Article submitted: Let’s bring in the floods: de-poldering the Noordwaard

Last Tuesday I submitted a manuscript to the Water International journal and hopefully they will accept it for publication – no doubt after several rounds of addressing comments, corrections and other changes ;p. For those interested, a short summary is provided below. Also check out the infographic, initially made in Dutch by Loek Weijts, who was so kind to send me the ‘empty’ file (with only credits due), in which I inserted the English translation. Thanks again! A very and illustrative way to get familiar with the project.

Let’s bring in the floods: de-poldering the Noordwaard

The Noordwaard is an agricultural polder in the Southwest of the Dutch delta. It has been appointed to be de-poldered (or in other words, the embankments of the polder will be lowered or removed, in order to reconnect the area to the river) to enable the discharge of extreme volumes in the Merwede river. By de-poldering the area, fresh water tidal fluctuations (more or less along the edges of the polder), and water from the river flooding the polder (yearly during winter, and during peak river water levels, will overflow the lowered embankment and enter into the area) are restored.

Main driver of this project were the (near) floods in the Dutch rivers in the mid-1990s that initiated the Room for the River programme. In the programme, various measures were proposed to create more space for rivers to deal with extreme discharges, and included dike relocation, river widening and bypasses. De-poldering the Noordwaard has long been a contested measure which severe impacts on the local farmers – some of them had to move out of the polder. After a long period of contrasting views, support, protests and negotiations, the Ministry of Transport, Public Works and Water Management decided in 2005 to de-polder the area.

What I find most interesting about the project, is what may be covered by a slogan: ‘restore delta dynamics’: this includes facilitating flood regimes (yearly small scale floods while being able to accommodate larger floods), the growth of the Biesbosch river wetlands, providing ‘room’ for natural dynamics and environmental quality, lots of green and seeing benefits from delta floods. But at the same time, some typical delta dynamics are deemed ‘unfit’ for the area. Restored floods are expected to bring in sediments, but this will affect the hydraulic discharge the project initially was designed for. So, sediments (but also excessive growth of vegetation) should be removed as to guarantee ‘free’ discharge of peak river water flows. The Room for the River hydraulic objective of carrying a peak 18,000 m3/s (although still debates in scientific and political arenas) needs to be met. Understandable, but how about the storyline that ‘the safest areas in the Southwest delta are the areas outside the dike, that have received most of the sediment during the last centuries’. How about sediments increasing the height of the area – very very slowly, but still: one way to be safe from larger floods is to have your land high enough.

To me this aspect is a point to make and food for thought. If you have any comments, please leave them in the 'comments' field below!
PS: see also an earlier news item on the project (in Dutch): http://nieuwsuur.nl/video/517058-hoe-nederland-de-voeten-droog-houdt.html