Papers by STAVROS YANNOPOULOS
ΤΕΧΝΗΤΗ ΕΠΑΝΑΠΛΗΡΩΣΗ ΕΝΟΣ ΕΛΕΥΘΕΡΟΥ ΥΔΡΟΦΟΡΕΑ ΜΕ ΤΗ ΒΟΗΘΕΙΑ ΤΗΣ ΑΣΑΦΟΥΣ ΛΟΓΙΚΗΣ
Στο παρόν άρθρο πeριγράφeται, σe γeνικές γραμμές, η δυνατότητα eπίλυσης πρακτικών προβλημάτων της... more Στο παρόν άρθρο πeριγράφeται, σe γeνικές γραμμές, η δυνατότητα eπίλυσης πρακτικών προβλημάτων της υδραυλικής eπιστήμης για την πeρίπτωση που ορισμένeς παράμeτροι του προβλήματος παρουσιάζουν ασάφeιeς ώς προς την πραγματική τους τιμή. Η eπίλυση τέτοιων προβλημάτων γίνeται μe τη βοήθeια της ασαφούς λογικής και eδώ παρουσιάζeται η μeθοδολογία των αριθμητικών πράξeων των ασαφών αριθμών σe ένα πρόβλημα τeχνητής eπαναπλήρωσης eνός eλeύθeρου νδροφορέα, στον οποίο οι υδραυλικές παράμeτροι παρουσιάζουν ασάφeιeς. Η έμφαση δίνeται στον αποθηκeυμένο όγκο του νeρού μέσα στον υδροφορέα για διάφορα eπίπeδα πιθανότητας, παρουσιάζονται οι συναρτήσeις eμπιστοσύνης για διάφορeς χρονικές στιγμές, καθώς και ο όγκος του νeρού που αντιστοιχeί στο κέντρο βάρους των συναρτήσeων eμπιστοσύνης.
Water Resources Management of an Aquifer with Fuzzy Linear Programming
A pure peer-to-peer method for (1) an efficient discovery of data in large distributed raw datase... more A pure peer-to-peer method for (1) an efficient discovery of data in large distributed raw datasets and (2) collection of thus procured data is considered. It is based on ant colony optimization (ACO) and supports a user-specified extraction of structured ...
Management of Water Bodies Pollution due to the Interurban Roads Stormwater Runoff
Recent Progress in Computational Sciences and Engineering, 2019
In order to simulate unsaturated flow it is necessary to know: (a) the unsaturated hydraulic cond... more In order to simulate unsaturated flow it is necessary to know: (a) the unsaturated hydraulic conductivity K as a function of the soil water pressure head h or of the water content 6 and (b) the soil moisture retention curve 6(h). For this purpose hydraulic conductivity models have been developed for the prediction of K(6 ) on the basis of 6(h). The analytical expression of the d(h) curve contains fitting parameters, as well as the so-called residual and saturated water contents, denoted as Qj. and 6$ respectively. Van Genuchten' s twoand three-parameter closed form analytical models are widely used both for 6(h) and for the prediction of K(d). Another hydraulic conductivity prediction model was formulated by Jackson in the past, but it is presently not preferred, mainly because of its tabular and not analytical form. However, its sensitivity behaviour warrants reconsideration. A sensitivity analysis is carried out, after dealing with particular problems that are due to the discr...
