Jacques Ganoulis

Modelling of water pollution in the Thermaikos Gulf with fuzzy parameters

Abstract The fuzzy set theory is applied for the definition of the imprecise parameters, which are used in a water pollution model. The physico-chemical coefficients and the loads of pollution sources are expressed in the form of triangular fuzzy numbers. A two-dimensional finite element algorithm, combined with fuzzy logic analysis, is used for the solution of the advection–dispersion equation for ten different water quality variables. The characteristic Galerkin technique was employed for the temporal discretisation, whereas interval operations were conducted for the solution of the algebraic system of equations with fuzzy coefficients. The model was applied for the study of pollution in the Gulf of Thermaikos, located in Northern Greece, for water velocities obtained from a wind-induced circulation model. The concentration distributions of the water quality variables considered are derived in the form of fuzzy numbers, and are presented in relevant diagrams.

Water Resources Engineering Risk Assessment

Although many theoretical developments have been achieved recently, the progress both in understanding and application of risk and reliablity analysis in water resources and environmental engineering remains slow. Presenting, in a unified and comprehensive framework, the various aspects of risk and reliability in both water quantity and quality problems, this text describes methods for total risk management, risk analysis of extremes in hydrology, groundwater clean-up, and river and coastal pollution.

Risk analysis of water pollution

WATER RESOURCES: QUANTITY AND QUALITY Water Pollution and Risk Analysis Water Pollution in Transboundary Regions The EU Water Framework Directive Uncertainties in Water Resources Management Environmental Risk Assessment and Management Aim and Organisation of the Book Questions and Problems - Chapter 1 RISK IDENTIFICATION Definition of Risk Typology of Risks and the Precautionary Principle Uncertainties in Water Pollution Problems Water Quality Specifications Probabilistic Risk and Reliability Fuzzy Risk and Reliability Questions and Problems - Chapter 2 RISK QUANTIFICATION Stochastic Approach Fuzzy Set Theory Time Dependence and System Risk Questions and Problems - Chapter 3 RISK ASSESSMENT OF ENVIRONMENTAL WATER QUALITY Risk in Coastal Water Pollution Risk in River Water Quality Risk in Groundwater Contamination Questions and Problems - Chapter 4 RISK MANAGEMENT Performance Indices and Figures of Merit Objective Functions and Optimisation Basic Decision Theory Elements of the Utility Theory Multi-Objective Decision Analysis Questions and Problems - Chapter 5 CASE STUDIES Coastal Pollution: The Thermaikos Gulf (Macedonia, Greece) River Water Quality: The Axios River (Macedonia, Greece) Groundwater Pollution: The Campaspe Aquifer (Victoria, Australia) APPENDIX A: THE PROBABILISTIC APPROACH Basic Probability The Multiplicative Law Statistical Independence Rare Events Theorem of Total Probability Bayes-Theorem Random Variables Expectation, Variance and Standard Deviation Derived Distributions Two-Dimensional Distributions Functions of Random Vectors APPENDIX B: THE FUZZY SET THEORY Basic Definitions Fuzzy Sets h-Level Sets, Normal and Convex Fuzzy Sets Fuzzy Numbers Cartesian Product Extension Principle Arithmetic Operations on Fuzzy Numbers as Extension of Interval Analysis Arithmetic Operations on Intervals APPENDIX C: HINTS FOR ANSWERING QUESTIONS AND SOLUTIONS TO PROBLEMS

Risk analysis of wastewater reuse in agriculture

Two of the main concerns for wastewater reuse in agricultural irrigation are environmental and human security. Different research studies and practices have been developed recently in order to quantify the risk of possible environmental contamination of surface and groundwater resources as well as the risk to public health from enteric viruses. Other, far from negligible, related issues are largely of a socio-economic and technical character. For example, the social acceptance, especially by farmers, of wastewater reclamation and reuse in agriculture is influenced by specific local cultural, religious and socio-economic conditions. Economic and technical factors should also be taken into consideration, such as the water and wastewater treatment costs, the cost of maintenance, the employment of rural labour, the structure of irrigation networks and crop patterns. In this paper, the concept of sustainability in wastewater reclamation and reuse is formulated by using a general risk analysis framework and by taking into account all the above factors. The paper suggests a methodology for sustainable wastewater reuse in agriculture by considering not only technical and economic factors, but also environmental and social risks. Alternative strategies based on different treatment and irrigation technologies are evaluated using the multicriteria decision analysis technique. The methodology is illustrated in a case study of wastewater reclamation and agricultural reuse in the city of Thessaloniki, Macedonia, Greece.

Impact of global climate change on temperature and precipitation in Greece

Abstract A stochastic space-time model is used at four locations in Greece for estimating the effect of global climate change on daily temperature and precipitation. The approach is based on a semi-empirical downscaling of simulated daily atmospheric Circulation Patterns (CP) of General Circulation Models (GCM). Historical data and a 10-year outputs of the Max Planck Institute GCM for the 1 × CO 2 and 2 × CO 2 cases are used. Nine CP types for the winter and summer half years are obtained to characterize large-scale climatic forcing in Greece, Local temperature and precipitation appear to be highly dependent on CP types. The space-time response of daily temperature to global climate change is slightly variable in Greece. In general, a warmer climate will imply nearly 3°C increase in fall and in winter. The variability within the month will not change considerably. A slight but statistically significant increase of precipitation is obtained at one location and an insignificant increase is found at the other three locations.

