概論
Fresh water is a fundamental constituent of life and is essential to a wide range of economic activities. In fact, fresh water also plays a key role in many biological and physical aspects of the ‘Earth system’. For example, water cycle is important in affecting the climatic changes and variability. Fresh water is a limited resource. Less than 0.01% of the world's water is easily accessible in lakes and rivers. However, global water use has increased 300% since 1950 and is growing faster than the Earth's population. The tragic effects of drought, flooding and water pollution have frequently seen in Taiwan and other parts of the world such as Asia, Africa, Europe and the Americas as a consequent of over-use and mismanagement of water resources. Such problems are widespread and will be made more acute by accelerating demand on fresh water arising from trends in economic growth.