A Study on the Integrated Numerical Model of Groundwater Resources and Seawater Intrusion

• Main Authors: Chi-Kai Chang, 張祉凱
• Other Authors: 譚義績
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/rybjj7

碩士 === 國立臺灣大學 === 生物環境系統工程學研究所 === 105 === Pingtung Plain is an important area for the usage of groundwater resources, with irrigation and household as the main usage in the past. In recent years, the development of fishing industry starts to flourish, which causes a competitive utilization of groundwater resources in Taiwan’s coastal areas, resulting in groundwater overdraft and an increase demand in the needs of water, which leads to various problems such as land subsidence, seawater intrusion and salinization. In order to explore the situation of seawater intrusion in Pingtung Plain, this research applies Soil Water Assessment Tool (SWAT), MODFLOW groundwater model and MT3D to stimulate the numerical model of integrated groundwater, seawater intrusion and the development of water resources in Pingtung Plain. This study applies the external factors of Pingtung Plain provided by Water Resources Agency, to stimulate the change of chloride concentration in groundwater due to the increasing pumpage phenomenon causes by future economic growth and rise in sea level as climate changes. The study is divided into two simulation conditions: i.To stimulate in 2020 to 2039, the rise in sea level in 3 different cases: 27cm, 40cm and 54cm. The stimulated result has shown that, under the current pumping situation, the rise in sea level in the mentioned cases has no significant effect towards the inland chloride concentration. However, the high concentration of chloride in coastal area moves towards inland. ii.Based on the future economic development, predict groundwater pumpage will respectively increase by 10%, 20% and 30% over the existing percentage. Result has shown that, the chloride concentration in the first aquifer has a significant growth as pumpage increases. However, the second and third aquifer has no significant changes as pumpage increases. The numerical model of integrated groundwater, seawater intrusion and water resources development set up in this research investigates the spatiotemporal changes of chloride concentration as climate changes and water demand increases. This model can examine the affects towards the quality of water resources as the increase usage in water amount due to future economic development, and act as a reference for the government in decision making and implementation.