In the present paper we develop a software in order to describe, in quantitative terms, the time variation of the shape and dimensions of a landform. The software is based on an iterative cellular automata algorithm. In each step, the algorithm calculates the altitude and soil thickness of each cell, which represents a piece of land. The calculations are based on the continuity equation. Parameters which express the intensity of weathering of rock masses, soil transport along slopes and fluvial transport of sediments by rivers (physical processes parameters), are incorporated in the continuity equation, using empirical relations. These parameters may be time constant or time dependent. The physical meaning of a time dependent parameter is that the rate of a geomorphological process may change with time, as a result of human activities or changes in the climate. The temporal variation of the physical processes parameters are expressed by simple mathematical expressions, which may represent smooth, rapid or periodical changes.This software may be useful in geomorphological and environmental research, inorder to estimate the future development of a landform, as a result of physicalprocesses and human activities.

Paros Island is part of the complex of Cyclades Islands, situated in the central Aegean Sea, Greece. It is characterized by the Mediterranean type of climate, with abrupt rainfalls and lower temperatures during winters and long term sunshine accompanied by dry periods during the summer, which constitutes a tough environment for the land. The low vegetation of the island leaves the ground exposed and very vulnerable to erosion. Also the recent change to the activities of the local people from agricultural to touristic ones and especially the abandonment of the agricultural terraces during the last 50 years has influenced the soil cover of the island in an unfavorable way, leading to total soil loss and exposure of the bedrock in many areas. Aggravating this fact, the slopes of the island are high in general terms thus making soil regeneration almost impossible. The soil that is transferred is either moving towards the small alluvial plains or, in most cases, is lost directly to the sea. In this paper there is an effort to depict the situation that currently exists on the island by pointing out the areas that still appear to be in a high risk for erosion and to estimate the average amount of soil loss. For the later the Universal Soil Loss Equation (USLE) was tested on the data of the island. The application of the USLE took place with the use of MapInfo and ArcGIS Tools.

Cyprus is experiencing negative impacts from flooding due to rainstorms in its urbanenvironment. There are no official figures on the extent of urban flood damage.However, the information from insurance companies is that, although Cyprus lies in a seismic region and its climate is semi-arid, the extent of the urban flood damage ismore than the extent of earthquake damage. Main causes of such damages are thelack of storm water drainage systems, the disruption of pre-existing naturalwatercourses by urbanisation, the blockage of man-made watercourses, the everchanging land use. The main effects/ impacts of these damages are the flooding of basements and low lying floors, where could me caused damages to parked cars, central heating systems, stored goods. Some consequential damage is the loss of productive time, loss of guarantees/ warranties of electrical/ mechanical equipment.This paper presents an institutional analysis, highlighting the gaps in planning,implementation, maintenance of urban flood management systems. It includes a case study of flooding caused due to institutional gaps and proposes measures to reduce the risk of urban flood damage.

As evidenced by the development of tools that enable proper analysis of river systems, floodplain modeling is more important than ever before. Current legislative and socioeconomic aspects of integrated water resource management often require a hydraulic analysis prior to development or construction in a floodplain. To aid in accurate floodplain modeling, scientists use computer models in planning and analyzing floodplain hydraulic situations while having difficult modeling problems depending on data needs and data availability. On the one hand, floodplain models are successful in dealing with time variation, and models with hundreds or even thousands of time steps are common. On the other hand, spatial disaggregating of the study area has been relatively simple, assuming, in many cases, uniform spatial properties or allow for small numbers of spatial subunits within which properties are uniform. Geographical Information Systems (GIS) offer the potential to increase the degree of definition of spatial subunits, in number and in descriptive detail. This paper focuses in integrating GIS and floodplain modeling in order to produce fast, accurate and easy to understand, through thematic and animated maps, results, through the development of an integrated Decision Support System (DSS). The system was applied in Prasianos watershed, Rethimnon, Crete isl., to enable prediction of spatial runoff distribution, calculate flood hydrographs and simulate the flooding following an earthen dam breach.

The scope of the present research is to examine the spatial consequences of the predicted future sea-level rise upon the active area of the delta of the River Acheloos, which forms part of the NW coast of the Gulf of Patras (Ionian Sea). The growth of the Acheloos River deltaic plain, prior to the construction of dams and channelization of the lower part of the river, took place through the progradation of four main distributaries which transported 5-6 million tones of sediments annually.Following the construction of the dams, the hydraulic regime of Acheloos has changed and its propagation has ceased. The present investigation aims to quantify coastal changes on the deltaic plain of the Acheloos river due to the combined effect of (i) the process of inundation induced by a future sea level rise of 0.5 and 1 m and (ii) coastal erosion caused by the increased exposure to wave action due to sea-level rise and subsequent coastline retreat. The results of our analysis show severe shoreline recession (up to 1900m), extensive submergence of the active deltaic plain (~ 2586⋅103 m2 or 61.4 %) and elimination of most of the lagoonal areas. The substantial loss of deltaic land, accompanied by salinisation of the groundwater table, will cause severe damage to the agricultural economy of the area. Furthermore, we show that the consequences of a future sea-level rise on a low-relief fluviallydominated delta cannot be predicted accurately by simple conceptual models; instead, a holistic approach incorporating topographic, geomorphological, sedimentological, morphodynamic and hydrodynamic analyses is required.

