Ensuring sustainable water provision in the face of extreme precipitation events and human land use in the watersheds of the Cantareira System
Collaborators: Jean Paul Metzger (University of São Paulo – USP, Brazil) and Leandro Reverberi Tambosi (Federal University of ABC – UFABC, Brazil).
One of the most urgent challenges facing the world today is ensuring an adequate supply and quality of water in light of burgeoning and often conflicting human and ecosystem needs and climate variability and change. Humans influence water provision in a number of ways. They engineer water management structures and develop governance systems to meet diverse needs; these include water consumption, ecosystem protection, flood control and storm water management. Human impacts on water provision also occur through land use and land cover change in watersheds while substantial indirect effects occur via the atmosphere and hydrosphere. Any effort to ensure the sustainability of water provision to humans and ecosystems within existing water management systems must take into account the compounded effects of climate variability, particularly precipitation, and human land use dynamics on water supply and quality.
This project will quantify the relative importance of extreme precipitation events and LUCC dynamics on the quantity and quality of fresh water delivery to rivers and reservoirs in the watersheds from the Cantareira system, which provide water to the São Paulo Greater Metropolitan Region (RMSP). With more than 20 million people, the RMSP is often subject to extreme rainfall events and climate models predict increased climate variability for the region. Between 1950 and 2003, the frequency and intensity of rainfall increased in this region and regional climate models predict an increase in the frequency of these events. In 2013-2014, regional drought has brought the levels of reservoirs in the Cantereira system to 14% of their capacity, a historical low, highlighting the vulnerability of the large urban population to climate extremes.
Figures 1 and 2. Historically low levels in the Bragança Paulista Reserevoir (left) and water levels in the Jaguari Reservoir in March 2014, São Paulo, Brazil (Photos: SABESP-SP).
Figure 3. Schematic of the Cantareira System.