Trends in flood risk management in deltas around the world: Are we going ‘soft’?

Flood-risk management (FRM) is shaped by context: a society’s cultural background; physical possibilities and constraints; and the historical development of that society’s economy, politi- cal system, education, etc. These provide different drivers for change, in interaction with more global developments. We compare historical and current FRM in six delta areas and their con- texts: Rhine/Meuse/Scheldt (The Netherlands), Pearl River (China), Mekong (Vietnam), Ganges/ Brahmaputra/Meghna (Bangladesh) Zambezi/Limpopo (Mozambique), and Mississippi (USA). We show that in many countries the emphasis is shifting from ‘hard’ engineering, such as dikes, towards non-structural ‘soft’ measures, such as planning restrictions or early warning systems, while the ‘hard’ responses are softened in some by a ‘building with nature’ approach. However, this is by no means a universal development. One consistent feature of the application of ‘hard’ FRM technology to deltas is that it pushes them towards a technological ‘lock-in’ in which fewer and fewer ‘soft’ FRM alternatives are feasible due to increased ood risks. By contrast, ‘soft’ FRM is typically exible, allowing a range of future options, including future hard elements if needed and appropriate. These experiences should lead to serious re ection on whether ‘hard’ FRM should be recommended when ‘soft’ FRM options are still open.