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Water discharge and suspended and dissolved sediment data from three rivers (Napo, Pastaza and Santiago) in the Ecuadorian Amazon basin and a river in the Pacific basin (Esmeraldas) over a 9-year period, are presented. This data set allows us to present: (a) the chemical weathering rates; (b) the erosion rates, calculated from the suspended sediment from the Andean basin; (c) the spatio-temporal variability of the two regions; and (d) the relationship between this variability and the precipitation, topography, lithology and seismic activity of the area. The dissolved solids load from the Esmeraldas basin was 2 × 106t year-1, whereas for the Napo, Pastaza and Santiago basins, it was 4, 2 and 3 × 106t year-1, respectively. For stations in the Andean piedmont of Ecuador, the relationship between surface sediment and the total sediment concentration was found to be close to one. This is due to minimal stratification of the suspended sediment in the vertical profile, which is attributed to turbulence and high vertical water speeds. However, during the dry season, when the water speed decreases, sediment stratification appears, but this effect can be neglected in the sediment flux calculations due to low concentration rates. The suspended sediment load in the Pacific basin was 6 × 106t year-1, and the total for the three Amazon basins was 47 × 106t year-1. The difference between these contributions of the suspended sediment load is likely due to the tectonic uplift and the seismic and volcanic dynamics that occur on the Amazon side. EditorZ.W. Kundzewicz CitationArmijos, E., Laraque, A., Barba, S., Bourrel, L., Ceron, C., Lagane, C., Magat, P., Moquet, J.-S., Pombosa, R., Sondag, F., Vauchel, P., Vera, A., and Guyot, J.L., 2013. Yields of suspended sediment and dissolved solids from the Andean basins of Ecuador.Hydrological Sciences Journal, 58 (7), 1478–1494. [ABSTRACT FROM AUTHOR]

A total of 40 water samples were collected from five sites in the Danjiangkou Reservoir, an important drinking water source in China. Over the period November 2004-June 2006, eight field surveys were conducted and water temperature, pH, EC, major ions (Na+, K+, Ca2+, Mg2+, Cl-, [image omitted] and [image omitted]) and Si were monitored to determine their temporal and spatial patterns across the reservoir. The controlling factors were analysed using the stoichiometry of the water chemicals and multivariate statistics including a correlation matrix and analysis of variance. The results revealed that waters in the reservoir are sub-alkaline and have a low solute load, and most water variables exhibit notable spatial and temporal variations. The major ion chemistry of the reservoir was controlled by carbonate weathering (of limestone) with the dominant ions Ca2+ and [image omitted] contributing 63-81% and 73-81% to the major cation and anion budgets, respectively. Carbonate dissolution was produced by both sulfuric and carbonic acids; in particular carbonic acid and silicate contributed little to the reservoir waters, while [image omitted] was important and originated primarily from anthropogenic inputs. This research will help water quality conservation in the Danjiankou Reservoir, China. Citation Li, S. & Zhang, Q. (2010) Major ion chemistry and weathering processes of the Danjiangkou Reservoir, China. Hydrol. Sci. J. 55(8), 1385-1395. [ABSTRACT FROM AUTHOR]