Water is the essential resource of people for their livelihood and is the foundation for the economy to develop unceasingly. Based on the trend of economic growth, population growth, and the improvement of the quality of life, the demand for water is expected to continuously increase. When the demand for water resources is continuing to increase, burdens are added to the environment and ecology. The severe challenge for human beings is how to promote the sustainable development of economy, society, an ecological environment, and to achieve sustainable use of water resources.
The Penghu Island has endured water scarcity for a long time. The government also takes great pains over the water resource problem. The purpose of this study is to establish indicators of a framework for the sustainable development of water resources in Penghu County. This can be used to construct a model of the system dynamics to conduct simulations of various scenarios. After that, we can understand the current situation and problems of the subject of water resources and sustainable development in Penghu County to provide suggestions for the government to make decisions. First, literature should be collected that relates to the indicators of a sustainable development system of water resources, adopting the D-S-R (Driving forces-State-Response）indicator framework proposed by the United Nations. We should draw up a water resource sustainable development indicators system which suits the characteristic of the native environment in Penghu County initially, estimating by using Delphi and AHP. Moreover, we will construct a model of the system dynamics and proceed to do the simulation of scenarios.
There are 43 indicators in this study which built up the D-S-R water resources sustainable development indicator framework in Penghu County. They belong to 8 different assessment categories, which include watershed conservation and management, groundwater conservation and management, diverse use and development of water resources, allocation and management of water resources, drought and flood mitigation, promotion of water conservation measures, technology research and develop of water resources, personnel training and education about cherishing water resources. Among them, there are 14 driving force indicators, 14 state indicators, and 15 response indicators.
According to the dynamic system model constructed in this research, the continuous increase of the population and number of tourists represent the social and economic development of the driving force aspect. When the groundwater is overdrawn, this causes the seawater to invade and it becomes salty. The State aspect is and the people's health and welfare. In the Response aspect, there are 4 strategies regarding the management scenarios, including the control of overdrawn groundwater, building a seawater desalination factory, rational water price adjustment, and the promotion of water conservation measures are drafted. According to the simulation and scenarios, some results were found, such as the rational water price adjustment and promotion of water conservation measures have a limited effect upon slowing down the groundwater overdraw because of the severe water resource shortage in Penghu County. The control of overdrawn groundwater can appropriately decelerate the groundwater being drawn excessively, but can't retard the rise in demand for water. Building a seawater desalination factory can satisfy the continuous rise in demand for water, and have the greatest effect on decelerating the aggravation of the water resource ecology and the quality of the water environment.
The strategy of improving the shortage of water resources usually can be executed from two directions: water resources development and economization. This study found that the key points to overcome in order to achieve the sustainable development of water resources in Penghu County are mainly: the destruction of the ecological environment because of deep groundwater overdraw, and the negative influence of setting up a seawater desalination factory on marine ecology resources. The relation is very clear that deep groundwater overdraw causes seawater invasion and the result is salty water. But it's not clear whether the waste water produced from the seawater desalination factory will effect the rich marine resources of Penghu County. The residents, mainly fishermen, still have doubts about building a seawater desalination factory. There should be more thorough analysis and research.