Sustainable water extraction on campus | University of Cape Town

UCT’s use of sustainable water-extraction and water-sensitive technologies on campus and in nearby living labs

UCT both implements on-campus rainwater-harvesting and water-sensitive measures (harvest tanks, reuse for irrigation/toilet flushing, metering and demand management) and leads off-campus pilots that experiment with sustainable water extraction/augmentation (stormwater harvesting, managed aquifer recharge) through its Future Water Institute and the PaWS living-lab work in Mitchells Plain. The interventions are a mix of operational installations (e.g., rainwater tanks on new builds) and research/pilot projects (stormwater pond retrofits, MAR trials) that are verified in official UCT reports and peer-reviewed outputs.

Below are the specific examples (2022–2025 reporting, with emphasis on 2023–2024 activity where available).

1. Rainwater harvesting and reuse on campus (operational examples)

d-School Afrika rainwater tanks (Upper/Middle Campus): UCT’s Khusela Ikamva sustainability reporting and UCT News explicitly note that the d-School Afrika building has rainwater storage tanks used to irrigate gardens and flush toilets as part of creating a water-sensitive campus. This is an on-campus, operational system rather than only a concept.
Engineering building / other harvest installations: UCT communications and social posts describe rainwater harvesting being built into new engineering and refurbishment projects as part of the university’s commitment to reduce water consumption and capture rain for non-potable uses (flushing/irrigation). (UCT News / social media reporting refers to rainwater capture on new builds.)
Institutional monitoring and strategy: UCT’s Water Task Team, Water Desk and Sustainable Water Management Strategy (UCTSWMS) — documented in presentations and project reports — explicitly list rainwater harvesting among the technical measures the university is exploring and implementing to improve campus water resilience. The “Day Zero” presentation (Oct 2024) lists rainwater harvesting, greywater, borehole drilling and treated effluent access as part of UCT’s practical responses.

2. PaWS living-lab (stormwater harvesting → Managed Aquifer Recharge) - off-campus, research-to-practice

PaWS living laboratory in Mitchells Plain (Fulham Road pond): The Pathways to Water-resilient South African cities (PaWS) project — led by UCT’s Future Water Institute with the University of Copenhagen (Danida funded) — has run a six-year living lab (2019–2025) in a stormwater detention pond in Mitchells Plain. The project tests nature-based solutions, stormwater treatment, stormwater harvesting and opportunities for managed aquifer recharge (MAR) to augment urban water supply and resilience. UCT News and PaWS project pages describe in detail the pond retrofit experiments and community engagement.
Peer-reviewed / technical evidence for pond retrofits & MAR: Research outputs linked to the PaWS work (and related projects) report empirical and modelled evidence that retrofitting detention ponds can significantly enhance infiltration and recharge to the Cape Flats Aquifer — for instance, a 2025 modelling study found retrofits increased recharge substantially and evaluated operational constraints (the study also notes monitoring challenges such as theft/vandalism in low-income areas). These are technical confirmations that UCT’s off-campus work uses sustainable extraction/augmentation methods (stormwater → aquifer recharge).
Policy / implementation guidance: Outputs from this research feed into implementation guidelines and WRC technical reports on retrofitting stormwater ponds with blue–green infrastructure to enhance MAR, an approach the PaWS project directly field-tested. These guidelines are intended to help cities and communities sustainably harness stormwater and augment groundwater supplies.

3. Campus-wide planning, pilots and evaluation work (integration and monitoring)

Khusela Ikamva (Secure the Future) project: This R10-million sustainable-campus research programme (supported by UCT’s Research Office) targets water as one of five research areas. The project has funded feasibility work, rainwater-harvesting assessments, living-lab pilots and monitoring to shift UCT to a water-sensitive campus. The campus project documents and news items (2022–2024) report progress on harvesting, monitoring and behaviour change campaigns.
Rainwater-harvesting feasibility and technical studies: UCT academics (Civil Engineering / Future Water) have produced feasibility studies assessing the yield, storage sizing and economic viability of rainwater harvesting across representative buildings on UCT’s Upper and Middle campuses. Peer-reviewed and institutional reports (2024–2025) analyse harvestable rainfall, yield-after-spillage methods and multi-criteria assessments for implementing RWH systems on residences and other buildings — confirming that UCT is systematically evaluating and planning rainwater systems backed by technical analysis. The viability of rainwater harvesting (RWH) as a fit-for-purpose water source for supply at the University of Cape Town (UCT) was investigated to reduce dependence on municipal water treated to unnecessarily high standards for purposes like toilet-flushing. Representative buildings on the UCT Upper and Middle Campuses, a parking area, and the tennis court on Upper Campus were identified as potential catchment areas. The ‘Yield after spillage’ (YAS) algorithm was used to identify the relationship between water demand and supply for various flush frequencies and storage sizes. The cost savings from harvested rainwater were estimated using the City of Cape Town (CoCT) 2021/2022 tariffs for Level 1 and Emergency Response water restrictions. A 20-year discount period and a 4% interest rate were used to determine the capital recovery amounts of the cost of ownership of the RWH systems. A multi-criteria analysis (MCA) tool that considered 3 weighting scenarios of the harvestable rainfall and economic viability was used to identify the most viable RWH systems. It was found that student residences could potentially reap the greatest benefits from installing RWH systems. Approximately 4 900 kL·yr−1 and 4 000 kL·yr−1 of rainwater can be harvested from Woolsack and Fuller Hall, respectively, if 100 kL tanks are provided, depending on the toilet flush frequency. The tennis court was identified as the most viable catchment for RWH. Approximately 7 500 kL·yr−1 of rainwater could be harvested if 1 000 kL tanks are provided when the rainwater from the tennis court catchment is supplied to all Upper Campus buildings. It was also concluded that UCT is in a relatively good location for RWH due to its rainfall pattern as compared with those enjoyed by other universities across South Africa.
Operational measures taken during drought (‘Day Zero’ response): UCT’s Day-Zero review and presentation describe actions taken (2017–2018 drought response and subsequent resilience building): digital metering, leak detection, buckets & behaviour change campaigns, geohydrological surveys and borehole drilling, exploration of treated effluent access, and a programmatic push to harvest rain and stormwater as alternative supplies. This shows UCT’s sustainability strategy includes sustainable extraction and alternative supply technologies.