A Standardized Index for Assessing Seawater Intrusion in Coastal Aquifers: The SITE Index

Abstract

A large number of coastal aquifers worldwide are impacted by seawater intrusion. A major aim of European Directives 2000/60/EC and 2006/118/EC is to achieve good ecological status in groundwater bodies, including coastal aquifers. To this goal, information is needed about the current state of, and changes over time in, individual aquifers. This information can be obtained by applying methods that determine the status of aquifers in an uncomplicated manner. Methods for this type of assessment must comply with three essential criteria. First, calculation of the index must be straightforward and should be based on easy-to-obtain or commonly available data. Next, the index should be able to highlight important characteristics in understandable terms. Finally, the results should be objective and should be expressed in such a way that different time periods and different aquifers can be compared. In this paper we describe the development of a method to characterize seawater intrusion that meets these criteria and is based on four basic parameters: surface area, intensity, temporality, and evolution. Each parameter is determined by specific calculations derived from the groundwater chloride concentrations. Results are specified as a numerical index and an alphanumeric code. This index, known as SITE, has been applied to four Mediterranean coastal aquifers. The standardized results allowed us to discriminate between, and objectively compare the status of these groundwater bodies. Further, this index will make it possible to prioritize management actions and evaluate the effectiveness of these actions over time.

Groundwater Temperature as an Indicator of the Vulnerability of Karst Coastal Aquifers

“…To date there is not any specific method to define the vulnerability in karst coastal aquifers. Literature mostly considers methods for coastal porous aquifers (or porous aquifer systems) of limited thickness and extension [12][13][14][15][16][17][18][19][20][21][22][23][24][25] that mainly represent variations of the original GALDIT method [26,27]. GALDIT is the acronym for Groundwater occurrence, Aquifer hydraulic conductivity, water Level above mean sea level, Distance from the coastline, Impact status of existing seawater intrusion and aquifer Thickness, selected as vulnerability indicators.…”

Global Assessment of Seawater Intrusion Problems (Status and Vulnerability)

“…Both aquifers are unconfined, heterogeneous, detrital and multilayer aquifers composed of gravel and sand levels in a silty clay matrix (Ballesteros et al 2016). Figure 2 also shows the hydrogeology of these aquifers.…”

“…However, vulnerability methods only highlight specific areas in the aquifer that are at risk or prone to pollution due to their intrinsic characteristics, whereas it might be interesting to adopt measures in order to improve them. In the literature, there are examples of works developed to provide a global assessment of aquifer status (e.g., Ballesteros et al 2016), but none that address aquifer vulnerability.…”

Evaluación multiparamétrica de un esquema MAR (Managed Aquifer Recharge) en un acuífero costero salinizado (Plana de Castellón, España)

“…However, in this study, the behaviour of Mg 2+ versus Clis similar. The explanation for this behaviour may be related to the fact that the study area has been subject to marine intrusion for decades (Morell et al, 1987, Morell et al, 1988, Giménez and Morell, 1990,1992Fidelibus et al, 1992;Giménez 1994;Giménez et al 2008, Capítulo 4 Caracterización hidrogeoquímica del área de la Rambleta 105 Ballesteros et al, 2016). Because of the overexploitation of the aquifer, groundwater used for irrigation in the study area is of poor quality (electrical conductivities of up to 2,750 -3,500 μS/cm).…”

“…Dada la importancia del proceso de intrusión marina en la zona de investigación y que su conocimiento detallado es fundamental para desarrollar la experiencia de recarga artificial, se aborda un tratamiento más pormenorizado de este proceso desde dos puntos de vista. Por un lado, se ha tratado de establecer un método que refleje las principales características de la salinización por intrusión marina (Ballesteros et al 2016). Por otro lado, se ha abordado la caracterización espacial del proceso intrusivo en la zona de estudio, que se caracteriza por la formación de un cono salino (upconing) .…”