圖書典藏及影音數位平台

臺灣水文豐枯差異顯著，降雨多集中於5月至10月豐水期間，係由梅雨鋒面及颱風所帶降雨為主，然而因全球暖化所產生氣候變遷日益加劇，依據相關研究指出，未來降雨型態將呈現降雨日數減少降雨強度增加之情況，雖整體降雨量不至減少，惟降雨過度集中，加上臺灣整體蓄水空間不足，將使水資源調度運用更為困難，發生於枯水期之乾旱情況亦將更為頻繁，因應未來可能乾旱缺水問題，應尋求緊急備援用水，以避免對於經濟民生產生過大之衝擊。 臺灣地區地下水資源豐沛，已為我國重要水資源之一，然而地下水使用需考量超量使用所可能帶來之危害，如地層下陷或海水入侵等。地下水具有水量穩定及水質良好等優點，因此，於乾旱發生時，地下水可作為緊急備援用水，穩定水資源之供應，惟考量地下水超抽可能帶來危害，需設定各項限制條件，評析可供備援用水之地下水取水地點及餘裕量，以作為乾旱應變決策之參考。 臺灣地區現有完善地下水觀測網，對於地下水水位資料掌握甚為完整，藉由水位觀測資料配合歷史水位統計分析成果，可據以研判地下水情勢，亦可作為評估乾旱應變備援用水之方法，因此，善用地下水觀測網水位觀測資料，提昇其應用之可能，增加其附加價值，並建立自動化乾旱時期備援用水評估系統，將可有效提昇我國因應乾旱之應變能力，使相關決策作為更具科學根據。

This project provides technical staff support in accordance with the professional requirements of the Water Resources Agency. Additionally, it aims to improve the value-added applications of the groundwater observation network. The establishment of an evaluation system for groundwater resources as a supportive water supply source during the drought period in Taiwan could strengthen a plethora of response actions against such phenomena as well as establish effective decision-making policies. This research was developed based on references related to assessments of supportive water supply sources. In order to characterize groundwater areas as supportive water supply sources, among other factors, the assessment methods should evaluate the location, hydrogeological conditions, groundwater levels, water subjects, water pipeline distance, follow-up maintenance and management issues. Regarding the implementation strategy, the allocation of water resources management during the early drought period should be carried out in the form of water saving technologies, reclaimed water utilizations, and surface water allocations. Once the drought is serious, the groundwater and hyporheic flow resources should act as supportive water supply sources. This project follows the existing groundwater management water level setting methods of Taiwan to upgrade the management water level of the 751 existing observation wells (including safe water level, lower limit water level, and serious lower limit water level). The water level correlation analysis of 136 observation wells was investigated by using subsurface subsidence, seawater intrusion or groundwater salinization and by maintaining the ecological base flow rate. A total of 77 observation wells were highly correlated and the management water level was reviewed. The process of groundwater resources as supportive water supply sources during the drought period should also be highlighted. This project applied the Thiessen Polygons control area multiplied by the observation well water level difference (current water level minus the lower limit water level of management water level) multiplied by the specific yield (unconfined aquifer) or storage coefficient (confined aquifer) multiplied by the conservative value (60%) access to the Thiessen Polygons control area of supportive water supply sources during the drought period. Furthermore, all the assessment factors and processes of the location of groundwater wells as supportive water supply sources during the drought period were also included in this project. These assessment factors included the water quantity, water quality, 3km range along the high-speed rail, water purification facilities and raw water pipelines, alluvial or adjacent river areas, and the existing pumping wells of the supportive water supply sources during the drought period for all the assessments of a total of 6 types of drought water supply programs. Moreover, the evaluation system for groundwater resources as supportive water supply sources during the drought period was developed based on Web GIS, various groundwater related spatial information and data, the Geographic Information System (GIS) and spatial analysis technology, allowing the user to investigate various related layers on the map, view data, and analysis system architecture. The system was designed and divided into 5 modules: groundwater level and water quality assessments, groundwater operation management assessments, groundwater reserve assessments, management, maps and other functions, and user right management.