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Papers by ΧΡΗΣΤΟΣ ΠΕΤΑΛΑΣ

<jats:p>ΤΟ ΑΝΤΚΕΙΜΕΝΟ ΤΗΣ ΔΙΑΤΡΙΒΗΣ ΕΙΝΑΙ Η ΔΙΕΡΕΥΝΗΣΗ ΤΟΥ ΚΑΘΕΣΤΩΤΟΣ ΠΟΥ ΔΙΕΠΕΙ ΤΗ ΛΕΙΤΟΥΡ... more <jats:p>ΤΟ ΑΝΤΚΕΙΜΕΝΟ ΤΗΣ ΔΙΑΤΡΙΒΗΣ ΕΙΝΑΙ Η ΔΙΕΡΕΥΝΗΣΗ ΤΟΥ ΚΑΘΕΣΤΩΤΟΣ ΠΟΥ ΔΙΕΠΕΙ ΤΗ ΛΕΙΤΟΥΡΓΙΑ ΚΑΙ ΤΙΣ ΣΥΝΘΗΚΕΣ ΕΠΙΒΑΡΥΝΣΗΣ ΤΗΣ ΥΠΟΓΕΙΑΣ ΥΔΡΟΦΟΡΙΑΣ ΣΤΟ ΠΑΡΑΚΑΤΩ ΤΜΗΜΑ ΤΟΥ Ν. ΡΟΔΟΠΗΣ ΚΑΙ Η ΔΗΜΙΟΡΓΙΑ ΤΟΥ ΚΑΤΑΛΛΗΛΟΥ ΠΛΑΙΣΙΟΥ ΓΙΑ ΤΗΝ ΟΡΘΟΛΟΓΙΚΗΔΙΑΧΕΙΡΙΣΗ ΑΥΤΗΣ. ΤΟ ΚΛΙΜΑ ΤΗΣ ΠΕΡΙΟΧΗΣ ΕΙΝΑΙ ΤΟΥ ΤΥΠΟΥ CSA. Η ΜΕΛΕΤΗ ΤΗΣ ΓΕΩΜΟΡΦΟΛΟΓΙΑΣ, ΓΕΩΛΟΓΙΑΣ (ΤΕΚΤΟΝΙΚΗ), ΣΤΡΩΜΑΤΟΓΡΑΦΙΑΣ ΚΑΙ ΥΡΔΟΓΕΩΛΟΓΙΑΣ ΕΔΕΙΞΕ ΟΤΙ ΣΤΗΝ ΠΕΡΙΟΧΗ ΚΑΙ ΜΕΣΑ ΣΕ ΣΧΗΜΑΤΙΣΜΟΥΣ ΤΟΥ ΑΝΩΤΕΡΟΥ ΜΕΙΟΚΑΙΝΟΥ ΣΧΗΜΑΤΙΖΕΤΑΙ ΕΝΑ ΑΞΙΟΛΟΓΟ ΥΔΡΟΦΟΡΟ ΣΥΣΤΗΜΑ ΥΠΟ ΠΙΕΣΗ. Η ΥΔΡΟΦΟΡΙΑ ΕΠΗΡΕΑΖΕΤΑΙ ΑΜΕΣΑ ΑΠΟ ΤΗΝ ΤΕΚΤΟΝΙΚΗ ΚΑΙ ΑΠΟ ΤΟ ΠΕΡΙΒΑΛΛΟΝ ΙΖΗΜΑΤΟΓΕΝΕΣΗΣ ΕΝΤΟΣ ΤΟΥ ΟΠΟΙΟΥ ΦΙΛΟΞΕΝΕΙΤΑΙ. Η ΑΞΙΟΛΟΓΗΣΗ ΤΩΝ ΔΕΔΟΜΕΝΩΝ ΤΩΝ ΑΝΤΛΗΤΙΚΩΝ ΔΟΚΙΜΑΣΙΩΝ, ΤΗΣ ΥΔΡΟΧΗΜΕΙΑΣ, ΤΩΝ ΙΖΗΜΑΤΟΛΟΓΙΚΩΝ ΧΑΡΑΚΤΗΡΙΣΤΙΚΩΝ ΚΑΙ ΤΗΣ ΠΙΕΖΟΜΕΤΡΙΑΣ ΕΠΙΒΕΒΑΙΩΝΕΙ ΤΗΝ ΠΑΡΟΥΣΙΑ ΑΞΙΟΛΟΓΩΝ ΥΔΡΑΥΛΙΚΩΝ ΧΑΡΑΚΤΗΡΙΣΤΙΚΩΝ. ΤΕΤΑΡΤΟΓΕΝΗΣ ΥΔΡΟΦΟΡΙΑ ΦΙΛΟΞΕΝΕΙΤΑΙ ΜΕΣΑ ΣΤΟΝ ΑΛΛΟΥΒΙΑΚΟ ΚΩΝΟ ΤΟΥ ΠΟΤΑΜΟΥ ΚΟΜΨΑΤΟΥ ΣΕ ΙΔΑΝΙΚΕΣ ΣΥΝΘΗΚΕΣ ΛΕΙΤΟΥΡΓΙΑΣ. ΕΞΑΙΤΙΑΣ ΤΗΣ ΥΠΕΡΕΚΜΕΤΑΛΛΕΥΣΗΣ ΤΩΝ ΥΠΟΓΕΙΩΝ ΝΕΡΩΝ, ΟΙ ΣΤΑΘΜΕΣ ΑΝΤΛΗΣΗΣ ΚΑΙ ΗΡΕΜΙΑΣ ΒΡΙΣΚΟΝΤΑΙ ΣΕ ΕΝΑ ΣΗΜΑΝΤΙΚΟ ΤΜΗΜΑ ΤΗΣ ΜΕΙΟΚΑΙΝΙΚΗΣ ΥΔΡΟΦΟΡΙΑΣ, ΔΙΑΡΚΩΣ ΚΑΤΩ ΑΠΟ ΤΗΝ ΕΠΙΦΑΝΕΙΑ ΤΗΣ ΘΑΛΑΣΣΑΣ. Ο ΕΜΠΛΟΥΤΙΣΜΟΣ ΤΩΝ ΥΔΡΟΦΟΡΩΝ ΟΡΙΖΟΝΤΩΝ ΠΡΑΓΜΑΤΟΠΟΙΕΙΤΑΙ ΜΕΣΩ ΤΕΣΣΑΡΩΝ ΔΙΑΦΟΡΕΤΙΚΩΝ ΔΙΑΔΙΑΚΑΣΙΩΝ.ΟΙ ΙΣΟΤΟΠΙΚΕΣ ΑΝΑΛΥΣΕΙΣ ΔΕΙΓΜΑΤΩΝ ΤΩΝ ΥΠΟΓΕΙΩΝ ΝΕΡΩΝ ΣΥΝΕΒΑΛΑΝ ΟΥΣΙΑΣΤΙΚΑ ΣΤΗΝ ΑΠΟΣΑΦΗΝΙΣΗ ΤΟΥ ΚΑΘΕΣΤΩΤΟΣ ΤΡΟΦΟΔΟΣΙΑΣ ΚΑΙ ΕΠΙΒΑΡΥΝΣΗΣ ΑΥΤΩΝ. ΤΟΠΙΚΑ ΛΑΜΒΑΝΕΙ ΧΩΡΑ ΠΡΟΣΦΑΤΗ ΔΙΕΙΣΔΥΣΗ ΤΗΣ ΘΑΛΑΣΣΑΣ (ΠΑΡΑΚΤΙΟΙ ΥΔΡΟΦΟΡΕΙΣ) ΜΕ ΤΟ ΜΗΧΑΝΙΣΜΟ ΔΙΕΙΣΔΥΣΗΣ ΠΟΥ ΠΡΟΤΑΘΗΚΕ ΚΑΙ ΑΝΑΛΥΘΗΚΕ ΑΠΟΚΟΠΗ ΠΕΡΙΛΗΨΗΣ</jats:p>

