An approach for determining the nutrient sensitive areas: a case study for Gediz River Basin, Turkey

This study presents an approach to the determination of nutrient sensitive areas (SA) based on National Urban Wastewater Treatment Regulation harmonized under the Water Framework Directive (WFD). A three-stage approach that covers designation of potential sensitive areas (PSA) which are under the risk of eutrophication, physicochemical and biological monitoring at PSA, and application of the suitable biotic indices is used for the determination of sensitive areas. PSA are identified as a result of either available monitoring data or if this is not available according to indexing method which developed in this study based on pressure and impact analysis. The Gediz River Basin, one of the most polluted basins in Turkiye, is chosen as a pilot area. According to the results of the study, 40% of the total drainage area of the basin was designated as sensitive area.