Tide-induced head fluctuations in a coastal aquifer: effects of the elastic storage and leakage of the submarine outlet-cappingFluctuations de la hauteur piézométrique induites par la marée dans un aquifère côtier : emmagasinement élastique et décharge par le toit sous-marin Fluctuaciones piezométricas inducidas por la marea en un acuífero costero: efectos del almacenamiento elástico y filtración de la cubierta en la descarga submarina 潮汐引起的某沿海含水层水头变化 : 海底露头盖层的弹性储水和越流效应。Flutuações piezométricas induzidas pelas marés num aquífero costeiro: efeitos do armazenamento elástico e da drenância de níveis confinantes submarinos海岸帯水層の潮によって誘発された水頭波動 : 海底アウトレットキャッピングの弾性貯蔵量と漏出量の影響効果と反応نوسانات ارتفاع آب بر اثر جزر و مد در یک آبخوان ساحلی: اثرات ذخیره الاستیک پوشش خروجی زیر دریا و تراوش از آن

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 is covered by a silt-layer with properties dissimilar to the aquifer. Recently, Li et al. (2007) gave an analytical solution for such a system which neglected the effect of the elastic storage (specific storage) of the outlet-capping. This article presents 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 the horizontal direction, its elastic storage has a significant enhancing effect on the tidal head fluctuation. Ignoring this elastic storage will lead to significant errors in predicting the relationship of the head fluctuation and the aquifer hydrogeological properties. Quantitative analysis shows the effect of the elastic storage of the outlet-capping on the groundwater head fluctuation. Quantitative conditions are given under which the effect of this elastic storage on the aquifer’s tide-induced head fluctuation is negligible. Li, H.L., Li, G.Y., Chen, J.M., Boufadel, M.C. (2007) Tide-induced head fluctuations in a confined aquifer with sediment covering its outlet at the sea floor. [Fluctuations du niveau piézométrique induites par la marée dans un aquifère captif à décharge sous-marine.] Water Resour. Res 43, doi:10.1029/2005WR004724