Agricultural Water Management, 2011

Three alternative irrigation projects for the East Macedonia-Thrace Region, Greece, are considere... more Three alternative irrigation projects for the East Macedonia-Thrace Region, Greece, are considered. Given the presence of valuable natural ecosystems in the area, environmental considerations are of great importance. In order to evaluate the projects, a fuzzy multicriteria benefit-cost approach is proposed. The overall goal is the rational management of water resources, and the projects appraisal is based on economic, social, and environmental criteria. Alternative scenarios on the availability of water resources are also incorporated in the decision model. The decision problem is formulated as two hierarchies, and the projects are ranked according to the benefit-cost ratio of their global priorities. The proposed method is proved to be, on the one hand, very suitable when both costs and benefits cannot be easily expressed into monetary terms as the traditional benefit-cost analysis requires; and, on the other hand, a valuable tool to cope with vague judgments.

Environmental Processes, 2019

This paper aims, using classic hydrogeologic techniques, Time Series Analysis, Principal Componen... more This paper aims, using classic hydrogeologic techniques, Time Series Analysis, Principal Component Analysis, Standardized Precipitation Index, and MRC methods to better understand the hydrogeological, and hydraulic characteristics of a mature karst aquifer system, and to analyze its behavior under drought conditions. The study area is the karst aquifer system of Aggitis (AAS), Northern East Greece, characterized by a mountainous terrain consisting of highly fissured and karstified Falakro marbles of Mesozoic age. AAS catchment extends 63.4 km 2 and exhibits a duality of conduit and/or diffuse flow model. AAS is drained by the permanent large Maaras spring with a mean annual value of 4.656 m 3 /s. The dominant chemical type is Ca-HCO 3. PCA and hydrochemical analysis were effectively used in combination to interpret the main hydrogeochemical mechanisms controlling karst water quality. A combined methodology provides a useful and effective tool for assessing the characteristic behavior of karst springs under drought conditions. It enables also, to gain insight into the prevailing processes in a karst aquifer system. The statistical analysis of hydrological data revealed the karst system is mainly recharged by diffuse infiltration.

Environmental Processes, 2017

This study intends, using classic and new techniques (e.g., Time Series Analysis, TSA), and hydro... more This study intends, using classic and new techniques (e.g., Time Series Analysis, TSA), and hydrogeological data for the period February 2008-May 2011, to improve the existing knowledge on the hydrogeology of the immature karst Philippi aquifer system (PHAS), Northeast Greece, in order to introduce the sustainable integrated water management of this system. The PHAS catchment consists of Mesozoic fissured and slightly karstified marbles, and covers an area of 121.7 km 2. It discharges through the perennial, fault-controlled, overflow Voirani spring, which serves the needs of 85,000 inhabitants. Source of recharge is direct diffuse infiltration of precipitation. The Voirani spring mean discharge rate is 1.48 m 3 /s and ranges from 1 to 2.1 m 3 /s. Its variability index ranges from 1.73 to 2.07 m 3 /s. Auto-and cross-correlation and spectral analyses were used in combination with PHAS hydrogeological characteristics to study the interrelationship of daily spring discharge and rainfall, and provided useful information about the PHAS memory effect. PHAS baseflow prevailed greatly and had a behavior similar to a porous aquifer. The catchment area recharges and stores deep circulating water, while its karstification is poorly developed with high storages. The Voirani spring water is of Ca-HCO 3 chemical type, of high quality, and oversaturated with respect to calcite. Examination of hydrograph and chemograph data revealed that PHAS is dominated by diffuse flow of stable hydrochemical composition. The application of TSA combined with classic hydrogeological techniques can be used in order to achieve a sustainable integrated water management of this system.

Journal of Environmental Science and Health, Part A, 2012

A groundwater monitoring and modeling program in two aquifers within the lower Nestos river basin... more A groundwater monitoring and modeling program in two aquifers within the lower Nestos river basin in Northern Greece is presented. A monitoring network of 54 wells was developed in the two study areas, and groundwater level measurements and water quality sample analyses were conducted for a period of 2.5 years, from March 2007 to October 2009. The field data were used for the calibration and verification of the mathematical model MODFLOW in the two aquifers. The validated model was used to examine ten alternative management scenarios regarding groundwater abstraction in the two aquifers. The study showed that MODFLOW, if properly validated, is a useful and flexible tool in groundwater resources management.

