Two Decades of Nutrient Dynamics in Polish Rivers: Long-Term Trends in Nitrogen and Phosphorus

This repository contains input data and analysis results used in the article titled: "Two Decades of Nutrient Dynamics in Polish Rivers: Long-Term Trends in Nitrogen and Phosphorus". The dataset includes both raw monitoring data and processed outputs used in long-term trend analyses. Nutrient concentrations were combined with simulated daily river discharge data, and trends were evaluated using the WRTDS (Weighted Regressions on Time, Discharge, and Season) approach, implemented through the EGRET and EGRETci R packages. The input data were collected from 52 monitoring sites across Poland between 2005 and 2022 from the Polish Chief Inspectorate of Environmental Protection (GIOŚ), operating within the framework of the State Environmental Monitoring Program. The data include nitrate nitrogen (NO₃-N), total nitrogen (TN), and total phosphorus (TP) concentrations in flowing surface waters. The dataset is saved in *.xlsx format and contains the following four tables:Legend – provides descriptions of column headings used in the other tables.waterQualityLocation – contains information (metadata) about the surface water monitoring sites,waterQualityData – summarizes the results of concentration and flow measurements (input data),EGRET_bootPairOut – presents the trend analysis results generated by the ECRETci model (output data).Each table is included in a separate sheet in which the first line contains a table heading described by abbreviations without spaces.