Pub Date : 2025-10-25DOI: 10.1016/j.geogeo.2025.100468
Abdoul Aboubakar , Bertille Ilalie Manefouet Kentsa , Grace Nissia Rodo , Oussena Bébé Nzie , Stella Nome May , Clotaire José Pako Perabi , Merlot Tongnang Kenzo , Thomas Tatietse Tamo
This study highlights the contribution of geo-electricity to the characterization of geological formations in the Ngaoundal area. Electrical mapping using the Schlumberger device was carried out over 29.9 km², with fifty-one vertical electrical soundings (VES) conducted at 700 m intervals across a zone entirely covered by soils developed on a granitic bedrock. Apparent resistivity maps, for depths ranging from AB/2 = 1.5 to 100 m, reveal low, medium, and high resistivity ranges. Ten main types of VES curves (Q, HK, KH, H, KQ, QH, HKH, K, KQH, and QHK) were identified, classified according to depth and resistivity. Integrated analysis of resistivity maps and VES curves shows lateritic soils dominating the surface, sandy-clay soils at intermediate depth, and fractured or sound bedrock at greater depth. Four pseudo-resistivity sections highlight weak (ρ < 350 Ω·m), medium (350 ≤ ρ ≤ 1800 Ω·m), and strong (ρ ≥ 1800 Ω·m) anomalies, corresponding respectively to loose weathered formations (weathered granite, gravelly soils), fractured granites, and sound granites forming the bedrock. The lateritic layer thickness map identifies three classes: low (1.33–2.58 m), medium (2.59–2.84 m), and high (2.85–8.94 m). Comparison with existing water borehole data confirms the consistency of geophysical models. This complementarity between geophysical methods and direct borehole observations reinforces the reliability of the approach and provides a robust framework for geological and hydrogeological interpretation of the subsurface in the Ngaoundal region.
{"title":"Contribution of the geoelectric method to the identification of geological formations in the Ngaoundal locality (Adamawa, Cameroon)","authors":"Abdoul Aboubakar , Bertille Ilalie Manefouet Kentsa , Grace Nissia Rodo , Oussena Bébé Nzie , Stella Nome May , Clotaire José Pako Perabi , Merlot Tongnang Kenzo , Thomas Tatietse Tamo","doi":"10.1016/j.geogeo.2025.100468","DOIUrl":"10.1016/j.geogeo.2025.100468","url":null,"abstract":"<div><div>This study highlights the contribution of geo-electricity to the characterization of geological formations in the Ngaoundal area. Electrical mapping using the Schlumberger device was carried out over 29.9 km², with fifty-one vertical electrical soundings (VES) conducted at 700 m intervals across a zone entirely covered by soils developed on a granitic bedrock. Apparent resistivity maps, for depths ranging from AB/2 = 1.5 to 100 m, reveal low, medium, and high resistivity ranges. Ten main types of VES curves (Q, HK, KH, H, KQ, QH, HKH, K, KQH, and QHK) were identified, classified according to depth and resistivity. Integrated analysis of resistivity maps and VES curves shows lateritic soils dominating the surface, sandy-clay soils at intermediate depth, and fractured or sound bedrock at greater depth. Four pseudo-resistivity sections highlight weak (<em>ρ</em> < 350 Ω·m), medium (350 ≤ <em>ρ</em> ≤ 1800 Ω·m), and strong (<em>ρ</em> ≥ 1800 Ω·m) anomalies, corresponding respectively to loose weathered formations (weathered granite, gravelly soils), fractured granites, and sound granites forming the bedrock. The lateritic layer thickness map identifies three classes: low (1.33–2.58 m), medium (2.59–2.84 m), and high (2.85–8.94 m). Comparison with existing water borehole data confirms the consistency of geophysical models. This complementarity between geophysical methods and direct borehole observations reinforces the reliability of the approach and provides a robust framework for geological and hydrogeological interpretation of the subsurface in the Ngaoundal region.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100468"},"PeriodicalIF":0.0,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145464839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-18DOI: 10.1016/j.geogeo.2025.100467
Svetlana Yurievna Artamonova
This paper comprehensively discusses data from electrical resistivity tomography, land geomagnetic surveys, radionuclides, and the major-ion chemistry of water flowing at the epicenter of the Crystal peaceful underground nuclear explosion (it was carried out in 1974). The integrity of the seal at the emplacement hole cap was compromised during the explosion, the soils at the epicenter were contaminated by radionuclides. To immobilize these radionuclides cryogenically and prevent migration of radionuclides from the central explosion area (at a depth of 98 meters), the head of the emplacement hole and its surroundings were buried in 1992 with block-rubble stone material composed of pure limestone and dolomite fragments. Additionally, the block-rubble artificial cover was further reinforced in 2006. The artificial cover is revealed to remain unfrozen and waterlogged nowadays. Snowmelt and rainwater are observed to seep through this cover, while air convection within it likely leads to the condensation of atmospheric moisture. The bicarbonate magnesium-calcium waters that originate from the percolation of rain, melted snow, and atmospheric condensate through the cover are enriched with technogenic ions such as SO₄²⁻, Mg²⁺, Ca²⁺, Li⁺, K⁺, and Sr, alongside natural components like Cl⁻, Mg²⁺, Ca²⁺, K⁺, Na⁺, Br, Sr, I, and Li⁺, which are derived from underground natural gas-brine fluids that rise along the open emplacement hole and the damage zone. It is hypothesized that Li⁺ could be a component of the nuclear explosive device. Given the low current activity of radionuclides in water flowing from beneath the artificial cover (measured in Bq/dm³): ³H, 4–12; ⁹⁰Sr, 0.004–0.4, and diminishing levels of ²³⁹,²⁴⁰Pu (<10⁻⁶), the current migration of technogenic radionuclides with water is assessed as insignificant. Therefore, there is no immediate need for additional measures to strengthen or modify the block-rubble artificial cover.