The present contribution is dealing with the outcrops and the hydrogeological behaviour of the fractured rocks (mainly igneous, metamorphic and not karstified carbonate rocks, as they have been defined by the I.A.H Commission of the Hardrock Hydrogeology). The presentation starts with the description of the geotectonic regime of the Hellenic territory into the adopted different geotectoniczones. For each zone a general lithological and structural description is attempted accompanied by the description of the main aquifers and the general directions of the groundwater flow related to the formation of the rock mass fractures. Finally, an analytical description of some case studies is presented.

In this paper we investigate the relations between the landforms and thediscontinuous tectonism. A multistep methodology has been adopted. Thus, first westudy the topography of a given area and by proper procedures we classify thegeoforms. We next examine the geological formations of the area, the drainagesystem, the landuse, the vegetation and the human impact.Finally, we study the tectonic zones of this area (faults and fractures zones). Datahas also been obtained by airphotos and satellite images. All the above information is analyzed in a G.I.S platform using expert system methodology. This procedure has been applied to some selected places of the Greek territory.

The Paros Island (Cyclades Islands, Aegean Sea, Greece) is characterized by a Mediterranean type of climate, while the Tihany Peninsula (Trans Danubian Middle Range Mountains, Lake Balaton, Hungary) is characterized by a Sub-Mediterranean type of climate. The Paros Island has abrupt rainfalls and lower temperatures during winters and long term sunshine accompanied by dry periods during the summer. The situation is similar in the Tihany Peninsula, except that there is snowfall in the winter and very intensive but short rainfalls in the summertime. These circumstances constitute a tough environment for the land. The low or sparse vegetation and steep slopes of the investigated areas leaves the ground exposed and very vulnerable to erosion. The recent change to the activities of the local people from agricultural to touristic ones and especially the abandonment of the agricultural terraces during the last 50 years has influenced the soil cover of the island, leading to total soil lossand exposure of the bedrock in many areas. The increase of tourist activities caused the same results however the agricultural activities have not ceased but increased a little. The slopes of the examined areas are high in general terms thus making soil regeneration almost impossible. The soil that is transferred is either moving towards the small alluvial plains of the island and inside the peninsula in Hungary. We try to compare the situation of the investigated Greek island and Hungarian peninsula bypointing out the areas that still appear to be in a high risk for erosion and to estimate the average amount of soil loss. For the later the Universal Soil Loss Equation (USLE) was tested on the data of the island. The application of the USLE took place with the use of MapInfo and ArcGIS Tools. We wish to give some details about the experiences of using the USLE model on these two territories.

Kernel discriminants are greatly appreciated because 1) they permit to establish nonlinear boundaries between classes and 2) they offer the possibility of visualizing graphically the data vectors belonging to different classes. One such method, called Generalized Discriminant analysis (GDA) was proposed by Baudat and Anouar (2000). GDA operates on a kernel matrix of size N x N, (N denotes the sample size) and is for large N prohibitive. Our aim was to find out how this method works in a real situation, when dealing with relatively large data. We considered a set of predictors of erosion risk in the Kefallinia island categorized into five classes of erosion risk (together N=3422 data items). Direct evaluation of the discriminants, using entire data, was computationally demanding. Therefore, we sought for a representative sample. We found it by a kind of sieve algorithm. It appeared that using the representative sample, we could greatly speed up the evaluations and obtain discriminative functions with good generalization properties. We have workedwith Gaussian kernels which need one declared parameter SIGMA called kernelwidth. We found that for a large range of parameters the GDA algorithm gavevisualization with a good separation of the considered risk classes.

We present our experience in visualization multivariate data when the data vectors have class assignment. The goal is then to visualize the data in such a way that data vectors belonging to different classes (subgroups) appear differentiated as much as possible. We consider for this purpose the traditional CDA (Canonical Discriminant Functions), the GDA (Generalized Discriminant Analysis, Baudat and Anouar, 2000) and the Supervised SOM (Kohonen, Makivasara, Saramaki 1984). The methods are applied to a set of 3-dimensional erosion data containing N=3420 data vectors subdivided into 5 classes of erosion risk. By performing the mapping of these data to a plane, we hope to gain some experience how the mentioned methods work in practice and what kind of visualization is obtained. The final conclusion is that the traditional CDA is the best both in speed (time) of the calculations and in the ability of generalization.

