Sustainable Asset Valuation of Nature-Based Flood Mitigation Infrastructure in Drakenstein, South Africa

The analysis finds that investing in nature-based infrastructure (NBI) in Drakenstein, South Africa, can reduce flood damages by up to USD 36 million against costs of USD 8.65 million over 25 years. The study indicates a benefit-cost ratio of up to 5:1 (ZAR 5 return for every ZAR 1 invested), with net benefits reaching ZAR 600 million (USD 34.2 million). These benefits include avoided flood damages, job creation, and improved mental health, with NBI proving most valuable in climate scenarios characterized by frequent and intense floods.

• Nature-based infrastructure (NBI) in Drakenstein can reduce flood damages by up to USD 36 million, which significantly exceeds the projected costs of USD 8.65 million over a 25-year period. The value of NBI increases in climate scenarios featuring intense and frequent floods.
• The investment in NBI offers a high return on investment, with a potential return of between ZAR 1 and ZAR 5 for every ZAR 1 invested over 25 years, resulting in net benefits of up to ZAR 600 million (USD 34.2 million).
• The proposed NBI scenario covers 214 hectares and includes the restoration of riverbanks and floodplains, the creation of constructed wetlands, and the development of urban green spaces. This approach aims to address flooding caused by extreme rainfall, human encroachment on floodplains, and degraded river and wetland systems.
• Beyond flood mitigation, NBI provides socio-economic and environmental co-benefits, including the creation of jobs, the value of recreational areas, and the reduction of mental health impacts.

APA

Guzzetti,, H. C. B. (2025). Sustainable Asset Valuation of Nature-Based Flood Mitigation Infrastructure in Drakenstein, South Africa. International Institute for Sustainable Development. https://www.iisd.org/publications/report/flood-mitigation-infrastructure-drakenstein-south-africa

Chicago

Guzzetti,, Henri Contor,Ronja Bechauf,Marco. Sustainable Asset Valuation of Nature-Based Flood Mitigation Infrastructure in Drakenstein, South Africa. International Institute for Sustainable Development, 2025. https://www.iisd.org/publications/report/flood-mitigation-infrastructure-drakenstein-south-africa.

Wikipedia

{{cite report |last1=Guzzetti, |first1=Henri Contor,Ronja Bechauf,Marco |title=Sustainable Asset Valuation of Nature-Based Flood Mitigation Infrastructure in Drakenstein, South Africa |publisher=International Institute for Sustainable Development |date=12 February 2025 |url=https://www.iisd.org/publications/report/flood-mitigation-infrastructure-drakenstein-south-africa |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{guzzetti2025sustainable, author = {Guzzetti,, Henri Contor,Ronja Bechauf,Marco}, title = {{Sustainable Asset Valuation of Nature-Based Flood Mitigation Infrastructure in Drakenstein, South Africa}}, institution = {International Institute for Sustainable Development}, year = {2025}, month = feb, url = {https://www.iisd.org/publications/report/flood-mitigation-infrastructure-drakenstein-south-africa}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }