Participatory groundwater modeling for managed aquifer recharge as a tool for water resources management of a coastal aquifer in Greece

A participatory modelling approach is presented for effective groundwater management at the Mediterranean coastal plain of Marathon, Greece. The main objective was to identify groundwater problems in the area and to propose a viable groundwater management plan. Detailed investigation, using scientific literature and field work in the area, was conducted in order to specify the main hydrologic characteristics of the aquifer units and their quality and quantity status. Model application was accomplished with the FREEWAT platform, an open-source and public domain GIS integrated platform for effective groundwater management. SEAWAT code was utilized for variable-density groundwater flow and solute transport simulation. The participatory approach included several stakeholders' groups from groundwater users, policymakers, environmental groups and other organizations involved in groundwater management in the area. The main issue recorded amongst all stakeholders was the high salinity of groundwater in Marathon. The outcomes of the participatory workshop were used to generate five different groundwater management scenarios and to promote the application of a managed aquifer recharge (MAR) setup that could be installed in the area. For the assessment of model results, an index was generated with the cooperation of the stakeholders in order to quantify the advantages and disadvantages of the several scenarios and to support the stakeholders in the decision-making process. The index suggested that the installation of the pilot MAR setup could facilitate salinity reduction in the shallow aquifer.