Preface
Groundwater is one of the most important resources in the world. In many
areas, water supplies for industrial, domestic, and agricultural uses are dependent on groundwater. As an "open" system, groundwater may exchange
mass and energy with its neighboring systems (soil, air, and surface water)
through adsorption, ion-exchange, infiltration, evaporation, inflow, outflow,
and other exchange forms. Consequently, both the quantity and quality of
groundwater may vary with environmental changes and human activities.
Due to population growth, and industrial and agricultural development,
more and more groundwater is extracted, especially in arid areas. If the
groundwater management problem is not seriously considered, overextraction may lead to groundwater mining, salt water intrusion, and land
subsidence. In fact, the quality of groundwater is gradually deteriorating
throughout the world. The problem of groundwater pollution has appeared,
not only in developed countries, but also in developing countries. Groundwater pollution is a serious environmental problem that may damage human
health, destroy the ecosystem, and cause water shortage.
In the protection and improvement of groundwater quality, two challenging problems have been presented: for uncontaminated aquifers, it is
required to assess the potential dangers of pollution; for contaminated
aquifers, it is required to draw up remediation projects. In both situations, we
need a tool to predict the pollutant distribution in groundwater. Obviously,
field experiments cannot serve this purpose. The only tool that we can use is
mathematical modeling. In the past two decades, mathematical modeling
techniques were extensively used in the study of mass and heat transport in
groundwater and soil. Presently, we can simulate a three-dimensional multicomponent transport in a multi-phase flow using a computer without any
essential difficulty. Since simulation models can provide forecasts of future
states of groundwater systems, the optimal protection or rehabilitation strategy may be found by incorporating a simulation model into a management
model.
There are, however, several difficult problems in groundwater quality
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Groundwater is one of the most important resources in the world. In many
areas, water supplies for industrial, domestic, and agricultural uses are dependent on groundwater. As an "open" system, groundwater may exchange
mass and energy with its neighboring systems (soil, air, and surface water)
through adsorption, ion-exchange, infiltration, evaporation, inflow, outflow,
and other exchange forms. Consequently, both the quantity and quality of
groundwater may vary with environmental changes and human activities.
Due to population growth, and industrial and agricultural development,
more and more groundwater is extracted, especially in arid areas. If the
groundwater management problem is not seriously considered, overextraction may lead to groundwater mining, salt water intrusion, and land
subsidence. In fact, the quality of groundwater is gradually deteriorating
throughout the world. The problem of groundwater pollution has appeared,
not only in developed countries, but also in developing countries. Groundwater pollution is a serious environmental problem that may damage human
health, destroy the ecosystem, and cause water shortage.
In the protection and improvement of groundwater quality, two challenging problems have been presented: for uncontaminated aquifers, it is
required to assess the potential dangers of pollution; for contaminated
aquifers, it is required to draw up remediation projects. In both situations, we
need a tool to predict the pollutant distribution in groundwater. Obviously,
field experiments cannot serve this purpose. The only tool that we can use is
mathematical modeling. In the past two decades, mathematical modeling
techniques were extensively used in the study of mass and heat transport in
groundwater and soil. Presently, we can simulate a three-dimensional multicomponent transport in a multi-phase flow using a computer without any
essential difficulty. Since simulation models can provide forecasts of future
states of groundwater systems, the optimal protection or rehabilitation strategy may be found by incorporating a simulation model into a management
model.
There are, however, several difficult problems in groundwater quality
vii