Intermittent rivers are prevalent in many countries across Europe, but little is known about the temporal evolution of intermittence and its relationship with climate variability. Trend analysis of the annual and seasonal number of zero-flow days, the maximum duration of dry spells and the mean date of the zero-flow events, is performed on a database of 452 rivers with varying degrees of intermittence between 1970 and 2010. The relationships between flow intermittence and climate are investigated using the standardized precipitation evapotranspiration index (SPEI) and climate indices describing large-scale atmospheric circulation. The results indicate a strong spatial variability of the seasonal patterns of intermittence and the annual and seasonal number of zero-flow days, highlighting the controls exerted by local catchment properties. Most of the detected trends indicate an increasing number of zero-flow days, which also tend to occur earlier in the year, particularly in southern Europe. The SPEI is found to be strongly related to the annual and seasonal zero-flow day occurrence in more than half of the stations for different accumulation times between 12 and 24 months. Conversely, there is a weaker dependence of river intermittence with large-scale circulation indices. Overall, these results suggest increased water stress in intermittent rivers that may affect their biota and biochemistry and also reduce available water resources.

The main aim of the article was application of some statistical tests for investigation of weak stationarity of hydrologic time series. The tests were applied to mean monthly flow and maximum annual flow on three rivers: two Polish and one American river. Firstly, the modified Mann–Kendall test for autocorrelated data was used to detect trend. After detrending we used “unit root tests” based on the DF test and “stationarity tests” based on the KPSS test. The tests were investigated and compared in some aspects: analysis of residuals, application to seasonal series, AIC and Schwarz values.

The study analyzed changes in surface areas of individual land use types in five administrative regions of Poland in the eastern-most part of the country. Annual time series for the following variables were used: agricultural land, forest land, built-up and urbanized land, and wasteland. The primary objective of the paper was to assess land use changes (LUC) in Eastern Poland in 2002–2016. The paper employed a Mann-Kendall (MK) test and Cox-Stuart (CS) test for monotonic trend and the autoregressive-moving-average (ARMA) model. The deterministic part was selected with the Akaike criterion. The power of the tests was estimated using the Monte Carlo simulation in order to assess their reliability. The results indicate a trend in each of the four series in all the five voivodeships. For forest and built-up land, the trend was upward in each voivodeship. A downward trend was found for the agricultural land and wasteland in all the voivodeships except the Podkarpackie Voivodeship. The results can help regional and local authorities to properly monitor LUC.

This editorial provides a definitive review of ten articles published in the Special Issue of the journal Water, entitled “Water Resource Management: Hydrological Modelling, Hydrological Cycles, and Hydrological Prediction”