Collaborative Watershed Modeling as Stakeholder Engagement Tool for Science-Based Water Policy Assessment in Sao Paulo, Brazil

This study describes a collaborative modeling process deployed at the Cantareira Water Supply System (CWSS) in Sao Paulo City Metropolitan Area, Brazil. The CWSS faces challenges for meeting the increasing water demand, while land-use and climate change and their combined effect on its water cycle and balance have created a complex water resources management problem. Through a stakeholder engagement process-involving scientists and policymakers, the water utility company, and state administration-environmental simulation models were developed to elicit and represent multiple environmental, economic, and policy perspectives, developing a mutual language to communicate and establish common goals of water resources management. Study outputs include estimation of biophysical and economic benefits associated with prioritized native vegetation restoration activities in the source watersheds. These outputs are deployed in support of landscape planning and the decision process integrating multiple stakeholder perspectives in Sao Paulo state administration, the water utility company, and municipalities.