Fuzzy Analytical Solution of Horizontal Diffusion Equation into the Vadose Zone
Smart Data Blending Framework to Enhance Precipitation Estimation through Interconnected Atmospheric, Satellite, and Surface Variables

Journal Description

Hydrology

Hydrology is an international, peer-reviewed, open access journal of hydrology published monthly online by MDPI. The American Institute of Hydrology (AIH) and Japanese Society of Physical Hydrology (JSPH) are affiliated to Hydrology and their members receive a discount on the article processing charges.

Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
High Visibility: indexed within Scopus, ESCI (Web of Science), PubAg, GeoRef, and other databases.
Journal Rank: CiteScore - Q2 (Earth-Surface Processes)
Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 14.2 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the first half of 2023).
Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.

Impact Factor: 3.2 (2022); 5-Year Impact Factor: 3.1 (2022)

Imprint Information Journal Flyer Open Access ISSN: 2306-5338

Latest Articles

Open AccessReview

Evolution of Tunneling Hydro-Technology: From Ancient Times to Present and Future

Vasileios A. Tzanakakis

and

Hydrology 2023, 10(9), 190; https://doi.org/10.3390/hydrology10090190 - 20 Sep 2023

Abstract

Water tunnels are one of the oldest hydro-technologies for extracting water resources and/or transmitting them through water distribution systems. In the past, human societies have used tunneling for various purposes, including development, as a measure to enable underground resource extraction and the construction of transportation networks in challenging landscapes and topographies. The development of hydro-technology potentially involves the construction of tunnels to feed aqueducts, irrigation and waste water systems. Thus, the ability to make and maintain tunnels became an important component in creating lasting and sustainable water systems, which increased water supply and security, minimized construction costs, and reduced environmental impact. Thus, this review asks how, when and why human societies of the past included tunneling for the development of lasting water supply systems. This review presents a comprehensive overview across time and space, covering the history of tunneling in hydro technology from antiquity to the present, and it ponders how past experiences could impact on future hydro-technological projects involving tunneling. A historical review of tunnel systems enhances our understanding of the potential, performance, challenges, and prospects associated with the use of hydro-techniques. In the past, as the different examples in time and space demonstrate, tunneling was often dedicated to solving local problems of supply and disposal. However, across the world, some features were repeated, including the need for carving through the living rock or digging to create tunnels covered with stone slabs. Also, the world-wide use of extensive and costly tunnel systems indicates the high level of investment which human societies are willing to make for securing control over and with its water resources. This study helps us to gather inspiration from proven technologies of the past and more recent knowledge of water tunnel design and construction. As we face global warming and its derivate problems, including problems of water scarcity and flooding, the ability to create and maintain tunnels remains an important technology for the future. Full article

(This article belongs to the Topic Hydrology and Water Resources in Agriculture and Ecology)

► Show Figures

Figure 1

Open AccessArticle

Coastal Erosion Caused by River Mouth Migration on a Cuspate Delta: An Example from Thanh Hoa, Vietnam

and

Hydrology 2023, 10(9), 189; https://doi.org/10.3390/hydrology10090189 - 18 Sep 2023

Abstract

Coastal erosion poses a significant threat to the infrastructure of the coastal community at the mouth of the Ma River in Thanh Hoa Province, Vietnam. In response, emergency solutions such as hard, protective structures are often implemented. However, this approach exacerbates the problem as the underlying mechanisms of coastal erosion are not adequately investigated and understood. In this study, the long-term configuration of the mouth of the Ma River in Thanh Hoa Province, Central Vietnam, is investigated using Landsat imagery spanning from 1987 to 2023. An analytical solution of a one-line model for shoreline change was also used to examine the sand discharge from the Ma River and the diffusion coefficient for the sand transported along the shore by breaking waves. The results showed an asymmetric configuration of the mouth of the Ma River over the past 37 years. The supply of sand from the Ma River is around 350,000 m³/year. The majority of sand (ranging from 55% to 75%) is mainly transported to the northern beach of the Ma River delta. This uneven distribution of sand from the Ma River has led to the asymmetrical morphology of the delta apex in which the northern part of the Ma River delta is experiencing northward movement while the southern part of the Ma River Delta is moving southward and landward. The asymmetrical morphology of the delta at the mouth of the Ma River has recently been identified as the cause of severe coastal erosion. The diffusion coefficient value determined for the transportation of longshore sand along the deltaic lobes of the Ma River delta corresponds to 90 m²/day. This study offers a practical method for investigating morphological changes in cuspate deltas, especially when measured field data are limited. Full article

