment for ecosystem services (PES) with flood risk management plans.
For more details please refer to the entire article ‘Nature-based flood management needs joined-up policy approach to manage benefits and trade-offs'.