Relationships Among Land Use Patterns, Hydromorphological Features and Physicochemical Parameters of Surface Waters: WFD Lake Monitoring in Greece

The national monitoring network of waters in Greece, in the context of Water Framework Directive (WFD), comprises 50 lake water bodies, both natural and artificial. The aims of the study are: (i) to present the pressures resulting from land cover and population density at river basin level; and (ii) to link catchment area features with physicochemical results from the first period of WFD monitoring. Land cover, population data in the catchment and physicochemical parameters were the main variables used in order to assess the lakes of the Greek WFD monitoring network. Intensive agriculture and urbanization, described as population density, proved to be the main pressure of severe impacted lakes as they were both highly associated with total phosphorus. Principal Components Analysis was used to position the Greek lakes along physical and chemical attributes, such as secchi depth, total phosphorus and ion concentrations and separate them according to their water quality. Clear reservoirs and natural lakes with high secchi depth were separated from more impacted ones with low secchi depth revealing a gradient of eutrophication, the most crucial anthropogenic pressure in Greece and in the Mediterranean area. The sustainable management of Greek lakes requires mitigation measures at a catchment scale, in order to regulate land uses, as well as site specific measures when needed.