地下水環境限制水位與可用水量分析－以濁水溪沖積扇為例

為達到地下水資源永續經營目標，地下水使用應避免地下水超抽發生地層下陷或海水入侵等不良影響，合理的地下水抽用為地下水管理重要課題。本研究目的為分析濁水溪沖積扇之地下水環境限制水位與可用水量，而其中可用水量符合永續利用的原則即滿足生態基流量與地層下陷等環境限制。地層下陷限制水位乃利用MODFLOW-SUB模組，建立垂向一維單井地層下陷模式分析而得。再進一步建置地下水數值模式配合各限制水位，推估濁水溪沖積扇各分層之可用水量。經初步分析在2009年至2014年期間，濁水溪沖積扇每月的可用水量約在0.81～1.15億噸之間，而年總可用水量約為11.50億噸，比現況平均年抽水量13.44億噸約少1.94億噸，此可提供管理單位在水權管理之參考。

關鍵字

地下水環境限制水位；地層下陷；地下水可用水量

並列摘要

To achieve the goal of sustainable groundwater management, groundwater pumping should avoid inducing the environmental impacts such as land subsidence or seawater intrusion caused by over-pumping. Operation rules to guide adequate groundwater pumping are important issues. This study established a groundwater numerical model and computed the amount of groundwater available yield in Choshuichi Alluvial Fan based on groundwater level constraints. The groundwater level constraints are the minimum groundwater level to avoid creating an impact on ecological stream flow and inducing land subsidence. In this study, several one-dimensional land subsidence models for each well were constructed by using MODFLOW Subsidence and Aquifer- System Compaction (SUB) package. Each SUB model was calibrated and used to evaluate the minimum groundwater level to avoid land subsidence. A regional groundwater numerical model of Choshuichi Alluvial Fan was developed, and the available groundwater yield of the whole Alluvial Fan was simulated basing on the groundwater level constraint. The results showed that, in 2009~2014, Choshuichi Alluvial Fan, the available groundwater yield of the month is about 0.081~0.115 billion tons, and the annual available groundwater yield is about 1.150 billion tons, which is about 0.194 billion tons less than the current annual groundwater usage (about 1.344 billion tons). These results are a valuable reference for future groundwater analysis and policy assessment.

並列關鍵字

Environmental limiting level ； Land subsidence ； Available groundwater yield

國際替代計量

地下水環境限制水位與可用水量分析－以濁水溪沖積扇為例

全文下載

主題瀏覽