| 摘要: | 地下水資源已經逐漸成為臺灣地區較為重要之供水來源，由於臺灣特殊的水文及地質環境有其非均質之特性，導致地下水資源在不同時間與空間尺度下，水文特性存在極大的差異，然而作物種類、耕種方式及配合傳統節氣，使得相同地區在不同時期仍有不同的灌溉水量。因此本研究將針對農業不同灌溉水量是否造成地下水水位變化進行探討，進而分析農業灌溉用水對地下水資源的影響。
本研究之研究區域主要位於高雄兩個行政區，即美濃、旗山，將針對以旗山溪楠梓仙溪以及二重溪荖濃溪為邊界之區域地下水探討，使用3Di Water Management工具建立其地下水地表水第一含水層之模式，利用相關係數、均方根誤差（RMSE）及納什效率係數（NSE）三種驗證方式對模式進行檢驗。數據部份以2020年及2021年之現地狀況進行模擬，相關係數皆在0.7以上為高度相關；均方根誤差最大容許誤差值為 2 公尺，皆在0.5公尺左右；納什效率係數（NSE）皆在0.9以上接近1，表示模式的可信度高，藉此可以得知本研究所使用之模式是適用的。
最後本研究將農田有無灌溉進行比較，研究區域之水稻灌溉面積大約為1934公頃（19.34km²），分為「無灌溉」與「有灌溉」兩種情況進行模擬分析。結果表明在「有灌溉」之前提下，與無灌溉情況相比，2020年和2021年單位面積淨補注深度分別增加了7.87%和5.77%；蓄水變化量分別降低約78.13%和10.24%，由此可知灌溉量對地下水補注也不失為一重要的影響因子。;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. |
