Proceedings of the 11 th International Conference on Environmental Science and Technology Chania, Crete, Greece, 3 – 5 September 2009 ASSESSMENT OF EROCIVITY OF GEOLOGICAL FORMATIONS AND TRANSFERRED MATERIALS PRODUCTION OF THE DRAINAGE OF THRIASSION PLAIN, GREECE G. SIGALOS 1,2 , V. LOUKAIDI 1 , S. DASAKLIS 1 , A. ALEXOULI-LEIVADITI 2 and A. MAVRAKIS 3,* 1 ArcEnviro – Makrygianni 1 str, 157 72, Zografos, Athens, e-mail: sigalos@arcenviro.gr 2 National Technical University of Athens (NTUA), Department of Minerals Engineering Heroon Polytechniou 9 str., 157 80 Zografos, Athens, Greece 3 Department of Economic & Regional Development, Panteion University, 136 Syngrou Av., GR-176 71 Athens, Greece *e-mail: mavrakisan@yahoo.gr EXTENDED ABSTRACT The geomorphology and the lithology of an area is the basic factor that controls the erosional capability of the exogenic processes principally by the action of the water. The area of research is found at the Regional departments of Attica and Sterea Hellas and includes departments of prefectures of Western Attica and Viotia. The Thriassion basin occupies an area of 500 Km 2 of which approximately 100 Km 2 correspond to flat ground, while the rest corresponds to mountainous or hilly areas. The morphology of the region is generally smooth, slightly dipping towards the sea, with morphological slopes that do not exceed 3%. In order to investigate the intensity and the erosion that can be seen in every area we followed the following methodology. We prepared a series of maps, which helped us to work out and analyze the factors that affected the configuration of the relief. These maps are relative to the lithology of the formations, as well as their behaviour under the effect of the exogenic processes in connection to his morphological slope. The combination of the three final maps, of drainage texture, relief slopes and lithologic areas susceptible to erosion, produced the erosivity map. According to erosivity three different categories of areas were distinguished. As the map shows the larger part of the area belongs to the category of low erosivity. Finally in order to investigate erosivity under the present conditions we combined the erosivity map with the vegetation cover map. It is estimated that formations which are covered by forest, are significantly protected, with lower erosivity than the uncultivated areas. In this work we initially examined the degree of erosion vulnerability, as well as the production of brought materials of the region that includes the basin of the Thriassion Plain. The regions characterised by high and medium vulnerability at extreme conditions (that is without considering the presence of vegetation), that are covered by dense forests should be considered less vulnerable and be classified accordingly. On the contrary cultivations can significantly increase the vulnerability of a region because they provide insufficient protection toward erosive factors. The regions with high vulnerability at natural conditions (that is having considered the presence of vegetation), are regions that have sharper morphological slopes, extensive hydrographical network, formations characterised by lower erosional resistance as well as poor vegetation. KEYWORDS: Erocivity, erosive factors, drainage, transferred material production. B-848