{"title":"Paradox of the Сrystal peaceful underground nuclear explosion site (Yakutia, 1974): Evidence from electrical resistivity tomography and water runoff chemistry","authors":"Svetlana Yurievna Artamonova","doi":"10.1016/j.geogeo.2025.100467","DOIUrl":"10.1016/j.geogeo.2025.100467","url":null,"abstract":"<div><div>This paper comprehensively discusses data from electrical resistivity tomography, land geomagnetic surveys, radionuclides, and the major-ion chemistry of water flowing at the epicenter of the Crystal peaceful underground nuclear explosion (it was carried out in 1974). The integrity of the seal at the emplacement hole cap was compromised during the explosion, the soils at the epicenter were contaminated by radionuclides. To immobilize these radionuclides cryogenically and prevent migration of radionuclides from the central explosion area (at a depth of 98 meters), the head of the emplacement hole and its surroundings were buried in 1992 with block-rubble stone material composed of pure limestone and dolomite fragments. Additionally, the block-rubble artificial cover was further reinforced in 2006. The artificial cover is revealed to remain unfrozen and waterlogged nowadays. Snowmelt and rainwater are observed to seep through this cover, while air convection within it likely leads to the condensation of atmospheric moisture. The bicarbonate magnesium-calcium waters that originate from the percolation of rain, melted snow, and atmospheric condensate through the cover are enriched with technogenic ions such as SO₄²⁻, Mg²⁺, Ca²⁺, Li⁺, K⁺, and Sr, alongside natural components like Cl⁻, Mg²⁺, Ca²⁺, K⁺, Na⁺, Br, Sr, I, and Li⁺, which are derived from underground natural gas-brine fluids that rise along the open emplacement hole and the damage zone. It is hypothesized that Li⁺ could be a component of the nuclear explosive device. Given the low current activity of radionuclides in water flowing from beneath the artificial cover (measured in Bq/dm³): ³H, 4–12; ⁹⁰Sr, 0.004–0.4, and diminishing levels of ²³⁹<sup>,</sup>²⁴⁰Pu (<10⁻⁶), the current migration of technogenic radionuclides with water is assessed as insignificant. Therefore, there is no immediate need for additional measures to strengthen or modify the block-rubble artificial cover.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100467"},"PeriodicalIF":0.0,"publicationDate":"2025-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145618227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-13DOI: 10.1016/j.geogeo.2025.100465
André Mbabi Bitchong , Thierry Adatte , Serge P. Koah Na Lebogo , Cecile Olive Mbesse , Hamid Slimani , Jorge E. Spangenberg , Glwadys Ngo Mandeng , Simon Ngos III
The Paleocene–Eocene environment and vegetation evolution is widely documented worldwide. While a few similar studies have been undertaken in the Gulf of Guinea and the continental interior, they remain very limited, and provide no evidence of the Paleocene–Eocene thermal maximum (PETM). To address this gap, we conducted a comprehensive new sedimentological, palynological, mineralogical, and geochemical analysis of the Miang outcrop in the Douala Basin that encompasses silty-clayey deposits typical for swamp to back swamp coastal settings. The analysis of pollen and spore taxa, including Proxapertites operculatus, Proxapertites cursus, Echitriporites trianguliformis, Psilamonocolpites sp., Crototricolpites protoannemariae, Echitricolpites communis, Psilastephanocolporites sp., and Echimonocolpites rarispinosus and allowed the delineation of the pantropical Proxapertites operculatus Zone, corresponding to the Paleocene–Eocene transition, as well as Cameroon Spathiphyllum vanegensis (ZpI) and Retibrevitricolpites triangulatus (ZpII) zones, which indicate the late Paleocene and early Eocene epochs, respectively. This, combined with the organic carbon-isotope excursion (CIE: ∼-6.4‰), contributed to accurately determining the Paleocene–Eocene boundary (PEB). Geochemical and clay mineralogical data indicate that the paleoenvironment experienced intrusive volcanism linked with the Cameroon Volcanic Line (CVL), and enhanced primary productivity, both of which show marked decline prior to the PEB. Additionally, significant chemical alteration (CIA values: 85–94) occurred under warm and humid conditions (kaolinite: 70–88 % and smectite: 10–23 %), with sediments being reworked and deposited in a dysoxic setting conducive to organic matter preservation, especially from the pre-PETM period onwards. From the pre-PETM to early PETM, the Gulf of Guinea was probably covered by an extensive Lowland Rainforest/Open Forest ecosystem with a diverse flora, mostly angiosperms, that thrived in warm and humid conditions. From the mid-Lower Eocene onwards, Lowland Rainforest/Open Forest and Freshwater Swamp Forest species began to coexist with certain Mangrove-Coastal Swamp species, indicating proximity to the sea.