Rainfall-Runoff Process Simulation using the Watershed Modeling System (WMS) Software
Η ΔΙΑΧΕΙΡΙΣΗ ΤΩΝ ΔΙΕΘΝΩΝ ΛΕΚΑΝΩΝ ΑΠΟΡΡΟΗΣ ΚΑΙ Η ΟΔΗΓΙΑ 2000/60/ΕΚ. - ΠΡΟΒΛΗΜΑΤΑ ΚΑΙ ΠΡΟΟΠΤΙΚΕΣ
Η Οδηγία 2000/60/EΚ eισάγeι νέα πρότυπα, κριτήρια, θeσμούς και διαδικασίeς για την ολοκληρωμένη δ... more Η Οδηγία 2000/60/EΚ eισάγeι νέα πρότυπα, κριτήρια, θeσμούς και διαδικασίeς για την ολοκληρωμένη διαχeίριση των υδατικών πόρων σe eπίπeδο λeκάνης απορροής ποταμού και μπορeί να συμβάλλeι σημαντικά στη βeλτίωση της διαχeίρισης των διeθνών ποταμών και λιμνών της Eυρώπης. Προκeιμένου για πeριπτώσeις στις οποίeς eμπλέκονται τα Κράτη - Μέλη της EE. ή τα υποψήφια προς ένταξη κράτη, η γeνική προσέγγιση και οι λeπτομeρeίς απαιτήσeις της Οδηγίας eίναι μια άριστη βάση για διeθνή συνeργασία, ώστe να αποφeυχθούν οι προστριβές, οι eντάσeις και οι συγκρούσeις, που απeιλούν την eιρήνη σe αρκeτά σημeία του πλανήτη. Συγχρόνως, όμως, για τα κράτη της Eυρώπης για τα οποία δeν eίναι υποχρeωτική η eφαρμογή της νομοθeσίας της E.E. ή δeν θα eίναι στο eγγύς μέλλον, η Οδηγία μπορeί να αποτeλέσeι ένα «σύστημα αναφοράς» για τη βeλτίωση της διαχeίρισης των διeθνών τους υδάτων, μe διαδοχικά βήματα προς την ολοκληρωμένη διαχeίριση των υδατικών τους πόρων. Eιδικότeρα, στην παρούσα eργασία, eξeτάζονται οι προϋποθέσ...
Issue 1, 2013
Nowadays, it is a common ascertainment that stormwater runoff in the urban and interurban road ne... more Nowadays, it is a common ascertainment that stormwater runoff in the urban and interurban road network consist non-point source pollution which contributes to the degrading of the quality of water of ground and surface water bodies. Taking into account the fact that water pollution has impacts to people and also to flora and fauna, the need to take measures in order to confront this environmental problem becomes inevitable. The adverse impacts of the stormwater runoff can be minimized with structural and non-structural Best Management Practices (BMPs) or with a combination of them. Within the content of the present paper the following are included: a) the investigation and presentation of the receiving waters pollution issues from the highway road network stormwater runoff together with the European transport policy concerning the development of an integrated highway road network, b) the examination of the respective pollutant generation and characteristics, c) the presentation of t...
Application of Linear and Fuzzy Linear Programming for Water Management of an Aquifer
WSEAS Transactions on Systems
Comparative Analysis of Synthetic Unit Hydrograph Method using WMS Rainfall
Recent Progress in Computational Sciences and Engineering, 2019
The designating factors in the design of branched irrigation networks are the cost of pipes and t... more The designating factors in the design of branched irrigation networks are the cost of pipes and the pumping cost. They both depend directly on the hydraulic head of the pump. It is mandatory for this reason to calculate the optimal head of the pump as well as the corresponded optimal pipe diameters, in order to derive the minimal total cost of the irrigation network. The certain calculating methods in identified the above total cost that have been derived are: the linear programming optimization method, the non linear programming optimization method, the dynamic programming optimization method and the Labye's method. All above methods have grown independently and a comparative study between them has not yet been derived. In this paper, a comparative calculation of the pump optimal head as well as the corresponded economic pipe diameters, using the dynamic programming method and the Labye's optimization method is presented. Application and comparative evaluation in a particular irrigation network is, also, developed. From the study it is being held that the two optimization methods in fact conclude to the same result and therefore can be applied with no distinction in the studying of the branched hydraulic networks.
Evolution of water supply infrastructures of Thessaloniki city, hellas, through centuries
Thessaloniki city, in the east core of Thermaic gulf, has been continuously inhabited for about 2... more Thessaloniki city, in the east core of Thermaic gulf, has been continuously inhabited for about 2330 years. The choice of its founding at this specific location is very much attributed to the high availability of water in the wider region. However, the development of Thessaloniki in a big city and the simultaneous increasing population, created an increased need for water, which could not be covered by the water of the wells. Until the 19th century, water needs were met with cisterns, water channels, fountains and water towers in combination with the wells. Moreover, the city was also equipped with large scale and of high expertise water supply projects, which were exploiting the region’s water resources in four different places and were transferring water inside the walls. These water transfer works were associated with water distribution systems, with pipes located beneath roads or following the contour lines. Also, people who lived in the Hellenistic, Roman, Byzantine, Ottoman and newer Hellenic periods gave their own perspective in the problems related to water supply in the city. A review of all these techniques through centuries is presented and commented in this paper.
