One quarter of the Netherlands lies below sea level. Water safety is therefore hugely important in our densely-populated delta – both for society as a whole and economically. Despite climate change everybody wants to be able to go on living and working safely in the delta. Dikes, dams and locks protect the Netherlands against flooding from the sea, large rivers and lakes. Local residents, companies and vital infrastructure have to be kept safe from flooding.
The sea level is rising because of climate change. Heavy rainfall will occur more frequently and there will be longer dry periods. These circumstances resulted in a rethink of how we want to protect our delta. The Delta Programme 2015 unveiled new measures for water safety and for freshwater by means of adaptive delta management. On the website www.onswater.nl you can enter your postcode to find out whether your home is vulnerable to flooding.
The Department of Public Works and Water Management and the water authorities are implementing the measures contained in the Delta Programme to make sure that our flood defences meet the safety requirements, both now and in the years ahead. The Flood Protection Programme – part of the Delta Programme – is the lead factor. The Water Top Sector is organising the export of our water knowledge and workable solutions to other countries.
Traditionally, the Netherlands has protected itself against flooding by means of dikes, dams, water defences and locks. In recent decades the country has chosen to move in step with the water, to give it space and to make greater allowance for nature's potential for providing safety against water. Besides increasing water safety, nature can open up economic benefits (more recreation and employment opportunities) and enhance the quality of the landscape.
In various ways nature is adaptable to water safety by:
- creating water storage areas/water overflow areas (example: De Onlanden)
- creating sandy embankments off the coast (example: Sand Engine)
- creating sandy forelands at dikes (example: Houtrib dike)
- creating oyster beds in river mouths
- building on mounds
- building while accepting an occasional flood
If you are a water manager responsible for implementing the Flood Protection Programme, you may find some attractive opportunities by combining the measures for water safety, the economy and nature and recreation.
The recently adopted Delta Programme 2015 sets out the new policy framework for water safety in the Netherlands.
The Flood Protection Programme is part of the Delta Programme 2015 and focuses on improving water safety in the years ahead. The current action under the Flood Protection Programme consists of taking measures in respect of 731 kilometres of primary water defences (dikes) and 238 civil engineering works that provide flood protection (locks and dams). This action is being taken jointly by water authorities and the Department of Public Works and Water Management.
Depending on the situation, water managers can give consideration to integrating natural concepts from Building with Nature (see recommendations) when implementing the Flood Protection Programme. Building with Nature produces an integral effect: it improves water safety, helps reduce costs and increases the quality of our living environment because we get more nature and recreational opportunities. It also helps put the Netherlands on the map internationally.
A terrific example of water storage by nature is the area called De Onlanden. This nature area is located between Groningen, Roden and Peize. Together with a number of partners, the Noorderzijlvest water authority created here a combination of water storage, unique nature and recreation (walking, cycling and canoeing). Agriculture was relocated to higher, drier parts.
The De Onlanden project was opened in October 2014. The area now stands as an example of how cooperation between water authorities, landowners, farmers, nature managers, provincial authorities and municipal authorities produces success. It also demonstrates that combining nature and water storage enhances the quality of the living environment by opening the door to more recreational possibilities and less nuisance caused by water.
The most well-known example of Building with Nature is the Sand Engine off the North Sea coast. It is an innovative way of protecting and maintaining the coastline. Nature helps us to keep the country safe from the sea. By means of wind, waves and currents, the sand will spread out in the coming 20 years along the coast between Hook of Holland and Scheveningen, near The Hague. It will create new beaches and dunes, protecting us against the rising sea level and creating extra space for nature and recreation.
Natural forelands at dikes are another fine example of Building with Nature. At Lelystad, for example, a trial is being conducted around the Houtrib Dike with an innovative method of dike reinforcement: a large quantity of sand is being laid in front of the existing dike. This prevents waves from crashing against the dike, thus reducing the load on the dike. This method is designed to obviate the need to strengthen the dike itself. The advantage of this kind of dike reinforcement is that it is cheaper and more sustainable. Moreover, it also increases local nature values and recreation possibilities.
Maps will be available soon.