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A landscape framework for informal settlements to facilitate urban metabolism in Tete, Mozambique

Graduation work by Josje Hoefsloot

In 2050, approximately 62% of the African population will live in informal settlements. My thesis investigates the public spaces of informal settlements in Tete, Mozambique. The quality of these public spaces is decreasing because of uncontrolled open defecation, waste dumping and lack of a sewage system. My master thesis does not propose a radical new urban layout to solve these problems. Instead it researches how existing public spaces can be used, protected and improved.

Most municipalities of African cities cannot keep up with the request for cheap accommodation. The reason is twofold: high birth rates and migration from the rural to urban areas. In cities, people tend to earn more and have better access to education, health and a social network. New inhabitants, who do not have enough money to buy a house, build housing ‘illegally’, leading to so called ‘informal settlements’. Some authors claim that “in Mozambique, the informal system works relatively well and has in fact kept the country from more serious social crisis” (Watson, 2009).

My thesis is about Muthemba, an informal district in Tete, Mozambique. Below two aerial pictures (afbeelding 1 en 2) show the build surface of Muthemba in 2003 and 2016, representing the urban growth of the district. It is expected that the urban population of Tete will be doubled in 2040 (INE, 2010). When I saw the aerial pictures for the first time, I did not understand the urban composition of the neighbourhood. Thinking the only way to solve the occurring problems was to apply a new sewage system, wide roads and many private toilets. However, after studying the development of the neighbourhood over time and some interviews with inhabitants, the urban layout began to make more sense. For example, people avoid building on sandstone surfaces with steep slopes and too close to the natural streams. Incentives for building are water resources, functions, roads and family. Amongst other reasons, the clear relation with its underlying landscape creates identity of the place and, according to inhabitants, a liveable neighbourhood.

Afbeelding 1 + 2: build surface of Muthemba (informal district in Tete, Mozambique) showing the urban growth between 2003 and 2016

In Muthemba, the municipality introduced fresh drinking water tabs, waste collection and faecal sludge collection. However, some difficulties arise: 1) most areas have a hard sandstone surface, making sewage systems too expensive; 2) due to population growth, the amount of public space is declining, making it harder to collect wastes like faecal sludge and solid waste.

ARA Zambeze (water governance) stresses that open waste (water) disposal and open defecation contribute to the pollution of the drinking water aquifer of the city. This aquifer is situated at the foot of the hill on which Muthemba is located, Rosanne Vlaar has written her thesis about this area. The image below shows the unsustainable water circle between these two regions.

Afbeelding 3: the negative water cycle, contaminated water ends up in the Nhartanda valley where it is pumped up and used for drinking water

In Muthemba wastes mainly occur in the public spaces. The pictures below represent a private yard and a natural stream in Muthemba. As you can see the private yard is very well cared for, inhabiting a well-grown tree, clean surfaces and decorations. Unfortunately, both inhabitants and municipality do not feel responsible enough for the public spaces. According to the OECD public spaces should take up 30-40% of the space in cities because they are essential for the healthy urban environments and the collection and transportation of wastes. Below I will further explain how the existing public spaces can be used to improve the urban metabolism of the district. With improving the urban metabolism I mean optimizing the urban flows in Muthemba – like solid waste, faecal sludge, waste water and rain water – to decrease pollution and generate new resources.

Afbeelding 4 + 5: pictures showing the difference in terms of care and responsibility for private versus public spaces

The public spaces in Muthemba are logically distributed. Three public space typologies are distinguished: natural streams, roads and open spaces. Together they could form a landscape framework for the collection and transportation of urban resources. Three designs are made representing the different public space typologies to investigate its role for urban metabolism. My thesis argues that the sustainability of the public spaces goes hand in hand with increasing responsibility of the inhabitants. For this reason interventions are proposed that stimulate the use of public spaces such as public toilets, fresh water, urban agriculture, flat surfaces and a nice microclimate. Kris Kersten (Landscape architecture master student at Wageningen University) will research this topic more into depth. One of the designs is visualized below with a few images, maps and cross sections.

Afbeelding 6: open public space in Muthemba (informal settlement)

Afbeelding 7: visualisation of design for open public space in Muthemba

The following paragraphs, I will further elaborate on the open space design or ‘pocket park’ typology. During the dry season the wastewater coming from private taps is drained to the constructed wetland, which makes it available for irrigation of trees, agriculture or private use. During the rainy season the rainwater is safely guided along the roads to the natural drainage canal. Retaining walls are constructed that create flat surfaces, which mobilize new functions such as markets, playgrounds and meeting places. The walls consist of local and natural materials like granite and sandstone that suit the colours of the existing buildings, roads and gardens. The walls also provide many opportunities to sit, people can choose whether they prefer to watch the pocket park, road, farmers while having a seat below the trees.

Afbeelding 8: map of pocket park

Afbeelding 9: cross section A

Afbeelding 10: cross section B

Different tree species are used Mango, Lemon and Macanica trees that provide fruits different times throughout the year. When the Neem tree is trimmed it provides lots of shade, which is fortunate since the mean temperatures is 33 degrees. The water tap creates a node for fresh water year round, that people can use at all times. The constructed wetland contains reeds, rushes and plants creating a lush green colour-scheme which might remind people of the Zambeze floodplains. The different elements of the horizontal treatment bed are integrated in one tub, fringed by a wall of the same granite stones.

Afbeelding 11: image showing example of inhabitant’s interpretation and use of public space

The square is paved with cobblestone and freed of any stimulus that activates certain behaviour, expecting people’s own interpretation and use of the space. The trees along the roads and on the square grow well since they are irrigated with relatively clean wastewater and harvested rainwater. Multiple trees in the round basins create a fresh green mass from day one. When the trees grow some could be replaced to gardens or other pubic spaces. Enough water is available for agricultural purposes too, contributing to the local economy and health of the inhabitants.

Some elements of the design help to protect the landscape framework against informal settlements by functioning as an informal boundary like trees and gabions. Others help to improve the urban metabolism such as wastewater treatment, a public toilet and water harvesting.

The designs were translated in tools that mainly focus on 1) the protection of the public spaces against informal buildings 2) protection of soil water and atmosphere. Those tools can be applied elsewhere in the district or other informal settlements with similar landscape characteristics. When implementing the tools an additional local landscape analysis is crucial. Below a conceptual landscape framework for Muthemba is proposed, showing the potential of the existing public spaces. It also shows how the Muthemba is related to the Nhartanda Valley (green area), on which Rosanne Vlaar based her research.

Afbeelding 12: landscape framework in Muthemba protecting the public spaces and improving the urban metabolism of the district

VIA water supports ARA Zambeze to implement pilot cases of public toilets, helophyte systems, sand dams and trees to improve the public spaces in Muthemba and the Nhartanda valley. I am sure this is the first step towards demonstrating the potential of the public spaces in and around informal settlements. I am grateful for the collaboration with Rosanne and ARA Zambeze, and I am looking forward to read the thesis of Kris kersten. Last but not least, I am excited to return to Tete in May to discuss the implementation of the pocket park and sand dams in Muthemba.

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