As flash flood events are becoming more frequent, the development of flood estimation methods for areas with limited or lack of data has attracted the interest of many scientists. The aim of the present paper is to develop a GIS based methodology in order to study the flood risk in Karlovassi basin. The annual probability of a flood event is relatively high at Karlovassi area (Samos Island – Greece). Especially, after the forest fires that took place in the summer of 2000, during which 90.000 hectares were burnt in Kerketeas Mountain, the phenomenon has become more intense. Primary data were collected from maps, literature, aerial photos and field work. The collected information data were analyzed through the use of the software ArcGIS in order to generate the appropriate background for the formation of the flood risk model. All the input parameters were weighted and the model was calibrated in situ through field work. The proposed methodology and the preliminary results, as exported for the Karlovassi area, prove the suitability of GIS-based methods in the creation of flood risk maps.

The coastline of Attica incorporates a great number of pocket beaches, which are characterised further by the presence of extensive beachrock formations. The present study concerns the evolution (past, present and future) of the Kalyvia beach zone, located at the western coast of Attica and at a distance of 42 km from the city of Athens. The subaerial part of the beach zone consists of mixed materials (mainly sand, granules and gravel), while extensive beachrock formations exist on its shoreface. The beach is exposed primarily to southern wind-induced waves, the largest of which (offshore wave height up to 6m and period >11sec) begin to break at about 8 m of water depth and have a run-up capability of approximately 1.5 m. Most of the subaqueous part of the Kalyvia beach zone is lithified, as the beachrocks extend from the shoreline down to >8 m of water depth. This part of the beach zone may be subdivided further into three units: the deeper one (water depths >7m), the middle (depths 5-6.5 m) and the upper unit (from 4 m depth up to the shoreline). This almost continuous presence is related to the gradual sea level rise during the upper Holocene (past 6.000 years), indicating also a relative climatic stability and/or homogeneity during this period, although some morphological and structural differences in the beachrock indicate changes either in the rate of sea level rise or in the prevailing climatic conditions. Over the last decades, human activities and constructions have deprived the beach of hinterland sediment supply, changing, therefore, its sedimentological character. During this period, beachrocks have played a ‘protective role’ stabilizing and reducing substantially the retreat of the beach zone, which on the basis of the landward boundary displacement of the beachrocks has been estimated to be in the order of 30cm per year from 1969 to 2005. This retreat is attributed to the marine erosion of the sediment that used to cover the upper beachrock formations, in combination to the sea-level rise (approx. 18 cm over the past century) and the lack of sediment supply. Moreover, this degradation of the Kalyvia beach zone is expected to be intensified by the potential future sea level rise (approximately 38 cm for the year 2100).

Weathering formations resembling small caves, known by the name of Tafoni, are a characteristic, but not exclusive, feature of the Mediterranean area. Examples of such geomorphological formations have been recorded in Sardinia and Corsica (Klaer, 1956; Frenzel, 1965), in Tuscany (Martini, 1978), in S. Spain (Mellor et al., 1997) and in the Aegean Sea area (Greece) (Riedl, 1991; Hejl, 2005).

Santorini is an island of the Aegean Sea that belongs to the Prefecture of Cyclades. It is located southern of Ios Island and, along with Anafi, these are the southernmost islands of the Cyclades. Santorini is composed of Thera, with a crescent shape, and the islands of Therassia and Aspro (Aspronisi) in a circle. In the centre of the circle lies the caldera, which was formed by a volcanic eruption (or eruptions) and the simultaneous collapse of a part of the island. Santorini caldera is one biggest of the world, covering an area of approx. 83 km2, with a length of 11 km (N–S) and a width of 7.5 km (E–W). The volcanic islands of Nea Kameni and Palaia Kameni have formed within the caldera. Nowadays Santorini is a volcanic island that belongs to the Aegean volcanic arc and, with its fumaroles, gases and a high temperature, is the only active volcano in the Eastern Mediterranean.

The Cycladic islands are located in the central Aegean Sea (Greece) forming a partly submerged plateau separated into two parts: the eastern shallower one (Andros, Tinos, Mykonos, Naxos, Paros, Syros, Ios, Sikinos, Folegandros) which formed one big island (6.978 km2) at the end of the last glacial period; the western islands (Kea, Kythnos, Serifos, Sifnos, Milos) which remained separated during the same period. The eastern islands constitute an erosional plateau which is the end product of a Neogene palaeosurface that was partially submerged due to thinning of the crust during the Quaternary. The presence of numerous Neolithic sites both on land and submerged indicates the existence of an advanced civilization in the area for thousands of years. The location of the lost Atlantis could be found in this area probably between Naxos, Paros and Antiparos.

