Groundwater Response to Tidal Fluctuation and Rainfall in an Unconfined Sloping Aquifer

Abstract

本文提出了一種解決非線性Boussinesq 方程式線性化的方法，係對於一維潮汐及降雨造成非拘限傾斜含水層的地下水流變動進行研究，而與非線性解進行比較時，可得知線性解較能迅速掌握潮汐及降雨地下水位波動的真實情況。本文的基礎是使用Dupuit-Forchheimer 假設廣泛的淺層地下水流問題，然而同一個沿海含水層中可能會在不同區域有不同的降雨量，故將含水層分為兩個區域，沿海地區設為降雨區，內陸地區則為無降雨區。在此二區域的邊界條件成立時，可得到其交接水位為相等。研究結果顯示在非拘限含水層的底床傾角和地表降雨對地下水位波動的影響是顯著的。

This paper presents an algorithm which linearizes the non-linear Boussinesq equation characterizing the unsteady flow for one-dimensional tidal and rainy groundwater flow in a coastal unconfined sloping aquifer. In comparison with non-linear analytical forms, the present solution can improve the rate of solving those tidal and rainy groundwater fluctuations. The solution is based on the Dupuit-Forchheimer assumptions that problems of wide range in shallow unconfined groundwater flow. Two zones of different rainfall may well comprise a coastal aquifer, with the coastal zone of rainfall and the inland zone of non-rainfall, the analytical boundary condition of coastal and inland water table at both interfaces are equaled. The research result showed that the effect of the bottom angle and surface rainfall on the groundwater fluctuation is significant in an unconfined aquifer.