City to city learning and knowledge exchange for climate resilience in southern Africa

replacing water intensive plants with indigenous alternatives that are drought tolerant and allowing only public green spaces to be watered and this through wastewater irrigation [65]. More raw water is available from Harare city’s river catchment, where the Greater Harare area receives an average of more than 700mm of rainfall per rainy season as compared to Wind- hoek’s paltry 365mm and where very high mean evaporation rates (3,400mm) per year exist. Another issue is the reliance of these cities like Lusaka and CoW, on external and far water sources namely Kafue, Omatako, Swakoppoort and Von Bach dams located some 60 km to 200 km away from the cities; and Kafue River where several projects have and continue to take place to increase abstraction for Lusaka. Climate-induced flash floods and intense rainfall cou- pled with inadequate stormwater infrastructure result in health implications that are associated with unhealthy, sanitary conditions and affect vulnerable communities such as in Kanyama and Kalikiliki informal settlements of Lusaka. While Harare and Lusaka are also challenged with solid waste management, CoW in contrast has a reliable solid waste management plan and it implements ward contractor systems in informal settlements where waste is picked up weekly at households and business with daily clean-up of open spaces. This is a good practice that many African cities which also have high informal settlements can learn from as the cities struggle with solid waste disposal management of which the city of Harare, once called the

‘sunshine city’ because of its historic efficacious waste management systems from decades ago, is no exception. Harare and Lusaka municipalities, which can learn from CoW, appear to have failed to effectively deal with solid waste as well as waste water treatment as over the years, increased mushrooming of informal dumping sites and decomposed piles of garbage now characterize the cities; broken sewer pipes discharge raw waste into clean water sources and the provision of clean water is still way below the expected standards. Lessons were also learnt on waste management from Durban, which has numerous fully engineered landfill sites; one of which is the award-winning site at Buffelsdraai. The land recla- mation in the buffer zone of the Buffelsdraai landfill through planting of indigenous trees, is an example of climate adaptation and mitigation being practiced by the local authorities; through green job creation, carbon sequestration, and land restoration. The tree planting proj- ect in Durban which uses ‘treepreneurs’ in a Community Reforestation Project presented a via- ble option to planting trees around the city of Lusaka to increase the green spaces in the city. The Sihlanzimvelo Programme, which uses local community businesses to deal with the issue of waste and alien plants causing flooding of streams and rivers by blocking the waterways dur- ing flood events, was another learning opportunity from Durban for Lusaka. The city of Durban also illustrated the importance of biodiversity and ecological ‘green’

infrastructure as part of the urban ecosystem; and how the incorporation of this bioresource into city planning is important for building resilience and as part of the climate action response. This lesson is important for other southern African/African cities where bioresource conservation is often not a priority because city planners and decision-makers may not view the city as an ecosystem. In contrast to Durban, the city of Harare appears to be failing in the area of biodiversity conservation by allowing development in and around its wetlands [66]. Developments on wetlands in the past two decades are leading to less groundwater and throughflow recharge to the city’s rivers and eventually the reservoirs as wetlands are a major source of water for the city [67]. Despite the importance of these wetlands and their function as part of the city’s river recharge system and therefore the need for conservation measures [68], there has been unprecedented encroachment and degradation of wetlands across the city of Harare. This has posed a threat to the delicate wetland ecosystems and subsequent services and in this case the availability of raw and clean water for the city’s use. Informal settlements. The exchange visits to Lusaka and Windhoek; and illustrated to a lesser extent in Durban; showed high proportions of informal settlements in the cities with the City learning in southern Africa PLOS ONE | https://doi.org/10.1371/journal.pone.0227915 January 24, 2020 13 / 25