| dc.description.abstract | Groundwater resources have gradually become a very important source of water supply in southern Taiwan. Due to the special heterogeneity of Taiwan′s hydrology and geology, groundwater resources have great differences in time and space. However, different crop types, farming method and traditional solar tems may lead to diffferent irrigation in different time period. Therefore, this study explore whether different irrigation water levels cause changes in groundwater level, and then analyzes the impact of irrigation water on groundwater resources.
The study area are two districts of Kaohsiung, namely, Meinong and Qishan. Aiming at the prediction of the water level in the farmland bounded by Nanzixian River, Qishan River and Erchong River, Ernong River, 3Di Water Management tool was used to establish the model of the upper groundwater aquifer and surface water. Then, the correlation coefficient (R²) , root mean square error (RMSE) and Nash efficiency coefficient (NSE) were used to verify the model.
The data is simulated based on the current situation in 2020 and 2021. The correlation coefficients are all above 0.7, which is highly correlated. The maximum allowable error value of the root mean square error is 2 meters, and the results of this study are all within 2 meters. The Nash efficiency coefficients are all above 0.9 (close to 1) , indicating that the model is highly reliable. Above all, the model used in this study is suitable.
There will compare the farmland irrigated or not in this study. The irrigated area of rice in the study area is about 1934 hectares (19.34km²) . The results show that under the premise of ＂with irrigation＂, comparing to “without irrigation “, the net recharge per unit area in 2020 and 2021 will increase by 7.87% and 5.77%, and the changes of water storage decrease 78.13% and 10.24%, respectively. Therefore, irrigation is an important factor for the groundwater recharge. | en_US |