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 

OECD Report on Dutch Water Governance

The OECD published a report on the question whether the NL's  Water Governance is fit for the future (in English!).

Report can be found here

Controlled flooding in the Mekong

Six years after my last visit to Vietnam I returned to Ho Chi Minh City and the Mekong delta and it was amazing and a real delta adventure! So many things have changed (my former guesthouse is now a lively bar), but also many other things have remained exactly the same (motor bike taxi’s, go-with-the-flow traffic, and the hassle in Ben Thanh Market).

 

The purpose of the visit was to get an impression of how controlled or facilitated flooding in the Mekong delta takes shape, representing the third case of my PhD project. For that, I travelled together with Tran Duc Dung, who will start his own PhD project soon, to the northern part of the Mekong delta. There are some regions (and a project) where controlled flooding is an inherent part of the agricultural and water system of the delta: notably in An Giang and Dong Thap provinces. Most of the farmers there grow two rice crops per year, and during the flood season a layer of flood water flows overland from Cambodia (and to some extent via the several rivers that make up the Mekong) onto the fields, bringing the required sediments and nutrients in and flushing the water system. It is for that reason that farmers talk about mùa núóc nô, or ‘happy flood’. The slowly raising water levels are kept at bay until August (by the so-called August dikes). Then, the water overflows the dike and floods the area where the second rice crop has just been harvested from.

 

But (central) governmental policy makers are thinking about growing three rice crops per year, which would necessitate large scale infrastructure to block the overland and controlled floods. Various other actors, from local farmers to representatives from local governments, research institutes and NGO’s are worried about this development and expect increased flood risks in Can Tho (since flood water would not spread out in the north anymore), the largest urban area in the Mekong delta. In addition, preventing sedimentation and nutrient deposition is expected to lead to deteriorated agricultural production, and does not compensate anymore for soil subsidence. It is indeed the balance between facilitating regional ‘good floods’ versus preventing large scale ‘bad floods’ in the delta. These discussions are also taking place within the context of the recently issued Mekong Delta Plan, where Vietnamese and Dutch water experts have aimed to streamline various existing master plans and development trajectories for the delta.

 

During the first days, Dung and I had some informal discussions with staff from An Giang University. Then we spent a few days by motor bike driving about 250k to visit different districts of An Giang province. In the northwest we visited the flooded forest wetland, which requires a certain flood dynamic (timing and water level) to function as an ecosystem, providing ‘modern nature’ and lots of bird life to the region. On one of the island in the Mekong distributaries the North Vam Nao project proved a very interesting case: the project was designed for full flood control, but after local actors’ engagement, the area now employs rotational flooding in the fields. Also the interviews at the Mekong Delta Development Research Institute, Can Tho, and IUCN, Ho Chi Minh City, were very informative. The movie suggested by Andrew Wyatt (and Ngan Le, who will soon also post on this blog) are very interesting: the disappearance of the flooding season (see also parts 2 and 3).

 

The coming months I will continue working on this case and later on also plan some short re-visits. If you have ideas, comments or questions (I have lots of additional interesting literature), please let me kow. Thanks to Gerard Pichel for a nice lunch, Dung for sharing our  delta adventure, and Gerardo van Halsema for initial ideas, advices and a nice sea food dinner on the 27^th of Feb!

 

 

Islands of predictability at the Dies Natalis of Wageningen University

Yesterday I had the opportunity to give an 'elevator pitch' about my PhD research at the celebration of the 96th birthday of Wageningen University.

All pitches are somehow related to water and can be watched at WUR-tv. My contribution starts at 49:10 (you can navigate through the pitches by clicking the < arrow o the right side of the screen).

http://wurtv.wur.nl/p2gplayer/Player.aspx?id=cFqgjo

Prezi presentation doesnt work on the video, but it can be found here: