南勢溪跨域引水對翡翠水庫供水系統影響

台北都會區水資源仰賴南勢溪-翡翠水庫供水系統，普遍認知其水資源充沛。2020－2021年乾旱時期，政府評估南勢溪引水至石門水庫工程可行性，但引起社會爭議，而撤回該計畫環評。儘管如此，缺水、乾旱風險仍然存在，越域引水未來仍有可能再被討論。考量南勢溪流量占淨水場總取水量約7成，若越域引水應增加翡翠水庫供水系統壓力。為探討越域引水對供水系統可能的影響，本研究建立翡翠水庫供水系統之系統動力模式，以2009－2020年實際水庫入流量、依比例（0至20%）減少實際南勢溪流量進行模擬，並以多重水資源指標量化引水影響。引水情境包含（1）全年引水、（2）僅冬季引水。另外，也使用過去研究建立的模式模擬石門水庫水位。結果指出：若僅冬季引水不會令翡翠水庫供水系統「用水壓力」大幅增加；也無法有效提升石門水庫水位。全年引水雖提升石門水庫乾旱時水位，然而翡翠水庫水位大幅降低、用水壓力上升。不過，除2020年外，多數時間翡翠水庫供水系統用水壓力之風險分數並不會有可觀的增加。

關鍵字

水會計；系統動力模式；可用水量；用水壓力

並列摘要

Taipei Water Department serves the Greater Taipei Area with water resources that approximately 99% come from the Xindian River (Nanshi River, and Feitsui Reservoir releasing water), and has been considered water-sufficient. During the 2020-2021 drought event, the inter-basin water transport from Nanshi River to Shimen Reservoir had been planned and assessed by the Taiwan government. However, this engineering plan aroused intense social concern, and thus its environmental impact assessment for the plan was withdrawn. Nevertheless, the risks of water shortage and drought remain in Taiwan, and similar plans may reappear again in the future. Since stream flow from the Nanshi River catchment provides approximately 70% of the raw water supplied to purification plants, inter-basin water transport may increase the stress on the Greater Taipei Area. To quantify the impact of water transport, we built a system dynamic model (SDM) and simulated the operation of Feitsui Reservoir and the water resource system with the historical inflow of the Feitsui Reservoir. The inter-basin transported water was assumed as a ratio (0 to 20% was used) of the historical flow rate of the Nanshi River. Two scenarios were considered: (1) transporting year-round, and (2) transporting only during winter. We also simulated the water level of the Shimen Reservoir using an SDM constructed in our previous study. The simulation results indicate that "transporting only during winter" does not remarkably aggravate the water stress on the water supply system that belongs to the Feitsui Reservoir, nor does it noticeably raise the water level of the Shimen Reservoir. "Transporting year-round" noticeably increases the water level of the Shimen Reservoir during drought events, while this measure results in decreases in the Feitsui Reservoir's water level and increases in the water stress of Feitsui Reservoir. Nonetheless, the score of water stress risk usually increases inconsiderably, except during the severe drought event in 2020.

並列關鍵字

water accounting ； system dynamic modeling ； available water ； water stress

參考文獻

林皓華、黃群展、邱瑞彬、許少瑜(2021)。應用水會計架構初探農業水資源狀態-以桃園地區為例。中國土木水利工程學刊，33(3): 185-196。https://doi.org/10.6652/JoCICHE.202105_33(3).0002。

黃群展、李明旭、童慶斌、許少瑜(2017)。利用跨尺度天氣預報決定解除限水時間―以民國100年石門水庫為例。農業工程學報, 63(3), 60-73。https://doi.org/10.29974/JTAE.201709_63(3).0005。

Berger, M., Eisner, S., Van Der Ent, R., Flörke, M., Link, A., Poligkeit, J., et al. (2018). Enhancing the water accounting and vulnerability evaluation model: WAVE+. Environmental science & technology, 52(18), 10757-10766. https://doi.org/10.1021/acs.est.7b05164

Ebrahimi Sarindizaj, E., & Karamouz, M. (2022). Dynamic Water Balance Accounting-Based Vulnerability Evaluation Considering Social Aspects. Water Resources Management, 36. https://doi.org/10.1007/s11269-021-03046-4

Hofste, R. W., Kuzma, S., Walker, S., Sutanudjaja, E. H., Bierkens, M. F., Kuijper, M. J., et al. (2019). Aqueduct 3.0: Updated decision-relevant global water risk indicators. World Resources Institute, 1-53. http://dx.doi.org/10.46830/writn.18.00146

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