(This article belongs to the Section Marine Environment and Hydrology Interactions)

► Show Figures

Figure 1

Open AccessArticle

Analysis of Groundwater Depletion in the Saskatchewan River Basin in Canada from Coupled SWAT-MODFLOW and Satellite Gravimetry

Mohamed Hamdi

and

Kalifa Goïta

Hydrology 2023, 10(9), 188; https://doi.org/10.3390/hydrology10090188 - 15 Sep 2023

Abstract

The Saskatchewan River Basin (SRB) of central Canada plays a crucial role in the Canadian Prairies. Yet, climate change and human action constitute a real threat to its hydrological processes. This study aims to evaluate and analyze groundwater spatial and temporal dynamics in the SRB. Groundwater information was derived and compared using two different approaches: (1) a mathematical modeling framework coupling the Soil and Water Assessment Tool (SWAT) and the Modular hydrologic model (MODFLOW) and (2) gravimetric satellite observations from the Gravity Recovery and Climate Experiment (GRACE) mission and its follow-on (GRACE-FO). Both methods show generalized groundwater depletion in the SRB that can reach −1 m during the study period (2002–2019). Maximum depletion appeared especially after 2011. The water balance simulated by SWAT-MODFLOW showed that SRB could be compartmented roughly into three main zones. The mountainous area in the extreme west of the basin is the first zone, which is the most dynamic zone in terms of recharge, reaching +0.5 m. The second zone is the central area, where agricultural and industrial activities predominate, as well as potable water supplies. This zone is the least rechargeable and most intensively exploited area, with depletion ranging from +0.2 to −0.4 m during the 2002 to 2011 period and up to −1 m from 2011 to 2019. Finally, the third zone is the northern area that is dominated by boreal forest. Here, exploitation is average, but the soil does not demonstrate significant storage power. Briefly, the main contribution of this research is the quantification of groundwater depletion in the large basin of the SRB using two different methods: process-oriented and satellite-oriented methods. The next step of this research work will focus on the development of artificial intelligence approaches to estimate groundwater depletion from a combination of GRACE/GRACE-FO and a set of multisource remote sensing data. Full article

► Show Figures

Figure 1

Open AccessArticle

Assessing Terrestrial Water Storage Variations in Southern Spain Using Rainfall Estimates and GRACE Data

Eulogio Pardo-Igúzquiza

Jean-Philippe Montillet

José Sánchez-Morales

Peter A. Dowd

Juan Antonio Luque-Espinar

Neda Darbeheshti

and

Francisco Javier Rodríguez-Tovar

Hydrology 2023, 10(9), 187; https://doi.org/10.3390/hydrology10090187 - 15 Sep 2023

Abstract

This paper investigates the relationship between rainfall, groundwater and Gravity Recovery and Climate Experiment (GRACE) data to generate regional-scale estimates of terrestrial water storage variations in the Andalucía region of southern Spain. These estimates can provide information on groundwater depletion (caused by periods of low rainfall or droughts) and groundwater recovery. The spatial distribution of groundwater bodies in southern Spain is complex and current in situ groundwater monitoring methods are deficient, particularly in terms of obtaining representative samples and in implementing and maintaining groundwater monitoring networks. The alternative approach proposed here is to investigate the relationship between precipitation time series and changes in the terrestrial water storage estimated from GRACE observations. The results were validated against the estimated fluctuation in regional groundwater. The maximum correlation between the mean groundwater level and the GRACE observations is 0.69 and this occurs at a lag of one month because the variation in gravity is immediate, but rainfall water requires around one month to travel across the vadose zone before it reaches the groundwater table. Using graphical methods of accumulated deviations from the mean, we show that, in general, groundwater storage follows the smooth, multi-year trends of terrestrial water storage but with less short-term trends; the same is true of rainfall, for which the local trends are more pronounced. There is hysteresis-like behaviour in the variations in terrestrial water storage and in the variations of groundwater. In practical terms, this study shows that, despite the abnormal dryness of the Iberian Peninsula during the 2004–2010 drought, the depleted groundwater storage in Andalucía recovered almost to its pre-drought level by 2016. In addition, groundwater storage and terrestrial water storage show very similar trends but with a delay in the groundwater trend. Full article

