Just before the plane started to land I looked out of the small airplane window. I had a beautiful view on the Mozambican city, Beira, situated along side the Indian Ocean. I thought to myself: what are those white dots in that blue area over there, so I asked my supervisor. He said: “the white dots are new houses, but that blue…” He looked startled down at the ground. The rainy season had just started, and the houses were already flooded.
Why is it flooded, I asked? Because it’s a very low place, he said, it’s a wetland that becomes naturally flooded. But why do people build their houses in flooded area’s? Well, think of the people in Mozambique; on average they have 7 children and many people choose to move to the city, preferably in cities along side the river or sea. Then, what happens? The city grows and expands more and more in the lower areas and eventually in the wetlands. The problem is that the poorest people live in these flooded places while having the least means to adapt (Douglas, 2008). Houses become flooded and then that mixes with the sewage and causes serious diseases like Malaria and Diarrhea. This is not the end of the story. Climate change will likely bring heavy rains, El Niño’s and raising sea water levels (IPCC, 2007). The plane descended and I was afraid to land in the water.
So what is the solution to this problem, I asked. It’s hard to find the right solution, he said, not for nothing is flooding one of the most damaging problems in the world (Cooley, 2006). Urbanization is happening anyway and everywhere, so we have to solve it as we face it area by area. When we walked out of the airplane, he handed me a piece of paper with a ‘Western’ golden formula. The title of the scientific paper stated: ‘Green-blue infrastructure as a tool to reduce flooding’. What the heck do they mean by that? A network of trees and waterways? How would that reduce flooding? I expected high-tech engineering… I didn’t have much time to think about it because I was already on the road to the hotel and the driver was like a drunken man dodging the big holes and other cars: all I could focus on was being up straight in the back of the jeep. I wondered if they even understood the word ‘planning’ in this country. And even if they could, it surely wasn’t to be seen through their roads. Although there was a kind of beauty in the informal houses under the Mango’s and palm trees. Actually those were the only plants I recognized in all the thousands of shades of green. Anyway, it doesn’t matter, at least they provide the necessary shade from the hot sun that almost boiled my brains.
I lived at the beach for 2 months, 5 kilometers away from the work field (and the malaria). With my Dutch wisdom I bought a bike, which gave me the additional advantage of not having to explain my origins anymore. Together with my guide Gaidar we biked everyday for field work that included soil drillings, interviews and observations. It was always an adventure to bike from the busy Portuguese centre to the more rural and informal settlements that were surrounded by rice fields. Our lunch included dozens of mandarins, bananas and papaya.
In someones backyard I was able to put my three meter drill in the ground. All of a sudden we were surrounded by what looked like a whole African tribe, they all watched curiously as we penetrated the ground. While we drilled in the ground, it became more and more difficult. This neighbourhood is built on a three meter layer of heavy clay, deposits of thousands of years of flooding. Could you ask about the severity of the flooding, I asked Gaidar? He translated my questions for the locals. “Bom dia, como agora fez a inundação em sua casa? Na última temporada, foi mais de um metro!” More than one meter! I wondered how it was even possible to live in such conditions. They told us that the municipality allocated plots for them in this area. When I asked about their problems I was astounded how nonchalant they responded to the flooding problem: “It’s no problem, that’s every year, if the flooding gets worse, we just move to our neighbours on the higher located sand ridge or you can build the house with an extra level”. Of course, after more questions, the flooding was a troublesome and caused serious diseases. Actually, they also wanted a better drainage system, infrastructures and public facilities. And trees, I asked? Having in mind the golden formula. Trees would be wonderful, the elders responded. But how could we grow trees in this heavy clay that floods every rainy season?
Back in the Netherlands, I was thinking and reading for a long time about the golden formula ‘green-blue infrastructure’. It is defined as “an interconnected network of green (and blue) spaces that conserves natural ecosystem values and functions and provides associated benefits to human populations” (Benedict & Mc Mahon, 2006). It was defined in a language I barely understood and in such a way that it could mean anything. How could I ever design something vague on such a big scale? I looked at some kids playing in the sand. Suddenly I remembered that as a child I used to play with water and sand. The water eroded in the sand or it became small streams and started to form small scale floods on the lowest areas. Interestingly, water on the grasses didn’t form streams, but somehow disappeared without erosion or flooding. That was the golden formula in a nutshell! Green-blue infrastructure acts like a sponge, a place where water can flood, infiltrate and slowly disappear. Urbanization replaces the vegetated areas, no wonder that the district Chota becomes flooded. The question is, how to integrate green and blue spaces in Chota that reduces the flooding? What will fit in the culture and demands of the residents?
