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

This methodology report describes the development and piloting of an integrated cost-benefit analysis (CBA) model designed to estimate the direct and indirect benefits of nature-based infrastructure (NBI)—such as conservation and reforestation—for road resilience in Indonesia. The model expands traditional CBA by incorporating 'non-road' benefits, including socio-economic and environmental externalities, to provide a more holistic view of the value of investing in climate-resilient infrastructure.

• The report identifies that up to 65% of Indonesia's national road network is at risk from climate impacts and could be improved through conservation and restoration efforts.
• The developed model utilizes an 'integrated' or 'extended' cost-benefit analysis (CBA) that accounts for both tangible impacts (market-value cash flows) and intangible impacts (societal externalities) to determine the net contribution of resilience investments to society.
• The model uses an 'extreme wet event' indicator to estimate road damage, as floods and landslides are the most frequent natural hazards in Indonesia and are primarily caused by rainfall.
• The model quantifies 15 distinct non-road impacts resulting from road disruption, including fuel and vehicle O&M costs, travel time, air, noise, and water pollution, GHG emissions, nature and landscape harm, lost revenue from crops, fish, and livestock, access to essential services, access to workplaces and schools, and mental health impacts.
• In the Pekanbaru pilot, the Base Case scenario showed a benefit-to-cost ratio (BCR) of 11.45 and an internal rate of return (IRR) of 66.6% when non-road benefits were included, compared to a BCR of 0.89 and an IRR of -1.00% when they were excluded.
• In the West Kalimantan pilot, the Base Case scenario yielded a BCR of 6.05 and an IRR of 69.5% including non-road benefits, whereas the investment was not financially viable (BCR 0.35) when considering only road-related impacts.
• The pilot results demonstrate that while conventional CBAs focusing only on road-related impacts often show that costs outweigh benefits, the inclusion of non-road benefits makes nature-based resilience investments economically viable in both tested locations.
• The model's results are highly sensitive to local economic activity; for example, in Pekanbaru, livestock revenue and access to services were primary drivers, while in West Kalimantan, crop and fruit revenue (specifically palm oil) and air pollution were more significant.

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} }