Changing climate both increases and decreases European river floods

Climate change has led to concerns about increasing river floods resulting from the greater water-holding capacity of a warmer atmosphere. These concerns are reinforced by evidence of increasing economic losses associated with flooding in many parts of the world, including Europe. Any changes in river floods would have lasting implications for the design of flood protection measures and flood risk zoning. However, existing studies have been unable to identify a consistent continental-scale climatic-change signal in flood discharge observations in Europe, because of the limited spatial coverage and number of hydrometric stations. Here we demonstrate clear regional patterns of both increases and decreases in observed river flood discharges in the past five decades in Europe, which are manifestations of a changing climate. Our results—arising from the most complete database of European flooding so far—suggest that: increasing autumn and winter rainfall has resulted in increasing floods in northwestern Europe; decreasing precipitation and increasing evaporation have led to decreasing floods in medium and large catchments in southern Europe; and decreasing snow cover and snowmelt, resulting from warmer temperatures, have led to decreasing floods in eastern Europe. Regional flood discharge trends in Europe range from an increase of about 11 per cent per decade to a decrease of 23 per cent. Notwithstanding the spatial and temporal heterogeneity of the observational record, the flood changes identified here are broadly consistent with climate model projections for the next century, suggesting that climate-driven changes are already happening and supporting calls for the consideration of climate change in flood risk management

The potential hydro energetic assessment of the river in Albania with a monthly discharge flow estimation module

This thesis assesses the hydropower potential of a river in Albania using an estimation module that calculates the monthly discharge (surface and ground water) based on input variables such as monthly precipitation, intensity and frequency of rainfall, snowfall, air temperature and solar radiation as well as regional specific discharge. The monthly discharge simulations of this module help in a rapid assessment of the hydropower potential if no observed discharge data are available. The module is designed as a lumped, deterministic rainfall-runoff model. It is calibrated, validated and tested with observed discharge data from the Institute of Energy, Water and Environment of Albania, AKBN, and other official sources. The thesis specifically focuses on the Vjosa river. Potential sites for the construction and installation of new runoff hydropower plans with low dams at the Vjosa river are identified and the expected annual average power generation is estimated. The effect of future climate change on the power generation is also assessed.15

Changing climate shifts timing of European floods

A warming climate is expected to have an impact on the magnitude and timing of river floods; however, no consistent large-scale climate change signal in observed flood magnitudes has been identified so far. We analyzed the timing of river floods in Europe over the past five decades, using a pan-European database from 4262 observational hydrometric stations, and found clear patterns of change in flood timing. Warmer temperatures have led to earlier spring snowmelt floods throughout northeastern Europe; delayed winter storms associated with polar warming have led to later winter floods around the North Sea and some sectors of the Mediterranean coast; and earlier soil moisture maxima have led to earlier winter floods in western Europe. Our results highlight the existence of a clear climate signal in flood observations at the continental scale