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Due to complex hydrogeological contexts, mapping groundwater potential zones in karst regions is a difficult task. This study was conducted on a karst terrain in Sete Lagoas, Brazil, where rapid urban growth without adequate water resources management resulted in the drilling of unproductive wells and possible aquifer over-exploitation due to the concentration of wells. The objective was to develop a method for mapping groundwater potentiality for karst aquifers, serving as water resources management tool, based on 3D geological modelling, field work and pumping test data, remote sensing, geophysics analysis and production of thematic maps, resulting in the hydrogeological conceptual model. The groundwater potentiality map showed that most potential zones are on the central area, limited by grabens, where limestones are in contact with unconsolidated sediments, on areas with higher density of morphostructural and geophysical lineaments, mainly in east–west and north–east directions, near karst surface features, on thicker karstified zones, with higher recharge rates. [ABSTRACT FROM AUTHOR]

Modeling an aquifer provides significant advantages when evaluating and estimating the water resource for its sustainable use. This study focuses on the rural parish Manglaralto, a semi-arid area with a shortage of water, and without supply service by the public network. Still, it has a great demand for supply by the local and floating population (tourism). This has caused the coastal aquifer, which supplies the area’s water, to show signs of overexploitation, and its natural balance is compromised. The aim is to establish a geometric model of the aquifer through geological and geophysical analysis to set sustainable water-use guidelines. The methodology includes: (i) the processing of the current technical and hydrogeological information to know the aquifer’s data; (ii) geometric modeling of the aquifer through the correlation of technical information, using the GeoModeller software; (iii) proposals for the sustainable use of water in the framework of the United Nations’ Agenda 2030. The geometric model results reveal that the aquifer’s thickness varies from 4 m at the head of the river to 30 m at the sea’s mouth. The volume of water is estimated at 13.6 Hm3. The sustainable-use proposals ensure that more than half of the population receives the community company’s service. More than 40% of the territory is a protected area, and 64% of the population has sewerage service. This geometric model is a visual contribution that allows us to know the aquifer’s shape and establishes guidelines that help strengthen the water supply’s development and sustainability over time.

Summary The challenge of this study was to create a 3D geological and structural model of the Kasserine Aquifer System (KAS) in central Tunisia and its natural extension into north-east Algeria. This was achieved using an implicit 3D method, which honors prior geological data for both formation boundaries and faults. A current model is presented which provides defendable predictions for the spatial distribution of geology and water resources in aquifers throughout the model-domain. This work has allowed validation of regional scale geology and fault networks in the KAS, and has facilitated the first-ever estimations of groundwater resources in this region by a 3D method. The model enables a preliminary assessment of the hydraulic significance of the major faults by evaluating their influence and role on groundwater flow within and between four compartments of the multi-layered, KAS hydrogeological system. Thus a representative hydrogeological model of the study area is constructed. The possible dual nature of faults in the KAS is discussed in the context that some faults appear to be acting both as barriers to horizontal groundwater flow, and simultaneously as conduits for vertical flow. Also discussed is the possibility that two flow directions occur within the KAS, at a small syncline area of near Feriana. In summary, this work evaluates the influence of aquifer connectivity and the role of faults and geology in groundwater flow within the KAS aquifer system. The current KAS geological model can now be used to guide groundwater managers on the best placement for drilling to test and further refine the understanding of the groundwater system, including the faults connectivity. As more geological data become available, the current model can be easily edited and re-computed to provide an updated model ready for the next stage of investigation by numerical flow modeling. [ABSTRACT FROM AUTHOR]

A three-dimensional model of the gold-rich Paleoproterozoic Ashanti Greenstone Belt has been built with a "hybrid" geological modeling method using Geomodeller and Gocad, then inverted using VPmg software. The model helps to identify the main regional-scale controls leading to abundant gold mineralization in the southeast of the belt by highlighting the lithological distribution and geometry of geological structures. The three-dimensional geological model shows that 85% of gold occurrences in the Ashanti Greenstone Belt are proximal to a specific tholeiitic metabasaltic horizon "BV1". This result is noteworthy given that the relatively thin, 300 m thick, BV1 layer represents only 10%, by volume, of the modeled Sefwi Group stratigraphy. A map of distance between the topography and the BV1 layer is produced and identifies areas showing a high probability to host gold deposits in the southeast of the Ashanti Belt. Possible structural controls performed by the BV1 tholeiitic metabasaltic rocks on the location of gold occurrences are discussed, and we hypothesize that the BV1 layer acted as a mineralization trap or source of gold. Both hypotheses agree with examples from the literature and explain the observed distribution of the mineralized sites. [ABSTRACT FROM AUTHOR]

Abstract: True 3D geological models are instrumental in addressing practical geology problems. A 3D geological modeling method is a vital module which converts raw data in lower dimensions into 3D bodies. To be geologically practical, the method must take cross-sections as the main data source and must be capable of modeling areas with complex faults, maintaining data consistency as well as carrying out multi-body modeling. To realize such a practical geological modeling system, GSIS (Geological Spatial Information System) is developed based on the core method of 3D geological multi-body modeling from netty cross-sections with topology. According to the intersecting netty cross-section approach, the presented method divides the modeling area into several cross-section grids. Thus, the modeling is simplified into the independent modeling of each cross-section grid and their merger into an integrated model. Different approaches are employed when constructing models in a specific cross-section grid, depending on whether a fault is present in the grid in question. In the absence of a fault, the basic approach is employed; otherwise, the basic approach is extended to add fault-related treatments. In both approaches, arcs are classified into subsets by their connections, attributes, and topological relationships. Arcs in the same subset of the lowest level are triangulated and interpolated to generate stratum interfaces. In this work, the application of GSIS in the Beijing multi-parameter stereo geological survey project is presented. Among seven successfully constructed models, the engineering geological model of the new city zone in Shunyi district and the bedrock geological model of the central city zone are cited as examples. These demonstrate GSIS’s capacity in modeling large areas with complex geology. [Copyright &y& Elsevier]

Modeling an aquifer provides significant advantages when evaluating and estimating the water resource for its sustainable use. This study focuses on the rural parish Manglaralto, a semi-arid area with a shortage of water, and without supply service by the public network. Still, it has a great demand for supply by the local and floating population (tourism). This has caused the coastal aquifer, which supplies the area's water, to show signs of overexploitation, and its natural balance is compromised. The aim is to establish a geometric model of the aquifer through geological and geophysical analysis to set sustainable water-use guidelines. The methodology includes: (i) the processing of the current technical and hydrogeological information to know the aquifer's data; (ii) geometric modeling of the aquifer through the correlation of technical information, using the GeoModeller software; (iii) proposals for the sustainable use of water in the framework of the United Nations' Agenda 2030. The geometric model results reveal that the aquifer's thickness varies from 4 m at the head of the river to 30 m at the sea's mouth. The volume of water is estimated at 13.6 Hm3. The sustainable-use proposals ensure that more than half of the population receives the community company's service. More than 40% of the territory is a protected area, and 64% of the population has sewerage service. This geometric model is a visual contribution that allows us to know the aquifer's shape and establishes guidelines that help strengthen the water supply's development and sustainability over time. [ABSTRACT FROM AUTHOR]