scholarly journals Conceptual model of a coastal aquifer system in northern Greece and assessment of saline vulnerability due to seawater intrusion conditions

2006 ◽  
Vol 51 (3) ◽  
pp. 363-363 ◽  
Author(s):  
A. Kallioras ◽  
F. Pliakas ◽  
I. Diamantis
Keyword(s):  
Conceptual Model ◽  
Seawater Intrusion ◽  
Coastal Aquifer ◽  
Northern Greece ◽  
Aquifer System

scholarly journals Hydrochemical and Isotopic Characterization of the Waters of the Manglaralto River Basin (Ecuador) to Contribute to the Management of the Coastal Aquifer

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 537
Author(s):  
Paúl Carrión-Mero ◽  
F. Javier Montalván ◽  
Fernando Morante-Carballo ◽  
Javier Heredia ◽  
F. Javier Elorza ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Conceptual Model ◽  
River Basin ◽  
Seawater Intrusion ◽  
Coastal Aquifer ◽  
Mixing Processes ◽  
Groundwater Levels ◽  
Isotopic Characterization ◽  
Semi Arid Region

Coastal aquifers are strategic and fundamental in the development of touristic areas. The coastal aquifer within the Manglaralto River Basin in Ecuador is essential, as it is the only source of water supply for a large part of the northern part of the Santa Elena province. It is a semi-arid region where high volumes of water are pumped from the aquifer, causing a significant drawdown of groundwater levels, thus affecting the water quality. This work aims to characterize the characteristics of groundwater in the coastal aquifer using hydrochemistry and stable isotopes to propose a hydrogeological conceptual model. The methodology for determining the chemical and isotopic characteristics of groundwater follows the following scheme: (i) studies of ionic concentrations using the Piper diagram, (ii) assessment of the origin of salinity through the Cl/Br ratio, the presence of seawater intrusion through the Hydrochemical Facies Evolution Diagram HFE-D, (iii) characterization of precipitation events using stable isotopes (18O and 2H), and, (iv) development of a hydrogeological conceptual model of the study area. The results indicate that in the basin there are mixing processes of the existing water in the aquifer with recharge water, direct cation exchange processes in the freshening process during recharge, and evaporation in the unsaturated zone. A conceptual model of the flow system in the basin is built, based on the mentioned processes. The main conclusions are: seawater intrusion is present in the areas of the wells located closest to the coast, urban activity through septic tanks is affecting the quality of the aquifer, and rainfall is highly relevant in the different hydrochemical and isotopic processes that operate in the basin.

scholarly journals Modelling tools for quantitative evaluations on the Versilia coastal aquifer system (Tuscany, Italy) in terms of groundwater components and possible effects of climate extreme events

2020 ◽  
Vol 9 (3) ◽  
Author(s):  
Matia Menichini ◽  
Marco Doveri
Keyword(s):  
Seawater Intrusion ◽  
Extreme Events ◽  
Coastal Aquifer ◽  
Climate Extreme ◽  
Aquifer Recharge ◽  
Hydrogeological Model ◽  
Groundwater Exploitation ◽  
Aquifer System ◽  
Open Platform ◽  
Adequate Knowledge

The Versilia coastal plain hosts an important and strategic aquifer for water supply. Like all coastal aquifers, it is particularly vulnerable to the saltwater intrusion, which can be amplified not only by fresh water over-exploitation, but also by the effects of climate change, including the increase of extreme events. For an optimal management of this precious resource and for its protection both in quantitative and qualitative terms, an adequate knowledge of the aquifer system is necessary through the development of conceptual and mathematical hydrogeological models. The conceptual hydrogeological model was defined on the base of an integrated multidisciplinary approach with the elaboration of stratigraphic, hydrogeological and geochemical-isotopic data. Subsequently, groundwater flow mathematical models were created using the ModFlow code and Groundwater Vistas like graphical interface, subsequently transferred to the Freewat open platform. The models enabled acquiring further knowledge about this aquifer system and to identify and, where possible to quantify, the main processes and groundwater components involved, including the seawater ingression. An important groundwater component, both in terms of water quantity and quality,resulted widespread in the fan of the Versilia River and mainly fed by the river itself in the foothill zone. Although this component seems to be able to guarantee relative protection against marine ingression, in the summer season some piezometric depressions tied to groundwater exploitation tend to expand and move towards the coast, thus favouring the seawater intrusion process. These issues can be amplified by the extreme rainy events that frequently occur in the Apuan Alps region. The huge quantity of water that quickly flows by the river up to the sea during extreme events represents a lack of feeding respect to the aquifer, and consequently the mitigation role of the fan component towards seawater intrusion can be significantly weakened. Thanks to the water budget achieved by numerical model and considering real extreme events recently occurred in the Apuan-Versilian region it was possible to make considerations about possible effects these climate regimes on the aquifer system. As outcomes, we concluded that extreme events as those occurred in the area in the past, and awaited more frequently in the future, represent a concrete threat for the coastal aquifer system that over next decades could suffer more and more seawater intrusion. Given the reliance of local human activities on groundwater, far-sighted actions of water management (e.g. managed aquifer recharge) are recommended for mitigating such as climate effects.