The characteristic curve of almost all the existing soils can be satisfactorily simulated by an S... more The characteristic curve of almost all the existing soils can be satisfactorily simulated by an S-shape curve. However, in cases where the medium has a double porosity (macroporous soils, unsaturated fractured rocks and fissured ground water systems), the S-shape curve fails to describe the characteristic curve. Gerke and van Genuchten [l41 have described the physical structure of such a medium and Zhang and van Genuchten [33] have proposed a new model with five parameters, which can simulate the double porosity soils. In this article a special algorithm is developed in order to optirnize the new function describing the double porosity characteristic curve. The algorithm is based on the theory of the quasi-Newton method (BFGS)
Healthcare Access - Regional Overviews [Working Title], 2019
The relation between human health, water, and hygiene facilities has been realized since during t... more The relation between human health, water, and hygiene facilities has been realized since during the Bronze Age, the explanations of illness and health problems were based on theocratic elements. However, the Greeks during the Classical and mainly the Hellenistic period clearly differentiated their thinking from all other civilizations by inventing philosophy and empirical science. Drains/sewers, baths and toilets, and other sanitary installations are reflecting high cultural and technological level, while they also are associated with observations and ideas about hygiene and medicine. The aim of this paper is to examine the knowledges about the influence of water on human health throughout antiquity. In other words, it focuses on the views that Greeks and Romans had on water quality and its impact on the human body.
Water, 2019
Nowadays, available water resources face severe pressures due to demographic, economic, social ca... more Nowadays, available water resources face severe pressures due to demographic, economic, social causes, environmental degradation, climate change, and technological changes on a global scale. It is well known that rainwater harvesting, a simple and old method, has the potential to supplement surface and groundwater resources in areas that have inadequate water supply. In recent decades, many countries have supported the updated implementation of such a practice to confront the water demand increase and to reduce the frequency, peak, and volume of urban runoff. These considerations motivate interest in examining the current situation and the prospect of further development of this method worldwide. The present paper aims at the investigation of the current situation of rainwater harvesting (RWH) as an alternative water source to confront water scarcity in various countries around the world. In particular, the paper presents the following: (a) the causes of water shortage; (b) a concis...
Historical development of rainwater harvesting and use in Hellas: a preliminary review
Water Science and Technology: Water Supply, 2016
The uneven temporal and partial distribution of water resources in Hellas, and especially southea... more The uneven temporal and partial distribution of water resources in Hellas, and especially southeastern regions, has resulted in the construction of various water systems for collection and storage of rainwater, since their very early habitation. Ever since, technologies for the construction and use of several types of cisterns and other relevant hydraulic strictures have been developed. The main diachronic achievements in rainwater harvesting and use in Hellas from the earliest times of humankind to the present is studied. Emphasis is given to the periods of great achievements such as the Hellenistic and the Roman. The major necessity of water justifies not only the innovations found throughout the historical time-line of these constructions but also the most advanced engineering of each era applied to these constructions. Also, the importance of this hydrotechnology and the concept of the value of water-saving to present and future times is considered. Aspects referring to hygienic...
Journal of Water Sanitation and Hygiene for Development, 2017
Sanitation and hygiene technologies have existed in ancient Hellas since the Bronze Age (ca. 3200... more Sanitation and hygiene technologies have existed in ancient Hellas since the Bronze Age (ca. 3200–1100 bc), when extensive sewerage and drainage and other elaborate sanitary structures were known in Minoan palaces and towns. Classical and Hellenistic periods should be considered as the most progressive eras in the design of sanitary engineering. At that time anatomically shaped toilet seats are found in several sites since many private houses and public buildings have them. As cities grew in size the pressure of larger populations resulted in the construction of communal toilets with seats that were more densely packed together. Drainage and sewerage systems and sanitary installations reflect high cultural and technological levels and they are associated with contemporary observations and ideas about hygiene and medicine. Before the Hellenic advances, medicine was entirely confined to religious beliefs and metaphysical rituals. In the early Roman period, the knowledge of the ancient...
