Hydrology

30 pages, 6041 KiB

Open AccessReview

Global Perspectives on Groundwater Decontamination: Advances and Challenges of the Role of Permeable Reactive Barriers

by Graciela Cecilia Sánchez Hidalgo, Jessie Ábrego-Bonilla, Euclides Deago and Maria De Los Angeles Ortega Del Rosario

Hydrology 2025, 12(4), 98; https://doi.org/10.3390/hydrology12040098 - 21 Apr 2025

Viewed by 174

Abstract

Ensuring access to clean water for drinking, agriculture, and recreational activities remains a global challenge. Groundwater, supplying approximately 50% of domestic water and 40% of agricultural irrigation, faces increasing threats from climate change, population growth, and unsustainable agricultural practices. These factors contribute to [...] Read more.

Ensuring access to clean water for drinking, agriculture, and recreational activities remains a global challenge. Groundwater, supplying approximately 50% of domestic water and 40% of agricultural irrigation, faces increasing threats from climate change, population growth, and unsustainable agricultural practices. These factors contribute to groundwater contamination, notably nitrate pollution resulting from excessive fertilizer use, which poses risks to water quality and public health. Addressing this issue demands innovative, efficient, and sustainable remediation technologies. Permeable reactive barriers (PRBs) have emerged as promising solutions for in situ groundwater treatment, using reactive media to transform contaminants into less toxic forms. PRBs offer advantages like low energy consumption and minimal maintenance. This study uses bibliometric analysis to explore the scientific production of PRBs for nitrate remediation, revealing research trends, key focus areas, and significant contributions. It included 141 articles published from 1975 to 2023. Early research focused on basic mechanisms and materials like zero-valent iron (ZVI), while recent studies emphasize sustainability and cost-effectiveness using low-cost materials such as agricultural byproducts. The findings highlight a growing focus on the circular economy and the need for more in situ studies to assess PRB performance under varying conditions. PRBs show significant potential for enhancing groundwater management and long-term water quality in agricultural contexts. Full article

(This article belongs to the Special Issue Groundwater Pollution: Sources, Mechanisms, and Prevention (Second Edition))

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25 pages, 14713 KiB

Open AccessReview

From Flood Mitigation to Environmental and Socioeconomic Disruption: A Case Study of the Langue de Barbarie Sand Spit Breach

by Souleymane Fall

Hydrology 2025, 12(4), 97; https://doi.org/10.3390/hydrology12040097 - 19 Apr 2025

Viewed by 223

Abstract

In October 2003, an artificial canal was dug across the Langue de Barbarie sand spit at the mouth of the Senegal River to prevent the city of Saint-Louis (Senegal) from being submerged by floods. This study aimed to explore the multiple facets of [...] Read more.

In October 2003, an artificial canal was dug across the Langue de Barbarie sand spit at the mouth of the Senegal River to prevent the city of Saint-Louis (Senegal) from being submerged by floods. This study aimed to explore the multiple facets of this sudden environmental change to provide a holistic overview of the situation and a better understanding of man-made alterations of coastal features, a crucial step for implementing efficient management of such situations and developing appropriate mitigation and adaptation policies. Satellite imagery from the US Geological Survey was used to show the historical evolution of the breach, and a comprehensive overview of the existing literature was conducted to explore its hydrological, geomorphological, ecological, and socioeconomic impacts. Although the canal facilitated the rapid evacuation of floodwaters and saved the city from a major flooding event, the breach widened considerably, becoming the new river mouth and resulted in unforeseen adverse consequences. Environmental consequences included the partial dismantling of the spit, increased tidal range, salinization of land and water, and loss of habitat and local biodiversity. Socioeconomic consequences were severe, including the loss of agricultural land and reduced yields, declining fishing productivity, the destruction of villages, the displacement of entire communities, and the forced migration of many young people. Affected communities developed resilience strategies, with women playing a leading role in these adaptive responses. This study highlights the need for integrated coastal management and policies that consider both environmental and human factors, as well as for future research that will help improve the management of coastal ecosystem alterations. Full article

(This article belongs to the Section Water Resources and Risk Management)

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14 pages, 4599 KiB

Open AccessArticle

Towards a Classification of Tunisian Dams for Enhanced Water Scarcity Governance: Parametric or Non-Parametric Approaches?

by Safouane Mouelhi, Sabri Kanzari, Sana Ben Mariem and Nesrine Zemni

Hydrology 2025, 12(4), 96; https://doi.org/10.3390/hydrology12040096 - 18 Apr 2025

Viewed by 173

Abstract

Classifying dams is important to ensure proper management, safety, and maintenance based on their size, purpose, and risk level. This helps in planning for emergency responses, structural inspections, and efficient water resource utilization. This study used the analysis of variance (ANOVA) technique to [...] Read more.

Classifying dams is important to ensure proper management, safety, and maintenance based on their size, purpose, and risk level. This helps in planning for emergency responses, structural inspections, and efficient water resource utilization. This study used the analysis of variance (ANOVA) technique to categorize the main Tunisian dams according to their precipitation to potential evapotranspiration (P/PET) ratio. The data were obtained from the NASA POWER platform, with potential evapotranspiration estimated using the Oudin model. Despite the violation of the normality assumption, the robustness of the ANOVA test for classification purposes remained unaffected. A comparison between Duncan’s test (parametric) and the Kruskal–Wallis test (non-parametric) revealed similar class structures, although Duncan’s test provided greater precision. The analysis identified four primary dam classes, reflecting regional differences in water availability and evaporative demand, and included dams in north-west Tunisia, considered the ‘water tower’ of the country, and those in semi-arid and arid regions. Full article

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23 pages, 1120 KiB

Open AccessReview

Leaky Dams as Nature-Based Solutions in Flood Management Part I: Introduction and Comparative Efficacy with Conventional Flood Control Infrastructure

by Umanda Hansamali, Randika K. Makumbura, Upaka Rathnayake, Hazi Md. Azamathulla and Nitin Muttil

Hydrology 2025, 12(4), 95; https://doi.org/10.3390/hydrology12040095 - 17 Apr 2025

Viewed by 537

Abstract

Natural flood management strategies are increasingly recognized as sustainable alternatives to conventional engineered flood control measures. Among these, leaky dams, also known as woody debris dams or log dams, have emerged as effective nature-based solutions for mitigating flood risks while preserving essential ecosystem [...] Read more.

Natural flood management strategies are increasingly recognized as sustainable alternatives to conventional engineered flood control measures. Among these, leaky dams, also known as woody debris dams or log dams, have emerged as effective nature-based solutions for mitigating flood risks while preserving essential ecosystem services. This review traces the historical evolution of leaky dams from ancient water management practices to contemporary applications, highlighting their development and adaptation over time. It presents a comparative examination of leaky dams and conventional flood control structures, outlining their respective strengths and limitations across ecological, hydrological, and economic dimensions. The review also introduces a conceptual classification of leaky dams into naturally occurring, engineered, hybrid, and movable systems, showing how each form aligns with varying catchment characteristics and management objectives. By synthesizing foundational knowledge and strategic insights, this paper establishes a theoretical and contextual framework for understanding leaky dams as distinct yet complementary tools in integrated flood management, laying the groundwork for further technical evaluations. The findings offer valuable insights for end users by highlighting the potential of leaky dams as integral components of sustainable flood management systems, elucidating their roles in mitigating flood risks, enhancing water retention, and supporting ecosystem resilience. Full article

(This article belongs to the Special Issue Advances in Nature-Based Solutions for Hydrometeorological Risk Reduction)

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27 pages, 3344 KiB

Open AccessArticle

Runoff Variations and Quantitative Analysis in the Qinghai Lake Basin Under Changing Environments

by Li Mo, Xinxiao Yu, Yonghan Feng and Tao Jiang

Hydrology 2025, 12(4), 94; https://doi.org/10.3390/hydrology12040094 - 17 Apr 2025

Viewed by 220

Abstract

This study examines runoff variations and their drivers in the Buha and Shaliu Rivers of the Qinghai Lake Basin (1960–2016), a key ecological area in China. Abrupt changes were detected using the Mann–Kendall and cumulative anomaly methods, while the Budyko framework attributed runoff [...] Read more.