Risk Analysis of Water Quantity and Quality Problems: The Engineering Approach

A unified approach to risk analysis in water quantity and quality problems is presented. This is done by overviewing the definitions and methodologies for risk and reliability analysis in water resources and environmental engineering, including the concepts of fuzzy sets. The various steps to be undertaken for a comprehensive application of engineering risk analysis to a specific problem are first analyzed. These are (1) hazard identification, (2) risk quantification, (3) consequences of risk, (4) perception of the consequences and (5) risk management. Then, methods and tools used in uncertainty analysis, stochastic simulation and the fuzzy set approach are summarized.

Floodplain Protection and Management in Karst Areas

Karst floodplains are vulnerable to flooding especially in the Mediterranean area. At the same time, important groundwater resources are available in karst areas. Protection of karst floodplains and management may be provided by use of risk and reliability techniques. Uncertainties induced by karst formations are analyzed first in this chapter. Then, after defining the engineering risk of flooding, it is shown how risk may be quantified. Karst floodplain management can be developed by formulating objectives and using single or multiple criteria decision analysis techniques.

Transboundary water resources management: a multidisciplinary approach.

By paraphrasing statements made in the foreword and preface, it is obvious that rivers, lakes, mountains and plains, as well as ecosystems along with their environment, fall within the jurisdiction of different states, provinces and other administrative units. However, natural resources, running water in particular, do not know the man-made borders and, therefore, cross-border cooperation is essential in order to manage them sustainably and effectively. Transboundary waters have only recently gained significance in the international dialogue. Climate and other global changes are rapidly increasing pressure on water resources, which bring to the further increase in the need for cooperation in the field of water management among sovereign states. As almost half of the world’s land is situated in transboundary river basins, the transboundary water resource management issues are gaining increasing attention in the recent years. The application of the principles of the integrated water resource management (IWRM) is faced with many challenges, e.g. the integration of the water policy into other sectoral policies within a country, financial and human resource constraints, institutional barriers for the implementation of the IWRM, etc. However, probably the biggest challenge is the implementation of the water management policies on transboundary water resources shared by two or more countries. Many efforts have been made in the recent years to establish the framework for an effective transboundary water resources management (TWRM). Numerous legal, institutional, technical, environmental, economic and social issues have to be integrated into this framework, as only a multidisciplinary approach can result in an effective management framework. Although the principles of a sound TWRM may be universal, the actual implementation of the transboundary water resource management greatly depends on local physical, social, economic and other conditions. The experience of different TWRM endeavours is therefore an invaluable resource in an effort to improve our current understanding of the problem and approaches applied at the transboundary level. In this context, the publication can be perceived as a tool that may substantially upgrade the current practices of the TWRM. It presents various aspects of the transboundary water resources management from the perspective of scientists and experts who tackled this issue in specific TWRM projects. The topics are presented through series of essays and case studies, offering a detailed insight into the complex structure of the TWRM. One of important attributes of the book is that it presents the TWRM experience from different regions of the world. The book suggests a conceptual model, as illustrated below, on how to foster cooperation and integration in TWRM (bridging the gaps). Desalination and Water Treatment www.deswater.com

Flood retention basins in the Mediterranean urban areas

Although the Mediterannean climate is known to be dry and warm, rainstorms in autumn and winter can produce floods in coastal cities and damage of important economic consequences. Where topography permits, storm-water retention basins may be used to reduce the peak rate of discharge to the sewer system. These basins can be integrated into the urban site and are compatible with environmental requirements. Green areas of sport facilities can be located in these retention basins, which are designed to contain floods of 20- or 50-year return periods. In the text, different methodologies for design of flood retention basins are reviewed. Examples of application are given from the city of Rethymnon, where the risk of flooding is high.

Urban Flood Control in Karst Areas: The Case of Rethymnon (Greece)

Rainstorms in autumn and winter in the Mediterranean region produce floods and damage of important economic consequence, especially in coastal cities. Examples of damaging floods in urban areas located in the Greek Mediterranean coast are frequent, as in the case of the flood in the city of Rethymnon, Crete Island, on October 1991 and more recently, November 1993, in Athens. The above examples are located in karst areas, where the relation between rainfall and overland flow has a special form, due to the geological characteristics of karst formations and relatively large runoff coefficient. Traditional engineering structures for protection against floods should take into account the specific conditions of karstic terrain, which in Greece represent approximately half of the total area of the country. A relatively low-cost solution for defence from floods in urban areas may be based on the design of flood retention reservoirs. These can be integrated into the urban space and are compatible with environmental requirements. Green areas and sport facilities may be used as flood retention basins, which are designed to contain floods of 1:20 or 1:50 return periods. The case of flood control in the city of Rethymnon, Crete Island, is the subject of this chapter. A computerized conceptual model has been developed in order to assess the hydrological risk of flooding in karst areas, as a function of the volume and location of retention reservoirs. By using the geomorphological, geological and hydraulic characteristics of karst areas, the model was calibrated in order to reproduce the available runoff data.