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This study focuses on changes of biogeochemical parameters related to variable rainfall-runoff conditions and to land cover types for eight headwater catchments in Central Europe. Linear regression, Spearman rank correlation, principal component analysis and C/Q (concentration – discharge) hysteresis loops revealed the main relationships. The presence of peatbogs and waterlogged spruce forests had a decisive influence on the biogeochemistry (COD = chemical oxygen demand measured using the permanganate methodMn, humins, Fe, P-PO43− TP = total phosphorus, N-NO3−). The strongest positive correlation of organic matter and Fe is represented in a catchment with the largest area of damaged forest (70%), but with a smaller proportion of waterlogged areas (8%). High flow rates influence greater release of organic matter and N-NO3−. The catchment with the highest (80%) peatbog cover and the catchment that had undergone revitalization showed similar behaviour in terms of water biogeochemistry. The type of rainfall-runoff event affected the velocity of pH changes, whereas the variability in electric conductivity was also controlled by the catchment characteristics and hydrological preconditions. [ABSTRACT FROM AUTHOR]

This study investigates changes in seasonal runoff and low flows related to changes in snow and climate variables in mountainous catchments in Central Europe. The period 1966–2012 was used to assess trends in climate and streamflow characteristics using a modified Mann–Kendall test. Droughts were classified into nine classes according to key snow and climate drivers. The results showed an increase in air temperature, decrease in snowfall fraction and snow depth, and changes in precipitation. This resulted in increased winter runoff and decreased late spring runoff due to earlier snowmelt, especially at elevations from 1000 to 1500 m a.s.l. Most of the hydrological droughts were connected to either low air temperatures and precipitation during winter or high winter air temperatures which caused below-average snow storages. Our findings show that, besides precipitation and air temperature, snow plays an important role in summer streamflow and drought occurrence in selected mountainous catchments. [ABSTRACT FROM AUTHOR]