Combined Geospatial, Geophysical And Geochemical Studies On Coastal Aquifer At Muttom-Mandaikadu Area, Tamilnadu, India

A study was conducted in the Muttom-Mandaikadu coastal region, which is among the profitable coastal sectors in Tamil Nadu, to find the groundwater potential as well as its quality by an integrated geophysical, geospatial, and geochemical approach. The GIS-based weighted overlay analysis was used to merge different thematic layers to create the groundwater potential zone map. The geophysical resistivity survey was performed in the study area at 26 stations by applying a Schlumberger vertical electrical sounding technique. The observed data were interpreted using one-dimensional software AGI Earth Imager. The combined vertical electrical sounding result and remote sensing thematic maps have exposed the potential zone of groundwater in the study area. From the inferred results, it was observed that 20.8% of the area has ample groundwater potential, and 7.7 % of the area has scanty groundwater potential. The saltwater intrusion zone has been predicted by validating aquifer resistivity with Dar-Zarrouck (D-Z) parameter. From the geophysical and geochemical interpreted results, it was found that aquifers in 34.6% of the study area are vulnerable to saline contamination. The 4-D model with integrated groundwater quantity and quality suggests that the study area's Western part falls under excellent to good groundwater potential zone and excellent water quality.

Evaluation of Groundwater Resources in Minor Plio-Pleistocene Arenaceous Aquifers in Central Italy

The hilly landscape of the Periadric area in Central Italy is characterized by mainly marly–clayey foredeep basin deposits (Plio–Pleistocene age). These lithotypes are generally considered aquicludes, if compared with the regional limestone aquifers of Apennines. However, a coarsening upward trend characterizes the upper portion of this stratigraphic sequence, with arenaceous deposits and even conglomerates on the top. From a geomorphological viewpoint, the areas with coarser outcrops show a flat shape and sub-vertical slopes, like boundaries. At the base of these scarps, springs can be found at the interface between coarse and fine deposits, whereas these arenaceous bodies are actual aquifers. Until now, the hydrodynamics and hydrochemical features of this kind of aquifer have not been investigated deeply, because they have always been considered a worthy water resource. However, they could play a crucial role in integrated water management, especially to cope with climate changes and drought periods. Considering these, the main purpose of this study was to investigate from a hydrogeological point of view and to assess the groundwater quantity and quality. Five examples throughout the Abruzzo region were considered. For evaluation and comparisons between water resources, the water volume that infiltrates yearly at each squared kilometer of an aquifer (Mm3/y/km2) was applied. This value was calculated through three different approaches to provide a recharge estimation for this kind of aquifer that is as exhaustive and representative as possible. The results allowed us to characterize the hydrogeological model and to quantify the resources between 0.1 and 0.16 Mm3/y/km2, to be suitable for multi–purpose utilization.

Groundwater level oscillation analysis in shallow alluvial aquifers in Pomurje, NE Slovenia

Systematic hydrologic monitoring of groundwater quantity at the national level in Slovenia has been ongoing since 1952. An insight into long-term groundwater level data enables us to delineate parts of aquifers with similar groundwater level oscillation properties as well as to identify changes of those properties in time. We used variety of statistical methods to identify long-term behaviour of groundwater level oscillation of groundwater body (GWB) Murska kotlina. Results showed that fluctuation of groundwater level in time reflect complex set of events that originate in natural or anthropogenic interferences. Using percentile analysis in combination with cluster analysis, we were able to isolate areas with a related groundwater fluctuation. Results of long-term data trends analyses of monthly groundwater level showed the impact of the research area climate on long-term and seasonal groundwater level fluctuation. In addition to natural causes, by performing trend analysis on groundwater level data, we were able identify some human induced interventions into the environment made in the past.

Evaluating the groundwater quality of Damodar Fan Delta (India) using fuzzy-AHP MCDM technique

In recent years, groundwater pollution has become increasingly a serious environmental problem throughout the world due to increasing dependency on it for various purposes. The Damodar Fan Delta is one of the agriculture-dominated areas in West Bengal especially for rice cultivation and it has a serious constraint regarding groundwater quantity and quality. The present study aims to evaluate the groundwater quality parameters and spatial variation of groundwater quality index (GWQI) for 2019 using the fuzzy analytic hierarchy process (FAHP) method. The 12 water quality parameters such as pH, TDS, iron (Fe−) and fluoride (F−), major anions (SO42−, Cl−, NO3−, and HCO3−), and cations (Na+, Ca2+, Mg2+, and K+) for the 29 sample wells of the study area were used for constructing the GWQI. This study used the FAHP method to define the weights of the different parameters for the GWQI. The results reveal that the bicarbonate content of 51% of sample wells exceeds the acceptable limit of drinking water, which is maximum in the study area. Furthermore, higher concentrations of TDS, pH, fluoride, chloride, calcium, magnesium, and sodium are found in few locations while nitrate and sulfate contents of all sample wells fall under the acceptable limits. The result shows that 13.79% of the samples are excellent, 68.97% of the samples are very good, 13.79% of the samples are poor, and 3.45% of the samples are very poor for drinking purposes. Moreover, it is observed that very poor quality water samples are located in the eastern part and the poor water wells are located in the northwestern and eastern part while excellent water quality wells are located in the western and central part of the study area. The understanding of the groundwater quality can help the policymakers for the proper management of water resources in the study area.