This study examines runoff variations and their drivers in the Buha and Shaliu Rivers of the Qinghai Lake Basin (1960–2016), a key ecological area in China. Abrupt changes were detected using the Mann–Kendall and cumulative anomaly methods, while the Budyko framework attributed runoff variations to dominant factors. Correlation and grey relational analyses assessed multicollinearity, and a lake water balance model with climate elasticity theory quantified the effects of climate and land surface changes on runoff components and lake levels. Results indicate that the Buha River experienced an abrupt runoff change in 2004, while the Shaliu River exhibited a change beginning in 2003. Based on the trends and abrupt change points of each factor, the study period was divided into four segments: 1960–1993, 1994–2016, 1960–2003, and 2004–2016. The correlation coefficients are significantly different in different periods. The climate elasticity coefficients were as follows: P (precipitation), 1.98; ET₀ (potential evapotranspiration), −0.98; Rn (net radiation), 0.66; T (average temperature), 0.02; U₂ (wind speed at 2 m height), 0.16; RHU (relative umidity), −0.56. The elasticity coefficient of runoff with respect to precipitation is significantly higher than that for other climate variables. Net radiation and relative humidity contribute equally to runoff, while wind speed and temperature have relatively smaller effects. In the Qinghai Lake Basin, runoff is sensitive to precipitation (0.38), potential evapotranspiration (−0.07), and the underlying surface parameter ω (−98.32). Specifically, a 1 mm increase in precipitation raises runoff by 0.38 mm, while a 1 mm rise in potential evapotranspiration reduces it by 0.07 mm. A one-unit increase in ω leads to a significant runoff decrease of 98.32 mm. According to the lake water balance model, climate contributes 88.43% to groundwater runoff, while land surface changes contribute −11.57%. Climate change and land surface changes contribute 93.02% and 6.98%, respectively, to lake water levels. This study quantitatively evaluates the impacts of climate and land surface changes on runoff, providing insights for sustainable hydrological and ecological management in the Qinghai Lake Basin. Full article

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30 pages, 10990 KiB

Open AccessArticle

Numerical Modeling of the Concentration of Microplastics in Lakes and Rivers in Kazakhstan

by Natalya S. Salikova, María-Elena Rodrigo-Clavero, Lyudmila A. Makeyeva, Zinep M. Shaimerdenova and Javier Rodrigo-Ilarri

Hydrology 2025, 12(4), 93; https://doi.org/10.3390/hydrology12040093 - 16 Apr 2025

Viewed by 134

Abstract

This research presents a detailed numerical modeling study focused on estimating the concentration of microplastics (MPs) in freshwater ecosystems. This research covers three lakes (Kopa, Zerendinskoye, and Borovoe) and the Yesil River, applying differential equations to model the spatial distribution and seasonal variations [...] Read more.

This research presents a detailed numerical modeling study focused on estimating the concentration of microplastics (MPs) in freshwater ecosystems. This research covers three lakes (Kopa, Zerendinskoye, and Borovoe) and the Yesil River, applying differential equations to model the spatial distribution and seasonal variations in MP concentrations. The methodology integrates field survey data collected during three different seasons (spring, summer, and autumn) from both sediment and water samples. The MP concentrations were found to follow an exponential decay pattern from the shore toward the center of the lakes, with higher concentrations near the shoreline. The modeling framework is calibrated using regression analysis, which provides the best-fit parameters for the distance–concentration curves. This study employs sensitivity analysis to justify the decay coefficient, resulting in a selected value of k = 0.09. Model performance is assessed using statistical metrics such as the root mean square error (RMSE) and the coefficient of determination (R²), ensuring accuracy in predicting MP concentrations across different environmental compartments. This work represents a novel contribution to the field by applying numerical modeling techniques to an understudied geographical area. The findings highlight significant seasonal and spatial variations in MP concentrations, emphasizing the need for comprehensive monitoring. This study’s results contribute valuable insights into the environmental behavior of MPs in freshwater systems and support efforts to develop effective management strategies to mitigate pollution. Full article

(This article belongs to the Special Issue Recent Research Advances in Microplastics in Water and the Environment)

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19 pages, 12753 KiB

Open AccessArticle

Impact Assessment of Floating Photovoltaic Systems on the Water Quality of Kremasta Lake, Greece

by Angeliki Mentzafou, Elias Dimitriou, Ioannis Karaouzas and Stamatis Zogaris

Hydrology 2025, 12(4), 92; https://doi.org/10.3390/hydrology12040092 - 16 Apr 2025

Viewed by 254

Abstract

Floating photovoltaic systems (FPV) are one of the emerging technologies that are able to support the “green” energy transition. In Greece, the environmental impact assessment of such projects is still under early development. The scope of the present study was to provide insights [...] Read more.

Floating photovoltaic systems (FPV) are one of the emerging technologies that are able to support the “green” energy transition. In Greece, the environmental impact assessment of such projects is still under early development. The scope of the present study was to provide insights into the potential impacts of a small-scale FPV system on the water quality of the oligotrophic Kremasta Lake, an artificial reservoir. For this reason, a hydrodynamic and water quality model was employed. The results showed that the water quality parameter variations were insignificant and limited only in the immediate area of the FPV construction and gradually disappeared toward the shoreline. Likewise, this variation was restricted to the first few meters of depth of the water column and was eliminated onwards. The water temperature slightly decreased only in the area of close proximity to the installation. Average annual dissolved oxygen, chlorophyll-a, and nutrient concentrations were predicted not to change considerably after the panels’ construction. FPV systems can provide an attractive alternative for energy production in artificial reservoirs, especially in regions of land use conflicts that are associated with land allocation for alternative energy development. Given the limited data on the long-term impact of such projects, robust monitoring programs are essential. These initiatives rely on public support, making collaboration between stakeholders and the local community crucial. Full article

(This article belongs to the Special Issue Novel Procedures and Methodologies for Surface and Underground Water Quality Analysis: Theory and Application)

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25 pages, 699 KiB

Open AccessReview

Leaky Dams as Nature-Based Solutions in Flood Management Part II: Mechanisms, Effectiveness, Environmental Impacts, Technical Challenges, and Emerging Trends

by Umanda Hansamali, Randika K. Makumbura, Upaka Rathnayake, Hazi Md. Azamathulla and Nitin Muttil

Hydrology 2025, 12(4), 91; https://doi.org/10.3390/hydrology12040091 - 16 Apr 2025

Viewed by 271

Abstract

Leaky dams have become essential nature-based solutions for flood management, providing sustainable alternatives to traditional engineered flood control methods. This review delves into the mechanisms by which leaky dams operate, including the regulation of water flow through velocity reduction and distribution across floodplains, [...] Read more.