{"title":"Paleoenvironmental and vegetation evolution during the PETM in the Gulf of Guinea: A study based on integrated palynological and chemostratigraphic analysis of the Miang section in the Douala Basin, Cameroon","authors":"André Mbabi Bitchong , Thierry Adatte , Serge P. Koah Na Lebogo , Cecile Olive Mbesse , Hamid Slimani , Jorge E. Spangenberg , Glwadys Ngo Mandeng , Simon Ngos III","doi":"10.1016/j.geogeo.2025.100465","DOIUrl":"10.1016/j.geogeo.2025.100465","url":null,"abstract":"<div><div>The Paleocene–Eocene environment and vegetation evolution is widely documented worldwide. While a few similar studies have been undertaken in the Gulf of Guinea and the continental interior, they remain very limited, and provide no evidence of the Paleocene–Eocene thermal maximum (PETM). To address this gap, we conducted a comprehensive new sedimentological, palynological, mineralogical, and geochemical analysis of the Miang outcrop in the Douala Basin that encompasses silty-clayey deposits typical for swamp to back swamp coastal settings. The analysis of pollen and spore taxa, including <em>Proxapertites operculatus, Proxapertites cursus, Echitriporites trianguliformis, Psilamonocolpites</em> sp., <em>Crototricolpites protoannemariae, Echitricolpites communis, Psilastephanocolporites</em> sp., and <em>Echimonocolpites rarispinosus</em> and allowed the delineation of the pantropical <em>Proxapertites operculatus</em> Zone, corresponding to the Paleocene–Eocene transition, as well as Cameroon <em>Spathiphyllum vanegensis</em> (ZpI) and <em>Retibrevitricolpites triangulatus</em> (ZpII) zones, which indicate the late Paleocene and early Eocene epochs, respectively. This, combined with the organic carbon-isotope excursion (CIE: ∼-6.4‰), contributed to accurately determining the Paleocene–Eocene boundary (PEB). Geochemical and clay mineralogical data indicate that the paleoenvironment experienced intrusive volcanism linked with the Cameroon Volcanic Line (CVL), and enhanced primary productivity, both of which show marked decline prior to the PEB. Additionally, significant chemical alteration (CIA values: 85–94) occurred under warm and humid conditions (kaolinite: 70–88 % and smectite: 10–23 %), with sediments being reworked and deposited in a dysoxic setting conducive to organic matter preservation, especially from the pre-PETM period onwards. From the pre-PETM to early PETM, the Gulf of Guinea was probably covered by an extensive Lowland Rainforest/Open Forest ecosystem with a diverse flora, mostly angiosperms, that thrived in warm and humid conditions. From the mid-Lower Eocene onwards, Lowland Rainforest/Open Forest and Freshwater Swamp Forest species began to coexist with certain Mangrove-Coastal Swamp species, indicating proximity to the sea.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100465"},"PeriodicalIF":0.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-10DOI: 10.1016/j.geogeo.2025.100464
Nyakno J. George , Nsikak E. Bassey
Akwa Ibom State University (AKSU) in southeastern Nigeria faces recurrent waterlogging, poor drainage, and declining groundwater quality due to shallow water tables, low-permeability soils, intense rainfall, and unregulated land development. These issues have caused environmental degradation, hindered agriculture, and disrupted infrastructure. This study aims to evaluate the spatiotemporal hydrogeological and hydrochemical conditions of the AKSU campus to inform sustainable groundwater and drainage management. A combination of geophysical methods—vertical electrical sounding (VES) and electrical resistivity tomography (ERT)—was employed alongside hydrochemical analyses, data mining (Pareto and AHP), and irrigation suitability assessments. Field investigations involved 25 VES points and 2D ERT surveys, processed using WINRESIST and RES2DINV. Results identified 3–4 geoelectric layers, including productive sandy aquifers, with transmissivity values ranging from 1195.3 to 6611.6 m²/day and high correlations (R² > 0.9) between bulk aquifer resistivity and hydrodynamic parameters. Laboratory analyses showed that most groundwater samples met WHO standards, though localized exceedances of Fe, Pb, Cu, Mn, Ni, and fluoride were observed. Irrigation indices revealed that high sodium levels limit long-term agricultural suitability. Pareto and AHP analyses highlighted drainage density, rainfall, and topography as key contributors to waterlogging. The study concludes with recommendations for subsurface drainage systems, improved land use planning, and targeted water quality monitoring to support long-term environmental and agricultural resilience.
