Dilution effect in SC2: In all the stations, concentrations of Na+ and Cl were lower in SC2 (mean over all stations = 6.2 mg/l for Na+ and 8.3 mg/l for Cl) than in SC1 (mean over all stations = 7.3 mg/l for Na+ and 9.9 mg/l for Cl), which reflects the dilution effect due to higher discharge in SC2. This is further supported by the concentrations of Ca2+ and K+, which are lower in SC2 in all the stations (mean over all stations = 40.2 mg/l for Ca2+ and 1.5 mg/l for K+) compared to SC1 (mean over all stations = 65.8 mg/l for Ca2+ and 2.2 mg/l for K+) (Table S1, Fig. 3).