Leaky dams have become essential nature-based solutions for flood management, providing sustainable alternatives to traditional engineered flood control methods. This review delves into the mechanisms by which leaky dams operate, including the regulation of water flow through velocity reduction and distribution across floodplains, effective sediment trapping and soil quality enhancement, and the facilitation of groundwater recharge and water table stabilization. These structures not only mitigate peak flood flows and reduce erosion but also contribute to enhanced biodiversity by creating diverse aquatic habitats and maintaining ecological connectivity. The effectiveness of leaky dams is assessed through various performance metrics, demonstrating significant reductions in peak flows, improved sediment management, and increased groundwater levels, which collectively enhance ecosystem resilience and water quality. However, the implementation of leaky dams presents several technical challenges, such as design complexity, hydrological variability, maintenance requirements, and socio-economic factors like land use conflicts and economic viability. Additionally, while leaky dams offer numerous environmental benefits, potential negative impacts include habitat disruption, sediment accumulation, and alterations in water quality, which necessitate careful planning and adaptive management strategies. Emerging trends in leaky dam development focus on the integration of smart technologies, such as real-time monitoring systems and artificial intelligence, to optimize performance and resilience against climate-induced extreme weather events. Advances in modeling and monitoring technologies are facilitating the effective design and implementation of leaky dam networks, promoting their incorporation into comprehensive watershed management frameworks. This review highlights the significant potential of leaky dams as integral components of sustainable flood management systems, advocating for their broader adoption alongside conventional engineering solutions to achieve resilient and ecologically balanced water management. Full article

(This article belongs to the Special Issue Advances in Nature-Based Solutions for Hydrometeorological Risk Reduction)

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24 pages, 3748 KiB

Open AccessArticle

Leveraging Recurrent Neural Networks for Flood Prediction and Assessment

by Elnaz Heidari, Vidya Samadi and Abdul A. Khan

Hydrology 2025, 12(4), 90; https://doi.org/10.3390/hydrology12040090 - 16 Apr 2025

Viewed by 282

Abstract

Recent progress in Artificial Intelligence and Machine Learning (AIML) has accelerated improvements in the prediction performance of many hydrological processes. Yet, flood prediction remains a challenging task due to its complex nature. Two common challenges afflicting the task are flood volatility and the [...] Read more.

Recent progress in Artificial Intelligence and Machine Learning (AIML) has accelerated improvements in the prediction performance of many hydrological processes. Yet, flood prediction remains a challenging task due to its complex nature. Two common challenges afflicting the task are flood volatility and the sensitivity and complexity of flood generation attributes. This study explores the application of Recurrent Neural Networks (RNNs)—specifically Vanilla Recurrent Neural Networks (VRNNs), Long Short-Term Memory (LSTM), and Gated Recurrent Unit (GRU)—in flood prediction and assessment. By integrating catchment-specific hydrological and meteorological variables, the RNN models leverage sequential data processing to capture the temporal dynamics and seasonal patterns characteristic of flooding. These models were employed across diverse terrains, including mountainous watersheds in the state of South Carolina, USA, to examine their robustness and adaptability. To identify significant hydrological events for flash flood analysis, a discharge frequency analysis was conducted using the Pearson Type III distribution. The 1-year and 2-year return period flows were estimated based on this analysis, and the 1-year return flow was selected as a conservative threshold for flash flood event identification to ensure a sufficient number of training instances. Comparative benchmarking with the National Water Model (NWM v3.0) revealed that the RNN-based approaches offer notable enhancements in capturing the intensity and timing of flood events, particularly for short-duration and high-magnitude floods (flash floods). Comparison of predicted disharges with the discharge recorded at the gauges revealed that GRU had the best performance as it achieved the highest mean NSE values and exhibited low variability across diverse watersheds. LSTM results were slightly less consistent compared to the GRU albeit achieving satisfactory performance, proving its value in hydrological forecasting. In contrast, VRNN had the highest variability and the lowest NSE values among the three. The NWM model trailed the machine learning-based models. The study highlights the efficacy of the RNN models in advancing hydrological predictions. Full article

(This article belongs to the Section Water Resources and Risk Management)

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22 pages, 4147 KiB

Open AccessArticle

Evaluation of the Extreme Precipitation and Runoff Flow Characteristics in a Semiarid Sub-Basin Based on Three Satellite Precipitation Products

by Rosalía López Barraza, María Teresa Alarcón Herrera, Ana Elizabeth Marín Celestino, Armando Daniel Blanco Jáquez and Diego Armando Martínez Cruz

Hydrology 2025, 12(4), 89; https://doi.org/10.3390/hydrology12040089 - 15 Apr 2025

Viewed by 249

Abstract

In this study, we analyzed the suitability of using the CHIRPS, CMORPH and TRMM platforms in monitoring extreme precipitation events, precipitation–runoff relationships, and seasonal/year-to-year variability in the Saltito semiarid sub-basin in the Mexican state of Durango. Satellite precipitation products (SPP) in 16 sites [...] Read more.

In this study, we analyzed the suitability of using the CHIRPS, CMORPH and TRMM platforms in monitoring extreme precipitation events, precipitation–runoff relationships, and seasonal/year-to-year variability in the Saltito semiarid sub-basin in the Mexican state of Durango. Satellite precipitation products (SPP) in 16 sites were contrasted point to point with data from rainfall gauge stations and with a daily temporal resolution for the period of four years (2015–2019). Using this information, we constructed Rx1d, Rx2d, R25mm, and RR95 extreme rainfall indices. For the precipitation–runoff relationships, a runoff model based on the Storm Water Management Model (SWMM) was calibrated and validated with gauge data, and we obtained the Qx1d, Qx2d, and Qx3d runoff indices. We used the bias volume (%), MSE, correlation coefficient, and median bias to evaluate the ability of satellite products to detect and analyze extreme precipitation and run flow events. Although these sensors tend to overestimate both precipitation levels and the occurrence of extreme precipitation events, their high spatial and temporal resolutions make them a reliable tool for the analysis of trends in climate change indices. As a result, they serve as a useful resource in evaluating the intensity of climate change in the region, particularly in terms of precipitation patterns. They also allow hydrological modeling and the observation of precipitation–runoff relationships. This is relevant in the absence of precipitation and hydrometric information, which is usually common in vast regions of the developing world. Full article

(This article belongs to the Section Hydrological Measurements and Instrumentation)

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16 pages, 7443 KiB

Open AccessArticle

Identification and Temporal Distribution of Typical Rainfall Types Based on K-Means++ Clustering and Probability Distribution Analysis

by Qiting Zhang and Jinglin Qian

Hydrology 2025, 12(4), 88; https://doi.org/10.3390/hydrology12040088 - 14 Apr 2025

Viewed by 191

Abstract

Characterizing rainfall events with recurrence periods of 1–5 years is crucial for urban flood risk assessment and water management system design. Traditional hydrological frequency analysis methods inadequately describe the temporal structure and intensity distribution of rainfall. In this study, we analyzed 1580 independent [...] Read more.

