Stable isotope and deuterium excess progression across the study domain. (A) Stable isotope enrichment and (B) increasing Deuterium excess are related inversely to elevation. A clear influence of the high-discharge rain-fed basins below 430 m is observed. In (A), Global Network of Isotopes in Precipitation (GNIP) monthly mean isotope values indicate a contrasting temporal variation of precipitation isotopes throughout the year between alpine (left edge) and jungle (right edge) records. DOI: https://doi.org/10.1525/elementa.290.f7