Model Development for Su-Ao Cold Springs and Analysis of Groundwater Level and Temperature Change

Only few countries exist resource of cold spring, and Taiwan is one of them. In Taiwan, Su-Ao Cold Spring, which locating in Su-Ao town in Yilan County, had been developed as not only the bath use, but only the sparkling water during the Japanese-Occupied Period. After 1985, it has been planned to build various types of baths and tourist recreation area. And in recent year, there are several researches about Su-Ao Cold Spring, and monitor the groundwater level and temperature. Because the cold spring dissolves much carbon dioxide, soaking in the cold spring has good benefit for cardiovascular circulation. Moreover, it suit for soaking all the year, especially in summer because the temperature of spring keeps 22℃ throughout the year. However, with the development of Cold Spring area, we need to pay attention to the problem of overdraft. In this research, the impact of precipitation and pumping on groundwater level and temperature is investigated. This research also analyzes different pumping quantity to observe the change of level and temperature. SWAT is applied to simulate the effective infiltration. This step requires gathering information such as land-use, soil-geology, surface elevation, river systems and weather. The effective infiltration then serves as input in SHEMAT. Along with setting hydrogeology and thermal parameters, the position of fractures, and the boundary and initial conditions, SHEMAT can simulate the change of water level and temperature. In this research, the observation groundwater level and temperature got from the hot spring quarterly report of Taiwan is used for model Calibration and validation. The result shows that the Go-Biang well has the best simulating result between three monitoring well because it is not a pumping well. However, the RSL well has the worst simulating result between three monitoring well. The worse result for RSL well is considered that the influence of deeper pumping well. The amount of correction of lateral recharge and spring relate to the rainfall trend. Another analysis in this research is changing the amount of pumping to analyze the impact of groundwater level and temperature. The result shows that increasing pumping quantity will decrease the groundwater level and temperature. The rational pumping quantity is 1409 tons / day which is higher than the currently pumping quantity, but lower than the maximum pumping quantity limited by government. Finally, this research analyzed the impact of infiltration for the groundwater level and temperature. In the normal condition which input infiltration in model, the groundwater level raise 0.8 to 1.1 meters during the winter, and 0.13 to 0.4 meters during the summer because of the infiltration. Moreover, the groundwater temperature average raise 0.016 ℃ at cold spring park well, 0.006 ℃ at Go-Biang well, and 0.007 ℃ at RSL well without the infiltration.