Characterizing rainfall events with recurrence periods of 1–5 years is crucial for urban flood risk assessment and water management system design. Traditional hydrological frequency analysis methods inadequately describe the temporal structure and intensity distribution of rainfall. In this study, we analyzed 1580 independent rainfall events in central Hangzhou (1950–2023) using PCA dimension reduction and K-means++ clustering to investigate typical rainfall types across different recurrence periods. The integrated approach effectively captures temporal characteristics while reducing dimensionality and improving clustering efficiency. Our results indicate that concentrated single-peak rainfall with short duration and a mid-to-late peak dominates the region, with longer recurrence periods exhibiting higher intensity, shorter duration, and greater temporal concentration. Furthermore, cumulative distribution function (CDF) and probability density function (PDF) analyses were conducted on these typical rainfall types, quantifying their distributional characteristics and yielding precise mathematical expressions. These standardized rainfall curves provide direct applications for engineering design and hydrological modeling, enabling more accurate flood prediction and mitigation strategies for Hangzhou’s urban infrastructure. Full article

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43 pages, 26833 KiB

Open AccessArticle

Estimation of Infiltration Parameters for Groundwater Augmentation in Cape Town, South Africa

by Kgomoangwato Paul Mavundla, John Okedi, Denis Kalumba and Neil Philip Armitage

Hydrology 2025, 12(4), 87; https://doi.org/10.3390/hydrology12040087 - 13 Apr 2025

Viewed by 336

Abstract

In early 2018, Cape Town, South Africa, experienced severe water shortages during the worst drought in nearly a century (2015–2017), underscoring the need to diversify water resources, including groundwater. This study evaluated infiltration rates and hydraulic properties of three representative stormwater ponds in [...] Read more.

In early 2018, Cape Town, South Africa, experienced severe water shortages during the worst drought in nearly a century (2015–2017), underscoring the need to diversify water resources, including groundwater. This study evaluated infiltration rates and hydraulic properties of three representative stormwater ponds in the Zeekoe Catchment, Cape Town, to assess their feasibility as recharge basins for transferring detained stormwater runoff into the underlying aquifer. Field infiltration data were analysed to estimate hydraulic properties, while laboratory permeability tests and material classification on 36 soil samples provided inputs for numerical modelling using HYDRUS 2-D software. Simulations estimated recharge rates and indicated wetting front movement from pond surfaces to the water table (~5.5 m depth) ranged between 15 and 140 h. The results revealed field hydraulic conductivity values of 0.3 to 19.9 cm/h, with laboratory estimates up to 103% higher due to controlled conditions. Simulated infiltration rates were 67–182% higher than field measurements, attributed to idealised assumptions. Despite these variations, ponds in the central catchment exhibited the highest infiltration rates, indicating suitability for artificial recharge. Explicit recognition of pond-specific infiltration variability significantly contributes to informed urban water security planning, enabling targeted interventions to optimise groundwater recharge initiatives. Full article

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21 pages, 8938 KiB

Open AccessArticle

Selection of a Probability Model Adapted to the Current Climate for Annual Maximum Daily Rainfall in the Benin Mono-Couffo Basin (West Africa)

by Voltaire Midakpo Alofa, Mathieu B. Hounsou, Grâce-Désirée Houeffa, Yèkambèssoun N’tcha M’po, David Houéwanou Ahoton, Expédit Vissin and Euloge Agbossou

Hydrology 2025, 12(4), 86; https://doi.org/10.3390/hydrology12040086 - 12 Apr 2025

Viewed by 273

Abstract

The control of rainfall extremes is essential in the design of hydro-agricultural works, as their performance depends on it. This study aims to determine the best-fit probability model suited to current climatic conditions in the Mono-Couffo basin in Benin. To this end, daily [...] Read more.

The control of rainfall extremes is essential in the design of hydro-agricultural works, as their performance depends on it. This study aims to determine the best-fit probability model suited to current climatic conditions in the Mono-Couffo basin in Benin. To this end, daily rainfall data from six rainfall stations from 1981 to 2021 were used. The application of the Decision Support System (DSS) with graphical and numerical performance criteria (such as RMSE, SD, and CC represented by the Taylor diagram; AIC and BIC) made it possible to identify the best distribution class and then to select the most suitable distribution for this basin. The results indicate that class C distributions, characterized by regular variations, are the most appropriate for the modeling maximum annual daily precipitation at all stations (78% of cases). Of these, the Inverse Gamma distribution proved to be the most suitable, although its estimation errors ranged from 16.47 mm/d at Aplahoué to 39.80 mm/d at Grand-Popo. The second most appropriate distribution is the Log-Pearson Type III. The use of the Inverse Gamma distribution is, therefore, recommended for hydro-agricultural development studies in the Mono-Couffo basin. Full article

(This article belongs to the Section Statistical Hydrology)

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12 pages, 272 KiB

Open AccessArticle

A Test of Factors Influencing One-Dimensional Mini-Disk Infiltrometer Experiments on Repacked Loam Soil Columns

by Vincenzo Bagarello, Stefano Barone, Gaetano Caltabellotta, Florina Kati Varadi, Francesco Zanna and Dario Autovino

Hydrology 2025, 12(4), 85; https://doi.org/10.3390/hydrology12040085 - 11 Apr 2025

Viewed by 140

Abstract

Performing infiltration experiments on sieved and repacked soil columns seems a generally underrated topic from a methodological point of view. This study assessed how the descriptive parameters of the infiltration process were influenced by (i) the operator; (ii) the number of replicated runs; [...] Read more.

Performing infiltration experiments on sieved and repacked soil columns seems a generally underrated topic from a methodological point of view. This study assessed how the descriptive parameters of the infiltration process were influenced by (i) the operator; (ii) the number of replicated runs; and (iii) the soil sample preparation method. A total of 135 loam soil columns, each 20 cm high were prepared by two operators. Four packing methods, differing by the number of steps required to prepare the sample, were applied. One-dimensional infiltration runs were carried out on each soil column using a Mini-Disk Infiltrometer set at a pressure head of −3 cm. A statistical, or at least practical, similarity of the infiltration parameters obtained by the two operators was detected. Six replicated runs were found to be enough to obtain an acceptable description of the entire infiltration process. Differences between the packing methods were noticeable since infiltration parameters differed by up to 2.7 times, probably because soil compaction energy varied with the applied packing method. Two operators can achieve consistent and reproducible results using the same equipment and packing method since the number of steps in which the soil column is prepared has an appreciable effect on its hydrodynamic response. Full article

(This article belongs to the Section Soil and Hydrology)

18 pages, 5008 KiB

Open AccessArticle

Tracking Nitrate Sources in the Lower Kagera River in the Lake Victoria Basin: Insights from Hydrochemistry, Isotopes, and the MixSIAR Model

by Catherine Mathenge, Stephen Mureithi, Pascal Boeckx, Benjamin Nyilitya and Cargele Masso

Hydrology 2025, 12(4), 84; https://doi.org/10.3390/hydrology12040084 - 11 Apr 2025

Viewed by 281

Abstract

Nitrate contamination poses a significant global environmental threat, impacting the water quality in surface and groundwater systems. Despite its considerable impact, there remains a lack of comprehensive understanding of nitrate sources and discharge patterns, particularly in the Lake Victoria basin of East Africa. [...] Read more.

