通用型水資源調配模式之發展與應用-枯水期石門水庫缺水風險分析

Abstract

近年來因為經濟的快速發展、社會結構的轉變以及人口的增加導致了民生用水和工業用水與年遽增，石門水庫的運用相當頻繁，使得石門水庫供水區的缺水風險尤其是乾旱時期大為增加。為避免極端缺水發生，乾旱時期除原有水庫規線操作外，當未來水文情勢不佳時，農業灌區休耕移用已成了常態的乾旱應變機制。 有鑑於此，本研究以線性規劃為基礎發展一通用化供水調配模式，可同時考量規線操作與乾旱應變規則，以作為石門水庫供水調配分析之基礎。本研究發展的供水調配模式屬於模擬優選法，較網流法及整數型規劃更有彈性，不受網流特殊架構或參數型態之限制，且納入農業用水移用規則，更能反映石門水庫實際操作之特性。為探討乾旱應變機制之缺水風險，本研究以蒙地卡羅分析為理論基礎，配合供水調配模式進行模擬分析，分析結果可作為石門水庫灌區農業供水策略調整之參考。 本研究經過簡例及石門水庫案例之驗證後，證實本研究發展之調配模式可以確實的考量水庫操作規線以及乾旱應變規則，而根據石門水庫枯水期的風險分析顯示，乾旱應變規則可有效的改善枯水期之公共缺水率，而由於乾旱應變規則之設定為農業的休耕與用水移用，導致了農業缺水率皆呈現提高的狀況。

Owing to the economic growth and population increase in the Taoyuan area, both domestic and industrial water use have increased rapidly. Increasing water demand raises the water supply loading of Shihmen reservoir and intensifies water shortage risk, especially during drought periods. In practice, to overcome such serious hydrological conditions, irrigated water is transferred for public use in the Taoyuan area. Hence, this study proposes developing a universal water supply model based on linear programming. This study applied the proposed model to assess the supply risk of water shortage during drought seasons in the Taoyuan area. First, the proposed model was designed considering the rule curve operation and agriculture water transfer in the study area and is more flexible than models based on network flow programming (NFP) or the mixed integer linear programming (MILP) because of the requirements of the cyclic flow network and integer variables for two programming. Second, a Monte Carlo analysis is integrated with the proposed water supply model to investigate the water shortage risk during drought seasons. The analysis results can be valuable quantitative references for decisions concerning the re-allocation of water supply between agricultural and public use. The simple example and field case study demonstrate the feasibility and capability of the proposed model. The risk analysis result indicates that the operation rule of drought seasons is useful in decreasing the supply risk of public water, but increases the supply risk of agricultural water.