水庫淤積之模擬研究

Abstract

台灣河川坡陡流急，兼之地質條件不佳及人為不當開發，造成頗大之泥砂輸送量，以致調蓄水資源之水庫遭受莫大威脅。在新水庫興建不易，為求水資源永續利用之前提下，對水庫淤積之分析有其重要性，並可供防淤策略研擬之參考。本研究先利用經驗面積縮量法及一維HEC-6與GSTARS2.0模式，進行以農業用水標的為主之大埔水庫淤積模擬，初步結果顯示該水庫之水力防淤對庫容之維持具有功效。然後以二維顯式有限解析法模式模擬大埔水庫沖淤情形，結果顯示可對水庫內淤積之空間分佈作更準確之模擬。最後利用二維模式進行水庫淤積之長期模擬，發現原操作規線應有改善空間。

The reservoirs in Taiwan are threatened by the upstream steep-slope river flows, weak geological conditions, and improper human developments, which result in tremendous sediment transport rate. On the premise sustainable utilization of existing reservoirs with the difficult situation of construction of new reservoirs, it is important to study reservoir sedimentation and the results can be useful for the decision making of desilting strategy. The empirical area-reduction method and the 1-D HEC-6 and GSTARS2.0 models were adopted for the sedimentation simulation of Ta-Pu Reservoir, which is a reservoir with the main objective of irrigation. The preliminary simulation results show that it is effective to execute the hydraulic desilting in Ta-Pu Reservoir. A 2-D explicit finite analytic model then was adopted and the results show that it can more accurately simulate the spatial distribution of the deposition in the reservoir. Finally, the 2-D model was used to simulate the long-term sedimentation in Ta-Pu Reservoir. It can be seen that the original operation curves could have the space to be improved.