Protection against flooding

Dunes and salt marshes are natural systems that directly or indirectly contribute to the protection of the Netherlands from flooding. The government wants all primary flood defences, including natural such as dunes, to comply with legal safety standards. The responsible water managers (Rijk and Water Boards) must keep the various water barriers at strength. Between 2001 and 2011, the responsible water managers gained more insight into the safety operation/contribution of dunes as (primary) flood defences. There has also been interest in contributing to the safety of floods of other natural habitats such as salt marshes, marshes and marshes. The vegetation in these areas has a wave-inhibiting effect and thus contributes to the safety and to limiting the maintenance of underlying primary flood defences such as dikes. With regard to the safety contribution of these foreshores to primary flood defences, a distinction is made to dyke sections with natural wave-inhibiting foreshores and dikes with only shallow water and with deeper water for the dike. However, dunes, salt marshes, marshes and (reed) marshes also represent important natural values (habitats) that have international status. The vegetation traps sludge, provides more breeding and habitat for organisms that grow up in their priority habitat. Maintaining these habitats is therefore important. The combination of primary flood defences with natural foreshores offers an innovative ‘nature inclusive’ solution that can contribute to flood protection. In the future, this combination could be taken into account when designing new flood defences. The number of kilometres of natural flood defences being tested has increased, but this currently concerns only the dunes. These are formally tested against the high water protection standards. For the other natural flood defences, a test protocol is (still) missing.