(This article belongs to the Section Hydrology–Climate Interactions)

► Show Figures

Figure 1

Open AccessArticle

Boron Isotopes in Fresh Surface Waters in a Temperate Coastal Setting

and

Hydrology 2023, 10(9), 186; https://doi.org/10.3390/hydrology10090186 - 14 Sep 2023

Abstract

The results from a four-year study of a freshwater pond on Long Island, NY, USA, do not point to a single source of boron (and by proxy other elements including nutrients) in this system. However, boron data from samples associated with this pond can be explained by mixing between average precipitation (weighted average δ¹¹B = 22.7) in the area and the local sources of boron, both natural and anthropogenic. This multiyear study provided the opportunity to see both yearly and seasonal differences. One algae sample from the pond showed significant fractionation and enrichment in light boron relative to the water and suggests algae may act as a boron sink. This type of biological fractionation could explain an observed down-gradient trend to heavier boron isotope values in pond water, which corresponds to the slight reduction in boron concentration seen in 2021. However, the trend was subdued in the following year, likely due to differences in the water flow rates and/or rate of algal growth. An opposite trend was seen with depth in the water, where δ¹¹B showed a positive correlation to boron concentration, which increased with depth from the surface of the pond. This gradient may be explained by the stratification of the pond with a heavy source concentrating in the bottom waters. The bottom water composition was consistent with goose feces (δ¹¹B = 25.8) or the addition of chemicals from the application of rock salt to local roads in winter. Surprisingly, boron from seawater (average δ¹¹B = 39.8) did not appear to have a direct impact on Setauket Pond, other than its influence on precipitation, providing heavy δ¹¹B and very low boron concentrations. Full article

(This article belongs to the Special Issue Advances in Isotope Investigations of Groundwater Resources)

► Show Figures

Figure 1

Open AccessArticle

Bloomin’ Ridiculous: Climate Change, Water Contamination and Algal Blooms in a Land Down Under

Andrea Crampton

and

Angela T. Ragusa

Hydrology 2023, 10(9), 185; https://doi.org/10.3390/hydrology10090185 - 14 Sep 2023

Abstract

Climate and anthropogenic change, particularly agricultural runoff, increase blue-green algae/cyanobacteria blooms. This article researches cyanobacteria alert-level identification, management, and risk communication in Lake Hume, Australia. Two methods, document and content analysis, evidence contamination events and risk communication, reflect water governance and data management limitations. Results found that Lake Hume had amber or red alerts for only one week, December 2021–December 2022. This failed to prevent government tourism promotion of recreational usage, contravening water authority red alert advice. Lake-use restrictions lacked compliance enforcement. Events during amber alerts lacked risk communication to vulnerable populations (children). Lake Hume’s governance by the Murray–Darling Basin Authority restricted risk communication to one authority that reproduced generic advice in minimal outlets/time points. Geophysical signage failed to address diversity needs (language, literacy, age, and disabilities). No risk communication was found for residents with diseases exacerbated by aerosolization. Despite WHO promoting cyanotoxin investigation, Australian research is absent in international literature. Further, Lake Hume cyanobacteria produce potentially carcinogenic microcystein. This coexists with census data revealing cancer rates higher than the national average in a waterside town. The results demonstrate the need to incorporate robust public health risk assessments, communication, and management into water management and advocate international legislation changes based on evidence-based research to reduce blooms and prevent agricultural runoff. Full article

(This article belongs to the Special Issue Climate Change Effects on Hydrology and Water Resources)

► Show Figures

Figure 1

Open AccessArticle

Simulating Phosphorus Load Reductions in a Nested Catchment Using a Flow Pathway-Based Modeling Approach

Russell Adams

and

Paul Quinn

Hydrology 2023, 10(9), 184; https://doi.org/10.3390/hydrology10090184 - 14 Sep 2023

