Linkages between physicochemical status and hydromorphology in Greek lakes under WFD policy

Abstract

The national monitoring network of waters in Greece, in the context of Water Framework Directive, has been operational since 2012. It comprises 50 lake water bodies, both natural and artificial (24 and 26 respectively). The aims of the study are i) to present the main features of Greek lakes; ii) to position them according to hydromorphological and physicochemical data from the first period of monitoring and iii) to investigate how the hydromorphological features influence water quality. Greek lakes are discerned in relation to hydromorphological aspects such as mean depth, volume, surface area, catchment area. Impacted and unimpacted lakes are separated when positioned along physical and chemical attributes, such as Secchi depth, TP and ion concentrations. The dataset covers a gradient of eutrophication, which seems to be the main anthropogenic pressure on lakes in Greece and probably one of the most widespread anthropogenic pressures on lakes across Europe. Catchment areas of the Greek lakes have undergone substantial agricultural, industrial, and urban development over recent years, leading to eutrophication and hydromorphological alterations. Management measures at a catchment scale aiming to control land uses would be needed in order to maintain and/or improve water quality in Greek lakes, supplemented by site-specific measures when appropriate. The monitoring network provides baseline data that will allow the assessment of status and trends of Greek lakes.