Due to insufficient operation efficiency, the studied treatment plant has undergone modernization. The aim of this study was to assess whether this modernization improved quality of the STP effluent and water quality in the receiver. The research period of fifty months covered time before and after the modernization. Samples were collected in four sites – upstream and downstream of the STP and by the sewage discharge. Electrolytic conductivity, water temperature and pH were measured onsite. Chemical analyzes were based on ion chromatography and determined the concentration of NH₄⁺, NO₃^-, NO₂^-, PO₄^3-, TDS. Microbiological analysis comprised serial dilutions to assess the number of mesophilic and psychrophilic bacteria and membrane filtration to enumerate E. faecalis, total and fecal coliforms as well as total and fecal E. coli. Values of most analyzed parameters did not improve after the modernization, or improved for a very short period of time (NH₄⁺), while some of them even increased, such as PO₄^3-, total and thermotolerant coliforms and E. coli. The maximum value of thermotolerant E. coli reached nearly 7 million CFU/100 ml and was observed after modernization. Also at the sites situated downstream of the STP some of analyzed parameters increased. The conducted modernization did not improve the quality of treated sewage and even a further deterioration was observed. It could have been a result of rapidly growing number of tourists visiting the studied area, thus generating large amounts of sewage causing STP overload coupled with poor water and wastewater management. Significant percentage of unregistered tourists hinders proper assessment of the STP target efficiency.

River intermittence was studied based on data from hydrological monitoring in Poland. We screened the entire state database and two another data sources applying the criterion for zero-flow event: discharge less than 0.0005 m ³∙s ^–1, and found five intermittent rivers with catchment area from 9.2 to 303.7 km ². We aimed at finding associations between intermittence and climatic driving forces (temperature and precipitation), and between intermittence and anthropogenic activity. We used the Spearman correlation coefficient, circular statistics, and statistical tests for trend.
The concentration of zero-flow days, mostly in summer, and the decreasing trend in the standardised precipitation evapotranspiration index ( SPEI) in all catchments at various aggregation levels, and an increasing trend in the total number of zero-flow days and in the maximum length of zero flow events in two rivers, were detected. The strong negative correlation (–0.62 ≤ ρ < 0) between intermittence and the SPEI backward lagged in time showed that intermittence resulted from prolonged deficits in climatic water balance due to increasing evapotranspiration. The reaction of the Noteć catchment, amplified by the anthropogenic pressure (brown coal mines), was reflected in the atypical shape of the rose diagram and in inhomogeneities in river discharges.
The results show that the rose diagram can serve as an indicator of the degree of anthropogenic impact on runoff conditions.