{"title":"Geoelectric and hydro-geochemical assessments of waterlogging and drainage for soil and agronomic groundwater evaluation at Akwa Ibom State University: Field and laboratory data mining approaches","authors":"Nyakno J. George , Nsikak E. Bassey","doi":"10.1016/j.geogeo.2025.100464","DOIUrl":"10.1016/j.geogeo.2025.100464","url":null,"abstract":"<div><div>Akwa Ibom State University (AKSU) in southeastern Nigeria faces recurrent waterlogging, poor drainage, and declining groundwater quality due to shallow water tables, low-permeability soils, intense rainfall, and unregulated land development. These issues have caused environmental degradation, hindered agriculture, and disrupted infrastructure. This study aims to evaluate the spatiotemporal hydrogeological and hydrochemical conditions of the AKSU campus to inform sustainable groundwater and drainage management. A combination of geophysical methods—vertical electrical sounding (VES) and electrical resistivity tomography (ERT)—was employed alongside hydrochemical analyses, data mining (Pareto and AHP), and irrigation suitability assessments. Field investigations involved 25 VES points and 2D ERT surveys, processed using WINRESIST and RES2DINV. Results identified 3–4 geoelectric layers, including productive sandy aquifers, with transmissivity values ranging from 1195.3 to 6611.6 m²/day and high correlations (R² > 0.9) between bulk aquifer resistivity and hydrodynamic parameters. Laboratory analyses showed that most groundwater samples met WHO standards, though localized exceedances of Fe, Pb, Cu, Mn, Ni, and fluoride were observed. Irrigation indices revealed that high sodium levels limit long-term agricultural suitability. Pareto and AHP analyses highlighted drainage density, rainfall, and topography as key contributors to waterlogging. The study concludes with recommendations for subsurface drainage systems, improved land use planning, and targeted water quality monitoring to support long-term environmental and agricultural resilience.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100464"},"PeriodicalIF":0.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-29DOI: 10.1016/j.geogeo.2025.100463
Pooria Kianoush , Ahmad Adib , Shahab Varkouhi , Nasser Keshavarz Faraj Khah
The Torud Playa Basin in northeastern Iran possesses significant brine and hydrocarbon exploration potential. Its complex geology—comprising playa basins, evaporites, and multi-layered aquifers—presents unique challenges for pumping test implementation. The Torud Playa hydrogeological reserves were evaluated through multi-level pumping tests and hydrogeochemical analysis. These methods addressed the basin's complex evaporite geology. The study aims to understand reservoir behavior and develop effective management strategies, including improved water management practices and the identification of new exploration targets. The study's results have significantly contributed to understanding the reservoir behavior and developing effective management strategies. It is indicated that the studied area is divided into four sections, with poor permeability in the central parts (<1.5 m/day) and good permeability in the northern region (>3 m/day). This work identifies the north-northeastern parts of the Torud Playa suitable for potash reserves, with an estimated volume of 27,200.18 million cubic meters (Mm3) solutes in the playa and salt crust and an excavated volume of 18,133.45 Mm3. Sustainable exploitation requires limiting extraction to 40–60% of static reserves (327–490 Mm³) to maintain hydrological balance, with 90 % extraction causing 3.2 m water table decline and 62% habitat loss. These findings provide novel insights into reserve assessment methodologies for playa basins, integrating hydrodynamic and geochemical approaches to guide evidence-based resource management in arid regions.
