Some reflections on the Dutch delta work, as seen on site

The Dutch delta work is a major social-technical response of the Dutch society and economy to coastal flood risk, clearly showed in the unforgettable flood event, early 1953. The core of this work is huge investments on water control infrastructures, aiming at reducing (as much as possible) coastal flood risk. What we can see nowadays as part of this delta work in Zeeland province are mega sea-dikes, sluice gates, embankment, and sophisticated river flow/level control systems along the coastline, especially at river mouths. Since its accomplishment, the Dutch delta work well served its purpose: effectively resolved the issues of coastal flood risk. At the same time, this mega investment shows the Netherland’s strong economic and engineering capacity; and equally important: people’s determination to create a safer living environment.

First reflection: Human land and water management seen as a layer superimposing on the natural landscape. At the landscape scale, I can relate very much the Dutch delta work to a layer of human’s management practices/infrastructure putting on top of the natural delta system. Once in place, this layer starts to modify the delta’s natural dynamics in ways that serves human’s wishes, in this case to reduce coastal flood risk. Of course there are also unwanted effects caused by this changed delta dynamics, like eutrophication caused by diminished tidal regime in regions after the sea-dikes. This idea of layering also triggers thinkings about alternatives, what if we put a different layer on this delta, how would such a layer look like?

Second reflection: History influences on Dutch delta approach, and issues of path dependencies. To me there is quite a strong influence of the Dutch’s long tradition of controlling water on the delta work. It looks like: from the countless years of water channelling, dikes construction and land reclamation, the ideology of controlling water emerged and solidified from generation to generation. And the delta work very well reflects this way of thinking. Then comes the question of path dependency. The water management history shows its role in shaping the basics of the current delta work, and the question then is: how this current work continues to shape the delta’s future. Is there any chance that this continuation could lead to a lock-in state, where the delta becomes so rigid that it becomes difficult to change? This way, the system becomes vulnerable to new risks.

Third reflection: Looking into the future, keep it or leave it? How long the current water management layer will last very much depends on its robustness in the future. As long as it ensures safety despite changes in sea level and hydro-climatic extremes, there are strong reasons to keep the system as it is. But this is also a matter of choice. The society might come up with other ideas, and people might start to think of changes, new ways to deal with water. Perhaps the emerging ideas of depoldering and natural tidal regime restoration are telling us something about the future of this delta?

May 20, 2014

Painting: The Rhone with Boats and a Bridge, Vincent van Gogh

Photos of the Deltatrip

Some photo's of the Deltatrip can be found here:
https://www.dropbox.com/sc/yzbusio6uxdontv/AABCKJhhaiyIFN945NiHC4-ca

A VALUABLE EXCURSION TO THE SOUTHWESTERN COASTAL DELTA, THE NETHERLANDS

The Water Management Group of the WU Environmental Sciences Organization kindly set a pocket field trip for 08 PhD students with the support of Dr. Gerardo. However, the idea for the excursion was initially planned and prepared by Arjen, Martijn.

                                                              Group photo

At 7:20 AM, 16th, May 2014, a field trip started at the Bonsesteeg apartment building, Wageningen in a minibus driven by Arijen. A list of visiting locations were put in a schedule as follows:
7:00 depart from bornsesteeg
9:00-10:00 the philipsdam, vantage point, AZ explains about the volkerak-zoom lake and blue green algae
10:15-11:45 visit the watersnood museum
12:15-13:00 lunch in zierikzee
13:30-13:45 photo moment Eastern Scheldt storm surge barrier
14:00-14:45 visit the town of Veere
16:30-17:30 biesbosch and noordwaard polder 
18:30 back in wageningen

Figure: The route of the field tip

Philipsdam:

           My first impression for the trip is the green tree space along the express ways which are hidden by barriers in some sections to avoiding noise for people living in residential areas. Specifically, people in the Netherlands are allocated in block buildings or village houses in residential areas which are built up along the street make a difference compared with Vietnam. During the route, we can also see some kinds of animals such as cow, sheep or even white kangaroos grazing grass in the farms which are owned by private Dutch families.

Reaching the coffee break dropped in a nice coffee restaurant, valuable explanations were taken by Dr. Gerardo, Arjen and Martijn during the field trip about the flood happened in the Netherlands 1953, which caused a severe damage for Dutch with nearly 2000 people died and a huge number of losses of houses and properties. In the situation, the Dutch government decided to have a historical revolution of large scale concrete water structures to protect the country against floods. With an urgent determination and agreement of government and people, a set of dams, dikes and related water items so-called Delta Water Works were constructed to convert the Netherlands to be one of the most a famous and successful countries worldwide in water management and flood control.

