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Are Pluvial and Fluvial Floods on the Rise?
The aim of this paper is accurately framed in its title: Are pluvial and fluvial (river) floods on the rise? First, physical mechanisms that drive changes in hazard of pluvial and fluvial floods were examined. Then, a review of literature was undertaken on detection and an attribution of changes in hazard of pluvial and fluvial floods in observation records for past to present, as well as in model-based projections for the future. Various aspects, factors, processes and mechanisms, as well as various indices of interest were considered. There is quite a common, even if not scientifically justified, belief that, generally, floods are on the rise. However, in this paper, a balanced, knowledge-based assessment was undertaken, with discussion and interpretation, including caveats and indicating considerable departures from such a flat-rate statement. Observation records show that precipitation extremes have been intensifying on a global scale and for many regions. A formal detection and attribution analysis shows that intensification of rainfall events may have been influenced by greenhouse gas forcing of anthropogenic origin. Frequency and magnitude of pluvial floods is on the rise with increasing intense precipitation, while changes of river floods are more complex. High river discharges were found to increase in some regions, but to decrease in other regions, so that no general corollaries can be drawn at the global scale. Heavy rainfall events and pluvial floods are projected to become, almost ubiquitously, more frequent and more intense with progressing climate change, while frequency and magnitude of fluvial floods are likely to increase in many but not all regions.
Challenges for Flood Risk Reduction in Poland’s Changing Climate
Floods are the main natural disaster in Poland, and the risk of both fluvial and pluvial floods is serious in the country. Pluvial floods are on the rise in the changing climate, particularly in increasingly sealed urbanized areas. In this paper, we examine the changes in flood risk in Poland, discussing the mechanisms, observations, projections and variability. Next, we discuss flood risk management in the country, including specific issues related to urban and rural areas and the synergies between flood and drought risk reduction measures. We identify and assess the weaknesses of the existing flood risk management plans in Poland for the first planning period 2016–2021 and for the second planning period 2022–2027. We find the level of implementation of plans in the former period to be very low. Many planned measures do not have much to do with flood risk reduction but are often linked to other objectives, such as inland navigation. The plans contain numerous small measures, which come across as inapt and economically ineffective solutions. We specify policy-relevant recommendations for necessary and urgent actions, which, if undertaken, could considerably reduce flood risk. We also sketch the way ahead for flood risk management in Poland within the timeframe of the implementation of plans for 2022–2027 and the next regular update of plans for 2028–2033.