Assessing recharge, discharge, and sea-level rise impacts in a coastal aquifer using a new approach

Abstract

This study examines a coastal aquifer located along the eastern sandy coast of Buenos Aires Province, Argentina, which serves as the primary water source for both local and seasonal tourist populations. The inhabitants in these resorts swell fivefold during the summer months, placing additional pressure on the aquifer’s resources. The study area, a 60 km-long coastal barrier, features a shallow freshwater aquifer that has been systematically monitored over several years, yielding a comprehensive conceptual understanding of its behavior. Water table data from wells positioned 100, 300, and 600 m from the shoreline, alongside rainfall and tidal records, were used to explore short-term variations, particularly the anthropogenic effects during the summer tourist influx. Due to data limitations attempts with conventional models produced results inconsistent with prior knowledge of the aquifer. To assess the dynamic response of this aquifer under these conditions, a simple, intuitive, and computationally efficient method was developed using a modified electrical–hydraulic analogy integrated with an electrical circuit analysis program (ECAP).The proposed methodology successfully quantified recharge and discharge dynamics, including flow reversals in the intertidal zone and delayed responses to rainfall in urbanized areas. Also, it was simulated sea-level rise effects on the discharge to the sea and inland. Additionally, it enables estimation of aquifer transmissivity or storativity, given one of these parameters is known. Importantly, this approach requires no software licensing and offers a practical tool for both short-and long-term dynamic analysis in data-limited contexts. It is well-suited for preliminary assessments, educational purposes and when conventional numerical models are impractical or unreliable. This study contributes to the sustainable management of the San Clemente del Tuyú aquifer, providing a transferable framework for other coastal aquifers facing similar data constraints. It highlights the value of the modified electrical–hydraulic analogy combined with an ECAP in complementing more complex modeling techniques.