The present contribution deals with the natural environment of Paros island coastal zone. More than 75% of the coastal zone consists of high and lower cliffs, whilst the relatively flat coastal plains are rare. The island receives a substantial amount of wave energy flux. The largest rocky and of high slopes coastal part is situated at the northeast and northwest part of the island being developed on hard (resistant to weathering processes) metamorphic rocks. Coastal plains (slopes < 2.5%) have been formed on Quaternary clastic formations. Furthermore, sandy and/or pebbly beach zones have been formed by the deposition of terrigenous (mainly) and marine sediments, along relatively sheltered from the wave activity parts of the coastline, i.e. the bays of Drios, Kephalos, Plastiras, Piso Livadi and Alikes. Palaeogeographic reconstruction with respect to sea-level rise within Holocene reveals that Paros island, at 10.000 yr BP, was much larger (some 1.025 km2) combined with the islands of Antiparos, Naxos and several islets, while at 6.000 yr BP was only connected to Antiparos island covering 264.3 km2. Finally, the predicted ca. 0.5 m of sea level rise for the year 2100, due to climatic change, will definitely threaten the socio-economy of the island as all touristic beaches will be deteriorated as well as several  onstructions along its coastline.

This chapter describes the study of the structural control of the Meganissi island coastal zone and its geomorphological evolution; based on these, it presents a coastal hazard risk map. The coastal geomorphology is affected by the lithological configuration, the tectonism, the wider seismotectonic status and the sea activity. For this study, a database has been created in GIS. using all data deriving from the above characteristics as well as from detailed fieldwork, aerial photos, satellite images and pre-existing maps. Data were analysed and processed in order to understand the geomorphological evolution of this island and its close connection with the structural evolution. Finally, we proceeded to develop a coastal hazard risk map using the slope gradient, the wave energy and the structural characteristics of this island as input variables. This has been achieved via a fuzzy inferences model using a loosen coupling between the Mat lab software package and the MapInfo GIS.

This chapter studies the counteractive dynamic marine and river environments responsible for a river mouth’s and a delta’s modulation. The Acheloos River (West Greece) was chosen as the case study due to the recent changes taken place in its Delta area; the geotechnical constructions and the agricultural planning have altered the basin’s conditions. The aim of this study is to analyze the present dominant environment and the impact of human activity on this balance with the application of modern technological tools; emphasis is placed on the geomorphological along with the land use changes taking place in the three district parts of the Acheloos’ delta within a period of four decades (1960–2000): delta plain, delta front, pro delta. Bibliographic references, geographical and geological maps, aerial and satellite imagery of different seasons and dates, were utilized in addition to extensive fieldwork measurements and mapping. A geographic database was developed and it is continuously updated.

The present contribution examines the various geomorphological, sedimentological and coastal hydrodymamic conditions that are related to the present erosive situation along the broader coastal area of the N/NW coast of Samos Island. The extended erosion, particularly evident during the past 2-3 decades, is attributed to the rise of sea level (>10 cm over the past 100 years according to IPCC report of 2007) in conjunction with the incoming relatively high wave energy, which favouring the offshore transfer of fine-grained beach material. In addition, the various man-made constructions either inhibit the terrigenous sediment fluxes to reach the coast and/or by altering coastal hydrodynamics contribute to erosion. Finally, the existed defence constructions seem to have served only to the stabilisation of the coastline and not to its natural recovery.

Karlovassi basin area has been studied for long period by the team from University of Athens. This area suffers from frequent floods which frequency even raised after large area of forests in Kerketeas Mountain area was burned down in year 2000. In recent period the area has been studied from the point of view of flood risk. High volume of data was collected and processed as an input to the flood risk model. The model was built using Arc Hydro toolset in ArcGIS environment (Maidment, 2002). Based on this model a GIS based flood risk map was created. In order to get more detail description of rainfall-runoff process a decision has been made to apply hydrologic model which works with more detail description of runoff process. For these purposes fully HEC-1 model (Hydrologic Engineering Center, 1998) was chosen. HEC-1 describes runoff process with semi-distributed approach. Results for modeling of precipitation event from November 2001 are presented here.