Abstract

Catchment models are essential tools to identify and predict water quality problems linked to excessive nutrient applications (in this case phosphorus (P)). The Catchment Runoff Attenuation Flux Tool (CRAFT) has been successfully used to model nutrient fluxes and concentrations in north-western European catchments. The model is extremely parsimonious due to the relatively small number of parameters. However, an improvement to the representation of soluble P and particulate P fluxes in the fast-subsurface and surface runoff flow pathways was required. A case study in the north of Ireland applied the original and the new, enhanced (Dynamic) version of the CRAFT to the trans-border Blackwater catchment (UK and Republic of Ireland) covering nearly 1500 km², with the land use predominantly livestock grazing. The larger size of the Blackwater also required a nested modeling approach to be implemented using a multiple sub-catchment variant (MultiCRAFT). P load reductions in the different sub-catchments were first identified using a simple approach based on the gap between the Water Framework Directive (WFD) limits for “Good” ecological status for soluble reactive P (SRP) concentrations and the recently observed concentrations. Modeling of different mitigation scenarios was then conducted using the MultiCRAFT framework with the best-performing variant of the CRAFT model embedded. The catchment was found to have flashy, episodic delivery of high concentrations of SRP and PP during runoff events which will require different sources (i.e., diffuse and point) of P to be targeted to achieve the WFD targets by the end of the decade. The modeling results thus showed that the required SRP load reductions could be best achieved using a combined scenario of mitigation measures that targeted diffuse sources contributing to both the surface runoff and fast-subsurface flow pathways, with point sources also identified as needing reduction in some sub-catchments. Full article

(This article belongs to the Special Issue Recent Advances in Hydrological Modeling)

► Show Figures

Figure 1

Open AccessArticle

Potential Impacts of Climate Change on the Al Abila Dam in the Western Desert of Iraq

Rasha Abed

Ammar Adham

Mohammed Falah Allawi

and

Coen Ritsema

Hydrology 2023, 10(9), 183; https://doi.org/10.3390/hydrology10090183 - 14 Sep 2023

Abstract

The potential impacts resulting from climate change will cause significant global problems, particularly in underdeveloped nations where the effects are felt the most. Techniques for harvesting water such as small dams provide an alternative supply of water and are adaptive solutions to deal with water scarcity in the context of future climate change. However, it is difficult to determine how rainwater harvesting (dams) may be impacted by climate change since general circulation models (GCMs), widely utilized for predicting potential future climate change scenarios, work on an extremely large scale. The primary aim of this research was to quantify the effect of climate change on water availability at the catchment scale by statistically downscaling temperature and rainfall from the GCMs. Then, using a water harvesting model, the performance of the Abila Dam in Iraq’s western desert was evaluated in both the current climate (1990–2020) and various future climate change scenarios (2020–2100). Precipitation generally decreases as the annual temperature increases. To simulate future water availability, these changes in meteorological factors were incorporated into the water harvesting model. In total, 15% or less of net storage might fulfil the whole storage capacity during the baseline period, whereas it is 10% in RCP 2.6 in 2011–2040 for future scenarios. In contrast, RCP 8.5 will be able to meet water needs at a pace of 6% in 2011–2040. The findings of this study proved that the Al Abila dam will be unable to supply the necessary water for the area surrounding the Al Abila dam in the future scenarios. Full article

► Show Figures

Figure 1

Open AccessReview

Dynamic Groundwater Contamination Vulnerability Assessment Techniques: A Systematic Review

and

Hydrology 2023, 10(9), 182; https://doi.org/10.3390/hydrology10090182 - 04 Sep 2023

Abstract

Assuring the quantity and quality of groundwater resources is essential for the well-being of human and ecological health, society, and the economy. For the last few decades, groundwater vulnerability modeling techniques have become essential for groundwater protection and management. Groundwater contamination is highly dynamic due to its dependency on recharge, which is a function of time-dependent parameters such as precipitation and evapotranspiration. Therefore, it is necessary to consider the time-series analysis in the “approximation” process to model the dynamic vulnerability of groundwater contamination. This systematic literature review (SLR) aims to critically review the methods used to evaluate the spatiotemporal assessment of groundwater vulnerability. The PRISMA method was employed to search web platforms and refine the collected research articles by applying certain inclusion and exclusion criteria. Despite the enormous growth in this field in recent years, spatiotemporal variations in precipitation and evapotranspiration were not considered considerably. Groundwater contamination vulnerability assessment needs to integrate the multicriteria decision support tools for better analysis of the subsurface flow, residence time, and groundwater recharge. Holistic approaches need to be formulated to evaluate the groundwater contamination in changing climatic scenarios and uncertainties, which can provide knowledge and tools with which to prepare sustainable groundwater management strategies. Full article