{"title":"Comprehensive assessment of the Torud Playa Basin hydrogeological reserves in NE Iran: Insights from utilizing pumping test methods","authors":"Pooria Kianoush , Ahmad Adib , Shahab Varkouhi , Nasser Keshavarz Faraj Khah","doi":"10.1016/j.geogeo.2025.100463","DOIUrl":"10.1016/j.geogeo.2025.100463","url":null,"abstract":"<div><div>The Torud Playa Basin in northeastern Iran possesses significant brine and hydrocarbon exploration potential. Its complex geology—comprising playa basins, evaporites, and multi-layered aquifers—presents unique challenges for pumping test implementation. The Torud Playa hydrogeological reserves were evaluated through multi-level pumping tests and hydrogeochemical analysis. These methods addressed the basin's complex evaporite geology. The study aims to understand reservoir behavior and develop effective management strategies, including improved water management practices and the identification of new exploration targets. The study's results have significantly contributed to understanding the reservoir behavior and developing effective management strategies. It is indicated that the studied area is divided into four sections, with poor permeability in the central parts (<1.5 m/day) and good permeability in the northern region (>3 m/day). This work identifies the north-northeastern parts of the Torud Playa suitable for potash reserves, with an estimated volume of 27,200.18 million cubic meters (Mm<sup>3</sup>) solutes in the playa and salt crust and an excavated volume of 18,133.45 Mm<sup>3</sup>. Sustainable exploitation requires limiting extraction to 40–60% of static reserves (327–490 Mm³) to maintain hydrological balance, with 90 % extraction causing 3.2 m water table decline and 62% habitat loss. These findings provide novel insights into reserve assessment methodologies for playa basins, integrating hydrodynamic and geochemical approaches to guide evidence-based resource management in arid regions.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100463"},"PeriodicalIF":0.0,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to climate change many basins are under water stress condition due to erratic rainfall. Hence, we aimed to study rainfall pattern over the last thirty-two years and to identify the new groundwater potential zones (GWPZs) using the remote sensing-based products, meteorological, hydrogeological, and groundwater level data in the lower Rapti River Basin (LRRB). The monthly data of thirty-two years (1990–2022) of eight stations viz. Balrampur, Shravasti, Siddharth Nagar, Maharajganj, Sant Kabir Nagar, Gorakhpur, Deoria, and Kushinagar were tested for standardized precipitation index (SPI) at multi-time scale (SPI-1, SPI-3, SPI-6, SPI-9, SPI-12, and SPI-24) to decipher wetness and dryness condition in the area. Afterwards, impact of rainfall was correlated with surface drainage characteristic and sub-surface recharge zone. Henceforth, different data sets pertaining to lithology, rainfall, geology, drainage density, geomorphology, land use/land cover, soil, slope and elevation were used to delineate GWPZ. Relative importance of thematic layers and weights on Saaty’s scale was determined by analytical hierarchy process (AHP) in order to normalize and standardize the weights. Eventually, in the GIS environment all thematic layers were combined using the weighted overlay method (WOM) for delineation of GWPZ. Result of GWPZ was validated with groundwater level and soil moisture data and categorized as excellent, good, fair and poor. The majority of area is under the category of good and fair GWPZs.
{"title":"Unraveling groundwater potential zones from alluvial plains using decision making method: A river scale analysis","authors":"Adesh Patel , M.M. Singh , S.C. Bhatt , Narendra Kumar Rana , Sudhir Kumar Singh , Nirmal Kumar , Hrithik Sachan","doi":"10.1016/j.geogeo.2025.100461","DOIUrl":"10.1016/j.geogeo.2025.100461","url":null,"abstract":"<div><div>Due to climate change many basins are under water stress condition due to erratic rainfall. Hence, we aimed to study rainfall pattern over the last thirty-two years and to identify the new groundwater potential zones (GWPZs) using the remote sensing-based products, meteorological, hydrogeological, and groundwater level data in the lower Rapti River Basin (LRRB). The monthly data of thirty-two years (1990–2022) of eight stations viz. Balrampur, Shravasti, Siddharth Nagar, Maharajganj, Sant Kabir Nagar, Gorakhpur, Deoria, and Kushinagar were tested for standardized precipitation index (SPI) at multi-time scale (SPI-1, SPI-3, SPI-6, SPI-9, SPI-12, and SPI-24) to decipher wetness and dryness condition in the area. Afterwards, impact of rainfall was correlated with surface drainage characteristic and sub-surface recharge zone. Henceforth, different data sets pertaining to lithology, rainfall, geology, drainage density, geomorphology, land use/land cover, soil, slope and elevation were used to delineate GWPZ. Relative importance of thematic layers and weights on Saaty’s scale was determined by analytical hierarchy process (AHP) in order to normalize and standardize the weights. Eventually, in the GIS environment all thematic layers were combined using the weighted overlay method (WOM) for delineation of GWPZ. Result of GWPZ was validated with groundwater level and soil moisture data and categorized as excellent, good, fair and poor. The majority of area is under the category of good and fair GWPZs.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100461"},"PeriodicalIF":0.0,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-22DOI: 10.1016/j.geogeo.2025.100462
Samuel Yaw Danso
Mapping regions prone to flooding constitutes a crucial step toward developing localized solutions for flood preparedness and mitigation. This study presents a geographic information system (GIS)-driven approach that combines the decision-making trial and evaluation laboratory (DEMATEL), criteria importance through intercriteria correlation (CRITIC), and simple additive weighting (SAW) methodologies to identify flood-prone areas in the Sekondi-Takoradi Metropolis (STM), Ghana. The study's originality lies in using the hybrid DEMATEL-CRITIC-SAW model for flood susceptibility assessment, a novel integration of decision-making methods and analytical techniques not previously applied together for this purpose. This novel framework provides a comprehensive approach to analyze relationships among 11 flood-inducing variables, determine variable importance, and integrate these findings to produce a more accurate and robust flood susceptibility map. The results reveal a constructed network structure that highlights the complex relationships and dependencies among the variables. Among the assessed criteria, stream power index was identified as the most significant factor due to its high total interaction with other criteria. The flood susceptibility zones within STM are classified into five levels: very low (15%), low (27%), moderate (21%), high (22%), and very high (14%). Notably, the coastal and central sections of STM were marked as areas with moderate to very high flood susceptibility. The results, measured using the area under the curve, indicate that the proposed approach achieved a score of 0.947, demonstrating its superior performance over other existing hybrid models in the literature. The method provides actionable recommendations to authorities in STM for developing flood prevention/mitigation measures.