The description of coastal recession is a difficult asset that is characterized by highuncertainty. This uncertainty stems from the nature of the different factors that constitute the coastal systems. Physical features such as the different geological formations, the tectonic state of the coastal area and the sea level are all factors that complicate the efforts to describe the situation. In addition, any GIS software is lacking the tools to explain or map the uncertainty factors. Therefore, it is necessary to introduce a tool that may handle the natural factors in a GIS interface. In this paper we present an algorithm that works on a GIS interface and uses grid modelingtechniques. Taking into account factors such as the geology of the areas that are examined, the drainage system, the coastal type etc., the system applies a set of user defined empirical rules, to estimate the evolution of the recession process in the affected areas. For this paper we have tested the algorithm at the island of Samos (Eastern Aegean, Greece). In the last 20 years, huge problems of coastal erosion have been observed at the northeastern part of the island near the town of Karlovassi and at the southwestern part near the Castle of Pythagorion.The algorithm may prove to be of great assistance as a decision support tool for the municipalities in these areas, since the measures that have been taken so far are temporary and do not envision the future development of the coastline.

The Karlovassi Basin is an area that has suffered many catastrophic events such as fires or floods within the last 10 years. These intense phenomena, that take place mostly at its northern part, along with the human activities, have significantly accelerated the evolution rate of the local landforms. The result is the noticeable alteration of the geomorphological landscape within these last ten years.When dealing with landscape evolution, the time is a basic factor since it determines the intensity of the morphologic development. For this paper we used an algorithm for the temporal analysis of the changes in the landscape, because of the erosional processes. The software that has been developed to apply the algorithm is GIS based and uses the concept of the cellular automata for the geospatial calculations. For each grid cell it calculates the altitude and soil thickness of the area, based on the continuity equation, which involves parameters of different natural processes such as the weathering of rocks, the river and slope sediment yield, etc. Since time is an important factor in this equation, each parameter is characterized as timeconstant or time dependent. The temporal variation of the physical process parameters is expressed by simple mathematical expressions, which may represent time constant values, as well as abrupt, smooth or periodical variations with time.This algorithm may support the local authorities in decision making issues, since it may identify the areas that require protection against the intense physical phenomena of the last years. Moreover, it may be useful in geomorphological and environmental research, concerning the way that some landforms evolve.

Sárvíz Valley is approximately 100km long, situated SW from capital of Hungary (Budapest). The total examined area of the valley is 60561.85ha. The soil cover is very mosaic, but the larger spots belong to Chernozems. We prepared the soil map of the valley, based on former soil maps, core samplings and aerial photographs. Based on the soil map we prepared the erosion map on the territory of the Sárvíz Valley Small Region Association. Erosion modeling was done by the USLE (Universal Soil Loss Equation) model. We marked areas where different amount of special attention and soil protection measures are needed. One of the basic aims of this study is the application of soil mapping and modeling for the calculation of erosion. With the help of these tools we are able to outline the areas which, as far as erosion is concerned, are in need of protection, as well as the less useful areas for agricultural production.

This chapter concerns the application of computing technologies in Geoarchaeology. The main issue is the combination of GIS and remote sensing technologies with on-site observations of the archaeological, geomorphological and geological characteristics of the area. This combination involves gathering all the necessary information of the spatial structures: geological, topographical, geomorphological and archaeological data. The main target is the composition of the palaeolandscape in order to reveal the paleotopography of Thera and the archaeological site of Akrotiri before the Minoan eruption. GIS analytical tools may help to recreate the different phases of landform evolution of Thera before the Minoan era till nowadays. Thus, 3D models before the Minoan, during the Minoan and after the Minoan phase were produced. Furthermore, the chapter focuses on the geomorphology of Akrotiri site, the most important archaeological site on Thera. The geological formations and the dominant erosion and deposition processes were mapped in order to understand the geomorphological evolution of the area. The extensive reworking and adaptation of the geomorphology from sustained volcanic activity over a long period has resulted in huge physical changes: loss of a central area of the island, coastline modifications, soil loss, deposition and abandonment of valleys and settlement sites. This abrupt evolution have played a major role to the land use change and land cultivation, strongly affecting the local communities, perhaps emphasising and coinciding with distinctive periods of cultural expansion and contraction.

In the present paper the differential equation of the temporal development of a landform (mountain) with a time dependent diffusion coefficient is solved. It is shown that the shape and dimensions of the landform at time t are independent of the specific variation of the diffusion coefficient with time; they only depend on the mean value of the diffusion coefficient in the time interval where the erosion process takes place. Studying the behaviour of the solution of the differential equation in the wave number domain, it is concluded that Fourier analysis may help in estimating, in quantitative terms, the initial dimensions, the age or, alternatively, the value of the diffusion coefficient of the landform. The theoretical predictions are tested on a hill of the southern part of the Ural mountainous region, in order to show how the results of the mathematical analysis can be used in describing, in quantitative terms, the morphological development of landforms due to erosion processes.