Nitrate contamination poses a significant global environmental threat, impacting the water quality in surface and groundwater systems. Despite its considerable impact, there remains a lack of comprehensive understanding of nitrate sources and discharge patterns, particularly in the Lake Victoria basin of East Africa. To address this gap, a study was conducted in the Kagera River basin, responsible for 33% of Lake Victoria’s surface inflow. This study utilized δ¹⁵N and δ¹⁸O isotope analysis in nitrate, hydrochemistry, and the Bayesian mixing model (MixSIAR) to identify and quantify nitrate sources. Spatiotemporal data were collected across three seasons: long rains, dry season, and short rains, in areas with diverse land uses. Nitrate isotopic data from water and potential sources were integrated into a Bayesian mixing model to determine the relative contributions of various nitrate sources. Notable spatial variations were observed at sampling sites with concentrations ranging from 0.004 to 3.31 mg L⁻¹. Spatially and temporally, δ¹⁵N-NO₃⁻ values ranged from +6.0% to +10.2‰, whereas δ¹⁸O-NO₃⁻ displayed significant spatial differences with mean ranges from −1% to +7‰. MixSIAR analysis revealed important contributions from manure and sewage sources ranging between 49% and 73%. A boron analysis revealed manure was the main source of nitrates in the manure and sewage. These results show that it is necessary to implement improved manure and sewage management practices, especially through proper waste treatment and disposal systems, to enable informed policy decisions to enhance nitrogen management strategies in riparian East Africa, and to safeguard the region’s water resources and ecosystems. Full article

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20 pages, 15030 KiB

Open AccessArticle

Analysis of Runoff Variability and Periodicity in the Qinghai Lake Basin

by Panpan Yao, Hongyan Gao, Xinxiao Yu, Yankai Feng and Yukun Wang

Hydrology 2025, 12(4), 83; https://doi.org/10.3390/hydrology12040083 - 10 Apr 2025

Viewed by 192

Abstract

This study, based on hydrological station data and wavelet analysis, explores the periodic variation characteristics and trends of the two main tributaries (Buha River and Shaliu River) in the Qinghai Lake Basin from 1960 to 2016. Wavelet transform is used to analyze the [...] Read more.

This study, based on hydrological station data and wavelet analysis, explores the periodic variation characteristics and trends of the two main tributaries (Buha River and Shaliu River) in the Qinghai Lake Basin from 1960 to 2016. Wavelet transform is used to analyze the runoff data, revealing long-term periodic fluctuations and their correlation with precipitation changes. The study finds that, from 2003 to 2016, the daily peak flow and daily minimum flow of the two rivers increase compared to the period from 1960 to 2003, though the magnitude and trends of the increase differ. At the monthly scale, runoff patterns show that June to October is the main period for concentrated runoff in the basin, with July and August being the peak months. Additionally, interannual runoff changes for both rivers show a gradually increasing trend amid fluctuations, with varying fluctuation intensities observed in different years. Wavelet analysis results indicate that the main periodicity of runoff is 23 years, closely linked to changes in precipitation. This study reveals the periodic variation patterns of runoff in the Qinghai Lake Basin, providing valuable insights for watershed water resource management and hydrometeorological forecasting. Full article

(This article belongs to the Section Ecohydrology)

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3 pages, 148 KiB

Open AccessOpinion

Modelling and Forecasting Processes in Urban Environments: Particularly in the UK and China

by Roger Alexander Falconer

Hydrology 2025, 12(4), 82; https://doi.org/10.3390/hydrology12040082 - 3 Apr 2025

Viewed by 193

Abstract

The modelling and forecasting of the impact of extreme rainfall events in urban environments is becoming increasingly challenging as historical tools have been found to need refinement to acquire improved flood risk predictions for river and coastal basins. This article discusses some of [...] Read more.

The modelling and forecasting of the impact of extreme rainfall events in urban environments is becoming increasingly challenging as historical tools have been found to need refinement to acquire improved flood risk predictions for river and coastal basins. This article discusses some of the key challenges faced by flood modellers addressing the growing effects of climate change, with the key findings reported in this article being that (i) improved flood models are needed for accurately predicting extreme flood elevations and inundation extents through the inclusion of shock-capturing algorithms; (ii) improved flood hazard risk formulae are need to predict the stability and vulnerability of vehicles and people in extreme flood events; and (iii) assessing the impact of floods on water quality in river and coastal basins can only be delivered accurately when storm events are modelled holistically from the source to sea (S2S), with a systems-based approach to dynamically integrate surface and sub-surface flows etc. Full article

(This article belongs to the Special Issue Understanding, Forecasting and Control of Flooding and Pollution in the Urban Environment: The 10th Anniversary of Hydrology)

29 pages, 15893 KiB

Open AccessArticle

Application of Temporal Fusion Transformers to Run-Of-The-River Hydropower Scheduling

by Rafael Francisco, José Pedro Matos, Rui Marinheiro, Nuno Lopes, Maria Manuela Portela and Pedro Barros

Hydrology 2025, 12(4), 81; https://doi.org/10.3390/hydrology12040081 - 3 Apr 2025

Viewed by 300

Abstract

This study explores the application of Temporal Fusion Transformers (TFTs) to improve the predictability of hourly potential hydropower production for a small run–of–the–river hydropower plant in Portugal. Accurate hourly power forecasts are essential for optimizing participation in the spot electricity market, where deviations [...] Read more.

This study explores the application of Temporal Fusion Transformers (TFTs) to improve the predictability of hourly potential hydropower production for a small run–of–the–river hydropower plant in Portugal. Accurate hourly power forecasts are essential for optimizing participation in the spot electricity market, where deviations incur penalties. This research introduces the novel application of the TFT, a deep–learning model tailored for time series forecasting and uncovering complex patterns, to predict hydropower production based on meteorological data, historical production records, and plant capacity. Key challenges such as filtering observed hydropower outputs (to remove strong, and unpredictable human influence) and adapting the historical series to installed capacity increases are discussed. An analysis of meteorological information from several sources, including ground information, reanalysis, and forecasting models, was also undertaken. Regarding the latter, precipitation forecasts from the European Centre for Medium–Range Weather Forecasts (ECMWF) proved to be more accurate than those of the Global Forecast System (GFS). When combined with ECMWF data, the TFT model achieved significantly higher accuracy in potential hydropower production predictions. This work provides a framework for integrating advanced machine learning models into operational hydropower scheduling, aiming to reduce classical modeling efforts while maximizing energy production efficiency, reliability, and market performance. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: The Flood Estimation and Forecasting Chain: Meteorological–Hydrological–Hydraulic Forecasts and Predictive Uncertainty towards Operational Decisions)

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19 pages, 4549 KiB

Open AccessArticle

Modeling the Impact of Water Hyacinth on Evapotranspiration in the Chongón Reservoir Using Remote Sensing Techniques: Implications for Aquatic Ecology and Invasive Species Management

by Carolina Cárdenas-Cuadrado, Luis Morocho, Juan Guevara, Manuel Cepeda, Tomás Hernández-Paredes, Diego Arcos-Jácome, Carlos Ortega and Diego Portalanza

Hydrology 2025, 12(4), 80; https://doi.org/10.3390/hydrology12040080 - 2 Apr 2025

Viewed by 360

Abstract

The proliferation of water hyacinth (Eichhornia crassipes) in the Chongón Reservoir, located within the Parque Lago National Recreation Area in Guayaquil, Ecuador, poses significant challenges to the local aquatic ecosystem and water resource management. This study assesses the impact of water [...] Read more.

