考慮三生效益下枯旱時期最佳休耕區域及面積之研究

Abstract

本研究考量農業生活、生態、生產即三生之效益，在不同枯旱程度供水情境，以休耕優選模式評估在不同之超越機率下，最佳配水量以決定最佳休耕面積及位置獲得最大農業三生效益。本研究首先分析濁水溪灌區與集集攔河堰用水特性，透過水文統計資料尋找集集攔河堰入流量資料機率之最適分布，並經由其最適機率分布求出各超越機率下相對應之流量，以計算不同超越機率流量評估不同枯旱程度下之供水情形。本研究以幹渠輸水損失優選模式為基礎加入農業三生及休耕考量因素，建立休耕優選模式，該模式應用於濁水溪灌區所得到農業供灌系統現況總效益約為540億元，其中生活及生產效益佔總效益之76%，生產值僅佔總效益之24%，而其總效益隨著入流量超越機率上升而有下降之趨勢。

In this study, the optimal decisions for agricultural benefits, area and location of fallow with consideration to environmental, ecological and productive functions in the drought period are obtained and estimated by the optimal drought model in the scenarios of different exceed probability of river discharge. The characteristics of water usage in the study area are analyzed and the appropriate probability distributions of river discharge to Ji-Ji weir are obtained for generating river discharge of each time step to calculate and assess the results of water supply in different drought situations when river discharges are generated with some exceed probabilities (50% to 90%). The optimal fellow model is constructed on the base of water transportation loss and consideration to environmental, ecological and productive functions, and the analytical result shows in the study area the total benefits are 54 billion dollars. In the total benefits, the benefits of environmental and ecological functions occupy 90% and the benefit of productive function occupies 10%, and the total benefits decrease as the exceed probability of river discharge increases.