Sustainable Asset Valuation (SAVi) of Stormwater Infrastructure Solutions in Johannesburg, South Africa

This report presents a Sustainable Asset Valuation (SAVi) assessment of three stormwater infrastructure options in the Paterson Park Precinct of Johannesburg, South Africa: a grey concrete culvert, a nature-based stream renaturalization, and a hybrid solution. Using data from the Copernicus Climate Change Service (C3S), the study compares these options through an integrated cost-benefit analysis (CBA) and climate change scenario analysis over 20- and 40-year horizons. The findings demonstrate that nature-based infrastructure is the most cost-efficient and climate-resilient choice, providing significant co-benefits in flood mitigation and water supply.

• The nature-based stream renaturalization is the most cost-efficient and value-generating investment among the three options, requiring the lowest upfront capital costs and providing the highest net benefits across all climate scenarios.
• Avoided flood damages represent the largest monetary benefit for nature-based solutions. Full stream renaturalization avoids approximately ZAR 103 million in flood damage costs over 20 years and over ZAR 184 million over 40 years, while the hybrid solution avoids approximately ZAR 87 million and ZAR 168 million over the same periods.
• Nature-based infrastructure provides significant additional water supply through increased soil permeability and groundwater recharge. Over 40 years, the renaturalized stream generates an estimated economic benefit of ZAR 55.52 million from additional water supply, which alone outweighs the total project costs by approximately ZAR 3.4 million.
• Grey stormwater infrastructure (concrete culvert) is the least efficient option, characterized by the highest upfront investment and a lack of environmental or social co-benefits, resulting in negative net results of approximately ZAR -85 million over both 20- and 40-year horizons.
• Climate scenario analysis indicates that nature-based infrastructure becomes increasingly advantageous as precipitation patterns become more volatile. While the RCP 6.0 scenario results in the poorest performance for all options due to a higher frequency of extreme rainfall, the renaturalized stream remains the most resilient.
• Beyond flood and water benefits, nature-based solutions provide additional socio-economic co-benefits, including income creation from labor-intensive maintenance, increased property values in surrounding neighborhoods (assumed at a one-time 2% increase), and carbon sequestration from planted trees.

APA

Uzsoki, D. (2021). Sustainable Asset Valuation (SAVi) of Stormwater Infrastructure Solutions in Johannesburg, South Africa. International Institute for Sustainable Development. https://www.iisd.org/system/files/2021-04/savi-stormwater-johnannesburg-south-africa.pdf

Chicago

Uzsoki, David. Sustainable Asset Valuation (SAVi) of Stormwater Infrastructure Solutions in Johannesburg, South Africa. International Institute for Sustainable Development, 2021. https://www.iisd.org/system/files/2021-04/savi-stormwater-johnannesburg-south-africa.pdf.

Wikipedia

{{cite report |last1=Uzsoki |first1=David |title=Sustainable Asset Valuation (SAVi) of Stormwater Infrastructure Solutions in Johannesburg, South Africa |publisher=International Institute for Sustainable Development |date=April 2021 |url=https://www.iisd.org/system/files/2021-04/savi-stormwater-johnannesburg-south-africa.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{uzsoki2021sustainable, author = {Uzsoki, David}, title = {{Sustainable Asset Valuation (SAVi) of Stormwater Infrastructure Solutions in Johannesburg, South Africa}}, institution = {International Institute for Sustainable Development}, year = {2021}, month = apr, url = {https://www.iisd.org/system/files/2021-04/savi-stormwater-johnannesburg-south-africa.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }