Bathymetry and morphometric analysis of Greek natural lakes through a hybrid GIS-acoustic methodology

Homogeneous and up-to-date bathymetric information on lakes is essential to improve limnological knowledge and produce evidence-based lake monitoring, assessment methods, and river basin management plans according to Water Framework Directive (WFD). The present study focused on the production of updated bathymetric information on the main natural Greek lakes and their morphometric analysis. The aim was to address the knowledge gap by providing updated homogeneous and accurate bathymetric information for the main freshwater natural lakes of Greece as part of the National Monitoring Network of Lakes in the context of WFD. We surveyed 14 freshwater lakes in mainland Greece using a dual frequency echosounder. Using the acoustic data collected during the surveys, bathymetric digital terrain models (DTMs) were produced for each lake and used to estimate morphometric characteristics (mean/maximum depth, volume, lake depth ratio, volume development, mean lake diameter, relative depth ratio, shoreline development factor, hypsographic curve). This analysis demonstrated the potential of the morphometric approach to generate valuable information using up-to-date bathymetric DTMs. The geospatial data derived by the present study are available through an online repository, the Greek National Monitoring Network of Lakes (http://ekbygis.biodiversity-info.gr/geoserver/web/). These data provide a valuable database for the advancement of limnological knowledge, the implementation of comprehensive monitoring programmes, and informed decision making in water resources management.