- 學位論文
考量三生效益下人工湖最佳設計容量訂定之研究
The Study on Deciding the Optimal Volume of Artificial Lake for Environmental, Ecology and Productive
摘要
本研究之目的在建立一考量生產、生活、生態即三生效益下，人工湖最佳設計容量之優選模式，並將其應用於雲林農田水利會斗六大圳續建段及古坑人工湖之灌溉系統，以供在提升水資源運用效率或最大三生淨效益下，優選出人工湖最佳之設計容量。 本研究優選模式採用線性網流模式進行人工湖系統最佳化水源調配，並將其運用於研究區域。本研究所提之線性網流模式，係由目標函數(objective function)及限制式(constraints)所組成。本研究之目標函數考慮兩種情況，優選模式(I)為使系統各田區的總缺水率最小，優選模式(II)為使系統各田區之淨效益總和最大；限制條件則包括人工湖蓄水之連續方程式、人工湖蓄水容量之限制、各節點之水平衡方程式、渠道最大流量之限制等。 本研究在考量缺水率為最小之條件下(即優選模式(I))所得之優選結果顯示，隨著人工之湖設計容量增加，可同時降低缺水率及提升耕作率，淨效益也隨之提高，當設計容量達到300萬噸時淨效益為最大。本研究在三生淨效益總合為最大之條件下(即優選模式(II))所得到的優選結果顯示人工湖之最佳設計容量約為436萬噸，且淨效益每年較未興建人工湖可增加5.06億元，但其田區之平均供水率及耕作率則較模式(I)低。本研究以不同之目標函數，推求各目標函數下人工湖之最佳設計容量，提出不同觀點之分析結果，可供決策者依其決策目地訂定最佳之人工湖設計容量。
並列摘要
The purpose of this study is to develop an optimization model of the optimal volume of an artificial lake considering environmental, ecological and productive benifits. The optimazation model develpoed by this study is the linear network flow model, which is composed of the objective fucntions and constraints. There are two objective functions mentioned in this study. The objective function of Model One is the minimization of total water deficit rates of the irragation areas. The objective function of Model Two is the maximization of the total net benefits of the areas. The constraints include the continuity eguations of the artificial lake, the water balance equations of each node and the restriction of channels’ maximum flow. The result of Model One shows that increasing the volume of the artificial lake can reduce the water deficit rate and raise the areas of rice fields. The net benefits are raised too. But when the volume comes to 3 million cubic meters, the net benefits reach to the highest. The result of Model Two shows that the optimal volume of the artificial lake is 4.36 million cubic meters. Comparing to the situtaion that the artificial lake isn’t constructed, the net benefits gain 506 million NT dollars each year. This study develops two different objective functions. And offer two different pionts of view to the decision makers to decide the optimal volume of the artificial lake.