Consequence of meteorological factors on flood formation in selected river catchments of Lithuania

Abstract

The increase in hydrological extremes during the last two decades has had a significant impact on natural and social environments. These hydrological extremes depend greatly on changes in the meteorological parameters. The task of this research was to evaluate the impact of meteorological factors (snow water equivalent and heavy rainfall) on the formation of spring floods in the basins of the Nemunas, Lielupė and Venta rivers. Five Lithuanian rivers (Venta, Šešuvis, M uša, Merkys and Žeimena) from these basins were analysed in detail. These rivers fall within the Western, Central and Southeastern hydrological regions of Lithuania. Long-time-series data for daily discharge, precipitation and thickness of snow cover from 12 meteorological and five hydrological gauging stations were used. The evaluation of the relation between these factors was carried out for two periods: 1961-1987 and 1988-2014. The relation between the maximum discharge of the spring flood, the maximum snow water equivalent before the flood and the precipitation amount 10 days before the flood was analysed by multiple regression analysis. The high correlation co-efficients between the observed and predicted maximum discharges of the spring flood for the created regression models fluctuated between 0.63 and 0.86. The verification of the selected regression model was performed with Hydrologiska Byråns Vattenbalansavdelning (HBV) software, which also showed a high correlation co-efficient (0.71). The applied methodology of this research could be used for better perception of flood-formation consequences in different hydrological regions of Europe.

Nordic hydrological frontier in the 21st century

“…Flood risk management deals with current and future flood risk scenarios (Parjanne et al 2018), showing how economic growth and urbanization play a major role in flood risk management. Climate change has led to severe impacts following an increasing number of extreme weather events (Silander et al 2006;Akstinas et al 2018), such as flash floods caused by extreme precipitation or wildfires caused by an extended dry period. These impacts call for immediate attention from society, including a shift from hazard forecasting to impact-based forecasting as recommended by WMO (2021).…”

“…Regions that are projected to experience increased floods in the future require adaptation depending on the type of flooding (Akstinas et al 2018), with the scenario changing based on whether it is traditional spring snowmelt flooding or flash floods following extreme precipitation. The latter is more difficult to forecast and predict compared to a larger flood caused by a frontal system or snowmelt (or a combination of the two).…”

Climate Change Impact on Hydropower Resources in Gauged and Ungauged Lithuanian River Catchments

“…(2) slope runoff, and (3) runoff in the watercourse and runoff transformation. This model has previously been successfully applied in Lithuanian conditions [23][24][25]. HBV is based on a water balance equation [26]:…”