Development of a Regional Growth Model Including Dynamics of Water Resources

本研究的目的是建立一个系统动力学模型来表达区域尺度上水资源、人口、粮食生产、环境污染和经济活动之间的关系，明确水资源的可获得性对人类活动的影响。为了达到这一目的，我们采取了以下方法：第一，将用水户分为农业、工业和市政三个部门。在农业部门，用稻田的枯竭深度来模拟水的需求。在工业和市政部门，通过日本过去的工业和用水统计数据，用多元回归模型表示用水量。其次，水消费部门与人口部门和区域水流动部门相连。移民部门的引入是为了向其他地区解释产品在一个地区的流动。最后，通过将各部门纳入一个系统动力学模型，分析了未来可能出现的情景下日本近海地区水资源系统的行为，并从水资源在全球范围内相互作用的角度，利用系统动力学建立了探索各大洲水资源需求的模型。利用这一模型，还可以识别严重缺水和发展受限的大陆。除了关注水对每个大陆的影响外，该模型的特点是将不同大陆的水处理为相互依赖的区块，并考虑了信息和材料的移动。这里开发的世界大陆水模型的几个运行和几个GCM情景结果使我们能够测试温室气体排放对水可获得性和人类社会的影响。

The purpose of this research is to develop a system dynamics model to express the relation among water resources, population, food production, environmental pollution, and economic activities at a regional scale and to make the influence clear that water availability will give to human activities. To achieve this purpose, the following approaches have been done.First, water users are categorized into agricultural, industrial and municipal sectors. In agricultural sectors, water demand is modeled by the use of depletion depth in paddy fields. In industrial and municipal sectors, water demand is expressed in terms of multiple regression models through the past industrial and water use statistics data in Japan. Next, water consumption sectors are connected to population sectors and regional water flow sectors. Emigration sectors are introduced to explain the movement of products in one region to others. Finally by putting all the sectors into one system dynamics model, the behavior of the water resources systems in Kinki-region in Japan is analyzed under the possible future scenarios.From the viewpoint of interaction in a global scale in terms of water resources, a model exploring water needs of the various continents is also developed using system dynamics. Identification of continents with acute water shortage and development limitations will also be possible with this model. Besides focusing on the effects of water on each continent, the model is characterized by its treatment on the various continents as inter-dependant blocks and movements of information and materials have been considered. Several runs of the world continental water model developed here with several GCM scenario results has allowed us to test the impacts of GHG emissions on water availability and the human society.