圖書典藏及影音數位平台

阿公店水庫因集水區地質因素，自民國42年水庫開始運轉以來，每年約有50萬立方公尺之泥砂淤積於庫內，歷年累積砂量大幅減低庫容。民國86年起台灣省水利處辦理「阿公店水庫更新工程計畫」進行水庫浚渫，標高40公尺以下泥砂清淤1,160萬立方公尺，庫區有效容量回復至1,837萬立方公尺，並改建溢洪管及灌溉管，實施空庫防淤操作大量減少洪水時之沉滓落淤，以永續維持水庫之有效容量。 然在水文、地文、泥砂運移等因素均具有相當高不確定性的情況下，需要更深入瞭解阿公店水庫更新改善工程完工後水庫空庫防淤操作成效，進而探討在不影響現有防洪排淤情況下，如何提高水源利用效能，為本計畫目的。

The objective of this project was to determine the maximum water levels suitable for empty-reservoir desilting periods, while taking into consideration the safety of flood prevention operations, flood prevention capacity, and the effectiveness ofdesilting efforts. The proposed optimization model was applied to the Agongdian Reservoir and Yuemei Weir Joint Water System to improve water quality, revise the operating rule curves for the Agongdian Reservoir, and suggest changes to the guidelines and rules for the operation of the reservoir and water gates. We suggest that the maximum water level during the empty-reservoir desilting period (early June to early August) be increased to the 31m mark and that regulated discharge strategies be implemented corresponding to the maximum regulated discharge. This would help to ensure the safety of flood prevention operations, preserve the effectiveness of the original desilting plans, reduce the concentration of ammonia-nitrogen and total organic carbon in raw water, and increase the water supply stability of the system. Currently, systems for the regulation of the riverbed downstream of the reservoir have yet to be completed; therefore, the maximum regulated discharge cannot be increased from 15 cms to 90 cms. However, work reports by the South Region Office of the Water Resources Agency on the disasters caused by Typhoon Morakot and Soudelor indicate that road blocks and traffic controls restricting pedistrians or vehicles access to the road crossing the river downstream of the Agongdian Reservoir below the high speed railway line could prevent disasters when reservoir discharge reaches 35 cms. Accordingly, we suggest increasing regulated discharge from the current 15 cms to 35 cms. Nonetheless, it is still advisable for the Agongdian Reservoir management or any supervising organizations to continue testing using various discharge volumes. 　　This project developed an operating rule curve for the Agongdian Reservoir in the Agongdian Reservoir and Yuemei Weir Joint Water System using the Design Method for Reservoir Operating Rule Curves. We used hydrometric records from 1959 to 2013 and the effective reservoir capacity measured in 2014. The empty-reservoir desilting period remains the same, running from early June to early September. The maximum water level was set at 31m for the empty-reservoir desilting period between early June and late August and increased to 32m from late August to early September. The baseline volumes for the supply of water for the public and agriculture were 29 million and 16.7 million cubic meters per year, respectively. In the event of surplus, water rights of up to 40.19 million cubic meters per year would be available. A one-stage water restriction principle was applied to limit supply to 70 % of the original. According to this operating rule curve, early water restrictions could be introduced between January and the end of May in response to severe droughts. During the period from mid-September to mid-December, the operating rule curve is expected to prevent water restrictions that might otherwise be implemented due to insufficiencies in the storage of water strage between mid-September and early October or unnecessary early water restrictions that might otherwise be implemented between mid-October and late December. 　　Based on the fact that the effective capacity of the Agongdian Reservoir has decreased from 19.16 million cubic meters to 16.47 million cubic meters and that the hydrometric records have been extended from 2001 to 2013, the supply capacity (SI=1) of the Agongdian Reservoir and Yuemei Weir Joint Water System was reduced from 81 thousand cubic meters in the original plans to 77 thousand cubic meters.