What is the potential of riverbeds in an arid, post-apartheid city adapting to climate change?

By Valentina Giombini, MSc Environmental Change and Management (University of Oxford)

Rivers in arid environments bring life, greenery and water, connect habitats and many species’ populations. Human settlements also often develop next to rivers. Today, the effects of climate change are increasingly becoming evident. Cities are trying to adapt to the consequences of higher temperatures and different rainfall patterns. What could then be the role of riverbeds and greenery in helping cities and citizens adapt to climate change?

Nature and green areas give humans free ecosystem services, such as creating shade, decreasing erosion or providing food, but they also increase the mental and physical wellbeing of people. Riverbeds can be managed to harness all these services along with those that are required in an urban environment, such as rainwater collection or transport infrastructure. This makes them multifunctional green spaces. The presence alone of green spaces like riverbeds, however, does not automatically mean that they are exploited to their full potential. Management and integration with the rest of the city play a key role.

To explore the potential of riverbeds in an African context, in July 2019 I travelled to Windhoek, the capital of Namibia, to join the Urban Ecolution climate adaptation project as a master’s student.

Namibia an arid country and 2019 was the sixth year of a consecutive drought, such that in May the president announced a state of emergency. Rivers are ephemeral, meaning that they flow only during the rainy season (November- March, 285 mm/yr) and in the dry season climate-adapted vegetation grows in riverbeds. Frequent droughts followed by flash floods intersect with high socio-economic inequality, and limited resources and institutional capacity. South African apartheid rule until 1990 deeply shaped the socio-economic characteristics of present-day Namibia, and also the spatial structure of the city of Windhoek today.

While much development progress has been achieved since independence (construction of new neighbourhoods, park and malls), many of the formerly racially-segregated residential neighbourhoods still have different house plot sizes, levels of greenery and distances to employment opportunities in the Central Business District. Residential neighbourhoods are also divided from the city centre by vacant land, highways and industrial areas, limiting social integration and access to other neighbourhoods, requiring often non-affordable motorised transportation.

Given this context, for my master’s thesis I wanted to understand the role of riverbeds in the greenery of the city; what their current state is and how they are experienced by citizens. To do so, I first mapped areas of low, average and high levels of greenery using satellite images and remote sensing techniques (by calculating the Normalised Difference of the Vegetation Index (NDVI) of the area). This showed where most of the greenery in the city is concentrated. Afterwards, I went door to door in different neighbourhoods to interview residents living alongside the riverbeds, asking how they use those spaces, and to hear their perspectives on green areas in general. I conducted interviews in Okuryangava, Katutura, Khomasdal and Ludwigsdorf (Klein Windhoek), which exemplify neighbourhoods of, respectively, informal settlements with shacks of corrugated iron, and former black, coloured and white-only residential areas established under apartheid rule. Working in these areas allowed me to explore how the river is managed and experienced over a gradient of different socio-economic and structural characteristics of the city. While studies on the ecology and geophysics of riverbeds have been done in the past, exploring the cultural ecosystem services and access to riverbeds as green urban spaces in Windhoek represents a novel approach.

What I found was that access to the (limited) greenery of the city is deeply unequal, illustrating a case of environmental injustice. As can be seen in the NDVI map to the right, most of the urban greenery (in dark green) is found in the former white neighbourhoods in the south-east of the city, and concentrated around the river system throughout the city. The lowest greenery (in yellow) is instead found mostly cein the Central Business District, and in the north and west areas, where former black and coloured neighbourhoods were built in the 1960s. In these historically disadvantaged areas, parks are under-supplied, and riverbeds represent most of the greenery available.  

We found that some people make a livelihood from collecting grasses and tree pods, and that some interviewees found spending time in riverbeds relaxing. Most residents were however concerned for their safety in the riverbeds.

In many under-serviced areas, riverbeds are used for open defecation, residents of informal settlements are often mugged when commuting on foot to work through riverbeds, and the natural vegetation is used as a hiding place for criminals and burglars. In all neighbourhoods, old and overcharged pipes leak smelly sewage water in the rivers, making the whole area unpleasant and a health hazard. While being one of the most attractive areas of the cities, the current urban design and management of the city diminishes their sociocultural and wellbeing potential.

In response to these challenges, community and municipal initiatives are underway. Residents’ networks monitoring the safety of the neighbourhood and communal clean-ups are widespread. Furthermore, an initiative of a non-profit organisation in partnership with the City of Windhoek is aiming to develop part of the riverbeds and surrounding vacant land into public areas of socio-economic opportunity, maintaining the ecological role of the riverbeds.

Nevertheless, if riverbeds were managed as natural urban parks preserving the local flora and fauna, riverbeds in Windhoek could have the added benefit of decreasing environmental injustice and providing much needed public space for social integration and the connection of historically segregated neighbourhoods. The human wellbeing value of green spaces and riverbeds should indeed be considered alongside their ecological functions in the design and management of the city. Public support for the conservation of natural areas that improve the wellbeing of residents could increase stewardship of green spaces amidst densification and development pressures.