Modelling Tidal Signals Enhanced By A Submarine Spring In A Semi-permeable Aquifer System

This paper considers a coastal leaky aquifer system with a submarine spring. The system consists of an unconfined aquifer, a leaky confined aquifer, and a semi-permeable layer between them. The unconfined aquifer terminates at the coastline, the semi-permeable layer and confined aquifer extend both seaward and landward infinitely. The submarine spring is represented by a highly permeable round column on the seabed, which penetrates completely the semi-permeable layer. On the basis of Li [11], both the leakage of the semi-permeable layer and the tidal loading efficiency are considered. The approximate analytical solution of the tidal head fluctuations in the confined aquifer is derived using the principles of groundwater hydraulics and the theories of complex functions and partial differential equations. Further more, the leakage speed up the degression of the approximate solution's error. Hypothetical studies indicate that tidal groundwaer head fluctuation from four observation wells at least are needed to determine the six model parameters: the location (2 parameters) of the submarine spring, the leakage of the semi-permeable layer, the tidal loading efficiency, the confined aquifer's tidal propagation parameter and the equivalent radius of the spring.