埤塘灌溉系統中擴充埤塘關鍵位置之辨識

Abstract

本研究之目的為建立一方法以供辨識埤塘灌溉系統中擴充埤塘之最關鍵位置， 透過所建立之埤塘灌溉系統優選模式最佳化供水結果後，得到最佳供水條件下各埤塘之入流率，入流率之大小順序即為擴充埤塘之重要性順序，由此即可辨識灌溉系統中埤塘擴充之關鍵位置。本研究埤塘灌溉系統優選模式其目標函數考慮田區缺水量總和最小化；模式限制條件則包括埤塘蓄水之連續方程式、埤塘蓄水容量之限制、埤塘蒸發、各節點之水平衡方程式、引水圳路之引水能力限制。本研究將所建立之方法應用於桃園大圳第 11 號支線，由研究結果可知 17 個埤塘之最佳入流率，其中埤塘 11-20 具有最大之入流率。本研究並利用敏感度分析以證明所決定關鍵埤塘之正確性。The purpose of this study is to identify the key ponds in a pond irrigation system. In order to identify the key pond for enlargement, an optimization linear model is developed and employed to calculate the optimal water distribution of a pond irrigation system and the inflow rate of each pond is computed. The order of the inflow rates is also the ranking of ponds for enlargement, and then the key ponds in a pond irrigation system are identified. The paper adopts the optimization linear model, constructed by using network flow structure, of each time step-wise to carry out the research work of the optimal water allocation. The model will include objective function and constraints. The objective function consists of the conveying water from ponds, weirs, reservoirs, etc. Then, the constraints include the balance equations of pond nodes, diversion nodes, general nodes, etc and arc limitation by nature conditions such as pipe capacity, ditch design, and pond volumes. The No. 11 branch of Taoyuan canal is employed as a case study area for assessing the capability of water supply in a pond irrigation system. The result shows the optimal inflow rate of 17 ponds, and the pond with maximum inflow is pond No. 11-20. This study could provide the optimal allocation strategy for policymakers and indentify the key ponds.