Tide-induced Head Fluctuations In A Coastal Aquifer: Effects Of The Elastic Storage And Leakage Of The Submarine Outlet-capping

This paper considers the tidal head fluctuations in a single coastal confined aquifer which extends under the sea for a certain distance. Its submarine outlet at the seafloor is covered by a silt-layer with properties dissimilar to the aquifer. Recently, Li et al. [2007, Water Resources Research, 43, W03404, doi:10.1029/2005WR004724] gave an analytical solution for such a system which neglected the effect of the elastic storage of the outlet-capping. This paper presented an analytical solution which generalizes their work by incorporating the elastic storage of the outlet-capping. It is found that if the outlet-capping is thick enough in horizontal direction, its elastic storage has significant enhancing effect on the tidal head fluctuation. Ignoring the elastic storage of the outlet-capping will lead to significant errors in predicting the relationship of the tidal head fluctuation and the aquifer hydrogeological properties. Quantitative conditions are given under which the effect of elastic storage of the outlet-capping on the aquifer's tide-induced head fluctuation is negligible. This paper also considers vertical flux of the confined aquifer and outlet-capping. We discuss the effect of the vertical flux on the confined aquifer system by simulating the two dimension model.