Physics and Chemistry of the Earth最新文献

{"title":"Modeling subsurface geotechnical integrity via interpolated resistivity–chargeability and SPT datasets with machine learning: A case study from Perak, Malaysia","authors":"Gabriel Abraham Bala ,&nbsp;Andy Anderson Bery ,&nbsp;Mbuotidem David Dick ,&nbsp;Adedibu Sunny Akingboye ,&nbsp;Mfoniso Udofia Aka ,&nbsp;Joseph Gnapragasan ,&nbsp;Nsidibe Ndarake Okonna ,&nbsp;Yeshua Elijah","doi":"10.1016/j.pce.2025.104093","DOIUrl":"10.1016/j.pce.2025.104093","url":null,"abstract":"<div><div>Accurate subsurface assessment is critical for ensuring the integrity and longevity of engineered structures, especially in weathered terrains characterized by highly variable soil and rock properties. This challenge is particularly evident in the complex granitic terrain of Ipoh, Perak, Malaysia, where differential weathering and fracturing introduce substantial uncertainty into foundation design. Despite increasing demands for resilient infrastructure, conventional site investigation methods often fall short in capturing the spatial and lithological heterogeneity required for informed decision-making. This study addresses these limitations by integrating electrical resistivity tomography (ERT), induced polarization (IP), standard penetration testing (SPT), and supervised machine learning (ML) algorithms to enhance subsurface characterization and predictive modeling of chargeability. The combined ERT–IP inversion results, supported by borehole logs and SPT data, delineated four distinct lithological units across the study area. Four ML algorithms—SLR, KNN, SVM, and CatBoost—were trained to model relationships between geophysical and geotechnical parameters, with all achieving strong performance (training R² &gt; 0.90; error metrics &lt;10 %). Among all the evaluated models, CatBoost exhibited the strongest overall performance, achieving high predictive accuracy and maintaining consistent generalization across validation and test sets, although with mild overfitting observed. Among all the evaluated models, CatBoost exhibited the strongest overall performance, achieving high predictive accuracy and maintaining consistent generalization across validation and test sets, although with mild overfitting observed. From a geotechnical perspective, the topsoil/residual and highly weathered/fractured units were deemed unsuitable for heavy structural loads due to poor consolidation and water retention. In contrast, the relatively weathered bedrock unit, defined by resistivity values of 800 to &gt;1000 Ωm and chargeability &gt;18 msec, was identified as a suitable foundation material after appropriate soil and rock modifications. This research introduces a novel, noninvasive geophysical–geotechnical framework enhanced by ML, offering a cost-effective and scalable approach for subsurface evaluation. The methodology significantly reduces uncertainty in engineering assessments and supports safer, data-driven construction decisions, with potential applicability to other complex weathered terrains, subject to site-specific calibration.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"141 ","pages":"Article 104093"},"PeriodicalIF":4.1,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogeophysical assessment of the Quaternary aquifer in Northwestern Hafit mountain, Al Ain, UAE","authors":"Amir Gabr ,&nbsp;Abdulaziz Alazzani ,&nbsp;Alaa Ahmed","doi":"10.1016/j.pce.2025.104098","DOIUrl":"10.1016/j.pce.2025.104098","url":null,"abstract":"<div><div>This study examines the geophysical and hydrogeological features of the Quaternary Aquifer System in Al Ain area of the United Arab Emirates (UAE). The study aims to achieve three main objectives: first, to investigate the geophysical properties of the Quaternary Aquifer System within the study area, which includes defining the aquifer's extent, measuring the thickness of the overburden, and analysing the underlying bedrock through the electrical resistivity methods; second, to explore the hydrogeological and hydrogeochemical characteristics of the groundwater in the Quaternary Aquifer System to assess groundwater patterns; and third, to evaluate the hydraulic properties of the aquifer through field measurements, which will present critical insights into its water-bearing capacity, sustainability, and potential for use. To address these objectives, six Electrical Resistivity Tomography (ERT) surveys and three Vertical Electrical Sounding (VES) surveys were conducted at selected sites, based on field accessibility. These geophysical methods were integrated with hydrogeological data collected from existing wells to assess the characteristics of the Quaternary aquifer. The ERT and