Introducing digital information products of the four GeoERA groundwater projects for assessment and sustainable use of water resources and the subsurface in a changing climate

<p>Sustainable evolution of groundwater quantity and quality is essential for sustainable development and protection of society and nature, globally, as acknowledged in the UN sustainable development goals and the European Green Deal. Too much? – too little? – and/or too polluted? are important questions to pose and answer in a changing climate with increasing pressures on water resources, severe loss of biodiversity, and a projected increase in extreme events resulting in an increasing risk of floods, droughts, landslides and land subsidence.   </p><p>Easy access to digital and FAIR (Findable, Accessible, Interoperable and reusable) data on groundwater quantity and quality is imperative for informed decision making and efficient climate change mitigation and adaptation to which sustainable groundwater management will contribute. Here we briefly present selected highlights and digital data products from the four GeoERA groundwater projects developed for and made available on the digital subsurface information platform of the European geological survey organizations. The ambition is to develop the digital information platform, EGDI (the European Geological Data Infrastructure) as the leading information platform for sustainable and integrated management of subsurface resources in Europe and one of the leading platforms, globally.</p>

Management of groundwater salinization under a climate change scenario in an aridarea

<p>Most future scenarios for water resources are predicting water scarcity, with a decrease in the amount<br>of precipitation and limitation on groundwater recharge for the next five decades. In arid and semi-<br>arid areas, the water quality is a great problem and groundwater salinization is one of the principal<br>causes of degradation of water resources worldwide.<br>Menzel Habib aquifer is located in the northwest of Gabès region (southeastern Tunisia), included in<br>the arid Mediterranean bioclimatic area, with dry hot summers and relatively warm winters.<br>Groundwater geochemistry from the study area shows a Na-Cl and Ca-Mg-Cl-SO 4 dominant facies.<br>The high groundwater mineralization and its correlation between total dissolved solids and major ions<br>suggest a contribution of SO 4 , Cl, Na, Ca and Mg in groundwater salinization processes.<br>The salinization of groundwater is mainly associated with the Triassic evaporites, with the dissolution<br>of halite, anhydrite and gypsum, occurring in the area, and related to the tectonic context of the<br>region. Additionally, other geochemical processes occurred, such is the cation exchange mechanisms.<br>Changes in precipitation patterns and intensity, with water scarcity, low recharge and excessive<br>pumping have affected groundwater quantity and quality. Nowadays, the occurrence of climate<br>changes scenarios is a major drawback for water use for irrigation and drinking water supply in arid<br>and semi-arid regions, such as Menzel Habib aquifer.</p>

Assessment of Causes and Effects of Groundwater Level Change in an Urban Area (Warsaw, Poland)

Monitoring the data of groundwater level in long-term measurement series has allowed for assessment of the impact of natural and anthropogenic factors on groundwater recharge. It allows for assessing the actual groundwater quantity, which constitutes the basis for balanced and sustainable groundwater planning and management in an urban area. Groundwater levels in three aquifers were studied: the shallow and deeper Quaternary aquifers and the Oligocene aquifer in Warsaw (Poland). Statistical analysis was performed on a 27-year (1993–2019) cycle of daily measurements of groundwater levels. The studies focused on determining the range and causes of groundwater level changes in urban-area aquifers. The groundwater table position in the Quaternary aquifer pointed to variable long-term recharge and allowed for the identification of homogenous intervals with identification of water table fluctuation trends. A decrease in the water table was observed within the Quaternary aquifers. The Oligocene aquifer displayed an opposite trend.

The Ecosystem Resilience Concept Applied to Hydrogeological Systems: A General Approach

We have witnessed the great changes that hydrogeological systems are facing in the last decades: rivers that have dried up; wetlands that have disappeared, leaving their buckets converted into farmland; and aquifers that have been intensively exploited for years, among others. Humans have caused the most part of these results that can be worsened by climate change, with delayed effects on groundwater quantity and quality. The consequences are negatively impacting ecosystems and dependent societies. The concept of resilience has not been extensively used in the hydrogeological research, and it can be a very useful concept that can improve the understanding and management of these systems. The aim of this work is to briefly discuss the role of resilience in the context of freshwater systems affected by either climate or anthropic actions as a way to increase our understanding of how anticipating negative changes (transitions) may contribute to improving the management of the system and preserving the services that it provides. First, the article presents the basic concepts applied to hydrogeological systems from the ecosystem’s resilience approach. Second, the factors controlling for hydrogeological systems’ responses to different impacts are commented upon. Third, a case study is analyzed and discussed. Finally, the useful implications of the concept are discussed.