Report

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

Methodology report and results of the application of the model to two pilot locations in Indonesia

Indonesia's complex geographical, climatic, and socio-economic context presents challenges for road infrastructure resilience. Traditional engineering approaches often struggle to address the range of natural hazards—landslides, erosion, and flooding—that threaten road infrastructure, especially when roads are built at the expense of natural land. Integrating nature back into the design and planning of road development offers a solution.

By Andrea Bassi, Liesbeth Casier, Marco Guzzetti on March 28, 2025

Key Messages

  • Nature provides significant value in enhancing road resilience by reducing direct costs associated with road damage and mitigating disruptions to road services.

  • By comparing the financial and economic benefits of NbS for road resilience, the analysis underscores the significance of recognizing the indirect and induced social, economic, and environmental benefits stemming from investments in road resilience.

This report discusses the development of integrated cost-benefit analysis to estimate the direct and indirect benefits of nature-based solutions (NbS) for road resilience in Indonesia. It presents a model developed to assess the contribution of nature in improving road resilience, and the results of two model applications in Indonesia. It describes the method used for quantifying the impacts of road disruption, particularly flooding, in both physical and economic terms, along with a mathematical model for conducting a comprehensive cost-benefit analysis of resilience investments. The model considers the impact of floods and landslides on road-related services, using climate forecasts and a spatially explicit assessment of relevant ecosystem services provided by nature in the proximity of roads.

The model was tested for two locations, but it can be applied to a variety of other road segments (existing or planned) in the future.

The report should be read in conjunction with the use of the Excel-based models applied to two pilot locations in Indonesia. It has been used for training of technical staff in the Ministry of National Development Planning (BAPPENAS).