傳統上，針對含水層垂直異質性對地下水流之影響的研究多使用層狀模式方法進行模擬，其中假設含水層由數過均質等向的次水層。每一個次水層有其特定的水力傳導係數(K)、比儲蓄係數(Ss)與厚度(b)，因此整個含水層的K值、Ss值與b值呈現離散性的深度變化。本研究中，將K值與深度以一個連續的指數函數表示，探討垂直異質性對含水層洩降分布之影響，且此指數方程亦能代表真實含水層垂直異質的一種可能性。發展部分貫穿垂直異質含水層之定水頭試驗模式，幫助我們瞭解抽水井之部分貫穿效應與含水層之垂直異質性對洩降及流量的影響。結果顯示在抽水井附近的洩降變化同時受到部分貫穿效應與垂直異質性的偶合影響。部分貫穿效應隨距離增加而減少，終至完全消失，此範圍外的洩降分布則只受垂直異質性影響。 In the past, the effect of vertical heterogeneity on groundwater flow was frequently evaluated using the layered-model approach, where the aquifer is assumed to be composed of a number of homogeneous and isotropic sublayers. Each sublayer has a distinctive hydraulic conductivity, specific storativity and thickness, so the hydraulic conductivity, specific storativity and thickness of the aquifer varies with depth in a discrete sense. Here, the effect of vertical heterogeneity on drawdown distribution is investigated using a continuous exponential function of K(z) which represents one possibility of vertical heterogeneity. The pumping well partially penetrates the aquifer and is pumped under a constant drawdown. Therefore, the model developed also serves the purpose of understanding the local vertical disturbance (the partial penetrating effect) versus the global (aquifer scale) vertical heterogeneity on drawdown and discharge. It is found that drawdown variation in the vicinity of the well is under the influence of the compound effect of the partial penetration and the vertical heterogeneity. At farther distance, however, the partial penetration effect disappears and drawdown is influenced by vertical heterogeneity.