There are about 15 focal water works mostly concentrated in coastal areas have been build (information referred from a Vietnamese website) to manage floods and tide throughout the country, enabling a protection of more than haft area below sea water level against floods and being a safe place to live over 60 years. However, Dutch people never satisfy with existing conditions of delta works and elaborate many researches, projects and innovative strategies dealing with water body. Informed by Dr. Gerardo, Arijen and Martijn, a growing challenge of Dutch Delta Committee is the management of saline, brackish and fresh water for sustainable environment in the context of climate change and sea level rise in coming years. The Philipdam is one of the two constructions (together Oester Dam) built behind the Oosterschelde Barrier. This dam is functionally constructed for reducing fresh water upstream flowing to the salt marshes for oyster cultivation since the appearance of Oosterschelde Barrier has been decreased the contrast of high and low tide from the sea good for oyster harvesting. Moreover, the maintenance of a saline environment is needed for blue typical aquaculture such as oyster and shellfish. Another problem derives from the Volkerak zoom lake, which was a saline water ecosystem in the history. However, after the construction of the Philipdams, the Vorkerak dam was closed permanently and the zoom lake was assigned as fresh water storage for local living. Growing water pollution appears with the emergence of blue green algae due to the nutrient from agricultural area upstream flowing to the lake (Arjen research) and this problem should be solved.

Watersnood museum: It is true to be called "caisson" museum, since it is a structure of 4 huge caissons used as tools for barrier constructions after the flood in 1953. All things and information in relation to the flood are shown inside. A documentary film gave us special emotion about what the Dutch suffered and overcame the flood damages.

Town of Veere: A small ancient village/town is located near the river bringing refresh and cool felling after a tour around is done.

Biescbosch and noordwaard polder/or Martijn polder (hahaha): This is actually one of the largest national parks of the Netherlands and one of the last extensive areas of freshwater tidal wetlands in Northwestern Europe. The Biesbosch consists of a rather large network of rivers and smaller and larger creeks with islands. Ever taught by Martijn about the de-poldering area (with dikes and ditch network) during his fied trip in the Mekong Delta, Vietnam, I was very eager to come. It is sided in a sensitive place, which initially maintains a natural ecosystem for local inhabitants. Entering a museum in the Biescbosch, it was nice to watch a video about the livelihood of 70 local families within the polders. The film also informed clearly the complex water regime in the region affected by both tide and upstream river discharge and about the contrast opinions from inhabitants. It is surprised since first time I can watch a video together with a presentation simulating the situation at the same time directly to a "polder model", it is really an animation scene. The problem which Martjn is elaborating for his PhD thesis is the reconstruction of ecosystem-based dikes. To the plan, the old dike will be cut with 4 intakes of about 100-200 meter width and allows flood water overflow during the flood season (in winter).

A thing I should not ignore to mention that a big Dutch dog running on the dike in Biescbosch is very lovely; a little Dutch worm in Zierikzee appeared in the lunch and welcomed the arrival of Mr. Wahid (Yemen), and a hurry drop for Mr.Long for catching up a train back to Amsterdam. All these things made the excursion more interesting and unforgettable.

In my opinion, all the interesting things learnt in the trip can contribute to a persuasion that the Netherlands is an ideal environment for student research. Again, on behalf of WMG PhD students, I would like express a sincere gratitude to Dr. Gerardo, Arjen and Martijn for giving us such a nicely unforgettable excursion.

The pursuit of permeability

Dams versus semi-closed storm surge barriers, dikes versus inlets, flood prevention versus flood restoration… the last weeks I’ve been thinking about a potential title for my PhD manuscript, and what seems to a central ‘issue’ in the themes and cases that I study, is how to strike a balance. The balance between the 'extremes' of fully closed and (partly) open, the balance between full flood prevention and ‘free’ tidal and river floods in the delta.

This made me come up with the preliminary title: the pursuit of permeability. It reflects the continuous attempt of human actors in aiming to strike the ‘right’ balance: in the past with (nearly) zero permeability ("this never again" motto after the 1953 flood), towards compromising semi-closed (or semi-open?) flood management infrastructure measures (Oosterschelde), and nowadays towards ideas that deal with floods by allowing and even facilitating floods. Over time, different social, political, technological and economic conditions have asked for continuously re-adjusting the balance between open and closed (or anything in between) rivers or estuaries.

Such ‘greener’ ideas are amongst others represented in practice by de-poldering projects or dike relocations, allowing more space for flood and tidal dynamics. Agricultural areas are converted into floodplains for the sake of flood safety (lowering peak river discharge levels) and go hand in hand with efforts in the domain of (new) nature development. The Overdiepse polder and the Noordwaard polder fit well into this picture. But de-poldering is also proposed on different grounds: as a compensation measures for dredging the Scheldt river (Hedwige polder) or the expansion of the Rotterdam harbour (Rhoonse polder), or aiming to stimulate socio-economic activities in a not-so-attractive-anymore area (Perkpolder). All have in common though, that they are the result of a ‘shift’ in balance: apparently we are moving away from full flood protection to open or semi-open approaches towards floods – at least, in some areas of the Netherlands. How to strike the ‘right’ balance, is the contemporary (and long term) challenge both in technological, policy and social domains.

Especially the Noordwaard polder (which is the Dutch case in my project) is interesting and connects to both ‘pursuing’ and ‘permeability’. Firstly, the water managers and environmentalist who, for different reasons, have pursued de-poldering and flood restoration in the area. And secondly, because the restored flood regime is controlled by semi-permeable dikes: partly lowered at four locations (representing inlets of flood water once the river reaches a certain height). Some water should stay behind the dike, while other water should turn into a managed flood – hence the ‘permeable’ dike.

Let's see in a few years time what has remained of this initial, working title ;p.