The implementation of agro-ecological practices such as rotation diversification and cover crop are a well-known solution for limiting pollutions and developing ecosystem services (e.g. soil fertility, biological regulations, climate change regulation). However, covering soils may significantly modify water flow in soils and hydrosystems with possible trade-offs between green and blue water flows. Accordingly, one key issue is to assess to what extent the development of diversified agricultural systems at landscape level can lead to water shortage problems in watersheds. To deal with this issue, we are implementing an integrated assessment and modelling (IAM) approach to assess impact of scenarios of development of agro-ecological practices in the Aveyron basin (800 km²) located in the southwest of France. This catchment is characterized by an intensive agriculture dominated by feedstock cereals and irrigated maize cropping and frequent and intense water shortage issues. The MAELIA multi-agent simulation platform (http://maelia-platform.inra.fr/) is used to perform the IAM approach. MAELIA simulates interactions between the farming practices, hydrology of the different water resources and water management decisions within a catchment area, at high spatial (field) and temporal (day) resolutions. It therefore allows the assessment of environmental, economic and social impacts of the combined changes in agricultural activities, water management strategies and climate. In this study, MAELIA is run on different scenarios in order to assess effects of irrigation optimisation, rotation diversification, cover crop, apply alone or in combination in different locations. The final objective is to identify to what extent there are important trade-offs between agricultural and water resource issues and what would be strategies to limit or overcome these trade-offs. Results of the whole set of simulations will be presented during the conference.