STUDY OF EVOLUTION OF THE SEAWATER INTRUSION IN COASTAL AQUIFERS. CASE STUDY: THE COASTAL AQUIFER SYSTEM OF NW ACHAIA

2004 ◽  
Vol 36 (4) ◽  
pp. 1952 ◽  
Author(s):  
K. Βουδούρης ◽  
K. Νίκας ◽  
A. Αντωνάκος
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Coastal Aquifer ◽  
Chemical Analyses ◽  
Salinity Distribution ◽  
Aquifer System ◽  
Hydrogeochemical Process ◽  
Groundwater Samples ◽  
Hydrochemical Types

Seawater intrusion problems are recorded in coastal aquifers, which constitute the main sources of drinking water and agricultural irrigation in many countries. The aim of this work is to describe the evolution of the salinity distribution by seawater intrusion, based on results from chemical analyses, of 29 groundwater samples in the NWAchaia area (Peloponnesus, Greece). The study of these data indicates that aquifer waters in large part of area reflect salinization related to seawater intrusion. The occurrence of Ca-CI hydrochemical types of groundwater indicates active seawater intrusion. Cation exchange is the most noticeable hydrogeochemical process in the movement of the saline front in the coastal aquifer. Geographical distribution of Careact index was mapped. The areas with advance or decline of the seawater intrusion front are defined from this map.

scholarly journals Modelling seawater intrusion in the Pingtung coastal aquifer in Taiwan, under the influence of sea-level rise and changing abstraction regime

2020 ◽  
Vol 28 (6) ◽  
pp. 2085-2103 ◽  
Author(s):  
Mahdieh Dibaj ◽  
Akbar A. Javadi ◽  
Mohammad Akrami ◽  
Kai-Yuan Ke ◽  
Raziyeh Farmani ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Sea Level Rise ◽  
Sea Level ◽  
Seawater Intrusion ◽  
Coastal Aquifer ◽  
Groundwater Resources ◽  
Element Model ◽  
Aquifer System ◽  
Pingtung Plain

Abstract A three-dimensional variable-density finite element model was developed to study the combined effects of overabstraction and seawater intrusion in the Pingtung Plain coastal aquifer system in Taiwan. The model was generated in different layers to represent the three aquifers and two aquitards. Twenty-five multilayer pumping wells were assigned to abstract the groundwater, in addition to 95 observation wells to monitor the groundwater level. The analysis was carried out for a period of 8 years (2008–2015 inclusive). Hydraulic head, soil permeability, and precipitation were assigned as input data together with the pumping records in different layers of the aquifer. The developed numerical model was calibrated against the observed head archives and the calibrated model was used to predict the inland encroachment of seawater in different layers of the aquifer. The effects of pumping rate, sea-level rise, and relocation of wells on seawater intrusion were examined. The results show that all layers of the aquifer system are affected by seawater intrusion; however, the lengths of inland encroachment in the top and bottom aquifers are greater compared with the middle layer. This is the first large-scale finite-element model of the Pingtung Plain, which can be used by decision-makers for sustainable management of groundwater resources and cognizance of seawater intrusion in coastal aquifers.

scholarly journals A Borehole-Based Approach for Seawater Intrusion in Heterogeneous Coastal Aquifers, Eastern Part of Jeju Island, Korea

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 609 ◽  
Author(s):  
Jehyun Shin ◽  
Seho Hwang
Keyword(s):  
Electrical Conductivity ◽  
Conceptual Model ◽  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Vertical Direction ◽  
Temperature Monitoring ◽  
Jeju Island ◽  
Aquifer System ◽  
Aquifer Systems ◽  
Sudden Decrease

Understanding the basaltic aquifer system and seawater intrusion on the volcanic island of Jeju, Korea, has received significant attention over the years, and various methodologies have been suggested in the contributions. Nevertheless, it is still difficult to effectively characterize groundwater systems due to the long period of volcanic activity and the lithological variability of basalt. In this study, geophysical well logging in seawater intrusion monitoring boreholes detected a sudden decrease of electrical conductivity within the saltwater zone in the eastern part of Jeju Island. This anomalous condition cannot be explained by the Ghyben-Herzberg model, which has historically been considered as the basic groundwater model of Jeju Island. This paper focuses on fine-scale temporal and spatial variability of groundwater flow using electrical conductivity and temperature logs and borehole temperature monitoring by a thermal line sensor. On the basis of the results, we evaluate an alternative model to replace the traditional conceptual model in the eastern part of Jeju Island. It is revealed that the area consists of heterogeneous aquifer systems, and the behavior of freshwater and saltwater is understood by temperature monitoring over the entire depth of boreholes. Coastal aquifers flow through two or more independent channels with weak vertical connections. In addition, seawater intrusion does not occur continuously in the vertical direction from the bottom depth, but instead occurs through these multilayered aquifers. In particular, the multilayered aquifers that are responsible for flow pathway, as well as the freshwater–saltwater interface form mainly at lithological boundaries. Our preliminary conceptual model is expected to be improved and revised by various measurements of hydrodynamic parameters such as flowmeter or packer test.

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