After a second flight to Mozambique I was again in the city hall of Beira. I saw some of the elderly which I recognized from the interviews I had taken and I was happy to see my guide Gaidar again. “Bom dia, como reduzir a inundação de uma infra-estrutura verde-azul”, my team manager opened the workshop. The team of water experts opened a box and revealed their newly developed climate change tool. A screen showed a complete set of green and blue measures (Voskamp & Van de Ven, 2014). It could even calculate the impact of the measures to reduce the flooding. Moreover, it showed the additional benefits of each measure (e.g. cooling, biodiversity). Unfortunately we didn’t get much input from the residents. Could you make some drawings, my supervisor asked. They have to see what it looks like. In our hasty creativity we crafted photos and drawings together which ended up being a quite convincing image. It was a success. In the end, the people showed their preferences. For example: (fruit)trees along the roads and canals would be fantastic, the canals and roads could also be widened and improved. Retention ponds are okay, but not ‘in their own backyard’, afraid of (malaria) mosquitos. Green roofs were nonsense: how could their corrugated roofs carry that weight?
I sat there housebound behind my laptop and after a year I could’nt even come up with a convincing design for Chota. Drinking coffee, writing articles for Topos and earning money, all seemed to be more important than finishing my thesis. It all happened on a depressing Monday morning, when I realized that all I had to do was to draw sketches. Looking back, I still wonder how I made the lovely drawings in just a week. These drawings helped me find structure in my design. For every type of landscape and infrastructure I drew a different profile. For example this road below.
The roads in Chota are full of cars, people and markets, but also full of holes and muddy pools. Could we improve this infrastructure and integrate it with the green and blue measures to resolve its flooding? I was thinking. What about a multifunctional separation, like the Netherlands? A bioswale with trees that separate the cars from the pedestrians. All the rain could now be absorbed in the bioswale, where it is slowly able to disappear into the canal (blue measure). The trees (green measure) will slow down the water, provide comfortable shade and a pleasant view, a place for species and probably some delicious fruits.
With the same thought in mind I also designed the other structures. I designed fruitful gardens on the edges of the sand ridges, rice fields that would buffer the water along the canals, a widened and recreational canal and a protected dune landscape at the coast with some great retention ponds. All these green-blue interventions together form a network that ‘absorb’ and drain the landscape of Chota. Moreover, all the green and blue areas make it a much more pleasant place to live.
It is difficult to guess whether green-blue infrastructure will really work in practice. Well, the area’s will definitely become less flooded, but this should be calculated by the water experts. Will it have potential? That is still a pending question. At least it’s not a good idea to build in a flood-plain. However, the concept itself is very accepted by the people because it is natural, simple and multifunctional. Thinking back to the time I spent in Mozambique, I have gotten to realize that it might be difficult to plan at all in their organic way of planning. However, as landscape architects we would be of great help bringing the people together to design and plan a livable future landscape. With that, visualization would be an excellent discussion tool. Never the less green-blue infrastructure is a great concept that must be taken into account from the start of every urban planning process. Green-blue infrastructure is the lively blood vessel of the city!
I was just relaxing after my thesis when I took a look in the newspaper: half a billion worth of damage due to heavy rainfall and flooding in the West of the Netherlands. That reminded me how nonchalant and flexible the Mozambican’s responded to their annual flooding. Green-blue infrastructure might be a great concept, we could learn a lot from their flexibility!
dr.ir. Ingrid Duchhart (Wageningen University)
dr.ir. Robbert Snep (Alterra, Wageningen UR)
ir. Carmen Aalbers (Alterra, Wageningen UR)
This thesis is part of the GreenInfra4Beira project. A test-case in Chota, the most flooded parts of Beira, which is the second biggest city of Mozambique. It aims to reduce the stormwater problems by means of green-blue infrastructure. The project is a collaboration of Deltares, Witteveen+Bos, Wissing Urban Design, Flood consultancy Adri Verwey en Alterra and supported by the Stichting N.H. Bos and Wageningen University. For my thesis I did a two month field study and designed a green-blue infrastructure for the neighbourhood.
Benedict, M. A., & McMahon, E. T. (2006). Green infrastructure. Island, Washington, DC. Cooley, H. (2006). Floods and Droughts. The World’s Water 2006-2007: the biennial report on freshwater resources. Island Press, Washington, DC. Douglas, I., Alam, K., Maghenda, M., Mcdonnell, Y., McLean, L., & Campbell, J. (2008). Unjust waters: climate change, flooding and the urban poor in Africa.Environment and Urbanization, 20(1), 187-205. IPCC, A. (2007). Intergovernmental panel on climate change. Climate change 2007: Synthesis report. Voskamp, I. M., & Van de Ven, F. H. M. (2015). Planning support system for climate adaptation: Composing effective sets of blue-green measures to reduce urban vulnerability to extreme weather events. Building and Environment, 83, 159-167.