ABSTRACT
ABSTRACT: The analysis of tidal effects on aquifer systems plays an important role in coastal aquifer management. Adequate knowledge of the hydraulic properties of aquifer systems such as transmissivity (T) or hydraulic conductivity (K), storage coefficient (S) and/or hydraulic diffusivity (D) is crucial for almost all the studies concerning groundwater quantity and quality, including themodeling of subsurface flow and transport processes. This paper deals with the numerical analysis of tide-aquifer interaction data of unconfined and confined aquifers for determining aquifer parameters by the Levenberg-Marquardt technique considering two approaches: (i) without tidal data resolution (henceforth called ‘‘Approach I’’), and (ii) with tidal data resolution (henceforth called ‘‘Approach II’’). In addition, the effect of tide-aquifer interaction data corresponding to Spring and Neap tidal events on the parameter estimates has also been examined. The tideaquifer interaction data for two unconfined sites and three confined sites located in two different coastal basins were used. The analysis of the results indicated that the aquifer parameters S and T, and hence hydraulic diffusivities (D) based on Approach II are more reliable and accurate for both the aquifers than those based on Approach I. Therefore, Approach II is strongly recommended for the determination of aquifer parameters by the tide-aquifer interaction technique. Furthermore, the Spring andNeap tide-aquifer interaction data significantly affected the parameter estimates; the use of such data should be avoided. It is concluded that a judicious use of the tide-aquifer interaction technique is essential for obtaining reliable estimates of aquifer parameters.
