STABLE ISOTOPES (d2H and d18O): UNVEILING THE ORIGINS OF SURFACE WATER IN SÃO PAULO STATE WATERSHEDS

Abstract

Stable hydrogen and oxygen isotopes of (1H, 2H, 16O e 18O) are important tools in understanding the movement of water along the hydrological cycle. In favorable conditions, knowledge of the isotopic composition of the main water sources (precipitation and groundwater) can be used for quantify the spatial and temporal variations of the contributions these sources in the stream flow, allowing the understanding the regional hydrological system. Based on these premises, the present project aims to study the isotopic composition variation in the watersheds of the Water Resources Management Units (WRMU) Piracicaba/Capivari/Jundiaí (WRMU 5) e Tietê/Jacaré (WRMU 13) for the understanding of factors directly related to hydrologic dynamic in the Sao Paulo State. The area presents great environmental representativeness with aquifers of diversified characteristics directly influencing the importance of the contribution base stream of the studied rivers. As well as the characteristics of the relief and the spatial variation of the precipitation that can influence the isotopic composition. The study presents a methodology little applied the local environmental characteristics to study surface water resources using stable isotopes. The proposal represents an important instrument for the management water resources, providing the understanding of the interaction between the components of the hydrological cycle to delineate actions outline actions that protect the source and allow to conserve strategic water reserves in the current context of water scarcity.