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

► Show Figures

Figure 1

Open AccessArticle

Relating Lake Circulation Patterns to Sediment, Nutrient, and Water Hyacinth Distribution in a Shallow Tropical Highland Lake

and

Hydrology 2023, 10(9), 181; https://doi.org/10.3390/hydrology10090181 - 01 Sep 2023

Abstract

Excess sediment and nutrient losses from intensifying agriculture degrade water quality and boost plant growth. The relationship between circulation patterns, spatial water quality degradation, and water hyacinth infestation is not adequately studied. The objective of this study is, therefore, to investigate the effect of lake circulation patterns on sediment and nutrient distribution and its implication on the spread of water hyacinth in a tropical lake. This study was carried out in Lake Tana, the largest freshwater lake in Ethiopia, where sediment and nutrient concentrations are increasing, and water hyacinths have become a challenge since 2011. The lake circulation pattern was simulated by the Delft3D model based on a bathymetry survey, discharge, and meteorological forcings. To predict the transport path of sediments and dissolved nutrients, an inert tracer was released in the four main river inlets of the lake. Observed lake water level measurements were used to validate the model. Our results show that the lake circulation pattern could explain the transport path of sediment and nutrients and the location of the water hyacinths found in the northeast of the lake. Sediments and nutrients from the largest river, Gilgel Abay, in the southeast of Lake Tana, flow through the two outlets nearby with little sediment deposition due to the relatively short retention time. The phosphorus-rich sediments of the 24 h at 105 °C remaining three main rivers joining the lake at the north and east are transported to the northeast. Thus, the management and control of water hyacinths should focus on the northern and eastern catchment areas of Lake Tana. Full article

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

► Show Figures

Figure 1

Open AccessArticle

A Hydrogeological Conceptual Model Refines the Behavior of a Mediterranean Coastal Aquifer System: A Key to Sustainable Groundwater Management (Grombalia, NE Tunisia)

and

Hydrology 2023, 10(9), 180; https://doi.org/10.3390/hydrology10090180 - 30 Aug 2023

Abstract

The Mediterranean coastal aquifer system of the Grombalia basin (NE Tunisia) offers immense potential as a source of fresh water for agriculture, industry, and drinking water supply. Nonetheless, due to its intricate hydrogeological characteristics and the prevailing issue of groundwater salinity, comprehending its groundwater system behavior becomes crucial for the effective and sustainable management of this aquifer system. Based on the hydrogeological characterization of the Grombalia basin, a novel 3D hydrogeological conceptual model was developed to enhance the understanding of its complex aquifer system. The integration of insights from geological, hydrogeological, hydrodynamic, and hydrochemical components facilitated the construction of the hydrogeological conceptual model. Although the model’s validity faced initial uncertainties due to spatial interpolation of lithological sequences, this study’s thorough and encompassing hydrogeological investigation overcame these limitations. As a result, a more informed comprehension of the aquifer system complexities was achieved. This study reveals that the basin is underlain by an extensive, cohesive Mio–Plio–Quaternary aquifer system. The model demonstrates vertical and lateral hydrogeological continuity between the Quaternary and underlying Mio–Pliocene deposits, enabling groundwater flow and exchange between these layers. Over-abstraction of the Mio–Plio–Quaternary aquifer system has led to a significant drop in piezometric levels and raised the risk of seawater intrusion. These findings emphasize the critical necessity of taking into account the interconnections among hydrogeological units to ensure sustainable groundwater management. The developed conceptual model offers a key tool for understanding the hydrodynamic functioning of the Grombalia aquifer system with a view toward guiding future groundwater management strategies. The application of this approach in the Grombalia basin suggests its potential applicability to other regional aquifers facing comparable challenges. Full article

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

► Show Figures

Figure 1

Open AccessArticle

Comparing Methods for the Regionalization of Intensity−Duration−Frequency (IDF) Curve Parameters in Sparsely-Gauged and Ungauged Areas of Central Chile