VES results revealed a promising potential conductive layer at depths between 10 and 90 m with resistivity values of 10–100 Ohm.m. Control wells (Well 2, Well 4, and Well 7) near VES sites confirm the water aquifer zone within this depth range, with water depths measured at 14 m, 11 m, and 7 m, respectively. In addition, the key hydro-geophysical parameters, including hydraulic conductivity (K) and transmissivity (T), were estimated. Hydraulic conductivity values ranged from 1.62 to 4.1 m/day, while average transmissivity values varied between 105.3 and 200.2 m²/day. These ranges suggest the presence of relatively permeable aquifers composed mainly of coarse sand or fine gravel, as well as highly productive aquifers associated with weathered sedimentary formations, often linked to coarse sediments (e.g., sand, gravel) or karstified bedrock. In conclusion, the findings of this study enhance our understanding of the Quaternary Aquifer System in the Al Ain area and provide a solid foundation for informed, sustainable water resource management and environmental protection. By identifying the aquifer extent, geometry and hydraulic properties, stakeholders can make decisions that promote sustainable usage of the water resources. Given the increasing demand for freshwater in hyper-arid and arid regions, it is essential to integrate these insights into management practices to secure long-term water sustainability and meet community needs. This study also offers valuable baseline data for future research and monitoring efforts, stressing the current and ongoing need for scientific investigation to ensure effective groundwater management in the study area.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"141 ","pages":"Article 104098"},"PeriodicalIF":4.1,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The operation of spatially dependent dispersion coefficients for contaminant transport through the river reaches","authors":"Jafar Chabokpour ,&nbsp;Amir Samadi","doi":"10.1016/j.pce.2025.104100","DOIUrl":"10.1016/j.pce.2025.104100","url":null,"abstract":"<div><div>The conventional advection-dispersion equation (ADE) with constant coefficients often fails to capture the spatial variability that characterizes flow velocity and dispersion in river systems, thus necessitating the use of models with spatially variable coefficients (SVC-ADE). This study proposes a new analytical solution for the SVC-ADE that successfully fills the current void in modeling sudden pollutant releases with linear velocity (u = k₁ x) and quadratic dispersion (D = k₂ x²) variation. Through Laplace transform and variable transformation techniques, the solution was verified with Conococheague Creek field data. The effects of coefficients (k₁, k₂, k, C₀) on breakthrough curve (BC) shapes were explored with similarities to classical ADE but with greater accuracy for spatial variability. Spatial moments decreased exponentially, and temporal moments increased as power functions with distance, while dispersivity increased linearly and maximum concentration decreased nonlinearly. Nonlinear relationships were established between SVC-ADE and conventional ADE parameters. Model performance (RMSE = 0.038–0.045 ppm, DC = 0.93) confirms its utility for environmental management.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"141 ","pages":"Article 104100"},"PeriodicalIF":4.1,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rare earth elements geochemistry, mineral hosts and recovery potential from Singrauli coalfield, India","authors":"P. Gopinathan ,&nbsp;Amit Karmakar ,&nbsp;Kanishk Kumar Karan ,&nbsp;Om Prakash Kumar ,&nbsp;Prabal Boral ,&nbsp;Sanjay Kumar Thakur ,&nbsp;Saroj Kumar ,&nbsp;Vivek Singh ,&nbsp;Priya Kumari ,&nbsp;Arshi Perween ,&nbsp;Jyoti Sharma ,&nbsp;Abhishek Mahato ,&nbsp;Gaurav Raghuvanshi ,&nbsp;Madhu Jha ,&nbsp;Ashish K. Ghosh ,&nbsp;Pradip K. Banerjee","doi":"10.1016/j.pce.2025.104101","DOIUrl":"10.1016/j.pce.2025.104101","url":null,"abstract":"<div><div>The geochemical behavior and mineralogical associations of critical and rare earth elements plus yttrium (REY) in the Singrauli Coalfield, India, were investigated. Representative samples were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray fluorescence (XRF) to determine REY concentrations and their correlations with major oxides (SiO₂, Al₂O₃, Fe₂O₃). Total REY concentrations ranged from 79 to 136 ppm (coal basis), with Ce, Nd, and La being the most abundant. Critical REY, such as Nd and Y, exceeded global averages for coal. Light rare earth elements (LREEs: La, Ce, Nd) showed strong positive correlations with SiO₂ and Al₂O₃. Scandium also displayed a high affinity for alumino-silicate