Abstract. The hydrological and biogeochemical response of rivers carries information
about solute sources, pathways, and transformations in the catchment. We
investigate long-term water quality data of 11 Swiss catchments with the
objective to discern the influence of major catchment characteristics and
anthropic activities on delivery of solutes in stream water. Magnitude,
trends, and seasonality of water quality samplings of different solutes are
evaluated and compared across catchments. Subsequently, the empirical
dependence between concentration and discharge is used to classify the
solute behaviors. While the anthropogenic impacts are clearly detectable in the concentration
of certain solutes (i.e., Na+, Cl−, NO3, DRP), the influence
of single catchment characteristics such as geology (e.g., on Ca2+ and
H4SiO4), topography (e.g., on DOC, TOC, and TP), and size (e.g., on
DOC and TOC) is only sometimes visible, which is also because of the limited sample
size and the spatial heterogeneity within catchments. Solute variability in
time is generally smaller than discharge variability and the most
significant trends in time are due to temporal variations of anthropogenic
rather than natural forcing. The majority of solutes show dilution with
increasing discharge, especially geogenic species, while sediment-bonded
solutes (e.g., total phosphorous and organic carbon species) show higher
concentrations with increasing discharge. Both natural and anthropogenic
factors affect the biogeochemical response of streams, and, while the
majority of solutes show identifiable behaviors in individual catchments,
only a minority of behaviors can be generalized across the 11 catchments
that exhibit different natural, climatic, and anthropogenic features.
Anthropogenic and catchment characteristic signatures in the water quality of Swiss rivers: a quantitative assessment