Water Science and Technology: Water Supply, 2016
Historical and archaeological evidence shows that ancient Hellenes had developed underground aque... more Historical and archaeological evidence shows that ancient Hellenes had developed underground aqueducts since the prehistoric times. However, innovative methods of underground aqueducts were developed in Hellas mainly during the Archaic, Classical, Hellenistic, and Roman periods. Since the well-known tunnel at the island of Samos, Hellas, was designed and begun its construction (ca. 550 bc) by Eupalinos of Megara (the first civil engineer in history), several underground tunnels (with and without well-like vertical shafts) were implemented in the country. The goal of Eupalinos tunnel was to transfer water into the town from a spring. This tunnel, representing the peak of ancient hydraulic technology, was dug through limestone by two separate teams advancing in a straight line from both sides of the mountain. Delivering fresh water to growing populations has been an ongoing problem since ancient times. Several underground aqueduct paradigms (e.g. Peisistration in Athens, Polyrrhenia i...
Water, 2015
The evolution of the major achievements in water lifting devices with emphasis on the major techn... more The evolution of the major achievements in water lifting devices with emphasis on the major technologies over the centuries is presented and discussed. Valuable insights into ancient water lifting technologies with their apparent characteristics of durability, adaptability, and sustainability are provided. A comparison of the relevant technological developments in several early civilizations is carried out. These technologies are the underpinning of modern achievements in water engineering. They represent the best paradigm of probing the past and facing the future. A timeline of the historical development
Environmental Processes, 2015
In 2007, the European Floods Directive (FD) 2007/60/EC came into force, introducing a framework f... more In 2007, the European Floods Directive (FD) 2007/60/EC came into force, introducing a framework for the assessment and management of flood risks. According to Article 6 of the Directive, Member States shall prepare flood hazard maps and flood risk maps at a catchment level, covering the areas that could be flooded under different probability scenarios. The former maps include crucial information towards flood management, such as flood extent -water levels -flow velocity, that will form the base of the flood risk management plans. Based on these data, Member States shall set their objectives and prepare measures concerning their flood management plans. Hence, it is obvious that effective flood management requires reliable methods for the estimation of the flooded areas, such as precise estimation of the peak discharge. This is a hard task for hydrological engineering, taking into account that in the majority of small catchments, especially in Greece, there is a substantial lack of hydrological data. The present paper presents the effect of the uncertainty, derived from lack of data, on the estimation of the peak discharge based upon which the flooded areas will be identified. Towards this direction, a methodology of peak discharge estimation is presented in an ungauged small catchment followed by hydraulic calculations using HEC-RAS and HEC-GeoRAS software packages. The results demonstrate the great variability of the estimated flood extent and the effect of it on the decision-making of the proposed flood measures.
Water Distribution System Reliability Based on Minimum Cut – Set Approach and the Hydraulic Availability
Water Resources Management, 2012
ABSTRACT Reliability analysis of water distribution systems is a complex task, as it requires bot... more ABSTRACT Reliability analysis of water distribution systems is a complex task, as it requires both definition and calculation of several reliability measures. In this paper, a methodology for evaluating water distribution system reliability is developed and demonstrated on a simple water distribution network based on the minimum cut-set approach. In general, the definition of the minimum cut-set can arise either from the mechanical reliability or from the concept of hydraulic reliability. In the case of mechanical reliability, a new method based on graph theory is developed, in order to determine the minimum cut-set. This method is based on the counting of paths between nodes. Furthermore, the general concept of reliability is proposed, to include apart from the mechanical reliability, more generally, the pressure availability at nodes as a main hydraulic property. Based on the pressure availability, the sense of hydraulic availability can be expressed as a fuzzy set, while the combination of the water unavailability of the nodes can be achieved by using fuzzy averaging aggregator. Finally, an overall reliability index is proposed based on both the hydraulic and the mechanical reliability. An illustrative example is developed to indicate the methodology.
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Papers by STAVROS YANNOPOULOS