phases, consistent with its known geochemistry. In contrast, heavy rare earth elements (HREEs: Lu, Yb) correlated positively with Fe₂O₃, suggesting incorporation into iron-bearing minerals like hematite or goethite. Erbium exhibited a distinct pattern, with a strong positive correlation to Al₂O₃ and a pronounced negative correlation with Fe₂O₃, potentially due to redox-sensitive fractionation. Field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy (FE-SEM-EDX) of coal ash revealed REY (Ce, Nd) within glassy Si–Al–P phases. Higher-magnification observations identified ferromanganese minerals, zirconium silicates, and potential monazite or xenotime associations. The study concludes that the distribution and host phases of REY in the Singrauli Coalfield, particularly from the Krishnashilla and Kakri mines, indicate significant potential for secondary recovery.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"141 ","pages":"Article 104101"},"PeriodicalIF":4.1,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unlocking water sustainability by addressing SDG 6: Macrophyte-based wastewater treatment for agricultural irrigation in Pakistan","authors":"Asim Qayyum Butt ,&nbsp;Ghulam Yaseen ,&nbsp;Allah Bachaya ,&nbsp;Abid Latif","doi":"10.1016/j.pce.2025.104099","DOIUrl":"10.1016/j.pce.2025.104099","url":null,"abstract":"<div><div>Pakistan's agriculture, a cornerstone of food security and economic stability, faces severe water scarcity, necessitating sustainable wastewater treatment for irrigation reuse. This study evaluates a small-scale Waste Stabilization Pond (WSP) using <em>Azolla pinnata</em> to treat municipal wastewater in Agha Pora, Multan, aligning with Sustainable Development Goal 6 (SDG 6) for clean water and sanitation. Wastewater parameters—Electrical Conductivity (ECw), Total Dissolved Solids (TDS), Sodium Absorption Ratio (SAR), sodium, chloride, boron, nitrate, bicarbonate, pH, and fecal coliforms—were measured across Hydraulic Retention Times (HRTs) of 3, 5, 7, and 10 days. After 10 days HRT, significant reductions were achieved: ECw (32.2 %), TDS (32.2 %), SAR (42.3 %), sodium (29.9 %), chloride (23.2 %), boron (33.3 %), nitrate (30.9 %), bicarbonate (49.0 %), pH (20.0 %), and fecal coliforms (41.3 %), meeting FAO Irrigation Water Quality Guidelines for restricted irrigation. These findings address gaps in species-specific (<em>Azolla pinnata</em>), region-specific (Pakistan), and HRT optimization research. The low-cost, low-maintenance WSP system offers a scalable solution for wastewater management in developing nations, supporting safe irrigation and freshwater conservation. However, single-location and single-species limitations suggest multi-site, multi-species trials to enhance scalability and broader applicability.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"141 ","pages":"Article 104099"},"PeriodicalIF":4.1,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of water quality in lowland Ramsar Wetlands: Insights on hydrochemistry analysis-sustainable development goals nexus","authors":"Barsha Khanal ,&nbsp;Ahmed M. Saqr ,&nbsp;Lalit Pathak ,&nbsp;Anueva Acharya ,&nbsp;Prekshya Subedi ,&nbsp;Mahesh Prasad Awasthi ,&nbsp;Charan Bhattarai ,&nbsp;Kiran Bishwakarma ,&nbsp;Khadka Bahadur Pal ,&nbsp;Lal B. Thapa ,&nbsp;Ramesh Raj Pant","doi":"10.1016/j.pce.2025.104097","DOIUrl":"10.1016/j.pce.2025.104097","url":null,"abstract":"<div><div>Wetlands are increasingly threatened by human activities and climate change globally. This study provides the first comprehensive assessment of water quality in Nepal's lowland riparian Ramsar wetlands. It focuses on Jagadishpur Reservoir (JR) and Nakrori Lake (NL), chosen for their ecological significance and contrasting artificial and natural features. The research examines seasonal water quality changes, identifies key hydrochemical processes, and evaluates suitability for drinking and irrigation. During pre- and post-monsoon periods, 156 water samples were collected from both lakes. Samples were analyzed for physicochemical parameters, including total dissolved solids (TDS), and major ions (Ca²⁺, Mg²⁺, HCO₃⁻), using standardized laboratory techniques. Statistical analyses and hydrochemical diagrams, such as Piper and Gibbs plots, revealed that both lakes exhibited similar physicochemical profiles. Ca²⁺-HCO₃^- was the dominant water type, indicating that carbonate and silicate weathering, along with cation-anion exchange, were key determinants of water chemistry. TDS levels averaged 182.7 mg/L in NL pre-monsoon and declined to 154.3 mg/L in JR post-monsoon, reflecting the effects of evaporation and monsoonal dilution. Water quality consistently met standards for both drinking and irrigation, with water quality index (WQI) and Sodium adsorption ratio (SAR) &lt; 50 and 10, respectively. These findings underscore the challenges in maintaining standard water quality and highlight the implementation of a sustainable action plan (SAP) that advances Sustainable Development Goal (SDG) 6 by 25 % and SDG 13 by 40 % through targeted pollution mitigation and climate resilience measures. This research can provide a transferable framework for wetland conservation and policy development in similar ecosystems worldwide.