Pablo García-Chevesich

and

Hydrology 2023, 10(9), 179; https://doi.org/10.3390/hydrology10090179 - 28 Aug 2023

Abstract

Estimating intensity−duration−frequency (IDF) curves requires local historical information of precipitation intensity. When such information is unavailable, as in areas without rain gauges, it is necessary to consider other methods to estimate curve parameters. In this study, three methods were explored to estimate IDF curves in ungauged areas: Kriging (KG), Inverse Distance Weighting (IDW), and Storm Index (SI). To test the viability of these methods, historical data collected from 31 rain gauges distributed in central Chile, 35° S to 38° S, are used. As a result of the reduced number of rain gauges to evaluate the performance of each method, we used LOOCV (Leaving One Out Cross Validation). The results indicate that KG was limited due to the sparse distribution of rain gauges in central Chile. SI (a linear scaling method) showed the smallest prediction error in all of the ungauged locations, and outperformed both KG and IDW. However, the SI method does not provide estimates of uncertainty, as is possible with KG. The simplicity of SI renders it a viable method for extrapolating IDF curves to locations without data in the central zone of Chile. Full article

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

► Show Figures

Figure 1

Open AccessReview

Unlocking the Potential of Microbially Induced Calcium Carbonate Precipitation (MICP) for Hydrological Applications: A Review of Opportunities, Challenges, and Environmental Considerations

Charalampos Konstantinou

and

Yuze Wang

Hydrology 2023, 10(9), 178; https://doi.org/10.3390/hydrology10090178 - 26 Aug 2023

Abstract

Microbially induced calcium carbonate precipitation (MICP) is an innovative biocementation technique that facilitates the formation of calcium carbonate within a pore network. Initially gaining prominence in the field of geotechnical engineering, MICP has attracted significant attention since its inception (the last three decades) and expanded its reach across various engineering disciplines. Examples include rock mechanics, geology and the oil and gas industry fields through the generation of rock-like specimens, and plugging of fractures, in civil and architectural engineering and material science for concrete repair, protection, and for self-healing of building materials, and in environmental engineering for the study of biomimetic materials. In response to this burgeoning interest, the current paper aims to present a comprehensive review of the main biochemical mechanisms underlying MICP (bacterial ureolytic activity, reactions duration and settling times, and chemical solution properties), their direct relevance to altering hydraulic and mechanical properties, both at the microscale and macroscale responses, and the precipitation mechanisms, particularly in relation to water resources and hydrology applications. Four main categories of relevant applications are identified, namely, the groundwater and soil remediation, the applications related to the generation of a low hydraulic conductivity barrier, those related to gaining cohesion, and the applications related to fluid flow studies in artificially generated porous media. Moreover, this comprehensive review not only aims to identify the existing applications of MICP within hydrological fields but also strives to propose novel and promising applications that can further expand its utility in this domain. Along with the investigation of the potential of MICP to revolutionize water resources and hydrology, it is imperative to delve deeper into its environmental implications to ensure sustainable and ecologically responsible implementation. Full article

► Show Figures

Figure 1

Open AccessArticle

Modeling Hydrodynamic Behavior of the Ottawa River: Harnessing the Power of Numerical Simulation and Machine Learning for Enhanced Predictability

and

Hydrology 2023, 10(9), 177; https://doi.org/10.3390/hydrology10090177 - 24 Aug 2023

