Development of an Optimization model for Conjunctive use of Surface Water and Groundwater

台灣地區降雨季節分布不均，就南部而言，夏季有颱風帶來豐沛的雨水，但台灣冬季降雨主要受到東北季風之影響，而其因受到中央山脈之阻擋，帶有水氣的雲層無法通過為南部地區帶來雨水，也影響到水庫可供水量。在水庫供水不足之情形下，地下水資源之使用在供給用水上佔了重要的角色，而如何善加利用地表水與地下水並進行聯合營運，成為水資源管理的重要之研究課題。本研究設計地表水與地下水聯合營運規線，並利用啟發式演算法優選供水規則，於面對未來可能面臨之缺水風險時，能適當抽取地下水以減輕地表水系統之負擔。本研究將參考水庫操作規線之建立概念，下限、嚴重下限及不同情況採用不同供水規則，於模式中利用水庫蓄水量及地下水儲存量進行分類，每一分類包含兩個屬性，分別為地表水與地下水之供水比例。本研究將以時期最大缺水量最小化為目標，結合啟發式演算法優選水庫及地下水量之分類界限與各類別之供水規則，提供水庫及地下水於不同水量情況下之用水規則，本研究並設計三種案例，包括僅使用地表水供應用水需求、地下水做為緊急供水系統，以及地表水與地下水聯合營運，藉此分析地下水可扮演之角色，有效地進行地面水與地下水之聯合運用，達到水資源永續利用之目標。In Taiwan, the seasonal distribution of rainfall is not even. The most rainfall centralizes in summer by typhoon, especially in southern Taiwan. Because the central mountain blocks monsoon, there is less rainfall in winter. The characteristics of rainfall influences the water supply of a reservoir in Taiwan. When a reservoir cannot satisfy water demands, how to use groundwater properly as a supplement source to mitigate the deficiency of water supply is important for the sustainable water resources management. First, this study adopts the concept of reservoir operational rule curves to formulate and classify water supply strategies based on reservoir and groundwater levels. After that, an optimization model for conjunctive uses of surface water and groundwater is constructed in this study to reduce the possibly deficiency of water supply. The objective of the model is to minimize the total water deficits, and then a heuristic algorithm is integrated to optimize the classification criteria and associated management strategies. This study is expected to apply the proposed research processes to develop appropriate management strategies for conjunctive use of surface water and groundwater and meantime to maintain the sustainability of water resources