The Analysis of Long-Term Trends in the Meteorological and Hydrological Drought Occurrences Using Non-Parametric Methods—Case Study of the Catchment of the Upper Note? River (Central Poland)

The study aims to identify long-term trends in the changes of drought occurrences using Mann-Kendall (MK) test and Theil-Sen estimator. Trend research was carried out on example catchment area Upper Note? River, which covers an agricultural Poland with some lowest water reserves. meteorological droughts were identified based Standardized Precipitation Index (SPI), while hydrological determined basis Runoff (SRI) various time scales (1, 3, 6, 9 12 months) period 1981–2016. relationship between SPI SRI Pearson correlation analysis. results showed that statistically significant (at significance level 0.05) at 3 8 stations (downward trend K?odawa station upward for Sompolno Ko?uda Wielka stations). Statistically increase ?ysek station, a downward noted No? Kalina station. No found Pako?? analysis strong dry years. maximum coefficient longer accumulation periods i.e., 6 months. River points necessity several indicators order assess actual condition