台灣水資源供需動態模型之建構與分析
蕭志同、林佳慧、程瑞祥
摘要
水是人類生活中不可或缺的必需品，然而水資源是有限的、且隨著經濟發展使需求量不斷增加致使水源過度開發產生破壞自然生態之虞，加上近年來受氣候變遷影響常導致枯水期有缺水危機，因此水資源的有效管理日趨重要。本文應用系統動態學方法論，並以經濟學的角度先建構一個全面性影響台灣水資源供需與管理之系統動態模型(the water resource administrative system in Taiwan，WRAT) 探討台灣水資源供需系統結構與嘗試解釋其系統行為。再進一步探討影響水資源需求面外生變數與政策之情境改變，分析當外在環境變數發生衝擊與政策改變時，對總用水量之影響。本文透過模擬「耕地面積減少」與「豬隻頭數減少」等變數改變後，由模擬結果發現，減少耕地面積對降低農業用水量有顯著影響；另外，大量減少豬隻飼養雖然無法有效降低農業用水量，卻能大幅降低牧業污水排放量，因此減少豬隻飼養確實能有效降低有關水、空氣及豬糞污染等環保問題。此外，本文亦探討「以價制量」之訂價策略是否能達到節約用水之目的，由模擬結果顯示，總用水量會隨價格提昇而減少。目前台灣水價過於低廉，往往在枯水期時面臨缺水之困境，若政府能合理化水價(提高水價)，應能有效達成節約用水之目的。本文之模擬結果可作為政府及各水資源事業單位擬定節水措施與環保政策之參考依據。
關鍵詞：水資源管理，系統動態學，永續發展，政策分析
Modeling of the Water Resource Dynamic Demand and Supply Model in Taiwan
Chih-Tung Hsiao, Jia-Huey Lin, Ray-Hsiang Cheng
Abstract
Water is one of the important resources in our daily life. Since there are many impact factors of water resource and those factors are getting more and more complicated. We need to construct the comprehensive model to analyze and simulate the policies of the water resource management systematically and dynamically. In this paper, we first discuss the general characteristics for the analysis of the water resource management. Second, we use system dynamic analysis method to construct the water resource administrative simulation system in Taiwan (WRAT) model and study the demand and supply of the water resource structure in Taiwan to explain its systematic behavior. We use WRAT model to investigate the changes of the total quantity of water supply, total water consumption and the adjustment of water demand and supply when the environmental variables are changed. Then, we simulate the effects on agricultural water consumption and total water consumption when the two variables – agricultural area and number of pigs are changed. We analyze the results of the simulation and evaluate if the purpose of water conservation can be achieved. The results of simulation can also provide the policy implication for government and water resource administration to formulate the water-saving policy and environmental conservation policy.
Keywords: Water Resource Management, System Dynamics, Sustainable Development, Policy Analysis
Received: 2017-06-19
Accepted: 2017-12-20