ΤΟ ΑΝΤΚΕΙΜΕΝΟ ΤΗΣ ΔΙΑΤΡΙΒΗΣ ΕΙΝΑΙ Η ΔΙΕΡΕΥΝΗΣΗ ΤΟΥ ΚΑΘΕΣΤΩΤΟΣ ΠΟΥ ΔΙΕΠΕΙ ΤΗ ΛΕΙΤΟΥΡΓΙΑ ΚΑΙ ΤΙΣ ΣΥ... more ΤΟ ΑΝΤΚΕΙΜΕΝΟ ΤΗΣ ΔΙΑΤΡΙΒΗΣ ΕΙΝΑΙ Η ΔΙΕΡΕΥΝΗΣΗ ΤΟΥ ΚΑΘΕΣΤΩΤΟΣ ΠΟΥ ΔΙΕΠΕΙ ΤΗ ΛΕΙΤΟΥΡΓΙΑ ΚΑΙ ΤΙΣ ΣΥΝΘΗΚΕΣ ΕΠΙΒΑΡΥΝΣΗΣ ΤΗΣ ΥΠΟΓΕΙΑΣ ΥΔΡΟΦΟΡΙΑΣ ΣΤΟ ΠΑΡΑΚΑΤΩ ΤΜΗΜΑ ΤΟΥ Ν. ΡΟΔΟΠΗΣ ΚΑΙ Η ΔΗΜΙΟΡΓΙΑ ΤΟΥ ΚΑΤΑΛΛΗΛΟΥ ΠΛΑΙΣΙΟΥ ΓΙΑ ΤΗΝ ΟΡΘΟΛΟΓΙΚΗΔΙΑΧΕΙΡΙΣΗ ΑΥΤΗΣ. ΤΟ ΚΛΙΜΑ ΤΗΣ ΠΕΡΙΟΧΗΣ ΕΙΝΑΙ ΤΟΥ ΤΥΠΟΥ CSA. Η ΜΕΛΕΤΗ ΤΗΣ ΓΕΩΜΟΡΦΟΛΟΓΙΑΣ, ΓΕΩΛΟΓΙΑΣ (ΤΕΚΤΟΝΙΚΗ), ΣΤΡΩΜΑΤΟΓΡΑΦΙΑΣ ΚΑΙ ΥΡΔΟΓΕΩΛΟΓΙΑΣ ΕΔΕΙΞΕ ΟΤΙ ΣΤΗΝ ΠΕΡΙΟΧΗ ΚΑΙ ΜΕΣΑ ΣΕ ΣΧΗΜΑΤΙΣΜΟΥΣ ΤΟΥ ΑΝΩΤΕΡΟΥ ΜΕΙΟΚΑΙΝΟΥ ΣΧΗΜΑΤΙΖΕΤΑΙ ΕΝΑ ΑΞΙΟΛΟΓΟ ΥΔΡΟΦΟΡΟ ΣΥΣΤΗΜΑ ΥΠΟ ΠΙΕΣΗ. Η ΥΔΡΟΦΟΡΙΑ ΕΠΗΡΕΑΖΕΤΑΙ ΑΜΕΣΑ ΑΠΟ ΤΗΝ ΤΕΚΤΟΝΙΚΗ ΚΑΙ ΑΠΟ ΤΟ ΠΕΡΙΒΑΛΛΟΝ ΙΖΗΜΑΤΟΓΕΝΕΣΗΣ ΕΝΤΟΣ ΤΟΥ ΟΠΟΙΟΥ ΦΙΛΟΞΕΝΕΙΤΑΙ. Η ΑΞΙΟΛΟΓΗΣΗ ΤΩΝ ΔΕΔΟΜΕΝΩΝ ΤΩΝ ΑΝΤΛΗΤΙΚΩΝ ΔΟΚΙΜΑΣΙΩΝ, ΤΗΣ ΥΔΡΟΧΗΜΕΙΑΣ, ΤΩΝ ΙΖΗΜΑΤΟΛΟΓΙΚΩΝ ΧΑΡΑΚΤΗΡΙΣΤΙΚΩΝ ΚΑΙ ΤΗΣ ΠΙΕΖΟΜΕΤΡΙΑΣ ΕΠΙΒΕΒΑΙΩΝΕΙ ΤΗΝ ΠΑΡΟΥΣΙΑ ΑΞΙΟΛΟΓΩΝ ΥΔΡΑΥΛΙΚΩΝ ΧΑΡΑΚΤΗΡΙΣΤΙΚΩΝ. ΤΕΤΑΡΤΟΓΕΝΗΣ ΥΔΡΟΦΟΡΙΑ ΦΙΛΟΞΕΝΕΙΤΑΙ ΜΕΣΑ ΣΤΟΝ ΑΛΛΟΥΒΙΑΚΟ ΚΩΝΟ ΤΟΥ ΠΟΤΑΜΟΥ ΚΟΜΨΑΤΟΥ ΣΕ ΙΔΑΝΙΚΕΣ ΣΥΝΘΗΚΕΣ ΛΕΙΤΟΥΡΓΙΑΣ. ΕΞΑΙΤΙΑΣ ΤΗΣ ΥΠΕΡΕΚΜΕΤΑΛΛΕΥΣΗΣ ΤΩΝ ΥΠΟΓΕΙΩΝ ΝΕΡΩΝ, ΟΙ ΣΤΑΘΜΕΣ ΑΝΤΛΗ...