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"141 ","pages":"Article 104097"},"PeriodicalIF":4.1,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physicochemical investigation of groundwater within the confinement of Sargodha city and remediation pathways for contaminants","authors":"Irum Fatima ,&nbsp;Asadullah Dawood ,&nbsp;Abdul Muneeb Khan ,&nbsp;Sumayya Kanwal ,&nbsp;Zainab Bibi ,&nbsp;Akbar Hussain","doi":"10.1016/j.pce.2025.104074","DOIUrl":"10.1016/j.pce.2025.104074","url":null,"abstract":"<div><div>Groundwater contamination in Sargodha city is a significant concern, with organic, inorganic, radioactive, and biological contaminants that pose critical challenges to public health and water security. The study focuses on investigating the physicochemical properties of the groundwater in Sargodha city to identify and address pollutants affecting the groundwater quality, covering a large spatial region for accurate assessment. For this study, groundwater was collected from 35 locations in Sargodha city in the dry season. The analysis of which displayed extreme mineralization, with high electrical conductivity, EC (mean 11,052.68 μS/cm) and extreme total hardness, TH (mean 757.40 mg/L), critical oxygen depletion with dissolved oxygen, DO (mean 2.87 mg/L) and highly alkaline conditions due to high pH (mean 7.54) and elevated total alkalinity, TA (mean 202.66 mg/L), and large amount of organic matter evident from the coexisting high turbidity (mean 3.74 NTU). The water quality index (WQI) evaluation reveals nuanced groundwater quality risks, with 28.6 % of the water unsuitable for drinking, 28.6 % in very poor condition, 37.1 % in poor condition, and only the remaining 5.7 % in good condition; however, no groundwater has an excellent quality status. This deterioration pattern of groundwater quality strongly correlates with urbanization and industrial zones, indicating clear anthropogenic contamination routes. The water quality issues in the city need to be further researched to understand the root cause, and decisive actions could be taken to solve them.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"141 ","pages":"Article 104074"},"PeriodicalIF":4.1,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145019308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal variability of football pitch surface properties under meteorological influences: A case study of Kasımpaşa Stadium","authors":"Kadir Gezici ,&nbsp;Erdal Kesgin ,&nbsp;Onur Harun Kamış ,&nbsp;Remziye Ilayda Tan Kesgin","doi":"10.1016/j.pce.2025.104076","DOIUrl":"10.1016/j.pce.2025.104076","url":null,"abstract":"<div><div>Understanding the effects of game traffic, field design, and meteorological variables on the hydrological and mechanical parameters of sports field surfaces is essential for creating quality fields that minimize surface-related injuries, and fulfill game requirements. In the presented study, it is aimed to assess six performance parameters (surface temperature, hardness, surface traction, turf coverage, root length, and rootzone soil moisture) measured in Kasımpasa Stadium, which is located in Istanbul and hosts Türkiye's Super League matches, over a 15-month period (August 2021–October 2022). The relationships between the relevant parameters and meteorological variables such as ambient temperature, total precipitation height, sunshine duration, and global solar radiation were also examined. Significant temporal variations were observed, whereas spatial differences across various points of the pitch were relatively minor. Surface temperature levels remained within acceptable ranges to prevent skin burns and injuries. Surface hardness was classified as a hard surface only in June-22, as a soft surface in April-22 and May-22 and was optimal during the remaining periods. A Spearman correlation analysis was conducted to reveal the pairwise relationships between the variables. Meteorological parameters, particularly ambient temperature, had a significant influence on surface temperature (r = 0.84), traction (r = 0.68), and root length (r = 0.73). This study provides a comprehensive evaluation of performance and quality monitoring in sports fields. Stadium location and design, especially sun exposure and its duration, are crucial for meeting the mechanical and hydrological requirements of field surfaces, maintaining game standards, and ensuring player safety.