近年臺灣濁水溪流域地下水儲存量變化趨勢探討

Recent Changes in Groundwater Storage in Jhuoshuei River Basin, Taiwan

黃嘉琦(Chia-Chi Huang) ； 林琨達(Kun-Ta Lin) ； 葉信富(Hsin-Fu Yeh)

《中華水土保持學報》 48卷1期 (2017/03) Pp. 36-43

https://doi.org/10.29417/JCSWC.201703_48(1).0004

摘要

在近年來受到氣候變遷的影響，造成臺灣乾濕季分明，濕季降雨強度增強但降雨時間縮短，而乾季雨量稀少，加上降雨時間與空間的分布不均以及坡陡流急無法有效攔蓄降水，因此臺灣成為雨量充沛但水資源缺乏的國家。臺灣的水資源主要來源包含地面水及地下水，其中地下水抽用量雖然僅佔可運用水量的五分之一，但因較不易受蒸發散及人為汙染影響，為相對穩定的水資源來源。本研究以濁水溪流域為研究案例，利用河川消退方法分析流域基流係數 (a) 與排水特徵時間 (K)，另由水平衡概念考量無降雨時期以及忽略蒸發影響下，利用低流消退分析評估地下水長期儲存量變化趨勢。研究結果顯示，流域內排水特徵時間常數介於82~189 天，平均為118±51 天。而本研究探討地下水儲存量變化趨勢的結果顯示，濁水溪流域內除了彰雲橋測站受集集攔河堰攔截溪水以供民生及工業用水而呈現下降趨勢 (-0.566 mm/y) 外，其它各個子集水區皆顯示出上升的趨勢。本研究之探討結果可以提供未來水資源管理及調配之重要參考。

關鍵字

低流分析 ； 排水 ； 地下水儲存量

並列摘要

As a result of recent climate change, the dry and wet seasons in Taiwan have become clearly distinguishable. Although the duration of rainfall has decreased during the wet season, the intensity of the rainfall has increased during this period. The dry season has low rainfall. Because of the inconsistency in the duration and spatial distribution of rainfall and the difficulty in retaining water on steep slopes and where the velocity of the flow is great, Taiwan currently has plentiful rainfall but lacks water resources. Taiwan's main water resources include surface water and groundwater. Since groundwater is less affected by evapotranspiration and man-made pollution, it is more stable water resource than other sources, although it only contributes to 20% of all usable water in Taiwan. This study uses a river recession analysis for the Jhuoshuei River Basin to analyze the basin's baseflow coefficient (a) and the characteristic drainage time scale (K). A water-balance conceptual model is used in this study. This uses low flow recession to determine the changes in long-term groundwater storage during periods when there is no rainfall, without taking into account the effect of evaporation. The results show that the Zhoushui River Basin's typical drainage duration constant is between 82 and 189 days, with an average of 118 ± 51 days. The analysis of changes in groundwater storage shows that except for the Zhangyun Bridge Station, which exhibits a decrease of 0.566mm/y, all gauge stations in the Jhuoshuei River Basin show increased storage. The findings of this study will serve as a reference for the future management and allocation of water resources.

並列關鍵字

Low flow analysis ； discharge ； groundwater storage