Desalination, 2010

The newest version of Soil and Water Assessment Tool (SWAT2005), coupled with a GIS interface (AV... more The newest version of Soil and Water Assessment Tool (SWAT2005), coupled with a GIS interface (AVSWATX), was applied to Kosynthos River watershed located in Northeastern Greece. The 440km2 drainage basin was discretized into 32 sub-basins using an automated delineation routine. The multiple hydrologic response unit (HRU) approach was used and the basin was discretized into 135 HRUs. The model was

Smart Innovation, Systems and Technologies, 2010

... Thus, the present methodology offers a fast and simple method to check the suitability of new... more ... Thus, the present methodology offers a fast and simple method to check the suitability of new areas for construction of such systems. Initially, the process involved the creation and analysis of several grids of different themes [4],[5]. The GIS based methodology resulted in various ...

Water Resources Management, 2006

Application of stepwise discriminant analysis to classify commercial orange juices using chiral m... more Application of stepwise discriminant analysis to classify commercial orange juices using chiral micellar electrokinetic chromatography-laser induced fluorescence data of amino acids The use of chiral amino acids content and stepwise discriminant analysis to classify three types of commercial orange juices (i.e., nectars, orange juices reconstituted from concentrates, and pasteurized orange juices not from concentrates) is presented. Micellar electrokinetic chromatography with laser-induced fluorescence (MEKC-LIF) and b-cyclodextrins are used to determine Land D-amino acids previously derivatized with fluorescein isothiocyanate (FITC). This chiral MEKC-LIF procedure is easy to implement and provides information about the main amino acids content in orange juices (i.e., L-proline; L-aspartic acid, D-Asp, L-serine, L-asparagine, L-glutamic acid, D-Glu, L-alanine, L-.arginine, D-Arg, and the non-chiral g-amino-n-butyric acid (GABA), i.e., g-aminobutyric acid). From these results, it is clearly demonstrated that some D-amino acids occur naturally in orange juices. Application of stepwise discriminant analysis to 26 standard samples showed that the amino acids L-Arg, L-Asp and GABA were the most important variables to differentiate the three groups of samples. With these three selected amino acids a 100% correct classification of the samples was obtained either by standard or by leave-one-out cross-validation procedures. These classification functions based on the content in L-Arg, L-Asp and GABA were also applied to nine test samples and provided an adequate classification and/or interesting information on these samples. It is concluded that chiral MEKC-LIF analysis of amino acids and stepwise discriminant analysis can be used as a consistent procedure to classify commercial orange juices providing useful information about their quality and processing. To our knowledge, this is the first report about the combined use of chiral capillary electrophoresis and discriminant techniques to classify foods.