The proliferation of water hyacinth (Eichhornia crassipes) in the Chongón Reservoir, located within the Parque Lago National Recreation Area in Guayaquil, Ecuador, poses significant challenges to the local aquatic ecosystem and water resource management. This study assesses the impact of water hyacinth coverage on evapotranspiration rates over a 20-year period from 2002 to 2022 using remote sensing data and geospatial analysis. The Normalized Difference Vegetation Index (NDVI), derived from Landsat satellite imagery, along with meteorological records, was utilized to model the spatial and temporal dynamics of water hyacinth coverage and its effects on evapotranspiration. Our results indicate that water hyacinth coverage fluctuates significantly between rainy and dry seasons, increasing from covering 10.42% of the reservoir area in 2002 to a peak of 42.33% in 2017 during the rainy seasons. A strong positive correlation (

r = 0.92

,

p < 0.001

) was found between water hyacinth coverage and net daily water loss due to evapotranspiration. The evapotranspiration rates associated with water hyacinth were significantly higher during the rainy season (mean of 2309.90 mm/year) compared to the dry season (mean of 1917.87 mm/year). These elevated evapotranspiration rates contribute to increased water loss from the reservoir, potentially impacting water availability for municipal and agricultural use. Controlling the spread of water hyacinth is therefore crucial for preserving the reservoir’s ecological integrity and ensuring sustainable water resource management. The findings of this study provide valuable insights for informing management strategies aimed at mitigating the effects of invasive species on freshwater resources and maintaining aquatic ecosystem health. Full article

(This article belongs to the Special Issue GIS Modelling of Evapotranspiration with Remote Sensing)

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19 pages, 8968 KiB

Open AccessArticle

Role of Hungry Water on Sediment Dynamics: Assessment of Valley Degradation, Bed Material Changes and Flood Inundation in Pamba River During Kerala Flood, 2018

by Sreelash Krishnan Kutty, Padmalal Damodaran, Jeenu Mathai, Micky Mathew, Asha Rani, Rajat Kumar Sharma and Maya Kesavan

Hydrology 2025, 12(4), 79; https://doi.org/10.3390/hydrology12040079 - 1 Apr 2025

Viewed by 223

Abstract

Flood frequencies, along with the associated loss of life and property, have risen significantly due to climate change and increasing human activities. While prior research has primarily focused on high-intensity rainfall events and reservoir management in flood management, the influence of sediment-starved water—termed [...] Read more.

Flood frequencies, along with the associated loss of life and property, have risen significantly due to climate change and increasing human activities. While prior research has primarily focused on high-intensity rainfall events and reservoir management in flood management, the influence of sediment-starved water—termed “hungry water”—released from dams in controlling flood dynamics has not gained much attention. The present study is aimed at exploring the potential role of sediment-starved water, or the “hungry water effect” on the valley degradation, bed material changes and flood inundation in the Pamba River during the Kerala Flood, 2018, through a detailed characterization of bed materials and their deposition in the channel bed. The release of sediment-starved water from the Kakki reservoir during the episodic precipitation event (15 to 17 August 2018) resulted in significant bed degradation and scouring of the valley slopes, leading to the deposition of large boulders and rock masses and the inundating of approximately 196 km² of floodplains. This study highlights the need for integrated sediment management strategies in reservoir operations by providing essential insights into sediment transport dynamics during extreme weather events. Understanding these processes is crucial for formulating effective flood mitigation strategies and improving the resilience of riverine ecosystems, particularly as the interaction between intense rainfall and sediment-depleted releases significantly exacerbated the flood’s severity. Full article

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6 pages, 533 KiB

Open AccessOpinion

Urban Flood Risk and Resilience: How Can We Protect Our Cities from Flooding?

by Dragan Savić

Hydrology 2025, 12(4), 78; https://doi.org/10.3390/hydrology12040078 - 31 Mar 2025

Viewed by 530

Abstract

This article draws on over 40 years of the author’s experience with hydroinformatics tools for water and sustainability challenges, including flooding. It aims to spark discussion on urban flood risk and resilience rather than provide a literature review or definitive answers. Assessing urban [...] Read more.

This article draws on over 40 years of the author’s experience with hydroinformatics tools for water and sustainability challenges, including flooding. It aims to spark discussion on urban flood risk and resilience rather than provide a literature review or definitive answers. Assessing urban flood risk and resilience is complex due to the spatio-temporal nature of rainfall, urban landscape features (e.g., buildings, roads, bridges and underpasses) and the interaction between aboveground and underground drainage systems. Flood simulation methods have evolved to analyse flood mitigation schemes, damage evaluation, flood risk mapping and green infrastructure impacts. Advances in terrain mapping technologies have improved flood analyses. Despite investments in flood management infrastructure, a residual flood risk remains, necessitating an understanding of the recovery and return to normality post-flood. Both risk and resilience approaches are essential for urban flood planning and management. Future challenges and opportunities include both technological and governance solutions, with artificial intelligence advancements offering the potential for digital twins to better protect urban communities and enhance the recovery from flood disasters. Full article

(This article belongs to the Special Issue Understanding, Forecasting and Control of Flooding and Pollution in the Urban Environment: The 10th Anniversary of Hydrology)

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22 pages, 4166 KiB

Open AccessArticle

Quantifying Mercury Use and Modeling Its Fate and Transport in Artisanal and Small-Scale Gold Mining in the Lom Basin

by Marie Sorella Bella Atangana, Pol Magermans, Jules Rémy Ndam Ngoupayou and Jean-François Deliege

Hydrology 2025, 12(4), 77; https://doi.org/10.3390/hydrology12040077 - 28 Mar 2025

Viewed by 163

Abstract

This research quantifies mercury use and models its transport in artisanal and small-scale gold mining (ASGM) in the Lom River during two key periods of intense mining activities and high water flow. Mercury concentrations from mining surfaces were estimated using a soil input [...] Read more.

This research quantifies mercury use and models its transport in artisanal and small-scale gold mining (ASGM) in the Lom River during two key periods of intense mining activities and high water flow. Mercury concentrations from mining surfaces were estimated using a soil input function approach. Industrial mercury releases were assessed with a ratio-based approach using official gold production data and the mercury-to-gold ratio. The PEGASE model was applied to simulate mercury transport and pollution in the Lom River and to analyze the pressure–impact relationships of ASGM activities on surface water. Field measurements of the mercury concentrations in the Lom River during the dry and rainy seasons of 2021 were used to validate modeling results. The results indicate that volatilization has a more significant impact on the predicted mercury concentrations than photodissociation. Three scenarios were modeled for mercury use: whole ore amalgamation (WOA), combined whole and concentrate ore amalgamation (WOA + COA), and concentrate ore amalgamation (COA). Mercury use estimates ranged from 2250–7500 kg during intense activity to 1260–4200 kg during high water for the gold production of 750 and 525 kg, respectively. Industrial discharges dominated mercury pollution during the dry season while leaching from mining surfaces was the primary contributor during the rainy season. Full article

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20 pages, 7282 KiB

Open AccessArticle

Stormwater Management and Late-Winter Chloride Runoff into an Urban Lake in Minnesota, USA

by Neal D. Mundahl and John Howard

Hydrology 2025, 12(4), 76; https://doi.org/10.3390/hydrology12040076 - 28 Mar 2025

Viewed by 214

Abstract

Stormwater runoff containing road deicing salts has led to the increasing salinization of surface waters in northern climates, and urban municipalities are increasingly being mandated to manage stormwater runoff to improve water quality. We assessed chloride concentrations in runoff from late-winter snowmelt and [...] Read more.