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"141 ","pages":"Article 104076"},"PeriodicalIF":4.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144988871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impacts of Landuse/Landcover change on groundwater recharge potential of the Lusaka Aquifer system using Fuzzy-AHP","authors":"Muumbe K. Lweendo ,&nbsp;Benjamin Mapani ,&nbsp;Kawawa Banda ,&nbsp;Samuel Adelabu ,&nbsp;Christoph Külls","doi":"10.1016/j.pce.2025.104073","DOIUrl":"10.1016/j.pce.2025.104073","url":null,"abstract":"<div><div>Landcover transformations exert pressure on aquifer systems by disrupting natural recharge, yet the extent of these impacts remain poorly understood. This study investigated impacts of land use and land cover (LULC) change on groundwater recharge potential zones (GRPZ) on the Lusaka Aquifer System. Geospatial techniques were combined with multi-criteria decision analysis to delineate GRPZs for the years 1990–2022 with seven thematic layers. Results indicated that built-up areas expanded significantly from 70.13 km² to 652.60 km² (<strong>830.49 %)</strong> while forest and cropland declined by 593.81 <span><math><mrow><msup><mtext>km</mtext><mn>2</mn></msup></mrow></math></span> (67.10 %) and 258.65 <span><math><mrow><msup><mtext>km</mtext><mn>2</mn></msup></mrow></math></span> (33.54 %) respectively. The transition matrix showed that built-up areas had a gain of 25.26 % of the total study area, largely sourced from cropland (10.37 %), forest (8.13 %), and vegetation (5.55 %). Forest cover underwent notable transformations with a loss of 25.75 %. Cropland exhibited the highest degree of persistence, with 11.19 % remaining unchanged. The areal coverage of GRPZ showed that low and moderate recharge zones increased by 134.21 km² (27.17 %) and 39.14 km² (3.13 %) respectively. In contrast, high and very high zones declined by 164.90 km² (33.33 %) and 8.47 km² (74.48 %). Analysis of built-up area expansion on GRPZs revealed notable encroachments on low, moderate and high recharge zones by 127.28 km², 332.02 km² and 106.65 km² respectively. This study highlights the ongoing shifts in recharge potential areas driven by urbanization, indicating a continued trend that increases the risk of reduced aquifer recharge and long-term groundwater depletion. The spatial overlap between built-up expansion and recharge potential zones indicates a disconnect between LULC change and groundwater management.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"141 ","pages":"Article 104073"},"PeriodicalIF":4.1,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Earth observation-based analysis of flood extent and impacts on land use and cover in the Cape Town Metropolitan Region, South Africa","authors":"Sibuyisele S. Pakati ,&nbsp;Cletah Shoko ,&nbsp;Timothy Dube","doi":"10.1016/j.pce.2025.104082","DOIUrl":"10.1016/j.pce.2025.104082","url":null,"abstract":"<div><div>This work leverages multi-source data spatial approach in mapping floods extents and their effect on key land use land cover in the Cape Town Metropolitan Region, for the 2023 period. Using the Google Earth Engine cloud computing platform, the study mapped flood extent through Sentinel-1 Synthetic Aperture Radar (SAR), and Sentinel 2- Multispectral Instrument (MSI) for landcover classification before and after a flood event. Landcover classification for the period before and after the flood occurrence were performed using the Random Forest (RF) algorithm. To assess the flood-affected categories, the pre-flood image was overlaid on the flood extent spatial layer. The research findings showed that the central and low-lying areas of the Metropolitan area were significantly affected by the floods. A total land area of about 2074 ha(ha) (84.30 %) was affected. Further results showed that floods mostly affected bare areas (32.64 % equivalent to 803.05 ha) and built-up (46.84 % equivalent to 1152.33 ha) areas. The affected built-up areas were mainly located in low-lying regions, near floodplains, and near water bodies. Overall, the findings of the study underscore the importance of spatially explicit techniques in flood mapping and informing early warning systems for disaster preparedness.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"141 ","pages":"Article 104082"},"PeriodicalIF":4.1,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144996829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}