The impact of land degradation on landscape in Northern Greece

Large areas of Greece are seriously degraded and landscape deterioration is mainly influenced by climatic factors, geological factors, overgrazing, forest fires and urbanisation. The examined area of Saint Panteleimon is located in northern Greece on the foot-slope of Mt. Olympus and exhibits aesthetic beauty of significant value owed to specific ecological, historical and cultural conditions. Due to intensive erosion and other geological factors, the old village, which is characterised by unique architecture, was abandoned. In the study area is located the castle of Platamon, which is dated to 1222 a.d. Overgrazing, which was very common a few decades ago, has enhanced erosion and affected the surrounding landscape. Another case of degradation concerns forestland, where erosion and landslides have influenced the loss of surface soil layers resulting in vegetation decline. The erosion impact increased due to urbanisation and recreational activities. Management of degradation at a local scale is very complex and requires a multidisciplinary approach. Recent works for soil stabilisation in conjunction with efforts for maintaining and recovering the protective vegetation have increased the degree of protection. Priorities for environmental protection in the study area are proposed to focus on reforestation, rational management of rangeland and restoration of hydrologic conditions of the watersheds.     

Application of MODFLOW for simulating groundwater flow in the Trifilia karst aquifer, Greece

Karst aquifers can have a complex flow as a result of the formation of large conduits from dissolution features. As a result, a three-dimensional finite-difference groundwater flow model (equivalent porous media) may not apply as the dual porosity nature of karst features and the effects of turbulent flow cannot be directly simulated. Statistical analysis of karst hydrographs of the Trifilia aquifer in Greece showed the existence of a slightly karstified mass with high primary porosity that regulates the flow. An equivalent porous media model was developed to simulate the Trifilia karst aquifer using MODFLOW. Steady state and transient state calibration gave encouraging results for the equivalent porous media approach, which does not consider pipe flow or turbulence. Detailed hydrogeological research conducted in the area helped define the aquifer hydraulic conductivity zones and extent; and flux to/from the aquifer. Only hydraulic conductivity and specific yield were adjusted during calibration, as the flux to/from the system was considered known and applied as boundary conditions. Small mean absolute and RMS piezometric head error of the model under both steady and transient state conditions were achieved.