Climate Change and Human Impact on Freshwater Water Resources: Rivers and Lakes

Different patterns of phenomena observed in rivers (water stages, discharges, water temperature and chemistry, ice phenomena, etc.) in an average annual cycle, determined by climate and catchment properties, are relatively stable. Under the influence of changing climatic conditions and increasing human impact, a flow regime might destabilize and turn over to another with sometimes quite different seasonal patterns, thus disturbing the established hydroecological conditions and availability of water resources. Depending on the sensitivity of a particular river regime model, its changes are temporarily and spatially diversified. In order to identify a change in any pattern (regardless of the reason), it is necessary first of all to adequately describe its initial state and the state after the transformation. There are diverse pattern recognition methods, and both supervised and nonsupervised approaches can be applied to describe the flow regime patterns.

The hydrological regime of lakes can be analyzed in terms of their thermal conditions, formation of ice, and water levels. Quantitative, physical, and biological transformation of lake ecosystems may result from both natural (changes in precipitation, evaporation etc.) and human-induced (water intakes and discharges, hydraulic structures) processes. The regime of lakes in many regions of the world has been destabilized by intensive land use and regulation of water relations. Fluctuations in water levels, and thus changes in the lake area and the amount of stored water in the lake, are crucial in many physical–chemical (mixing, dissolution of substances, water transparency etc.), biological (extent of ecotone zones, extent of photic zone etc.) or economic (possibility of water withdrawals for industrial, domestic, agricultural purposes etc.) processes.

The main aim of this Special Issue is to share the results of research on the impact of climate change and human activity on the characteristics of the flow regime of rivers in different regions of the world, mainly in terms of the transformation of the flow regime characteristics, their stability and predictability, and quantitative and qualitative assessment of water resources. Papers focusing on methods of detection changes and classifying the river regimes are particularly invited.

At the same time, this Special Issue addresses the impact of climate change and human activity on the lake regime characteristics in various regions of the world, mainly in terms of long-term changes in the amount of water resources, seasonal changes of water levels, and thermal and ice conditions.