The risk of flooding and soil erosion is rising because of the impacts of climate change: period of heat waves and drought are prolonged, and extreme rainfall events are becoming more intense and frequent. This worsening of climate conditions increases the vulnerability of transport infrastructure, the risk of undesirable movements of land and soil and the risk of flooding.

ADM (National Motorway Company of Morocco) is constantly working to combat water erosion and is deploying an important Research & Development programme in order to control the phenomenon via the modeling and mapping of erosion with the integration of prediction models: the aim is to determine the main high risk regions and find appropriate solutions.

With the research project conducted by ADM and carried out with GIZ, INRA and IPROconsult concerning the assessment and modeling of the risk of water erosion on highways in Morocco under the effect of climate change, an overall map of the risk of erosion in Morocco was developed. With this high-resolution modeling, the quantities of displaced materials (erosion / deposition) under the effect of precipitation specific to each region can be evaluated.

The simulations were carried out using the EROSION-3D model, which shows through physical laws the process of runoff formation and erosion for each given precipitation event.

In addition to the erosion risk overview map, medium-scale simulations were carried out in three potential-risk catchments. Consequently, the resilience of the drainage system of highway structures could be assessed, and relevant recommendations could be made.

The aim for the continuation of this project is to set up a monitoring system for a proactive management of the risk of erosion and flooding. In addition, a methodological handbook should be developed and used as a working tool for design engineers. This practical guide is aimed at contributing to a better management of the risk of flooding and water erosion in transport infrastructure projects, and may be extended to other land-use developments that are more vulnerable to this risk.

By strengthening the adaptation of infrastructures to future climatic conditions, this project responds directly to the overall objectives defined by the INDCs for Morocco: minimise the risk of the impacts of climate change and invest in adaptation to climate change. That is why this R&D project is set to continue. For a reproducible evaluation of the risk of erosion, an interdisciplinary approach is needed, with the implementation of integrated water management and the fight against soil degradation and desertification in the catchments along highways. This approach also aims to develop:

1. New contributions for strategic environmental planning to predict the potential benefits from the adoption of sustainable land management (SLM) practices that will minimize social and environmental risks to both road infrastructure and affected populations in rural areas.

1. The economic evaluation of the feasibility of adaptation measures to climate change (technical construction costs and economic aspects of the impact on affected land in the catchment areas of road sectors).