Stormwater runoff containing road deicing salts has led to the increasing salinization of surface waters in northern climates, and urban municipalities are increasingly being mandated to manage stormwater runoff to improve water quality. We assessed chloride concentrations in runoff from late-winter snowmelt and rainfall events flowing into an urban Minnesota, USA, lake during two different years, predicting that specific stormwater drainages with greater concentrations of roadways and parking lots would produce higher chloride loads during runoff than other drainages with fewer impervious surfaces. Chloride levels were measured in runoff draining into Lake Winona via 11 stormwater outfalls, a single channelized creek inlet, and two in-lake locations during each snowmelt or rainfall event from mid-February through early April in 2021 and 2023. In total, 33% of outfall runoff samples entering the lake collected over two years had chloride concentrations exceeding the 230 ppm chronic standard for aquatic life in USA surface waters, but no sample exceeded the 860 ppm acute standard. Chloride concentrations in outfall runoff (mean ± SD; 190 ± 191 ppm, n = 143) were significantly higher than in-lake concentrations (43 ± 14 ppm, n = 25), but chloride levels did not differ significantly between snowmelt and rainfall runoff events. Runoff from highway locations had higher chloride concentrations than runoff from residential areas. Site-specific chloride levels were highly variable both within and between years, with only a single monitored outfall displaying high chloride levels in both years. There are several possible avenues available within the city to reduce deicer use, capture and treat salt-laden runoff, and prevent or reduce the delivery of chlorides to the lake. Full article

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3 pages, 146 KiB

Open AccessOpinion

Challenges and Opportunities for Urban Water That Is Fit to Play in

by David Werner

Hydrology 2025, 12(4), 75; https://doi.org/10.3390/hydrology12040075 - 28 Mar 2025

Viewed by 226

Abstract

As cities in Europe and beyond recognize the flood protection, recreational, and biodiversity benefits of blue-green spaces, human interaction with urban water is increasing. This trend raises public health concerns that must be addressed by the scientific community, regulators, and the water industry. [...] Read more.

As cities in Europe and beyond recognize the flood protection, recreational, and biodiversity benefits of blue-green spaces, human interaction with urban water is increasing. This trend raises public health concerns that must be addressed by the scientific community, regulators, and the water industry. Advances in measurement and modelling have made continuous city-scale water quality monitoring for real-time risk communication a realistic goal. Achieving this goal requires quality-assured data on hydrology, water quality, drainage infrastructure, and land use, along with robust mechanistic models and a deeper understanding of human behaviour. Full article

(This article belongs to the Special Issue Understanding, Forecasting and Control of Flooding and Pollution in the Urban Environment: The 10th Anniversary of Hydrology)

23 pages, 13387 KiB

Open AccessArticle

Comparative Analysis of SPEI and WEI⁺ Indices: Drought and Water Scarcity in the Umbria Region, Central Italy

by Stefano Casadei, Sara Venturi and Silvia Di Francesco

Hydrology 2025, 12(4), 74; https://doi.org/10.3390/hydrology12040074 - 27 Mar 2025

Viewed by 277

Abstract

The purpose of this study is to assess the possibility of relating two phenomena: first, meteorological drought, which is exclusively dependent on climate; second, water scarcity and its uses, which are predominantly anthropogenic in nature. Sometimes these phenomena may overlap, with the former [...] Read more.

The purpose of this study is to assess the possibility of relating two phenomena: first, meteorological drought, which is exclusively dependent on climate; second, water scarcity and its uses, which are predominantly anthropogenic in nature. Sometimes these phenomena may overlap, with the former amplifying the latter, but direct correlation is not always highlightable due to the anthropogenic character of water shortage and the variability of water supply sources. In the literature, many papers evaluate these two phenomena separately: in particular, the SPEI (Standardized Precipitation-Evapotranspiration Index) is widely used for detecting meteorological drought, while the link between water shortage and its uses is assessed through an index of water resource exploitation, WEI⁺ (Water Exploitation Index Plus), which is based on the calculation of an anthropogenic factor, withdrawals net of restitutions. Specifically, this study examines the SPEI and WEI⁺, respectively, calculated for the July–August–September quarter (SPEI3 sept) and during the low-flow period (WEI⁺_EF low flow), according to the environmental flow constraint. These periods are considered seasonally overlapping in the study area of the Umbria region. The results analyzed by spatial method show the more critical areas, where SPEI3 sept and WEI⁺_EF overlap their critical values, respectively, <−1.0 and >100%. The proposed methodological approach provides stakeholders in the water sector with essential information to adopt a proactive approach to drought phenomena. Full article

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23 pages, 3999 KiB

Open AccessArticle

Water Resource Assessment and Management in Dalha Basalts Aquifer (SW Djibouti) Using Numerical Modeling

by Moumtaz Razack, Mohamed Jalludin and Behailu Birhanu

Hydrology 2025, 12(4), 73; https://doi.org/10.3390/hydrology12040073 - 27 Mar 2025

Viewed by 781

Abstract

In the Republic of Djibouti (Horn of Africa), fractured volcanic aquifers serve as the primary water resource. The country’s climatic characteristics (arid climate, average rainfall of 140 mm/year, and absence of surface water) have led to intensive groundwater exploitation to meet increasing water [...] Read more.

In the Republic of Djibouti (Horn of Africa), fractured volcanic aquifers serve as the primary water resource. The country’s climatic characteristics (arid climate, average rainfall of 140 mm/year, and absence of surface water) have led to intensive groundwater exploitation to meet increasing water demands. This study focuses on the Dalha basalts aquifer in the Dikhil region. The Dikhil region, located in the southwest of Djibouti and bordering Ethiopia, spans 7200 km². Its population is estimated at 112,000 inhabitants. The Dalha aquifer is intensively exploited to supply the region and its capital, the city of Dikhil (35,000 inhabitants). The primary objective of this work is to assess the current resources of this aquifer using numerical modeling and its capacity to meet future water demands under the impact of climate change. The RCP 2.6 (Representative Concentration Pathway) was used to simulate the climate scenario up to 2100. Superficial recharge is estimated at 3.86 × 10⁶ m³/year. The current wellfield abstraction amounts to 2.34 × 10⁶ m³/year, accounting for 60% of the aquifer’s recharge. The simulation under RCP 2.6 indicates a declining trend in the water table. These findings highlight the fragile state of the Dalha aquifer, which is critical for the socioeconomic stability of the region. Given its current vulnerability, any increase in exploitation is unsustainable, despite the growing water demand in the Dikhil region. To tackle this challenge, we recommend conducting further studies to deepen the understanding of this system and implementing a real-time monitoring network to track aquifer changes. Full article

(This article belongs to the Special Issue Hydrological Modeling and Sustainable Water Resources Management)

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23 pages, 2956 KiB

Open AccessArticle

Combining Hydro-Geochemistry and Environmental Isotope Methods to Evaluate Groundwater Quality and Health Risk (Middle Nile Delta, Egypt)

by Atef M. Abu Khatita, Robert van Geldern, Abdullah O. Bamousa, Dimitrios E. Alexakis, Esam Ismail, Wael R. Abdellah and Ibrahim A. A. Babikir

Hydrology 2025, 12(4), 72; https://doi.org/10.3390/hydrology12040072 - 27 Mar 2025

Viewed by 278

Abstract

This study aims to assess the vulnerability of groundwater in the Nile Delta to contamination and evaluate its suitability for drinking and irrigation. A total of 28 groundwater wells (ranging from 23 to 120 m in depth) and two Nile surface water samples [...] Read more.

