Seasonal and Long-Term Water Quality of Alfeios River Basin in Greece

The aim of the present work was to evaluate the seasonal and long-term concentration levels of several electrochemical and nutrient parameters in surface water and groundwater of the Alfeios River Basin, Greece. Seven seasonal sampling campaigns were conducted, each including 12 sampling sites located along the Alfeios River and its major tributaries, Enipeus, Kladheos, Selinous, Erymanthos, Ladhon, and Lousios. At each station, flow discharge was measured using four quick techniques, on-site measurements were performed, and water samples were taken for laboratory analysis. In locations near the river, on-site measurements were conducted, and water samples were collected from wells and boreholes to assess the groundwater quality. In addition, relative data from previous or later campaigns by other researchers is used to assess the long-term and possible seasonal variation of water quality along the Alfeios River and its tributaries. The results show a decrease in concentration for most of the parameters regarding surface and groundwater quality during the last few years. Statistical analysis showed that the dilution process is significant along the Alfeios River, upstream industrial wastewater discharges or agricultural runoff is responsible for high concentration values, while seasonality is evident only in the surface waters. Finally, comparing the water quality values to legislative limits of drinking water shows that exceedances occur, especially at nutrient compounds. This data could be useful for the evaluation of water quality, which is required by the implementation and update of the Alfeios River Basin Management Plan.