圖書典藏及影音數位平台

受到全球氣候變遷影響，臺灣的地面水文環境產生極大的變化，已影響到系統性的水文循環，降雨集中以及降雨強度變化，造成水資源匱乏以及災害現象益加明顯，地下水文環境同時也受嚴重影響。加上人口增加、經濟成長、生態環境變遷，過度使用造成部分區域地下水資源儲量減少，水質污染問題日趨惡化，且近年來民眾環境意識高漲，致使水庫或集水設施興建進度受阻，水資源調配明顯捉襟見肘。在政府提倡多水源多系統聯合經營區域性水資源策略下，傳統地下水分區之水資源規劃已見不足，從集水區觀點切入之水資源整體規劃，綜合考量山區以及平原之地下水系統管理，已成未來水資源之發展趨向。 因應地下水資源之保育及開發，經濟部水利署與經濟部中央地質調查所共同推動「臺灣地區地下水觀測網整體計畫(81-97年)」以臺灣九大地下水分區為主要標的進行水文地質測勘與地下水位觀測資料庫建置，成為臺灣地區地下水管理以及研究之重要依據。而為了解本島地區山區地下水賦存量、滲流通道以及監測其變動，經濟部中央地質調查所於99-102年完成?臺灣山區地下水資源調查研究整體計畫-第一期 臺灣中段山區地下水資源調查與評估」，以及目前執行中之「臺灣南段山區地下水資源調查與評估(103-106年)」計畫，針對山區地下水資源進行基本調查、匯整分析，建構水文地質架構及概念模式等重要工作，顯示對整體水資源之評估概念，已由傳統地下水分區延伸至集水區範圍。 高屏與嘉南集水區包含臺灣南部最主要二大地下水分區(嘉南平原與屏東平原)，同時為南部人口稠密區，水資源需求量高而臺灣南部乾濕季降雨差異甚大，造就濕季地面水量豐沛而乾季不足，如何有效運用地下水資源已成水資源規劃上最大之課題。高屏集水區用水以高屏溪地面水資源為主，在近年來氣候異常狀態下，降雨分配不均狀態更易造成水資源匱乏；嘉南集水區面積廣大，而乾濕季降雨同樣差異甚大，曾文水庫與烏山頭水庫為本區主要水資源來源，但於2014年之乾旱事件中，同樣面臨水資源不足之窘境。高屏與嘉南集水區同具台灣南部重要都會區與人口稠密區，在線今之氣候狀態下，須考量在水資源匱乏時，應有其他備援水資援系統可供支應。故本計畫選定高屏與嘉南集水區進行集水區尺度下地水資源評估，預期由河川流量資料推估地下水儲水指標以及潛能量變化，配合既有水利設施操作情況，以及地下水相關限制條件下綜合分析地下水開發場址區位，並估算地下水潛能開發量以及聯合運用可行性案例探討。

In the second year of this project, a watershed-scale assessment on groundwater resources in the Jianan region was carried out. Variations in the groundwater recharge volume in upper-stream areas of the watershed were estimated by using the streamflow data. Regional groundwater level management standards were established by focusing on the groundwater level information in the plain regions. Considering the existing water plant facilities and relevant groundwater constraints, an integrated analysis on locations for groundwater development was conducted. Finally, the potential groundwater yield volume and the effects of developments on regional groundwater resources were evaluated according to the established groundwater level management standards. The statistical and analysis results for streamflow in the Jianan region show that the wet season occurs approximately during the period between May and October, and the wet to dry season ratio for streamflow is about 9:1. In addition, the rainfall distribution in the watershed shows that the regional annual rainfall volume decreases gradually from the maximum of 3,200 mm in the east to about 1,100 mm in the west. This project estimated the average annual groundwater recharge volume in the Jianan region to be 11.15million tons, and the recharge volume was approximately 6.35 million tons in the Jianan Plain. The analysis on river dissipation characteristics in the Jianan region shows that the characteristic time scale K for sub-watersheds in the research area lies between 8 and 21 days, with an average value of 13 ± 5 days. This project reveals that the screening results of the regions suitable for groundwater development are related to the development time. The areas classified as area 1 for development projects are located in Yongkang and Liuying monitoring stations. To reduce the impact of development, the aforementioned remaining water volume and seven groundwater level drawdown conditions were considered before the volume of developable groundwater from the two selected sites was evaluated. The results show that the developable groundwater yield is finite and suggested to build redundant well in these two locations.