Abstract

The Ottawa River Watershed is a vast area that stretches across Ontario and Quebec and holds great importance for Canada’s people, economy, and collective history, both in the present and the future. The river has faced numerous floods in recent years due to climate change. The most significant flood occurred in 2019, surpassing a 100-year flood event, and serves as a stark reminder of how climate change impacts our environment. Considering the limitations of machine learning (ML) models, which heavily rely on historical data used during training, they may struggle to accurately predict such “non-experienced” or “unseen” floods that were not encountered during the training process. To tackle this challenge, our study has utilized a combination of numerical modeling and ML to create an integrated methodology. Indeed, a comprehensive dataset of river flow discharge was generated using a numerical model, encompassing a wide range of potential future floods. This significantly improved the ML training process to generalize the accuracy of results. Utilizing this dataset, a novel ML model called the Expanded Framework of Group Method of Data Handling (EFGMDH) has been developed. Its purpose is to provide decision-makers with explicit equations for estimating three crucial hydrodynamic characteristics of the Ottawa River: floodplain width, flow velocity, and river flow depth. These predictions rely on various inputs, including the location of the desired cross-section, river slope, Manning roughness coefficient at different river sections (right, left, and middle), and river flow discharge. To establish practical models for each of the aforementioned hydrodynamic characteristics of the Ottawa River, different input combinations were tested to identify the most optimal ones. The EFGMDH model demonstrated high accuracy throughout the training and testing stages, achieving an R² value exceeding 0.99. The proposed model’s exceptional performance demonstrates its reliability and practical applications for the study area. Full article

(This article belongs to the Special Issue Recent Advances in Hydrological Modeling)

► Show Figures

Figure 1

Open AccessArticle

Assimilating Soil Moisture Information to Improve the Performance of SWAT Hydrological Model

Maria Kofidou

and

Alexandra Gemitzi

Hydrology 2023, 10(8), 176; https://doi.org/10.3390/hydrology10080176 - 21 Aug 2023

Abstract

The present work aims to highlight the possibility of improving model performance by assimilating soil moisture information in the calibration and validation process. The Soil and Water Assessment Tool (SWAT) within QGIS, i.e., QSWAT, was used to simulate the hydrological processes within the test basin, i.e., Vosvozis River Basin (VRB) in NE Greece. The model calibration and validation were conducted via SWAT-CUP for a four-year period from 2019 to 2022, in three different ways, i.e., using the traditional calibration process with river flow measurements, using satellite-based soil moisture only in the calibration, and finally incorporating satellite-based soil moisture datasets and calibrating using simultaneously flow and soil moisture information. All modeling approaches used the same set of input data related to topography, land cover, and soil information. This study utilized the recently released global scale daily downscaled soil moisture at 1 km from the Soil Moisture Active Passive (SMAP) mission to generate soil moisture datasets. Two performance indicators were evaluated: Nash Sutcliffe (NS) and coefficient of determination (R²). Results showed that QSWAT successfully simulated river flow in VRB with NS = 0.61 and R² = 0.69 for the calibration process using river flow measurements at the outlet of VRB. However, comparing satellite-based soil moisture, NS and R² were considerably lower with an average derived from the 19 subbasins (NS = 0.55, R² = 0.66), indicating lower performance related to the simulation of soil moisture regime. Subsequently, introducing satellite-derived soil moisture as an additional parameter in the calibration process along with flow improved the acquired average soil moisture results of the 19 subbasins (NS = 0.85, R² = 0.91), while preserving the satisfactory performance related to flow simulation (NS = 0.57, R² = 0.66). Our work thus demonstrates how assimilating available satellite-derived soil moisture information into the SWAT model may offer considerable improvement in the description of soil moisture conditions, keeping the satisfactory performance in flow simulation. Full article

(This article belongs to the Topic Hydrological Modeling and Engineering: Managing Risk and Uncertainties)

► Show Figures

Figure 1

Open AccessArticle

Simple and Complex Substrates (Sugar, Acetate and Milk Whey) for In Situ Bioremediation of Groundwater with Nitrate and Actinide Contamination

and

Hydrology 2023, 10(8), 175; https://doi.org/10.3390/hydrology10080175 - 18 Aug 2023

