建立生命週期評估之動態水壓力指標以預估氣候變遷情境之水資源耗用衝擊

Developing LCA Dynamic Water Stress Indicator for Predicting Water Consumption Impact under Climate Change Scenarios

劉冠妤(Kuan-Yu Liou)

指導教授 ： 闕蓓德

國立臺灣大學/工學院/環境工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201600889

摘要

生命週期衝擊評估方法常以水壓力指標為基礎，評估對淡水資源的衝擊。然而，目前發展的方法在評估未來情境的環境衝擊時，僅預測未來盤查資料的改變，評估模式中的特徵化因子並未依未來情境改變而有所調整；且目前水壓力指標多以年為時間尺度，忽略了水資源在月尺度的變異性。因此，本研究欲修改水壓力指標以符合臺灣地區之水資源時空分佈型態，並建立提高水壓力指標時間與空間解析度之方法，以推估聯合國政府間氣候變遷專家委員會建議之氣候變遷情境下，未來四個時間區段之動態水壓力特徵因子。
本研究改良德國學者Berger et al.（2014）所提出之Water Accounting and Vulnerability Evaluation（WAVE）模式中的水壓力評價方式─水消耗指標（Water Depletion Index, WDI），為使指標能夠適當表現臺灣位於亞熱帶季風氣候區乾濕季分明的水文型態，本研究以Soil and Water Assessment Tool（SWAT）水文模式模擬集水區可用水量之月資料，將以年為尺度的WDI改以月尺度展現（WDImon）；同時，也將全球性水資源模擬之網格資料提升至以集水區為空間尺度，並選用地區性資料，以期指標能呈現在集水區內取用水所造成的地區性水壓力。氣候變遷情境部分則使用TaiWAP模式模擬未來溫度及雨量之改變，進而推估未來動態的水消耗指標。且將本研究所建立之動態水消耗指標用於分析研究大樓沖廁用水，以評估雨水回收系統對於氣候變遷調適之效益。
本研究的研究範圍為新店溪青潭水質水量保護區，結果顯示在臺灣大臺北地區，以年為尺度之WDI為0.723，然而WDImon最大值0.984出現在4月，而最小值0.249出現在10月，以月為尺度更能展現臺灣乾濕季的變異性。在氣候變遷情境下的WDImon，2021-2040年時間區段須面對較大的水壓力，而一年中的低點出現在8月或9月，1月及4月份則需面對較大的水壓力。在評估雨水回收系統之結果顯示，若增建雨水回收系統每個月能省下直接及間接用水量140.8立方公尺，且不同月份沖廁用水對淡水消耗的衝擊不同，若將省下的水量提供給其他用水需求便能減輕缺水時所面對的水壓力。

關鍵字

Water Accounting and Vulnerability Evaluation（WAVE）模式 ； 水消耗指標 ； Soil and Water Assessment Tool（SWAT）模式 ； 特徵因子 ； 雨水回收系統

並列摘要

Many countries all over the world are already under enormous water stress, and climate change will exacerbate the situation in many areas. The Water Depletion Index (WDI) is one of many water stress indicators used to estimate the impacts of water consumption. Most studies estimate available water with global-scale models; however, water resource management should be a local issue. Also, yearly timescales may hide the variety of precipitation from month to month. Therefore, this study aims to improve the temporal and spatial resolution of WDI in a regional watershed in Taiwan with a hydrological model. Additionally, this study developed a dynamic WDI under climate change scenarios as laid out in IPCC AR5. A case study for assessing benefits in water stress was conducted for substituting use of potable water for toilet flushing with rainwater. The results show that WDI varied greatly throughout the year, thus annual WDI may be a misleading measure for water management. Under climate change scenarios, there are decreasing trends in water stress in Taiwan due to decreasing population in the future. The case study showed that the rainwater harvesting system had significant advantages over using potable water according to the LCA study, due to saving available water and water treatment energy reductions.

並列關鍵字

Water Accounting and Vulnerability Evaluation (WAVE) ； Water Depletion Index (WDI) ； Soil and Water Assessment Tool (SWAT) ； Characterization Factor ； Rainwater Harvesting System

參考文獻

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