{"title":"GIS-driven hybrid multicriteria model for flood susceptibility assessment in a coastal metropolis of Ghana","authors":"Samuel Yaw Danso","doi":"10.1016/j.geogeo.2025.100462","DOIUrl":"10.1016/j.geogeo.2025.100462","url":null,"abstract":"<div><div>Mapping regions prone to flooding constitutes a crucial step toward developing localized solutions for flood preparedness and mitigation. This study presents a geographic information system (GIS)-driven approach that combines the decision-making trial and evaluation laboratory (DEMATEL), criteria importance through intercriteria correlation (CRITIC), and simple additive weighting (SAW) methodologies to identify flood-prone areas in the Sekondi-Takoradi Metropolis (STM), Ghana. The study's originality lies in using the hybrid DEMATEL-CRITIC-SAW model for flood susceptibility assessment, a novel integration of decision-making methods and analytical techniques not previously applied together for this purpose. This novel framework provides a comprehensive approach to analyze relationships among 11 flood-inducing variables, determine variable importance, and integrate these findings to produce a more accurate and robust flood susceptibility map. The results reveal a constructed network structure that highlights the complex relationships and dependencies among the variables. Among the assessed criteria, stream power index was identified as the most significant factor due to its high total interaction with other criteria. The flood susceptibility zones within STM are classified into five levels: very low (15%), low (27%), moderate (21%), high (22%), and very high (14%). Notably, the coastal and central sections of STM were marked as areas with moderate to very high flood susceptibility. The results, measured using the area under the curve, indicate that the proposed approach achieved a score of 0.947, demonstrating its superior performance over other existing hybrid models in the literature. The method provides actionable recommendations to authorities in STM for developing flood prevention/mitigation measures.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100462"},"PeriodicalIF":0.0,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Evaluating environmental vulnerability is crucial for efficient and sustainable management, particularly in regions that are ecologically sensitive and experiencing rapid transformations. Thus, the main goal of this study is to evaluate the environmental fragility of the Brahmani-Dwarka Interfluve by integrating key natural and human-induced factors through the analytical hierarchy process (AHP) and fuzzy analytical hierarchy process (FAHP) within a remote sensing and geographic information systems (RS-GIS) framework. To achieve this, ten unique factors influencing potential environmental fragility (PEF) were analyzed, along with four new factors to tackle emerging fragility (EEF). This study holds significant value as it focuses on a region profoundly affected by stone crushing industries, which encounter considerable threats of environmental harm. The results of the PEF model showed that high and very high fragility zones accounted for 23.96% and 22.38% of the area, according to the AHP and FAHP models. Similarly, EEF models highlighted a growing fragility, with FAHP and AHP indicating that 27.85% and 16.80% of the region were categorized as having high and very high fragility. Hotspot analysis indicated that environmentally fragile hotspots constituted 21.07% and 31.46% of the area in the AHP and FAHP-based models, respectively. ROC validation indicated that FAHP demonstrated superior performance compared to AHP in both PEF and EEF models, highlighting its exceptional predictive accuracy and reliability. The observed negligible difference between high and low sensitive parameters was 0.866% in FAHP-based PEF and 0.532% in FAHP-based EEF, indicating the models’ reliability. The findings of the study will help policymakers, planners, and stakeholders to develop environmentally resilient strategies and policies as well as achieve sustainability in the study region.
