We collected water samples from the river surface using a pre-rinsed HDPE 1 L bottle. A subsample for stable isotope analyses was decanted into a pre-rinsed polyethylene bottle, which was filled with minimal to no airspace and then kept cool (4°C) and dark until analysis. Oxygen (δ¹⁸O) and hydrogen (δD) isotopes were measured at the ISOLAB Facility at the Alfred Wegener Institute (AWI) Potsdam with DELTA-S Finnigan MAT mass spectrometers (USA) employing the equilibration method, described in Meyer et al. (2000). The isotope ratios are reported in per mil (‰) relative to the Vienna Standard Mean Ocean Water (VSMOW) as the international reference standard. Isotope compositions were calibrated against reference materials from the International Atomic Energy Agency (IAEA) including SLAP2, GRESP, and VSMOW2 and in-house reference materials, resulting in a precision of analyses of 0.1 – 2‰. An independent quality control was carried up against reference materials from the United States Geologic Survey (USGS) which were run as quality control. Deuterium excess (d) was calculated according to the equation (after Dansgaard, 1964): d = δD − 8 × δ¹⁸O.