This study aims to assess the vulnerability of groundwater in the Nile Delta to contamination and evaluate its suitability for drinking and irrigation. A total of 28 groundwater wells (ranging from 23 to 120 m in depth) and two Nile surface water samples were analyzed for total dissolved solids (TDS), heavy metals, groundwater quality index (GWQI), and hazard quotient (HQ). The findings reveal that deep groundwater (60–120 m) displays paleo-water characteristics, with low TDS, total hardness, and minimal heavy metal contamination. In contrast, shallow groundwater (<60 m) is categorized into three groups: paleo-water-like, recent Nile water with elevated TDS and heavy metals, and mixed water. Most groundwater samples (64%) are of the Ca-HCO₃ type, while 28% are Na-HCO₃, and 8% are Na-Cl, the latter associated with sewage infiltration. Most groundwater samples were deemed suitable for irrigation, but drinking water quality varied significantly—4% were classified as “excellent”, 64% as “good”, and 32% as “poor”. HQ analysis identified manganese as a significant health risk, with 56% of shallow groundwater samples exceeding safe levels. These findings highlight the varying groundwater quality in the Nile Delta, emphasizing concerns regarding health risks from heavy metals, particularly manganese, and the need for improved monitoring and management. Full article

(This article belongs to the Special Issue Novel Approaches in Contaminant Hydrology and Groundwater Remediation)

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25 pages, 4338 KiB

Open AccessArticle

Assessment of Satellite-Based Rainfall Products for Flood Modeling in the Ouémé River Basin in Benin (West Africa)

by Marleine Bodjrènou, Kaidi Peng, Dognon Jules Afféwé, Jean Hounkpè, Hagninou E. V. Donnou, Julien Adounkpè and Aristide B. Akpo

Hydrology 2025, 12(4), 71; https://doi.org/10.3390/hydrology12040071 - 27 Mar 2025

Viewed by 266

Abstract

Reliable rainfall data are critical for managing hydrometeorological hazards in West Africa, yet they are often sparse and temporally inconsistent. The current study assessed the accuracy of four near real-time satellite-based rainfall data, namely IMERGv7 Late, IMERGv6 Early, GSMAP-NRT and PERSIANN-DIR Now, for [...] Read more.

Reliable rainfall data are critical for managing hydrometeorological hazards in West Africa, yet they are often sparse and temporally inconsistent. The current study assessed the accuracy of four near real-time satellite-based rainfall data, namely IMERGv7 Late, IMERGv6 Early, GSMAP-NRT and PERSIANN-DIR Now, for rainfall estimation and hydrological modeling in the Ouémé basin. These datasets were compared with ground-based rainfall data, bias-corrected and used to calibrate and validate the hydrological model HBV light. While they demonstrated qualitative accuracy, their quantitative estimation shows obvious discrepancies on a daily scale, varying across subdomains. The original IMERGv7 product outperforms others in capturing the rainfall pattern and amount (KGE > 0.6), while GSMAP performs moderately (KGE ≈ 0.51) and IMERGv6 and PERSIANN show lower reliability with KGE < 0.5. Quantile mapping emerges as the most effective bias-correction method, improving the performance of all satellite products, with RMSE reductions ≤ 15%. The results of hydrological simulations demonstrate the potential of satellite-based rainfall, particularly IMERGv7 and corrected IMERGv6 (NSE > 0.75), for near real-time flood monitoring and water management in the study area. This study underscores their suitability as valuable alternatives to ground-based data for flood management decision making in the Ouémé basin. Full article

(This article belongs to the Section Hydrological and Hydrodynamic Processes and Modelling)

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19 pages, 3834 KiB

Open AccessArticle

Geogenic Contamination of Groundwater in a Highland Watershed: Hydrogeochemical Assessment, Source Apportionment, and Health Risk Evaluation of Fluoride and Nitrate

by Kashif Alam, Muhammad Nafees, Wajid Ali, Said Muhammad and Abdur Raziq

Hydrology 2025, 12(4), 70; https://doi.org/10.3390/hydrology12040070 - 26 Mar 2025

Viewed by 195

Abstract

Groundwater is one of the major sources of freshwater supply for drinking and domestic purposes. This study evaluates the hydrogeochemical processes, groundwater quality for human consumption, associated health risks from fluoride F⁻ and nitrate (NO₃⁻), and sources of dissolved [...] Read more.

Groundwater is one of the major sources of freshwater supply for drinking and domestic purposes. This study evaluates the hydrogeochemical processes, groundwater quality for human consumption, associated health risks from fluoride F⁻ and nitrate (NO₃⁻), and sources of dissolved solutes in a highland watershed in northern Pakistan. Groundwater samples (n = 51) were gathered and analyzed for a range of physicochemical parameters. To evaluate contamination, indices such as the nitrate pollution index (NPI) and fluoride pollution index (FPI) were applied, along with a composite groundwater pollution index to assess overall water quality. The findings revealed that total dissolved solid, turbidity, F⁻, and K⁺ levels exceeded health-based thresholds in 20%, 1%, 4%, and 2% of samples, respectively. Among the water sources, handpumps were identified as the most contaminated. According to the NPI and composite index, 96% and 92% of the samples did not show significant contamination, respectively. However, the FPI results highlighted that 59% of the samples exhibited low F⁻ pollution, while 41% fell under medium pollution levels. While NO₃⁻ ingestion posed no notable health risks,

F^{-}

exposure presented significant concerns, with 58.8% of the samples posing risks, particularly for children. The dominant hydrochemical facies were Ca-Mg-HCO₃, with the main influence on water chemistry by rock-water interactions and reverse ion exchange processes. Full article

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19 pages, 6743 KiB

Open AccessArticle

Comparative Analysis of Spatiotemporal Variability of Groundwater Storage in Iraq Using GRACE Satellite Data

by Hanan Kaduim Mohammed, Imzahim A. Alwan and Mahmoud Saleh Al-Khafaji

Hydrology 2025, 12(4), 69; https://doi.org/10.3390/hydrology12040069 - 26 Mar 2025

Viewed by 343

Abstract

Iraq and other semi-arid regions are facing severe climate change impacts, including increased temperatures and decreased rainfall. Changes to climate variables have posed a significant challenge to groundwater storage dynamics. In this regard, the Gravity Recovery and Climate Experiment (GRACE) mission permits novel [...] Read more.

Iraq and other semi-arid regions are facing severe climate change impacts, including increased temperatures and decreased rainfall. Changes to climate variables have posed a significant challenge to groundwater storage dynamics. In this regard, the Gravity Recovery and Climate Experiment (GRACE) mission permits novel originate groundwater storage variations. This study used the monthly GRACE satellite data for 2002–2023 to determine variations in groundwater storage (GWS). Changes in GWS were implied by extracting soil moisture, acquired from the Global Land Data Assimilation System (GLDAS), from the extracted Territorial Water Storage (TWS). The results demonstrated that an annual average ΔGWS trend ranged for the Goddard Space Flight Center (GSFC) mascon and Jet Propulsion Laboratory (JPL) mascon was from 0.94 to −1.14 cm/yr and 1.64 to −1.36 cm/yr, respectively. Also, the GSFC illustrated superior performance in estimating ΔGWS compared with the JPL in Iraq, achieving the lowest root mean square error at 0.28 mm and 0.60 mm and the highest coefficient of determination (R²) at 0.92 and 0.89, respectively. These data are critical for identifying areas of depletion, especially in areas where in situ data are lacking. These data allows us to fill the knowledge gaps; provide critical scientific information for monitoring and managing dynamic variations. Full article

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