Evaluating the impact of climatic changes on streamflow in headwater mountain catchments with varying human pressure. An example from the Tatra Mountains (Western Carpathians)

Abstract

Study region: Tatra Mountains, Western Carpathians Study focus: Our study aims to assess the impact of climatic changes on streamflow in headwater mountain catchments with varying human pressure. The research bases on hydrological and climatological data from a period 1971–2020 and includes trend analysis, wavelet analysis and paired catchment observations, comparing semi-natural and human-altered catchments. New hydrological insights for the region: Air temperature has increased (+0.4°C decade−1) in the region. Precipitation totals remained unchanged, however annual snowfall totals decreased (−69 mm decade−1, ∼6.3%) at the expense of rainfalls, especially in winter. Air temperature and precipitation exhibited altitude-dependent changes. Snow depths remained stable; however, snow cover duration has shortened (−2 to −4 days decade−1). The observed climatic changes have led to an increase in annual low flows (+7–11.5% decade−1), as well as winter low, average, and high flows, affecting the timing of snowmelt runoff. Streamflow changes were more pronounced in semi-natural catchments. Climatic-driven trends in streamflow were more evident in winter, whereas trends associated with human activities and land use were detected throughout the year. Discharge was more coherent with precipitation in human-altered catchments, and weaker in semi-natural catchments. The intensification of annual cycle in precipitation and semiannual cycle in snow cover at high altitudes, along with the intensification of semiannual cycle in streamflow, provide evidence of ongoing climatic changes.

Keywords

• Streamflow
• Climate change
• Human pressure
• Air temperature
• Precipitation
• Snow cover