Dar es Salaam in Tanzania is predicted to double in population by 2050. Growth of this magnitude and pace poses real challenges for the city, increasing an already high risk of flooding, urban heat, land degradation and soil erosion.
With our environmental engineering credentials top of mind, Arup was asked to assess how urban greening could help solve these issues and increase climate resilience. In collaboration with the Tanzanian Government, the World Bank and specialist local partners, our research explored the benefits of implementing nature-based solutions over grey infrastructure in Dar es Salaam. Insights from this assessment will allow for climate resilient urban development and infrastructure plans to overcome the challenges of flooding, water availability and rising temperatures. Our suggested greening interventions have the potential to improve quality of life, especially for those in low-income settlements.
Adding up the impacts of urban greening and nature-based solutions
Nature-based solutions are becoming a more established way of supporting climate resilience and biodiversity, but their impacts are rarely quantified. Framed on numerical evidence, our study’s aim was to assess the benefits of interventions such as urban greening, open space development, erosion control, and sustainable urban drainage systems.
We analysed existing land use to estimate the scale, extent, and types of greening interventions that could exist in the future. We found that, if greening interventions were incorporated by 2030, 300 Olympic-size swimming pools of rainfall (730,000m3) could be stored in the soil, helping replenish ground water supplies, restore soil health and support urban agriculture.
Our team created geospatial data to estimate Dar es Salaam’s future pattern of urbanisation for 2023, 2030, and 2040 projections. The data was presented through a series of maps showing changes over time, enabling our team to identify opportunities for city-wide greening across new developments and infrastructure. We proposed interventions based on their suitability for the city’s 17 dominant land types, enabling calculations to be completed on their impacts and visualising the benefits of greening on the lives of local people.