Influence of Vertical Heterogeneity on the Estimation of Transmissivity

• Main Authors: Chuan-Gui Lan, 藍釧桂
• Other Authors: Chia-Shyun Chen
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/y54kt8

碩士 === 國立中央大學 === 水文所 === 94 === 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.