Author(s): Joanna Wicher-Dysarz; Tomasz Dysarz; Mariusz Sojka; Joanna Jaskula; Zbigniew W. Kundzewicz
Linked Author(s): Mariusz Sojka, Joanna Wicher-Dysarz, Tomasz Dysarz
Keywords: Drought in Poland SRI SPI SPEI ThLM Warta River
Abstract: The area of Poland is characterised by high spatial variability of drought conditions. Drought events of varying severity occur in the winter and summer halves of the year. The study aims to identify periods when there is a systematic decline in surface water levels due to a long period without rain accompanied by high air temperatures, which manifests meteorological drought and subsequently results in hydrological drought. The study was carried out on the Warta River, Poland's third-longest river. It helps us better understand the variability in meteorological and hydrological conditions in this catchment. The analyses were based on publicly available data from the Institute of Meteorology and Water Management – National Research Institute. Daily temperature and precipitation data from 1990-2020 climatological stations and water discharges from 26 hydrological stations from 2000-2020 were used in this study. Four methods were used in the study to determine meteorological and hydrological droughts. The first group of methods focuses on identifying meteorological drought by analysing rainfall and temperature variability using the Standardised Precipitation Index (SPI) and Standardised Precipitation- Evapotranspiration Index (SPEI). The second group of methods addresses hydrological droughts based on daily flows: The Threshold Level Method (ThLM) and the Standardised Runoff Index (SRI). Based on the analyses carried out, it can be seen that the water level in the Warta River has been steadily decreasing over the past 20 years as a result of reduced rainfall, higher temperatures and more intense evaporation. Flows in the river have declined by 30% between 2000 and 2020, with a decrease of almost 70-80 % between 2019 and 2020.
Year: 2025