Journal of Hydrology, 2006

Environmental Processes

This study aims to present the hydrogeological and hydrochemical characteristics of Paradisos Kar... more This study aims to present the hydrogeological and hydrochemical characteristics of Paradisos Karst aquifer system (PAS), Northeast Greece. The average area of the PAS is estimated according to Thornthwaite and Mather (1957) (T-M) procedure at 74.2 km2. The karst system, which is largely fault-controlled, discharges through three permanent karst springs: KS15, KS20 and KS21. The average discharge rate was calculated for two of them at 0.726 m3/s. The time series analysis shows that: (a) the memory effect for the PAS is extremely high; and (b) the karst system is a poorly developed with high storage capacity and absence of a quick flow component. The chemical type for the majority of the groundwater samples is of Ca-HCO3 type. The chemical properties of the groundwaters are strongly influenced by alkaline earth metals and weak acids. The presence (sporadically) of high NH4+ content and slightly increased nitrate, ammonium and phosphate values in springs KS20 and KS21 is attributed to the presence of anthropogenic sources, especially septic tanks and agriculture. All studied groundwaters are oversaturated in calcite and aragonite, which suggests a mechanism of diffuse flow. The morphology and geology of the PAS catchment area, and data from hydrographs and chemographs, show that the hydrologic system is dominantly of diffuse flow. The use of time series analysis combined with classic hydrogeological techniques (i.e., degree of karstification, T-M procedure, chemographs and saturation indices) can be used in order to successfully characterize a karst system and achieve a sustainable integrated water management in it.

European Planning Studies, 2018

In this paper, the water supply conditions in the major Greek cities have been investigated and a... more In this paper, the water supply conditions in the major Greek cities have been investigated and a comprehensive description is provided. It has occurred that the choice of the catchment area as the administrative unit for water management purposes is rather more adapted to urban water management in Western Europe, than in Greece. In fact, while the major cities in France, Spain and the UK can be mainly supplied by water issued from the catchment area in which they are located, interbasin water transfer is necessary in Greece. The reasons are both hydrological, with the typical catchment area size in Greece being rather small, and because the economic activities of the Greek cities are not linked to rivers; so only a few of them are built on large watersheds. The reduction of water losses due to network leakage is suggested as a method for the decrease of interbasin transfer volumes.

Hydrological Processes, 2008

ABSTRACT The present study investigates the possible hydrologic effects of the proposed lignite o... more ABSTRACT The present study investigates the possible hydrologic effects of the proposed lignite open-cast mining in Drama lignite field (north Greece). Recent years have seen a rapid increase in surface mining. This activity has generated a growing concern for the potential environmental impacts associated with large scale surface mining.In order to achieve a safe mine operation and allow extraction of lignite to considerable depths, extensive dewatering by pumping will be necessary, while at the same time it is desirable to avoid presence of overpumping conditions in the broader area. Based on stratigrafic, hydrologic and hydrogeologic data, a three-dimensional finite difference model was developed in order to simulate the dewatering process of the western part of the lignite open-cast mine in Drama and to predict both spatially and temporally the decline of ground water level down to the lignite surface. The dewatering of the part of the aquifer which underlies the mine area will influence the hydrological conditions of the broader region. The most important anticipated effects will be the abandonment of shallow wells as well as the decrease of ground water pumping rates of deep wells. Aquifer discharge towards the ditches of the study area will cease and there will be an inversion of ground water flow from the ditches towards the underlying aquifer. Dewatering activities will probably result in minor subsidence of the nearby peat deposits of Drama Philippi marshes. Moreover, sand pumping as well as the presence of gasses is likely to cause local subsidence phenomena, mainly in the pit slopes. Copyright © 2007 John Wiley & Sons, Ltd.

The geological, hydrogeological and hydrochemical regimes of the coastal Rhodope aquifer system, ... more The geological, hydrogeological and hydrochemical regimes of the coastal Rhodope aquifer system, northeastern Greece, are described. The aquifer system includes two aquifers within coarse grained alluvial sediments. Both vertical and lateral saline water intrusion occurs, usually caused by over pumping. Water has been pumped from the aquifer system at an ever-increasing rate for many years. Water samples for chemical analyses were obtained from 36 productive wells and from 5 research wells at several depths to cover the entire study area. The EC and chloride concentration distribution clearly illustrate the large extent of saline water intrusion in the aquifer system of the study area. Although the ionic content of groundwater of the study area is highly variable, the dominant anions are HCO 3 ! and Cl ! and the dominant cations are Na + and Ca 2+. Water in the saline parts of the confined aquifer is generally of the Ca 2+-Cl ! type. Evidence of cation exchange and reverse cation reaction between fresh and saltwater in the Rhodope aquifer system are reflected in the Piper diagram and the expanded Durov hydrochemical diagram, respectively, both for productive and research wells. The results of this study show that the development of a strategy for managing the aquifer system is vitally necessary.

Environmental Earth Sciences, 2012