In developing countries, cities development puts an increasing pressure on water resources in their peri-urban areas. While peri-urban catchments often offer important services to their related city, their functioning are durably affected by urbanisation. In this interface, domestic water uses compete with various other water needs such as irrigation, recreational uses, flood control, etc. It results in increased competitions over water availability and quality degradation. These competitions are all the more exacerbated, that it is often combined with a competition for access to land as cities fringe supports the urban expansion processes and presents very diversified modes of land occupation. In South America, these tensions are accentuated by the expulsion to the periphery of economically, politically or sociologically marginalized communities. In a context of implementation of new institutional arrangements for more participative and integrated land and water management, can we contribute to improve the negotiation processes in the periurban interface? The specific objectives of the Negowat research project are to : (1) Design and test a methodology to facilitate negotiation and the avoidance of conflicts by using tools permitting to integrate various types of knowledge and explore the functioning of periurban catchment through scenarios simulation; (2) To increase the capacity of Latin American partners to undertake participatory and multidisciplinary research; and (3) To increase the negotiation capacity and participation of marginalized communities, positioned at the periphery of the discussion processes. In Brazil, the work is being developed in two sub catchment of the Metropolitan Region of São Paulo, the Guarapiranga catchment and the Cabeiceras-Tietê catchment. In Bolivia, the work is developed in the valley area of the municipality Tiquipaya, in the metropolitan region of Cochabamba. This report presents the state of advancement and first results of the