Abstract
This study examines the effects of geomorphological factors and the formation of intrinsic vulnerability, and include the geomorphological criteria, in order to formulate the vulnerability assessment methods and apply them in the case of Tinos Island, that will lead to the development of the final map of vulnerability together with the geomorphological characteristics for Tinos Island. The concept of groundwater vulnerability is based on the theory that the natural environment can offer some degree of protection to aquifers against contaminants entering the subsurface environment by natural or human causes. Thus, the need of studying groundwater vulnerability becomes continuously more essential, although it has underestimated or ignored the geomorphological factors. Tinos is the third largest island of Cyclades. Its shape is trianglular and it geographically belongs to the eastern Cyclades. The climate of the island is dry-temperate. The mean air temperature in July is 26°C and in Dece ...
This study examines the effects of geomorphological factors and the formation of intrinsic vulnerability, and include the geomorphological criteria, in order to formulate the vulnerability assessment methods and apply them in the case of Tinos Island, that will lead to the development of the final map of vulnerability together with the geomorphological characteristics for Tinos Island. The concept of groundwater vulnerability is based on the theory that the natural environment can offer some degree of protection to aquifers against contaminants entering the subsurface environment by natural or human causes. Thus, the need of studying groundwater vulnerability becomes continuously more essential, although it has underestimated or ignored the geomorphological factors. Tinos is the third largest island of Cyclades. Its shape is trianglular and it geographically belongs to the eastern Cyclades. The climate of the island is dry-temperate. The mean air temperature in July is 26°C and in December 10-11°C. The mean annual rainfall reaches 250-300mm. Relative humidity over Tinos reaches 65 to 70%. The prevailing winds during the year are northerly. The predominant direction is the Etesian northerly and northeasterly winds that prevail with high frequency and intensity during the summer months in the Aegean Sea. Tinos Island belongs to the geotectonic unit, known as Atticoclycladic complex. Three groups or sequences of rocks participate in the geological structure of Tinos, the sequence of metamorphic rocks, which is dominant, the sequence of ingenious rocks and that of quaternary sediments. The existence of three main categories of folds and two groups of faults is characteristic. The area is characterized by weak seismicity. The basic factors affecting the hydrogeologic character of the island are the generally permeable character due to secondary porosity of the geological formations, the alternations of relatively permeable and impermeable layers, the tectonics and the degree of dissection and weathering of the formations. Tectonism is the most important reason of valley development, along which most springs issue. As discontinuities fracture the upper part of the rock, surface water infiltration is facilitated. When surface water infiltrates in depth, it meets the bedrock, which is impermeable in relation to the weathered schist lying above, resulting the issuing of springs at the weathered rock/ bedrock contact. The island’s morphology is controlled mainly by the extension of lithological formations and tectonics, together with climate, as well as human activity. On the island three morphological units with different relief types can be distinguished: the first unit which covers the biggest part of the island, the second unit which is present at the two ends of the island, and the third unit which is found at the eastern part of the island and is characterized by granitic weathering forms. In the descriptive study, the most important geomorphological features were mapped, described and assessed in combination with intrinsic vulnerability. Specifically, the honeycomb weathering forms (tafoni and alveoles), the tors and core stones, the valley forms, the drainage network, the deep erosion forms, the inselbergs, the intramontane basins, the planation surfaces, the plains, the topographic bents and the coastal forms, were mapped. This study resulted in the creation of the island’s geomorphological map at a scale of 1:50 000.
show more