{"title":"Modelling environmental fragility in an industrial landscape: An integrated remote sensing-GIS framework for sustainable planning in Brahmani-Dwarka Interfluve","authors":"Bhaskar Mandal, Kaushalendra Prakash Goswami, Sharmistha Mondal","doi":"10.1016/j.geogeo.2025.100460","DOIUrl":"10.1016/j.geogeo.2025.100460","url":null,"abstract":"<div><div>Evaluating environmental vulnerability is crucial for efficient and sustainable management, particularly in regions that are ecologically sensitive and experiencing rapid transformations. Thus, the main goal of this study is to evaluate the environmental fragility of the Brahmani-Dwarka Interfluve by integrating key natural and human-induced factors through the analytical hierarchy process (AHP) and fuzzy analytical hierarchy process (FAHP) within a remote sensing and geographic information systems (RS-GIS) framework. To achieve this, ten unique factors influencing potential environmental fragility (PEF) were analyzed, along with four new factors to tackle emerging fragility (EEF). This study holds significant value as it focuses on a region profoundly affected by stone crushing industries, which encounter considerable threats of environmental harm. The results of the PEF model showed that high and very high fragility zones accounted for 23.96% and 22.38% of the area, according to the AHP and FAHP models. Similarly, EEF models highlighted a growing fragility, with FAHP and AHP indicating that 27.85% and 16.80% of the region were categorized as having high and very high fragility. Hotspot analysis indicated that environmentally fragile hotspots constituted 21.07% and 31.46% of the area in the AHP and FAHP-based models, respectively. ROC validation indicated that FAHP demonstrated superior performance compared to AHP in both PEF and EEF models, highlighting its exceptional predictive accuracy and reliability. The observed negligible difference between high and low sensitive parameters was 0.866% in FAHP-based PEF and 0.532% in FAHP-based EEF, indicating the models’ reliability. The findings of the study will help policymakers, planners, and stakeholders to develop environmentally resilient strategies and policies as well as achieve sustainability in the study region.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100460"},"PeriodicalIF":0.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-16DOI: 10.1016/j.geogeo.2025.100459
Arabe Khan , Md Mahmudul Hasan Rakib , Irteja Hasan , Apurba Roy , Mehedi Hasan Ovi , Md Mostafa Jaman Rabby , Raian Islam Evan , Nusrat Jahan Suborna , Maksudur Rahman , Rahat Khan , Dhiman Kumer Roy
Riverbank erosion is one of the significant natural hazards affecting the livelihoods of communities living along riverbanks in Bangladesh. This study develops a novel riverbank erosion susceptibility index (RESI) to quantitatively assess community susceptibility to this hazard. The RESI framework integrates five core dimensions: exposure, susceptibility, sensitivity, adaptability, and resilience, encompassing 34 context-specific indicators derived from household surveys, interviews, and field observations. The RESI scoring scale ranges from -1 (most resilient) to +1 (most susceptible), where higher positive scores indicate greater susceptibility to riverbank erosion. The findings in this study conclude that Chadpur Union is the most susceptible (RESI score: 0.47), followed by Shambupur (0.36) and Chanchra (0.29) union. These scores are further validated with historical remote-sensing analysis, and sensitivity tests show that varying indicator weights (equal, expert, or PCA) do not change the relative union ranking, underscoring the model’s robustness. The analysis highlights key drivers of vulnerability: frequent erosion occurrences, high population density along riverbanks, considerable losses in land and assets, and recurrent displacement due to erosion. All three unions are facing significant challenges in building adaptability and resilience, as indicated by low scores in infrastructure, financial resources, and social support systems. The study emphasizes the need for targeted interventions to reduce susceptibility, which include reinforcing protective structures, improving access to financial and technical resources, and promoting livelihood diversification strategies. Integrating the RESI into planning enables decision-makers to prioritize high-risk areas and allocate resources more effectively.
