Natural Flood Management (NFM), also known as Working with Natural Process (WwNP) or Catchment Based Approaches (CBA), are methods of reducing the risk of flooding by working with the way rivers operate naturally. Consequently, much of this work also falls under river restoration, the returning of the river to its natural state by removing previous engineering works. It also covers actions that seek to enhance the natural processes, such as the placing of small woody dams in the river to hold back and slow flood flows.
Wooden debris ‘leaky’ dams in action at Dalby Forest, North Yorks, UK.
We are working on a modelling toolkit within CAESAR-Lisflood that will enable us to predict the impacts NFM interventions will have, not just on flooding, but also on the movement of sediments across the river. This will allows to assess how the interventions might change the shape and function of the river, any unintended consequences on flooding, and evaluate the ongoing costs of maintaining the interventions.
Video clip showing an early test of the ‘leaky dam’ code in CAESAR-Lisflood
The toolkit will be free and open source. As it develops, we will support its use with written and video guidance here, and eventually workshops.