Hydrology

18 pages, 651 KiB

Open AccessArticle

Modelling Hydrological Droughts in Canadian Rivers Based on Markov Chains Using the Standardized Hydrological Index as a Platform

by Tribeni C. Sharma and Umed S. Panu

Hydrology 2025, 12(2), 23; https://doi.org/10.3390/hydrology12020023 - 31 Jan 2025

Abstract

The standardized hydrological index (SHI) is the standardized but not normalized (normal probability variate) value of the streamflow used to characterize a hydrological drought, akin to the standardized precipitation index (SPI, which is both standardized and normalized) in the [...] Read more.

The standardized hydrological index (SHI) is the standardized but not normalized (normal probability variate) value of the streamflow used to characterize a hydrological drought, akin to the standardized precipitation index (SPI, which is both standardized and normalized) in the realm of the meteorological drought. The time series of the SHI can be used as a platform for deriving the longest duration, L_T, and the largest magnitude, M_T (in standardized form), of a hydrological drought over a desired return period of T time units (year, month, or week). These parameters are predicted based on the SHI series derived from the annual, monthly, and weekly flow sequences of Canadian rivers. An important point to be reckoned with is that the monthly and weekly sequences are non-stationary compared to the annual sequences, which fulfil the conditions of stochastic stationarity. The parameters, such as the mean, standard deviation (or coefficient of variation), lag 1 autocorrelation, and conditional probabilities from SHI sequences, when used in Markov chain-based relationships, are able to predict the longest duration, L_T, and the largest magnitude, M_T. The product moment and L-moment ratio analyses indicate that the monthly and weekly flows in the Canadian rivers fit the gamma probability distribution function (pdf) reasonably well, whereas annual flows can be regarded to follow the normal pdf. The threshold level chosen in the analysis is the long-term median of SHI sequences for the annual flows. For the monthly and weekly flows, the threshold level represents the median of the respective month or week and hence is time varying. The runs of deficit in the SHI sequences are treated as drought episodes and thus the theory of runs formed an essential tool for analysis. This paper indicates that the Markov chain-based methodology works well for predicting L_T on annual, monthly, and weekly SHI sequences. Markov chains of zero order (MC0), first order (MC1), and second order (MC2) turned out to be satisfactory on annual, monthly, and weekly scales, respectively. The drought magnitude, M_T, was predicted satisfactorily via the model M_T= I_d× L_c, where I_d stands for drought intensity and L_cis a characteristic drought length related to L_T through a scaling parameter, ɸ (= 0.5). The I_d can be deemed to follow a truncated normal pdf, whose mean and variance when combined implicitly with L_cproved prudent for predicting M_T at all time scales in the aforesaid relationship. Full article

(This article belongs to the Section Statistical Hydrology)

23 pages, 4334 KiB

Open AccessArticle

Evaluation and Adjustment of Historical Hydroclimate Data: Improving the Representation of Current Hydroclimatic Conditions in Key California Watersheds

by Andrew Schwarz, Z. Q. Richard Chen, Alejandro Perez and Minxue He

Hydrology 2025, 12(2), 22; https://doi.org/10.3390/hydrology12020022 - 22 Jan 2025

Abstract

The assumption of stationarity in historical hydroclimatic data, fundamental to traditional water resource planning models, is increasingly challenged by the impacts of climate change. This discrepancy can lead to inaccurate model outputs and misinformed management decisions. This study addresses this challenge by developing [...] Read more.

The assumption of stationarity in historical hydroclimatic data, fundamental to traditional water resource planning models, is increasingly challenged by the impacts of climate change. This discrepancy can lead to inaccurate model outputs and misinformed management decisions. This study addresses this challenge by developing a novel monthly data adjustment approach, the Runoff Curve Year–Type–Monthly (RC-YTM) method. The application of this method is exemplified at five key California watersheds. The RC-YTM method accounts for the increasing variability and shifts in seasonal runoff timing observed in the historical data (1922–2021), aligning it with the contemporary climate conditions represented by the period from 1992 to 2021 at the study watersheds. This method adjusts both annual and monthly streamflow values using a combination of precipitation–runoff relationships, quantile mapping, and water year classification. The adjusted data, reflecting current climatic conditions more accurately than the raw historical data, serve as valuable inputs for operational water resource planning models like CalSim3, commonly used in California for water management. This approach, demonstrably effective in capturing the observed climate change impacts on streamflow at monthly timesteps, enhances the reliability of model simulations representing contemporary conditions, which can lead to better-informed decision-making in water management, infrastructure investment, drought and flood risk assessment, and adaptation strategies. While focused on specific California watersheds, this study’s findings and the adaptable RC-YTM method hold significant implications for water resource management in other regions facing similar hydroclimatic challenges in a changing climate. Full article

(This article belongs to the Special Issue Runoff Modelling under Climate Change)

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20 pages, 8692 KiB

Open AccessArticle

Forecasting Model for Danube River Water Temperature Using Artificial Neural Networks

by Cristina-Sorana Ionescu, Ioana Opriș, Daniela-Elena Gogoașe Nistoran and Constantin-Alexandru Baciu

Hydrology 2025, 12(2), 21; https://doi.org/10.3390/hydrology12020021 - 21 Jan 2025

Abstract

The objective of this paper is to propose an artificial neural network (ANN) model to forecast the Danube River temperature at Chiciu–Călărași, Romania, bordered by Romanian and Bulgarian ecological sites, and situated upstream of the Cernavoda nuclear power plant. Given the temperature increase [...] Read more.

The objective of this paper is to propose an artificial neural network (ANN) model to forecast the Danube River temperature at Chiciu–Călărași, Romania, bordered by Romanian and Bulgarian ecological sites, and situated upstream of the Cernavoda nuclear power plant. Given the temperature increase trend, the potential of thermal pollution is rising, impacting aquatic and terrestrial ecosystems. The available data covered a period of eight years, between 2008 and 2015. Using as input data actual air and water temperatures, and discharge, as well as air temperature data provided by weather forecasts, the ANN model predicts the Danube water temperature one week in advance with a root mean square deviation (RMSE) of 0.954 °C for training and 0.803 °C for testing. The ANN uses the Levenberg–Marquardt feedforward backpropagation algorithm. This feature is useful for the irrigation systems and for the power plants in the area that use river water for different purposes. The results are encouraging for developing similar studies in other locations and extending the ANN model to include more parameters that can have a significant influence on water temperature. Full article

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23 pages, 5265 KiB

Open AccessArticle

High-Resolution Flow and Phosphorus Forecasting Using ANN Models, Catering for Extremes in the Case of the River Swale (UK)

by Elisabeta Cristina Timis, Horia Hangan, Vasile Mircea Cristea, Norbert Botond Mihaly and Michael George Hutchins

Hydrology 2025, 12(2), 20; https://doi.org/10.3390/hydrology12020020 - 21 Jan 2025

Abstract

The forecasting of river flows and pollutant concentrations is essential in supporting mitigation measures for anthropogenic and climate change effects on rivers and their environment. This paper addresses two aspects receiving little attention in the literature: high-resolution (sub-daily) data-driven modeling and the prediction [...] Read more.

The forecasting of river flows and pollutant concentrations is essential in supporting mitigation measures for anthropogenic and climate change effects on rivers and their environment. This paper addresses two aspects receiving little attention in the literature: high-resolution (sub-daily) data-driven modeling and the prediction of phosphorus compounds. It presents a series of artificial neural networks (ANNs) to forecast flows and the concentrations of soluble reactive phosphorus (SRP) and total phosphorus (TP) under a wide range of conditions, including low flows and storm events (0.74 to 484 m³/s). Results show correct forecast along a stretch of the River Swale (UK) with an anticipation of up to 15 h, at resolutions of up to 3 h. The concentration prediction is improved compared to a previous application of an advection–dispersion model. Full article

(This article belongs to the Special Issue Hydrodynamics and Water Quality of Rivers and Lakes)

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17 pages, 15530 KiB

Open AccessArticle

Exploring Seasonality Indices for Low-Flow Analysis on Tibagi Watershed (Brazil)

by Alexandre Sokoloski de Azevedo Delduque de Macedo and Michael Männich

Hydrology 2025, 12(1), 19; https://doi.org/10.3390/hydrology12010019 - 17 Jan 2025

Abstract

This study investigated the seasonality of low-flow discharges in the Tibagi watershed, Paraná, Brazil, through the analysis of three indices: Seasonality Ratio (

S R

), Seasonality Index (

S I

), and Seasonality Histogram (

S H

). The indices were computed [...] Read more.

This study investigated the seasonality of low-flow discharges in the Tibagi watershed, Paraná, Brazil, through the analysis of three indices: Seasonality Ratio (

S R

), Seasonality Index (

S I

), and Seasonality Histogram (

S H

). The indices were computed and compared using previously calculated low-flow discharge data (

Q_{95}

) and physiographic information on sub-watersheds. A ‘Seasonality Calendar’ was developed, illustrating the period and intensity of low-flow discharge occurrences in the watershed. The results indicate that, despite the watershed not presenting a strong seasonality, there is a tendency for low-flow discharges to concentrate in certain months, notably in August, September, and October. Spatial analysis reveals varied patterns with a certain trend of increased seasonality intensity (parameter r) towards downstream (north) and as the watershed area increases. These indices emerge as valuable tools for water resource management, aiding decision-making for allocation and hydrological regionalization, such as optimizing granting water resource distribution during dry seasons based on the identified low-flow patterns and establishing different reference low-flow values throughout the year. Full article

(This article belongs to the Section Statistical Hydrology)

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17 pages, 10357 KiB

Open AccessArticle

Performance Assessment of a Permeable Reactive Barrier on Reducing Groundwater Transport of Nitrate from an Onsite Wastewater Treatment System

by Charles P. Humphrey Jr., Guy Iverson and Mike O’Driscoll

Hydrology 2025, 12(1), 18; https://doi.org/10.3390/hydrology12010018 - 17 Jan 2025

Abstract

Elevated concentrations of nitrate in potable water supplies have been linked to negative health outcomes such as methemoglobinemia and various cancers. Groundwater can become contaminated with nitrate from sources including onsite wastewater treatment systems (OWTSs). A groundwater well down-gradient from an OWTS serving [...] Read more.

Elevated concentrations of nitrate in potable water supplies have been linked to negative health outcomes such as methemoglobinemia and various cancers. Groundwater can become contaminated with nitrate from sources including onsite wastewater treatment systems (OWTSs). A groundwater well down-gradient from an OWTS serving an elementary school in Eastern North Carolina USA had 15 consecutive water samples collected over a 5-year period that exceeded the maximum contaminant level of 10 mg/L for nitrate. Corrective actions were required. A permeable reactive barrier (PRB) filled with woodchips was installed between the OWTS drainfield and the contaminated well. The concentration of nitrate in groundwater from the well steadily decreased after the PRB was installed, and a significant (p = 0.001) inverse correlation (−0.859) was observed between the mean annual nitrate concentration and years after the PRB. The nitrate concentration in groundwater from the well has been below 10 mg/L for the last 17 consecutive sampling events. The median nitrate concentration in the well was significantly lower (p = 0.007) post (6.93 mg/L) relative to pre (12.66 mg/L) PRB. The PRB has not required any maintenance over the past 10 years. The implemented PRB directly influences the sampling results from a monitoring well, but it is not necessarily confirmed that it intercepts the entire groundwater flow or fully prevents aquifer contamination. To confirm this, additional monitoring wells would need to be installed. This research has shown that PRBs can be an effective, low-maintenance, best-management practice to reduce the groundwater transport of nitrate. 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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23 pages, 25140 KiB

Open AccessArticle

Flood Risk Assessment and Zoning for Niamey and Lokoja Metropolises in Niger and Nigeria

by Youssoufa Doulla Nouhou, Martins Yusuf Otache, Salamatou Abdourahamane Illiassou, Olasunkanmi Habeeb Okunola, Appollonia Aimiosino Okhimamhe and Thanh Thi Nguyen

Hydrology 2025, 12(1), 17; https://doi.org/10.3390/hydrology12010017 - 15 Jan 2025

Abstract

With the increasing frequency of floods in recent decades, particularly in West Africa, many regions have faced unusual and recurrent flooding events. Communities in flood-prone areas experience heightened insecurity, loss of property, and, in some cases, serious injuries or fatalities. Consequently, flood risk [...] Read more.

With the increasing frequency of floods in recent decades, particularly in West Africa, many regions have faced unusual and recurrent flooding events. Communities in flood-prone areas experience heightened insecurity, loss of property, and, in some cases, serious injuries or fatalities. Consequently, flood risk assessment and mitigation have become essential. This comparative study between Niamey and Lokoja employs Geographic Information Systems (GIS) and the Analytical Hierarchy Process (AHP) to delineate flood susceptibility, vulnerability, and risk zones. The study utilized a comprehensive range of thematic layers, with weight percentages assigned to each parameter as follows: 29% for elevation, 24% for slope, 15% for the Topographic Wetness Index (TWI), 9% for drainage density, 9% for distance from rivers, 4% for both precipitation and the Normalized Difference Water Index (NDWI), and 2% each for the Normalized Difference Vegetation Index (NDVI) and soil type. To validate these weightings, a consistency ratio was calculated, ensuring it remained below 10%. The findings reveal that 32% of the Niamey study area is at risk of flooding, compared to approximately 15% in Lokoja. The results highlight a very high flood potential, particularly in areas near the Niger River, with this potential decreasing as elevation increases. Given the current prevalence of extreme weather events in West Africa, it is crucial to employ effective tools to mitigate their adverse impacts. This research will assist decision-makers in quantifying the spatial vulnerability of flood-prone areas and developing effective flood risk assessment and mitigation strategies in the region. Full article

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

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18 pages, 4329 KiB

Open AccessArticle

Integrating Nature-Based Solutions for Increased Resilience to Urban Flooding in the Climate Change Context

by George Radu, Maria Ilinca Chevereșan, Sorin Perju and Alina Bărbulescu

Hydrology 2025, 12(1), 16; https://doi.org/10.3390/hydrology12010016 - 15 Jan 2025

Abstract

As climate change intensifies with more frequent and severe flood events, urban areas face increasing challenges to protect population wellbeing. Amid urban development challenges, political uncertainty, and socioeconomic pressures, finding sustainable solutions to enhance urban resilience has become urgent and complex. This article [...] Read more.

As climate change intensifies with more frequent and severe flood events, urban areas face increasing challenges to protect population wellbeing. Amid urban development challenges, political uncertainty, and socioeconomic pressures, finding sustainable solutions to enhance urban resilience has become urgent and complex. This article explores the limitations of traditional drainage systems in an urban zone of Bucharest, Romania, and the integration of nature-based solutions for flood mitigation. We compare the existing situation with those simulated in a climate change scenario before and after implementing green solutions. The imperviousness of parking lots was set at 60%, that of green roofs at 65%, and that of parking lots at 85%. A hydraulic model was used for this purpose. The results demonstrate that the current stormwater systems struggle to meet the demands of increasing rainfall intensity and highlight how sustainable strategies can effectively address extreme weather challenges while contributing to the restoration of natural environments within the city. In the case of using ‘gray’ solutions, only 10–20% of the area affected by floods is reduced. In comparison, a combination of gray and green infrastructure achieved an average reduction in peak water levels of 0.76 m. Full article

(This article belongs to the Special Issue Sustainable Urban Water Resources Management)

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23 pages, 9846 KiB

Open AccessArticle

Assessing Groundwater Connection/Disconnection to Waterholes Along the Balonne River and in the Barwon–Darling River System in Queensland and New South Wales, Australia, for Waterhole Persistence

by Harald Hofmann and Jonathan Marshall

Hydrology 2025, 12(1), 15; https://doi.org/10.3390/hydrology12010015 - 14 Jan 2025

Abstract

Waterholes in semi-arid environment are sections of rivers that fill during high river flows or floods and keep water once flow ceases. They are essential water sources for rive ecosystems. Some waterholes remain even during prolonged droughts. The resilience of ecosystems in these [...] Read more.

Waterholes in semi-arid environment are sections of rivers that fill during high river flows or floods and keep water once flow ceases. They are essential water sources for rive ecosystems. Some waterholes remain even during prolonged droughts. The resilience of ecosystems in these environments depends on the persistence of the waterholes. While most semi-arid, ephemeral river systems are disconnected from regional groundwater and losing in most parts there may be some sections that can be connected to localised groundwater or parafluvial areas. To assess the persistence of waterholes the groundwater contribution to the water balance needs to be addressed. This study assesses groundwater connectivity to waterholes in a part of the Murray-Darling Basin, one of the largest watersheds in the world, using environmental tracers radon and stable isotopes. Approximately 100 samples were collected from 27 waterholes along the Narran, Calgoa, Barwon and Darling rivers, as well as 8 groundwater bore samples. The assessment of groundwater connectivity or the lack of is necessary from water balance modelling and estimation of persistence of these waterholes. As expected, the results indicate consistently low radon concentrations in the waterholes and very small deviation in stable isotopes

δ^{18}

O and

δ^{2}

H. In general, most of these waterholes are losing water to groundwater, indicated by low salinity (EC values) and low radon concentrations. While radon concentrations are small in most cases and indicative of little groundwater contributions, some variability can be assigned to bank return and parafluvial flow. It indicates that these contributions may have implications for waterhole persistence in ephemeral streams. The study demonstrates that in some cases local bank return flow or parafluvial flow may contribute to waterhole persistence. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Integrated Surface Water and Groundwater Resources Management)

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44 pages, 6676 KiB

Open AccessReview

Advancing Slope Stability and Hydrological Solutions Through Biocementation: A Bibliometric Review

by Armstrong Ighodalo Omoregie, Tariq Ouahbi, Fock-Kui Kan, Qurratu Aini Sirat, Hafsat Omolara Raheem and Adharsh Rajasekar

Hydrology 2025, 12(1), 14; https://doi.org/10.3390/hydrology12010014 - 13 Jan 2025

Abstract

Biocementation is an innovative and sustainable technique with wide-ranging applications in slope stabilization, watershed management, and erosion control. Despite its potential, comprehensive evaluations of its use in hydrology and geotechnical engineering are limited. This study addresses this gap through a bibliometric analysis of [...] Read more.

Biocementation is an innovative and sustainable technique with wide-ranging applications in slope stabilization, watershed management, and erosion control. Despite its potential, comprehensive evaluations of its use in hydrology and geotechnical engineering are limited. This study addresses this gap through a bibliometric analysis of 685 articles (2013–2023) from the Scopus database, employing VOSviewer and RStudio to explore global research trends, key contributors, and emerging themes. The analysis reveals that China, the United States, and Japan are leading contributors to this field, with significant advancements in microbial-induced (MICP) and enzyme-induced calcium carbonate precipitation (EICP) techniques. These methods have demonstrated effectiveness in improving soil strength, reducing erosion, and enhancing hydrological properties such as infiltration, runoff control, and water retention. Co-occurrence analysis identifies interdisciplinary connections between geotechnics and hydrology, highlighting research clusters focused on biomineralization, erosion resistance, and durability. The findings underscore biocementation’s pivotal role in addressing sustainability challenges by providing environmentally friendly alternatives to traditional soil stabilization techniques. This study not only maps the current research landscape but also offers valuable insights into the practical implications of biocementation for slope stability and hydrological management, laying the foundation for future advancements in sustainable engineering practices. Full article

(This article belongs to the Section Soil and Hydrology)

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19 pages, 11754 KiB

Open AccessArticle

Assessing the Impacts of Climatic and Water Management Scenarios in a Small Mountainous Greek River

by Angeliki Mentzafou, Anastasios Papadopoulos and Elias Dimitriou

Hydrology 2025, 12(1), 13; https://doi.org/10.3390/hydrology12010013 - 11 Jan 2025

Abstract

The water resource management of transboundary mountainous river basins under climate change is expected to be challenging. In order to contribute to the better understanding of climate change effects on the water resources of the mountainous and transboundary Prespa Lakes basin, a hydrological [...] Read more.

The water resource management of transboundary mountainous river basins under climate change is expected to be challenging. In order to contribute to the better understanding of climate change effects on the water resources of the mountainous and transboundary Prespa Lakes basin, a hydrological model of the Agios Germanos River, one of the main rivers discharging to Great Prespa Lake, was developed, and two water management plans under two different climate scenarios were examined. Based on the results, the impact of climate change on surface water resources was evident in all climate change scenarios examined, even under the most favorable water abstraction practices. Nevertheless, sensible water management can moderate the impact of climate change by up to 10% in an optimistic scenario in both the near- and long-term, and by up to 6% and 1% for the near- and long-term, respectively, in a pessimistic scenario. Integrated water management practices that moderate the impact of climate change on the water ecosystem services should be prioritized. Nature-based approaches could provide solutions regarding climate change adaptation and mitigation. Transboundary cooperation, data exchange mechanisms, common policy frameworks, and monitoring, reporting, and evaluation systems, could reduce human and ecosystems’ vulnerabilities and improve the water security of the area. Full article

(This article belongs to the Special Issue Runoff Modelling under Climate Change)

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22 pages, 14251 KiB

Open AccessArticle

The Development of Drawdown Dolines and Subsidence Dolines with the Comparison of Their Bedrock Resistivities—A Case Study

by Márton Veress

Hydrology 2025, 12(1), 12; https://doi.org/10.3390/hydrology12010012 - 10 Jan 2025

Abstract

The effect of the epikarst on the development of drawdown dolines and subsidence dolines is described. For this, the resistivity values of the bedrock determined by Vertical Electrical Sounding (VES) measurements were used. The higher resistivities below drawdown dolines are explained by the [...] Read more.

The effect of the epikarst on the development of drawdown dolines and subsidence dolines is described. For this, the resistivity values of the bedrock determined by Vertical Electrical Sounding (VES) measurements were used. The higher resistivities below drawdown dolines are explained by the deeper position of the piezometric surface, while the low resistivity values below subsidence dolines can be traced back to the more elevated position of the piezometric surface. Resistivities increasing towards the centre of drawdown dolines refer to cavity heterogeneity increasing towards the centre and increasing vertical percolation rate, while decreasing resistivity values indicate an increasing degree of cavity fill above the piezometric level. At their asymmetrical variety, the bedrock of their opposite slope is of asymmetric resistivity, which is explained by the different elevations of the piezometric surface and the latter by different infiltration that took place on slopes with different inclinations. The same resistivity values of the doline with a flat floor indicate the homogeneous cavity formation of the epikarst. This latter results in homogeneous vertical infiltration, which favours horizontal dissolution. The piezometric surface is not deflecting below the subsidence dolines because resistivity differences are small between the bedrock below the doline and the bedrock of its environment. Below subsidence doline, above the piezometric surface, cavities develop (the resistivity is higher relative to the resistivity of the environment), and then the cavities become filled by suffosion (therefore, the resistivity below the doline is lower relative to its environment). The passage below the doline develops into a shaft as a result of its concentrated water supply and the epikarst is separated into parts. Full article

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24 pages, 1884 KiB

Open AccessReview

Modeling Groundwater Resources in Data-Scarce Regions for Sustainable Management: Methodologies and Limits

by Iolanda Borzì

Hydrology 2025, 12(1), 11; https://doi.org/10.3390/hydrology12010011 - 9 Jan 2025

Abstract

Groundwater modeling in data-scarce regions faces significant challenges due to the lack of comprehensive, high-quality data, impacting model accuracy. This systematic review of Scopus-indexed papers identifies various approaches to address these challenges, including coupled hydrological-groundwater models, machine learning techniques, distributed hydrological models, water [...] Read more.

Groundwater modeling in data-scarce regions faces significant challenges due to the lack of comprehensive, high-quality data, impacting model accuracy. This systematic review of Scopus-indexed papers identifies various approaches to address these challenges, including coupled hydrological-groundwater models, machine learning techniques, distributed hydrological models, water balance models, 3D groundwater flow modeling, geostatistical techniques, remote sensing-based approaches, isotope-based methods, global model downscaling, and integrated modeling approaches. Each methodology offers unique advantages for groundwater assessment and management in data-poor environments, often combining multiple data sources and modeling techniques to overcome limitations. However, these approaches face common challenges related to data quality, scale transferability, and the representation of complex hydrogeological processes. This review emphasizes the importance of adapting methodologies to specific regional contexts and data availability. It underscores the value of combining multiple data sources and modeling techniques to provide robust estimates for sustainable groundwater management. The choice of method ultimately depends on the specific objectives, scale of the study, and available data in the region of interest. Future research should focus on improving the integration of diverse data sources, enhancing the representation of complex hydrogeological processes in simplified models, and developing robust uncertainty quantification methods tailored for data-scarce conditions. Full article

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10 pages, 599 KiB

Open AccessArticle

Study on the Stage Method of the Water Environmental Capacity Flood Season in the Ningxia Section of the Yellow River

by Yu Song and Hongrui Wang

Hydrology 2025, 12(1), 10; https://doi.org/10.3390/hydrology12010010 - 8 Jan 2025

Abstract

The rational use of the water environmental resources of the main stream of the Yellow River, which is the mother river of the Chinese nation, and the control of and reduction in water environmental pollution, especially in relation to water quality safety, have [...] Read more.

The rational use of the water environmental resources of the main stream of the Yellow River, which is the mother river of the Chinese nation, and the control of and reduction in water environmental pollution, especially in relation to water quality safety, have become important issues that must be considered in Ningxia’s economic and social development. Due to the influence of monsoons, river runoff in most of the river basins in China is mainly concentrated in the flood season, and its distribution is extremely uneven within and among years. Therefore, an analysis of the seasonal change law of heavy rainfall and flooding and a scientific and rational staging of the flood season can fully demonstrate the comprehensive benefits of the river and also address the inevitable need to master and utilize the capacity of the water environment. In this study, the abundant, level, and absent year division of the Ningxia section of the main stream of the Yellow River was carried out using the percentage of parity and the guarantee rate methods. Several commonly used flood periods staging methods were studied, and their applicable conditions were preliminarily analyzed. The research results not only provide a reference for the relevant management departments, a decision-making basis for rational planning, and the scientific and appropriate development of river basins but they also have scientific research significance. Full article

(This article belongs to the Special Issue Advances in Urban Hydrology and Stormwater Management)

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17 pages, 1919 KiB

Open AccessArticle

Design Flood Calculation Model for Extra-Small Watersheds in Ungauged Basin

by Yun Wang, Zengchuan Dong, Xinhua Zhu, Wenzhuo Wang, Yupeng Liu, Ronghao Chen and Yunjia He

Hydrology 2025, 12(1), 9; https://doi.org/10.3390/hydrology12010009 - 7 Jan 2025

Abstract

Designing floods in ungauged watersheds with limited data is a significant challenge in water conservancy projects. To address this, the method of calculating the design flood peak and flood volume using the weighted average method was proposed, which is based on the instantaneous [...] Read more.

Designing floods in ungauged watersheds with limited data is a significant challenge in water conservancy projects. To address this, the method of calculating the design flood peak and flood volume using the weighted average method was proposed, which is based on the instantaneous unit hydrograph method and the inference formula method, combined with the characteristics of heavy rainfall floods in ungauged watersheds. The calculation results are analyzed in terms of reasonableness through the distribution pattern of the flood peak modulus under different frequencies of the constructed reservoirs, the relative error analysis, and the HEC-RAS model. Based on the one-day flood process of the adjacent basin, the calculation of deducing the design flood process using the hydrological comparison method was proposed. Taking the “Stormwater Runoff Chart” as the data source, the runoff generation, and concentration model was established with the design flood of Baludi Reservoir in the Gelangram River basin of Menglian, Yunnan Province as the research object. A comparative study of the results of the design floods calculated by different methods was carried out. The results show that the new method can well describe the rainstorm process. The method has better performance in the application to the design flood calculation of ungauged basins due to its consideration of the influence of subsurface conditions. The method not only reduces the construction cost but also improves the safety of the reservoir through a better-fitted design flood calculation. Full article

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21 pages, 5692 KiB

Open AccessArticle

Kinetic Column Evaluation of Potential Construction Options for Lessening Solute Mobility in Backfill Aquifers in Restored Coal Mine Pits, Powder River Basin, USA

by Jeff B. Langman and Julianna Martin

Hydrology 2025, 12(1), 8; https://doi.org/10.3390/hydrology12010008 - 7 Jan 2025

Abstract

Following open-pit coal mining in the Powder River Basin, landscape reconstruction includes the construction of backfill aquifers from overburden waste rock. With overburden disaggregation and the re-introduction of groundwater, the weathering of newly available mineral surfaces and mobilization of nanomaterials can impact groundwater [...] Read more.

Following open-pit coal mining in the Powder River Basin, landscape reconstruction includes the construction of backfill aquifers from overburden waste rock. With overburden disaggregation and the re-introduction of groundwater, the weathering of newly available mineral surfaces and mobilization of nanomaterials can impact groundwater quality even when such issues were not previously detected in the overburden’s groundwater. Kinetic columns of Powder River Basin waste rock were used to evaluate backfill construction options—zeolite amendment, and soil amendment, compaction, rinse—that could reduce potential groundwater quality impacts. The leachate from each column was collected twice weekly for 20 weeks. The Eh and pH of the leachate substantially varied during an initial high-weathering period indicative of the traditional weathering of newly exposed mineral surfaces and the weathering and flushing of mobile particles. Correspondingly, select elements, such as arsenic and cadmium, were present in relatively high concentrations during this initial weathering period. Waste rock that was compacted or rinsed produced leachate with less solutes and potential contaminants when compared to the unaltered and zeolite- and soil-amended waste rock. Greater compaction during backfilling is possible but may require additional consideration for connecting the surface drainage network to the surrounding area. Rinsing of the waste rock is a viable construction option because of the temporary storage of the waste rock prior to backfilling but would require leachate collection for contaminant treatment. Full article

(This article belongs to the Topic Transport, Transformation and Cycling of Elements in Water and Soil and Their Response to Human Activities)

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22 pages, 7144 KiB

Open AccessArticle

Attribution of the Climate and Land Use Change Impact on the Hydrological Processes of Athabasca River Basin, Canada

by Sharad Aryal, Mukand S. Babel, Anil Gupta, Babak Farjad, Dibesh Khadka and Quazi K. Hassan

Hydrology 2025, 12(1), 7; https://doi.org/10.3390/hydrology12010007 - 7 Jan 2025

Abstract

Climate change (CC) and land use/land cover change (LULCC) are significant drivers of hydrological change, and an effective watershed management requires a detailed understanding of their individual and the combined impact. This study focused on the Athabasca River Basin (ARB), Canada, and investigated [...] Read more.

Climate change (CC) and land use/land cover change (LULCC) are significant drivers of hydrological change, and an effective watershed management requires a detailed understanding of their individual and the combined impact. This study focused on the Athabasca River Basin (ARB), Canada, and investigated how the basin responded to their changes using the MIKE SHE-MIKE Hydro River. Our findings revealed novel insights into ARB hydrological changes, including increment in non-vegetated lands (0.26%), savannas (1.28%), forests (0.53%), and urban areas (0.02%) while grasslands (2.07%) and shrublands (0.03%) decreased. Moreover, the basin experienced rising annual minimum (1.01 °C) and maximum (0.85 °C) temperatures but declining precipitation (6.2%). The findings suggested a significant impact of CC compared to LULCC as CC caused annual reduction in streamflow (7.9%), evapotranspiration (4.8%), and recharge (6.9%). Meanwhile, LULCC reduced streamflow (0.2%) and recharge (0.4%) but increased evapotranspiration (0.1%). The study revealed spatiotemporal variability across the ARB, with temperature impacts stronger in winter and precipitation influencing other seasons. Full article

(This article belongs to the Special Issue Hydrological Modelling for the Sustainable Management of Water Resources in River Basins)

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21 pages, 2112 KiB

Open AccessArticle

Climatic Factors Influencing Aleppo Pine Sap Flow in Orographic Valleys Under Two Contrasting Mediterranean Climates

by Ana M. Sabater, José Antonio Valiente, Juan Bellot and Alberto Vilagrosa

Hydrology 2025, 12(1), 6; https://doi.org/10.3390/hydrology12010006 - 6 Jan 2025

Abstract

Global climate change projections highlight the Mediterranean Basin as one of the most susceptible areas to the effects of intense and prolonged droughts, as well as increasing air temperatures. Accordingly, the productivity and survival of forests in this area will depend on their [...] Read more.

Global climate change projections highlight the Mediterranean Basin as one of the most susceptible areas to the effects of intense and prolonged droughts, as well as increasing air temperatures. Accordingly, the productivity and survival of forests in this area will depend on their ability to resist and adapt to increasingly drier conditions. Different climatic conditions across the Mediterranean Basin could drive differences in forest functioning, requiring trees to acclimate to them. Sea breeze dynamics along orographic valleys can also influence climatic conditions, accentuating differences between inland and coastal forests. However, there is limited information on whether the climatic factors regulating tree transpiration in Aleppo pine forest in orographic valleys vary according to climate. This study aims to identify and compare the climatic factors that regulate tree transpiration along a gradient and determine the thresholds at which these factors affect transpiration rates. This study was carried out by means of sap flow gauges, since this technique is a key feature for quantifying and understanding tree transpiration. It was conducted in two Aleppo pine dry sub-humid forests (inland and coastal, 750 and 675 trees ha⁻¹, respectively) and in two pine semi-arid forests (inland and coastal, 600 and 400 trees ha⁻¹, respectively) in the western Mediterranean basin during January–November of 2021. No significant rainfall events or droughts were recorded during the period of study, indicating a standard climatic condition in these areas. The main findings demonstrated that the variability in sap flow could be attributed to the interaction between soil water content and vapour pressure deficit in all the forests studied. However, the highest threshold values of these climatic factors in relation to the increase or decrease in maximum sap flow (i.e., less sensitivity) were exhibited in semi-arid forests, highlighting the adaptability of Aleppo pine to more limiting climatic conditions. These findings are relevant for the consequences of the predicted increase in harsh climatic conditions and the balance among vapour pressure deficit, temperature and soil water availability. Future research will be essential to confirm forest acclimatisation in the transitional dry to semi-arid forest ecosystems predicted by global climate change projections, given their potential to strongly alter ecosystem function and water cycles. Full article

(This article belongs to the Section Ecohydrology)

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16 pages, 4228 KiB

Open AccessArticle

Spatial and Temporal Variability of Extreme Hydroclimatic Events in the Bani River Basin

by Fousseini Kouyaté, François Kossi Guédjé, Assane Ndiaye and Orou Moctar Ganni Mampo

Hydrology 2025, 12(1), 5; https://doi.org/10.3390/hydrology12010005 - 5 Jan 2025

Abstract

Severe hydroclimatic events affect ecosystems and human livelihoods, creating significant challenges for managing water resources. This study analyzed the rainfall and river flow trends in the Bani River Basin (BRB) from 1991 to 2020. Using indices such as the maximum rainfall over a [...] Read more.

Severe hydroclimatic events affect ecosystems and human livelihoods, creating significant challenges for managing water resources. This study analyzed the rainfall and river flow trends in the Bani River Basin (BRB) from 1991 to 2020. Using indices such as the maximum rainfall over a one-day period (RX1DAY), maximum rainfall over a five-day period (RX5DAY), rainfall exceeding the 95th percentile (R95P), simple daily precipitation intensity (SDII), and peak discharge (Qmax), the modified Mann–Kendall test and Pettitt’s test were applied to assess the trends and identify potential breakpoints. The results revealed spatial variability, with southern regions showing reduced rainfall, while northeastern areas exhibit increasing extreme rainfall and river flow. The RX5DAY declined significantly after 2000, reflecting reductions in prolonged rainfall events, followed by the RX1DAY, which declined significantly after 2012, indicating a reduction in short-duration extremes. In contrast, the R99P, SDII, and Qmax exhibited positive trends, indicating intensifying rainfall intensity and extremes in discharge. A notable breakpoint was detected in 1993, marking a transition to increased extreme flows. The highest values of the rainfall indices (R95P, R99P, RX1DAY, RX5DAY, SDII) were concentrated in the southern part of the basin, while the north recorded lower values. These results highlight the basin’s vulnerability to climate variability and provide insights into hydroclimatic changes, serving as a basis for informed decision-making and future research. Full article

(This article belongs to the Section Statistical Hydrology)

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