{"title":"Developing a riverbank erosion susceptibility index: A pragmatic approach to reveal the level of vulnerability in coastal Bangladesh","authors":"Arabe Khan , Md Mahmudul Hasan Rakib , Irteja Hasan , Apurba Roy , Mehedi Hasan Ovi , Md Mostafa Jaman Rabby , Raian Islam Evan , Nusrat Jahan Suborna , Maksudur Rahman , Rahat Khan , Dhiman Kumer Roy","doi":"10.1016/j.geogeo.2025.100459","DOIUrl":"10.1016/j.geogeo.2025.100459","url":null,"abstract":"<div><div>Riverbank erosion is one of the significant natural hazards affecting the livelihoods of communities living along riverbanks in Bangladesh. This study develops a novel riverbank erosion susceptibility index (RESI) to quantitatively assess community susceptibility to this hazard. The RESI framework integrates five core dimensions: exposure, susceptibility, sensitivity, adaptability, and resilience, encompassing 34 context-specific indicators derived from household surveys, interviews, and field observations. The RESI scoring scale ranges from -1 (most resilient) to +1 (most susceptible), where higher positive scores indicate greater susceptibility to riverbank erosion. The findings in this study conclude that Chadpur Union is the most susceptible (RESI score: 0.47), followed by Shambupur (0.36) and Chanchra (0.29) union. These scores are further validated with historical remote-sensing analysis, and sensitivity tests show that varying indicator weights (equal, expert, or PCA) do not change the relative union ranking, underscoring the model’s robustness. The analysis highlights key drivers of vulnerability: frequent erosion occurrences, high population density along riverbanks, considerable losses in land and assets, and recurrent displacement due to erosion. All three unions are facing significant challenges in building adaptability and resilience, as indicated by low scores in infrastructure, financial resources, and social support systems. The study emphasizes the need for targeted interventions to reduce susceptibility, which include reinforcing protective structures, improving access to financial and technical resources, and promoting livelihood diversification strategies. Integrating the RESI into planning enables decision-makers to prioritize high-risk areas and allocate resources more effectively.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100459"},"PeriodicalIF":0.0,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-09DOI: 10.1016/j.geogeo.2025.100457
Irteja Hasan , Md Mahmudul Hasan Rakib , Dhiman Kumer Roy , Mehedi Hasan Ovi , Md. Fuad Hasan , Md. Sagirul Islam Majumder
The Patuakhali region is situated in the coastal area of Bangladesh and is bordered by major rivers, which are extremely vulnerable to foreseeable flooding disasters due to the detrimental effects of climate change. The primary objective of this study is to create a flood susceptibility map using AHP, GIS, and Remote Sensing techniques. The flood hazard map was constructed using seven important causative factors, where elevation (32 %) is the most influential in creating flood hazards, followed by slope (22 %) and drainage density (14 %). The flood hazard map shows that 10.30 % area is very highly hazardous, 22.20 % is in high, 30.45 % is moderate, 26.06 % is low, and 10.99 % area is in very low hazard zone in the study area. The flood vulnerability map was developed using four key factors: population density, distance from roads, land use/land cover (LULC), and NDVI, with population density emerging as the most influential factor, contributing 45 % to the overall vulnerability assessment. The map indicates that 30 % of the area is classified as very high, 23 % as high, 22 % as moderate, 17 % as low, and 9 % as very low vulnerability. Likewise, the flood hazard and vulnerability maps were overlaid to construct a flood risk map. In the final AHP-GIS flood risk map, 10 % of regions were classified as very high risk, 22 % as high risk, 28 % as moderate risk, 24 % as low risk, and 16 % as very low risk. The information contained in these maps will be beneficial to decision-makers in implementing flood-mitigation policies in priority areas of sustainable development, as well as in preventing and managing floods in the coastal belt of Bangladesh. Further analysis, which includes data on population and building density, proximity to nature, and economic and social activities, will enable the enhancement of sustainability in addition to this study.
{"title":"Geospatial flood susceptibility modelling using analytical hierarchy process: A case study in the south-central coastal region of Bangladesh","authors":"Irteja Hasan , Md Mahmudul Hasan Rakib , Dhiman Kumer Roy , Mehedi Hasan Ovi , Md. Fuad Hasan , Md. Sagirul Islam Majumder","doi":"10.1016/j.geogeo.2025.100457","DOIUrl":"10.1016/j.geogeo.2025.100457","url":null,"abstract":"<div><div>The Patuakhali region is situated in the coastal area of Bangladesh and is bordered by major rivers, which are extremely vulnerable to foreseeable flooding disasters due to the detrimental effects of climate change. The primary objective of this study is to create a flood susceptibility map using AHP, GIS, and Remote Sensing techniques. The flood hazard map was constructed using seven important causative factors, where elevation (32 %) is the most influential in creating flood hazards, followed by slope (22 %) and drainage density (14 %). The flood hazard map shows that 10.30 % area is very highly hazardous, 22.20 % is in high, 30.45 % is moderate, 26.06 % is low, and 10.99 % area is in very low hazard zone in the study area. The flood vulnerability map was developed using four key factors: population density, distance from roads, land use/land cover (LULC), and NDVI, with population density emerging as the most influential factor, contributing 45 % to the overall vulnerability assessment. The map indicates that 30 % of the area is classified as very high, 23 % as high, 22 % as moderate, 17 % as low, and 9 % as very low vulnerability. Likewise, the flood hazard and vulnerability maps were overlaid to construct a flood risk map. In the final AHP-GIS flood risk map, 10 % of regions were classified as very high risk, 22 % as high risk, 28 % as moderate risk, 24 % as low risk, and 16 % as very low risk. The information contained in these maps will be beneficial to decision-makers in implementing flood-mitigation policies in priority areas of sustainable development, as well as in preventing and managing floods in the coastal belt of Bangladesh. Further analysis, which includes data on population and building density, proximity to nature, and economic and social activities, will enable the enhancement of sustainability in addition to this study.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100457"},"PeriodicalIF":0.0,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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