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Computer simulation modeling plays a vital role in water quality studies. Numerical simulation techniques, when successfully calibrated and properly applied, allow a numerical representation of the main ecosystem phenomena, and substantially improve our understanding of the complex interactions among different parameters such as temperature, biological oxygen demand, dissolved oxygen, salinity, and eutrophication etc. Simulation models are capable of providing an objective evaluation of the consequences of future growth and pollution control measures. Therefore, simulation models are essential tools for water quality studies for urban, rural and industrial planning and decision making.
Water pollution issues represent a growing public concern and a major topic for scientific and industrial research. Water pollution, a problem that a few decades ago used to affect only the most industrial countries in the world, has expended to virtually all countries. Recently India also witnessed growing demand for good quality water for best designated uses.
Water is an important element for life on the earth. It is an essential natural resource for environmental sustenance, agricultural productivity, industrial growth, power production and enrichment and renewal of land and air. For easy assess to the water, the first human settlement occurred along the banks of rivers and ensuing civilizations flourished in river valleys. For example, Indian civilization of Mohanjodaro and Harappa developed in the Indus valley, the Egyptian civilization in the Nile valley, the Chinese civilization in the Yangtze valley, the Babylonian civilization between the Tigris and the Euphrates rivers, Aztec Maya and Incas civilizations in the basin of Amazon River.
Supply of water at any given location is limited and the limits vary considerably. The unprecedented economic development, social transformation, industrial flourishment and technological improvement that have occurred in the world have been in part due to human ingenuity in providing water to various designated best uses, often through well-scientific and engineered strategies for usage, storing of water and transporting it. There is a direct correlation between the development of these strategies and national development, as exemplified by the grouping of nations of the world into developed countries for example USA, Britain, Japan etc., developing countries like India, Sri Lanka, Pakistan etc., and under developed countries such as Kenya, Lozetho etc. From the middle of the nineteenth century to the beginning of twenty first century, hundreds of water resources projects, water harvesting projects, water pollution projects, water recycling projects, river linking projects, desalination projects for fresh water from ocean and water quality modeling studies were developed and built throughout the world including India, primarily for the purposes to predict how extent of pollution affected in the water resources such as rivers, lakes, reservoirs, coastal as well as oceans in the world. In India, water quality modeling studies were done for ecosystems from fresh water to marine water ecosystems for example Tehri reservoir, Chilka lake, Dal lake at Kashmir, Kodaikanal lake, Ooty lake, rivers like Ganges, Narmada, Kaveri, and all coastal regions like Chennai, Visakhapatanam, Hoogly estuary, Mangalore coast, Kongan coast, Gujarat coast. These projects were entirely funded or heavily subsidized by national and international agencies in recognition of the crucial role that water plays in an important role in the human life.
The book contains eighteen chapters reflecting objectives on various aspects of water quality modeling for rivers, streams, reservoirs, lakes, impoundments, coastal regions, seas and oceans. The chapter one explains about the importance of water, sources of water pollution, some organic and inorganic water pollutants, water quality meaning and scope, types of modeling, calibration methods, qualitative and quantitative models. The chapter two depicts modeling basics. It includes historical development, types of water quality models, model classification different water ecosystems, factors governing water quality models. The chapter three deal with processes and development. It includes model architecture, equation, chemical, physical and biological processes in the water ecosystem, computer programming, boundary and initial conditions, calibration and validation. Chapter four includes modeling application to different water bodies, spatial discretisation, concentration modeling and CORMIX. The chapter five explains methodologies. Chapter six deal with modeling of rivers and streams. Coastal and estuaries modeling will be provided in chapter seven. Eighth will be the lakes and impoundments modeling. Ocean and seas are provided with chapter nine and followed by water quality modeling of biological oxygen demand and dissolved oxygen. Temperature modeling is allocated in the chapter eleven. The chapter twelve includes nitrogen and phosphorus modeling. Eutrophication modeling explained in chapter thirteen. Oil spill and Tsunami modeling chapters are provided in fourteen and fifteen respectively. Chapter sixteen depicts about littoral drift modeling. An ecohydrological modeling and commercially available models are included in chapter seventeen and eighteen. A special technical terms and definitions are given as appendix.
A common feature of all the chapters is the emphasis given to the application of new computer technologies, such as super computers and graphical workstations and the use of advanced software tools for real time user friendly interactions between the models and the users in the subject of water quality models.
Many Engineers and Scientists are good enough to send me their research publication and their contribution to this work is highly acknowledged. A good deal of tiresome labour involved in putting togather the MS was shared by many friends, too numerous to be named individually, and I thank each one of them for cheerfully giving me their valuable time and knowledge. To my wife Mrs. S. Mekalamanivanan who helped in many ways, I wish to record my greatful thanks to her.