圖書典藏及影音數位平台

高屏溪流域水資源豐沛，地下含水層透水性良好，為台灣主要地下水資源地區之一，惟因高屏地區缺乏大型蓄水設施，又豐枯季節雨量分佈不均，豐水期間常因原水濁度太高而難以運用，枯水期間則川流量不足而取不到水，為使高屏溪流域地面水及地下水資源聯合運用，提高水資源運用效率，爰辦理本計畫。 本局前期計畫「高屏溪流域中上游地下水及伏流水調查及開發評估」，模擬成果顯示在里嶺大橋上游區域，伏流水資源量豐沛，然而因該區域地下水位資料較少，為掌握該區域地下水補注來源，本計畫將進行地下水及河川水位觀測，並規劃新設站址，以補充前期計畫中不足之地下水位資料，利用觀測資料分析地下水位變動及補注來源，進行水資源開發效益評估，並提出地下水運用管理之方案。

According to theregional geological data and local investigation, the geological structure of the right bank of LaoNong River is mainly composed of cobbles, quarry stones and gravel ; the left consists of cobblestones and sandy silt. The hydraulic conductivity (K) is between 10-4 m/s and 10-5 m/s. The result of the groundwater level observation indicates that the section between Ligang Bridge and Xiezhang Bridge is the one of groundwater recharge, where the groundwater level is close or slightly higher than the river water level. On the other hand, the groundwater level of the section between Gaoshu Bridge and Ligang Bridge of AiLiao River sees small fluctuation and higher stability during dry and wet seasons. The water testing result shows a sporadic excess of certain categories in the groundwater fromthe right river bank of the section between Gaomei Bridge and Xiezhang Bridge , which is situated on the lower reach of Laonog River. The categories include Escherichia coli, ammonia nitrogen, total organic carbon, heavy metal (lead) and chemical oxygen demand. As to Ailiao River, the groundwater of the lower reach where Gaoshu Bridge is situated shows a sporadic excess in total organic carbon and chemical oxygen demand, while in other criteria the results meet the standard of drinking-water quality The excessively high water hardness , may be reduced by water purification plants as it may be due to local geological properties according to careful study. This project aims to provide a comprehensive evaluation of the quantity of usable groundwater with a particular focus on the middle and upper reaches inPingtung Plain. In normal circumstances, areas of rich groundwater resources are ranked as Xipu, Dashu, Jiuru, and Guanfu. In alternative scenarios, ranking is ordered as Xipu, Dashu, Ligang, and Yanpu. In this case, in addition to considerations of hydropower, evaluation on factors including water quality, environmental friendliness, land uses and pipe arrangementis needed to facilitate the action plan. According to the analysis of underflow water development, the right bank of Ligang Bridge downstream offers the most abundant underflow water resource within the planned area. To be specific, the rate of obtaining 194,000 m3 of water as a daily average from Borehole 107BH01 is 90% from July to December every year. The rate of withdrawing approximately 160,000 m3 of water on average per day from Borehole 105BH08, which is at the left bank of Gaoshu Bridge on Ailiao River, is also as high as 90%. As to Liling Bridge, water withdrawal within the planned area is limited to the period between July to December, when surplus water is available, considering the right of the habitants at the lower reach. The variation of groundwater level in Meinong and Beiligang areas shows a significant negative trend. Therefore, it is recommended that from July to December, the facilities of underflow water proposed in this project can function as a replacement for the established wells in Shoujinliao area and supplement the shortage of water supply. Additionally, the groundwater withdrawn by the large wells proposed by this project can contribute to part of the water provision expansion. This project completes the recharge simulation of the following areas: (1) The floodplain at the right bank of Gaomei Bridge on Laonong River; (2) The quarry pit at the right bank between Gaomei Bridge and Ligang Bridge on Laonong River; (3) Sections of Meinong River. It shows that the floodplain at the right bank of Gaomei Bridge isof better recharge efficiency.It is mainly because the area is located upstream at groundwater recharge area, resulting in higher flow of groundwater. Therecharge efficiency of the quarry pit is lower, for the location is near the Ligang Bridge downstream. The impact of recharge is therefore limited to the area on the south-west of the pit. In the case of Meinong River, the efficiency tends to be low because of the shallow bedrock , thin aquifer and prevalent existence of thin layers of mud, which lead toto the leakage of the recharged water to the lower reach of the River. Initial plan of groundwater management has been proposed based on the comprehensive evaluation of water investigation, management and utilisation and water resource integration. To ensure the sustainability and management of groundwater resources, the practice of the plan should be adjusted in conformance with policy, construction agenda, and overall water source system.