The upper Miocene of Karlovassi Basin, Samos Island, Greece, contain continental evaporites such as colemanite, ulexite, celestite, gypsum and thenardite. These evaporites are related with volcanic tuffs, diagenetically altered in a saline-alkaline lake environment. The aim of the present paper is to: a) define the impact of the already known and possible buried borates and other evaporites to the geochemistry of the hydrogeological system of Karlovassi Basin, and; b) to assess the correlation between surface and underground evaporite deposits considering the spatial changes in the concentrations of the examined physicochemical parameters. Fieldwork, laboratory measurements and literature data revealed elevated boron values (2136–33012 ⧎/L) in the central part of Karlovassi Basin. In the same area, high amounts of strontium, sodium, lithium and sulfates also occur. It is proposed that these ions originate from the leaching of evaporites and authigenic minerals such as the Sr-rich clinoptilolite and the boron-bearing potassium feldspar. Boron values are abnormally high for freshwater aquifers, and are indicative of the presence of buried evaporites in the basin with unknown significance.

Inland sand dune activities that set an interesting example in terms of wind erosion and accummulation in the Aegean Region under the conditions of the Mediterranean climate, and that appear on lands where the annual rainfall is about 600 mm, exist on the Akselendi Plain, Manisa. Until today, some studies have been conducted on the Akselendi Plain, which has become famous worldwide for that matter. Besides, there is an ongoing Bilateral Project with GREECE, supported by TUBITAK, some results of which will be explained in this paper. Besides the erosive winds blowing on the Akselendi Plain, the existence of mostly coarse textured alluvial deposits, the first of which is the large bed of Kum Çayı, moreover, the misuse of agricultural and non-agricultural areas have caused wind erosion, and they also caused the sediments, moving from the bed of Kum Çayı by deflation, to give great damages along with the sand dune invasion in the south of the bed. This activity has especially increased in the last fifty years. The views that we reached on the subject of wind erosion on this area and the causes, evolution and effects of sand dunes will be reported in the paper. Moreover, information will be given on the problems and on the status and efficiency of the precautions that have been taken, besides on the precautions that will need to be taken in the short term and long term. Again, the continued sand plunder because of the incorrect applications, and the effects of that on the sand dune formation will be explained. Also, some interesting formations that we determined in the last studies we conducted and that can set an example in this scientific area will be submitted to the world of science.

The main objectives of this study are to identify, classify and map the badlands area, as well as to identify the underlain soil types and determine the connection between badlands and climatic changes during Quaternary. The area along the southern coast of the Central Corinth graben, near the town of Derveni (North Peloponese) was chosen as a case study, since extended erosion landforms display geomorphological characteristics, typical of badlands. The area is built up by Plio-Quaternary lacustrine clays with intercalations of distal parts of the fan deltas deposits and records an intensive structural elevation from Pliocene until today. The study focuses on the main factors that contributed in the formation and evolution of badlands in the area, with strong emphasis on geological structure, climatic and sea-level changes and human activity, as well as on the interaction of these factors. It concludes in a geomorphological map with the badlands distribution and discusses the impacts on land degradation and the possible actions against further expansion

The study area of St. Georgios coastal zone is located at the W coast of Naxos, the largest island of Cycladic plateau. The city of Naxos, located approximately 2.5 km from St. Georgios, is believed to be inhabitant since the early Cycladic period 5000 years ago. Archaeological evidence from Mycenaean times indicate the presence of a port whose remains along with a coastal road are found today underwater to a depth of about 2 m. In a distance of approximately 1.5 km from St. Georgios the archaeological site of the four temples of Yria, dedicated to god Dionysus, is situated. The first of the four temples is dating in the 8th century BC, while the last one in the 1st century AC. Moreover in Stelida area, adjacent to St. Georgios coastal zone, the existence of an ancient quarry is significant for the understanding of the palaeoenvironment of this area as well as the connection between these two archaeological sites. For the purposes of this study detailed geomorphological mapping, micropaleontological, sedimentological and dating analyses of the late Holocene coastal zone were conducted. The study of sea-land interactions during Upper Holocene, in relation to the eustatic sea level oscillations, as well as the geomorphologic observations and analysis on deposited sediments, aims to reveal the palaeo-geographic evolution of the landscape and its impact on the archaeological sites. To obtain information about the Holocene stratigraphy under the recent alluvial cover, four boreholes followed the detailed geomorphological mapping. The microfaunal (benthic foraminifera) analysis took place and ten samples of plants, shells, peat and charred material were also collected from several layers of the sedimentary sequence and were dated using AMS and conventional radiocarbon techniques providing temporal control of the sediments. In this study the tracing of the palaeo-shorelines and sea level changes and their effect to the palaeo-environment in the western Naxos are attempted. Sea level rise along with sea-land interactions to the landscape evolution and the transgression of sea in 6144 BP have been verified.