| Author: Garry Leisberg
| Turors: Alexander Herrebout, Catja Edens, Willemijn Lofvers
| Rotterdamse Academie van Bouwkunst
On a bench near the Esch I am enjoying the river water which courses through the canalized river the Maas. For hours I’ve been staring in front of me, the beating sound of the river intriguing me. Ships sailing past me bring with them a wave that moves across the water and breaks against the dike. The dike forms the transition between land and water. From one side, you can hear the characteristic sound of water splashing against the rocks.
During low tide, the water retreats which suddenly gives this sound another dimension. What captures the attention instead is the quiet and the rustling background noise of the flowing river water. The movement of the river ensures that the area is experienced differently throughout the day. Occasionally the quiet atmosphere is disturbed by ships passing by. On the dike a number of pedestrians can be observed; the jogger running his trail along the dike, the couple walking along the dike while holding hands to be able to see across the water to experience the skyline of Rotterdam, the fishermen a bit further. The other side of the dike tells a different story.
I continue my journey by walking from the higher positioned dike to the lower positioned land situated directly behind the dike. Suddenly an unexpected silence reigns, I am enclosed by the walls of the dike and it feels as if I have entered another world. The splashing sound of the river which I want to use for orientation, is gone. The only sound to be heard is created by the people walking across the dike and the birds in the area. When I look through the trees I see a few houses. People live here, on a lower located piece of land which has been shielded by a dike. By observing this at the Esch I have discovered how important the role of the dike is in this area.
The sea is a threat
The meandering of the river has left its mark through the years in a relief. Due to the carving, as a result of water erosion, a deep groove has been created. On the upper and lower parts of the river, space was created for humans to be able to settle as close as possible to the river. Yet the tract in the lower Rhine, e.a. the Delta, tells a different story. The Netherlands is located at the end of the river system. This is
where the delta is formed. The river delta is a system of branching rivers before it merges into the North Sea. As a country, we are the most vulnerable to this dynamic river system. As a result of events in the past we have been able to protect ourselves from the river. The North Sea flooding of 1953 shows how important that is. The disaster was caused by a storm surge in combination with the spring tide, where the water rose extremely high. A result being the collapse of the dikes. It was an enormous flood because the water moved land inwards. The hit villages were not protected against such a disasters.
To prevent natural disasters such as this one, extra measures had to be taken. The placing of dikes is one of the ways to protect us against a storm surge. In addition, there are initiatives which aim to relieve against extreme flow rates and climbing water levels. Dutch Room for the River Program is to give the river more room to be able to manage higher water levels. At more than 30 locations, measures are taken to give the river space to flood safely. This will allow the water to rise and flow into these locations during extremely high water.
From the first moment that humans settled on our coast, we have tried to cement the border between land and sea to protect us against the water. Until late Middle ages we did this by raising mounds. Later we started building dikes. Because of this we have been able to protect ourselves against the inside swirling sea water and the rise by melt water and rain water. Dikes transform the river into a channel. With the changing seasons, the sea water enters the channel. The entrance through the dike area is narrow and the water is propelled upwards. Due to the water being propelled upwards, larger differences between local and coastal tides are created. The water in the canalized river has less
space. This is a process called resonance, phenomenon in which a vibrating system or external force drives another system to oscillate with greater amplitude at specific waves.
Battle against the river
Ever since there has been a battle of human kind versus the river. Since time immemorial we try to use technical procedures to restrict the natural system of the river, to guarantee safety or enlarging economic gains. The static nature of the system is contradictory with the dynamic (moving, lively and changeable) nature of the natural system that is constantly searching for a natural balance. The stopping and canalization of the river can lead to unforeseen ecological problems and makes constant maintenance necessary. To alleviate the relationship between man and nature it is essential to not work against nature, but to allow the natural dynamic and grow alongside nature. Can we provide a way where man and nature are in balance? The river the Maas in Rotterdam is the starting point for the endeavor. I have been researching how the river works on a European scale, from origin until the mouth of the river. The river system in the Dutch delta knows two important rivers, the Maas (a rain river, direct rainfall and ground water) and the Rhine (a mixed river of glacier water and rain water).
The origin of the Maas lies in France. The Maas flows through Belgium and the Netherlands where it finally mouths in the North Sea. The Rhine origins in the Alps in Switzerland and flows downstream through Switzerland, Germany and the Netherlands where it reaches the sea. The Rhine has the largest power on the whole river system in the delta. Because humans constantly want to settle along the river. To expand they want to restrict the river, which naturally unbalances the natural system of the river.
If we continue like this, it will be necessary in the future to look for new solutions. My research, on the river system from origin to mouth of the river, has shown that there is a peculiar phenomenon. As a consequence of the river expanding and the downwards stream of river water that wants to move land outwards, it will create a clash with the upcoming tide that wants to move land inwards via the canalized river. The collision is a natural occurrence that cause the water level locally to climb higher than elsewhere. This occurs near Rotterdam and is significant higher than the normal tide. Due to the dikes the river water has no space to expand during this collision, therefore the water is being pushed upwards
by the collision. With the help of data, I have been able to discover where exactly this phenomenon occurs.
The Flood city
Our way of building is not designed to allow river water in our urban network. Due to climate change and the rising sea level we are unfortunately waiting for the next disaster. That is why it is necessary to change our ways and adjust our way of building to be waterproof. My design offers a dialogue between the urban network – the static – and the natural system of the river – the dynamic -. A delta concept that
allows the cities to grow towards the river and the river to expand. Flood cities is a network of amphibian cities situated alongside the river.
Location the Rijnhaven in Rotterdam was my case study for this intervention. The Flood city in the Rijnhaven is an autarkic self-sufficient neighborhood that allows the river to capture more space. For the residents, it should be a joy when the water enters the city. It generates energy and wipes the bottom clean. The water has the advantage that it brings nutrients with it. The bottom of these areas is a fertile bottom where agriculture is certainly possible. The ingenious part of this design is the border between land and water. By draining the Rijnhaven and introducing a lowered dike, the water will be stopped by the dike when the water level is low. During times of high water levels or locally extreme tides the river can submerge more land and the water will reach the flood cities via the lowered dike.
The design is based on a floating base, with a footprint of 60 x 60 meter, which represent a building block and is located on land. The Flood city is a preventive urban design concept that gives the river the space to reclaim more land during locally extreme water levels. During extreme tide the water enters the flood city and the floating bases will float along with the water level. Every building block has the task to provide the whole neighborhood of a certain need. The idea behind this is that people should rely on each other and live together. I notice that people are becoming more and more individual, anonymous, and lonelier. To enhance the social cohesion the building blocks have a common inside garden. In addition, all routes will go through the common garden. Due to this, multiple residents will cross paths before they enter their own residence. The Flood city offers a unique experience, where man and river complement each other, that is able to respond to challenges in the future.