Developing and Piloting a Model for Estimating the Direct and Indirect Benefits of Nature-Based Solutions for Road Resilience in Indonesia

The report introduces an Excel-based model designed to quantify the financial and economic viability of nature-based solutions (NBI), such as reforestation and mangrove restoration, to enhance road resilience against climate-induced hazards like floods and landslides in Indonesia. Moving beyond traditional CBAs, the model incorporates 'non-road benefits'—including socio-economic externalities like mental health, market access for crops and livestock, and air pollution—to provide a holistic view of investment value. The model was piloted in two distinct locations: Pekanbaru (an urban-rural connection) and West Kalimantan (a rural area). Results demonstrate that while conventional CBAs focusing only on road-related costs often show that costs outweigh benefits, the inclusion of non-road benefits makes these investments economically viable in all tested scenarios. For instance, in the Pekanbaru base case, the benefit-to-cost ratio (BCR) rose to 11.45 when non-road benefits were included.

• Traditional cost-benefit analyses that exclude non-road benefits indicate that the costs of road resilience investments outweigh the benefits in both pilot locations.
• Integrating non-road benefits into the analysis makes nature-based infrastructure investments economically viable across all five tested scenarios for both Pekanbaru and West Kalimantan.
• In the Pekanbaru base case scenario, the model estimates a benefit-to-cost ratio (BCR) of 11.45 and an internal rate of return (IRR) of 66.6% when non-road benefits are included.
• In the West Kalimantan base case scenario, the inclusion of non-road benefits results in a BCR of 6.05 and an IRR of 69.5%.
• The relative importance of non-road benefits varies by location: Pekanbaru is most impacted by livestock revenue, access to essential services, and access to workplaces/schools, while West Kalimantan is most impacted by crop and fruit revenue and air pollution.
• The model identifies 15 distinct non-road indicators for economic valuation, ranging from tangible costs like fuel and vehicle O&M to intangible impacts such as mental health and noise pollution.

APA

Bassi, A. M., Guzzetti, M., & Casier, L. (2025). Developing and Piloting a Model for Estimating the Direct and Indirect Benefits of Nature-Based Solutions for Road Resilience in Indonesia. International Institute for Sustainable Development. https://www.iisd.org/system/files/2025-03/indonesia-nature-based-solutions-road-resilience.pdf

Chicago

Bassi, Andrea M., Marco Guzzetti, and Liesbeth Casier. Developing and Piloting a Model for Estimating the Direct and Indirect Benefits of Nature-Based Solutions for Road Resilience in Indonesia. International Institute for Sustainable Development, 2025. https://www.iisd.org/system/files/2025-03/indonesia-nature-based-solutions-road-resilience.pdf.

Wikipedia

{{cite report |last1=Bassi |first1=Andrea M. |last2=Guzzetti |first2=Marco |last3=Casier |first3=Liesbeth |title=Developing and Piloting a Model for Estimating the Direct and Indirect Benefits of Nature-Based Solutions for Road Resilience in Indonesia |publisher=International Institute for Sustainable Development |date=March 2025 |url=https://www.iisd.org/system/files/2025-03/indonesia-nature-based-solutions-road-resilience.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{bassi2025developing, author = {Bassi, Andrea M. and Guzzetti, Marco and Casier, Liesbeth}, title = {{Developing and Piloting a Model for Estimating the Direct and Indirect Benefits of Nature-Based Solutions for Road Resilience in Indonesia}}, institution = {International Institute for Sustainable Development}, year = {2025}, month = mar, url = {https://www.iisd.org/system/files/2025-03/indonesia-nature-based-solutions-road-resilience.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }