This project merges three waste-related research endeavours to get a holistic understanding of waste challenges in Gauteng. The project has three components, running concurrently:

Component 1 (River plastic waste and wetland assessment using airborne radar data) is a Council for Scientific and Industrial Research (CSIR)-led campaign that is flying high-resolution radar and hyperspectral imagery over parts of the Gauteng City-Region (GCR). This is a collaborative project between the CSIR, the University of Pretoria and commercial stakeholders. Multiple collaborative projects have spawned from this campaign, and the Gauteng City-Region Observatory team will be involved in two of them: 1) Hennops River plastic island mapping using high-resolution multi-frequency (C- and L-band) SAR imagery; 2) Soil moisture estimation and teal carbon estimation using multi-frequency SAR in the Colbyn Wetland Nature Reserve (CWNR) in the City of Tshwane. These projects have strong links to the Sustainable Development Goals (SDGs) within the urban GCR boundary. The plastic island topic relates to SDGs 6 and 12, aiding monitoring of plastic waste, mainly in marine environments, using satellite sensors. Urban river studies are limited by narrow, obscured tributaries, but airborne SAR's high resolution and tree-penetrating capability make this possible. Separately, soil moisture and teal carbon estimation in CWNR support SDG 6 (target 6.6) and South Africa’s Wetland Monitoring. It also supports SDG 13 on climate action, with long-term goals to develop detailed airborne estimates that can be scaled to satellite data such as Sentinel-1 and ALOS PALSAR-2.

Component 2 (River plastic waste inventory) is a collaboration with Hanellie Cotzee, Kula Foundation, Alex Water Warriors, the University of California, Riverside (UCR), and the Moore Institute of Plastic Pollution Research. The objective of the project is to 1) use tools developed at UCR to effectively and robustly collect data on litter, specifically on plastic concentrations, characteristics, mass, and sources, in the aquatic river systems in Alex. 2) Use a citizen science approach through partnerships with a grassroots organisation, the Alex Water Warriors, to collect the information on litter in the aquatic system in their community. 3) This information will be used to identify waste management issues in the community and, in turn, inform policy development to better deal with these issues. In addition to contributing to the current literature on litter concentration estimates in river systems, which is currently lacking in the global south, the data will be used to identify waste management issues and, in turn, to inform policy development to address them.

Component 3 (Re-imagining waste in Gauteng) builds on research conducted in Diepsloot with UCL STEaPP, which examined nature-based solutions (NbS) and urban water management and revealed that inadequate waste collection led residents to dispose of waste in a nearby wetland. Expanding on these findings, the project explores the intersection of waste management, community engagement, and NbS across Gauteng, deploying geospatial, remote sensing, and GIS methods to detect illegal dump sites, map waste valorisation, map service delivery gaps against environmental vulnerability, and support waste management monitoring. These technological approaches are grounded in participatory methods - with residents as co-producers of spatial knowledge. With landfill capacity rapidly depleting in Johannesburg, the research centres waste reduction, recycling, and ecosystem restoration as essential alternatives, aligning with the Gauteng Department of Environment's provincial waste management priorities.

Project activity updates

Fieldwork was conducted in both study areas during the airborne campaign for Component 1 of the project. The campaign acquired an average of three images per month from January to May 2022 across a variety of land-use types (e.g., farming, urban, aquatic wetlands and rivers, and mining and defence). The initial project duration is expected to be two years, with an additional three years (starting in 2023) for the two PhD students who will be recruited to achieve some of the goals set out for this project.

Outputs

Related Publications

van Deventer, H., Naidoo, L., Apleni, P., Le Roux, J., Blaauw, C., Nel, W. and Tema, H. (2025). 'Remote sensing monitoring of soil moisture for South African wetlands'. The Water Wheel, 24 (2), p.28-31.

Selected Presentations

Samkelisiwe Khanyile and Samiksha Singh (August 2025). ‘Sustainability and Just Transitions theme research overview’: Waste projects, GCRO Waste Workshop, Wits Club, 20 August 2025.

Media Engagements

Dr Samiksha Singh, GCRO Researcher, was interviewed and cited in SUNCASA: Turning trash into treasure along the Jukskei River in Johannesburg

Dr Samiksha Singh, GCRO Researcher, was interviewed and cited in Reviving the Jukskei: Community, Art, and Science Unite to Restore Johannesburg’s Polluted River

Dr Samiksha Singh, GCRO Researcher, was interviewed and cited in Bid to save polluted Joburg river: Activists, scientists and artists come together to clear waste from the Jukskei River in Alexandra

Events

In August 2025, the project team held a Waste Management Workshop. The workshop brought together a diverse group of stakeholders from government, community organisations, academia, and other sectors, all united by a shared commitment to addressing waste management challenges in the Gauteng City-Region. Participants had the opportunity to learn about GCRO's current waste management initiatives and gain valuable insights into the work being carried out by other organisations in the field. Key issues and critical challenges related to waste management and pollution in the region were identified through open, constructive dialogue and engaging group activities. Several promising opportunities for partnership and collaboration emerged from the discussions. The workshop was a meaningful first step forward in GCRO's broader efforts to foster collective action and drive sustainable waste management solutions across the Gauteng City-Region.

Photo taken during the Waste Management Workshop held on 20 August 2025. Photo credit: Dr Samiksha Singh.

Last updated: 26 May 2026