Abstract

The complex contamination of groundwater near radioactive waste repositories by nitrates and actinides is a common problem for many nuclear fuel cycle facilities. One of the effective methods to remove nitrates and reduce actinide migration activity is bioremediation through the activation of native microbial communities by soluble electron donors and carbon sources. This work evaluated the effectiveness of using simple and complex electron donors to remove nitrate in the microbial community in an aquifer near the B2 storage of the Siberian Chemical Combine (Seversk, Siberia). The addition of sugar and milk whey led to the maximum efficiency of nitrate-ion removal and a decrease in the redox potential of the system, creating optimal conditions for the immobilization of actinide. Special attention was paid to the behavior of uranium, plutonium, neptunium, and americium under conditions simulating groundwater when sugar, acetate, and milk whey were added and when microbial metabolic products were formed. Neither microbial metabolites nor organic solutions were found to have a significant effect on the leaching of neptunium. At the same time, for plutonium, a decrease in yield was observed when rocks were treated with organic solutions were compared to groundwater treatment without them. Plutonium leaching is significantly affected by rock composition. In rocks with a low clay fraction content, its yield can reach 40%. At the same time, microbial metabolites can increase americium (Am) desorption from rocks with a low clay fraction content. Additionally, particle size analysis was performed using a step-by-step filtration approach, aiming to evaluate the risks that are associated with colloidal phase formation. It was shown that microbiological stimulation resulted in particle enlargement, substantially diminishing the presence of actinides in the form of dissolved or sub-50 nm nanoparticles. This outcome significantly reduced the potential for colloidal and pseudocolloidal transfer, thereby lowering associated risks. Full article

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

► Show Figures

Figure 1

Open AccessArticle

A First Step towards Developing a Decision Support System Based on the Integration of Environmental Monitoring Activities for Regional Water Resource Protection

and

Hydrology 2023, 10(8), 174; https://doi.org/10.3390/hydrology10080174 - 18 Aug 2023

Abstract

The topic of diffuse pollution is of particular interest from technical, scientific, and administrative management points of view. Diffuse pollution is defined as the contamination or chemical, physical, or biological alterations of environmental matrices caused by diffuse sources and not attributable to a single origin. In this study, various sources of diffuse pollution such as nitrates, pesticides, metals, and plastics were analysed. This was aimed at the implementation of a decision support system able to represent the state of environmental matrices degradation, with particular attention to water resources, and to make decisions evaluating similar environmental contexts. The potential of the developed system makes it possible to identify areas with the same environmental characteristics, referring to the various activities that create diffuse pollution and areas with the same pressure values on the environmental matrices. The system provides the political decision-maker with greater awareness of the environmental state, thus enabling him to apply more accurate land management policies. The created system, based on open-source software, which can be implemented with additional available data sources, is characterised by a data processing workflow that provides output information at the municipal level, so that it can be managed both by mayors and regional managers who are able to share the same information with all. Full article

► Show Figures

Figure 1

Open AccessArticle

Applying Geophysical and Hydrogeochemical Methods to Evaluate Groundwater Potential and Quality in Middle Egypt

Esam Ismail

Dimitrios E. Alexakis

and

Hydrology 2023, 10(8), 173; https://doi.org/10.3390/hydrology10080173 - 18 Aug 2023

Abstract

The El-Minia district is a location of interest for future urban development. Using hydrochemistry and electrical resistivity studies, this work aimed to evaluate the groundwater potentiality and it’s suitable for various uses. The groundwater potential in the study area was evaluated based on 24 VESs (vertical electrical soundings), and its quality was determined based on the analyses of 57 groundwater samples. EC (salinity index), Na% (salt hazard), SAR (ratio of sodium adsorption), chloride risks, SSP (soluble sodium percentage), MH (magnesium hazard), and other indicators were used to determine whether the collected water samples were suitable for irrigation. Four layers in the study area are mentioned in the geoelectrical cross-sections that have been constructed. The first is made up of silt and clay from the Nile River, while the second is made up of sandy clay, which has a resistivity range of 15 to 32 Ohm.m and a range thickness of 2 to 68 m. Dry limestone makes up the third layer; its resistivity ranges from 1222 to 3000 Ohm.m and its thickness varies between 75 and 95 m. The Eocene aquifer in the research area is represented by the final layer, which has a thickness of more than 250 m and resistivity values that range from 602 to 860 Ohm.m. Most groundwater samples that were collected are safe for drinking; however, none of them are fit for home usage because of their extreme hardness. According to the SAR and US diagram, RSC, KR, and PI, most groundwater samples from the Pleistocene and Eocene aquifers are fit for irrigation. Full article

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

► Show Figures

Figure 1

Open AccessArticle

Urban Flood Modelling under Extreme Rainfall Conditions for Building-Level Flood Exposure Analysis

Christos Iliadis

Panagiota Galiatsatou

Vassilis Glenis

Panagiotis Prinos

and

Chris Kilsby

Hydrology 2023, 10(8), 172; https://doi.org/10.3390/hydrology10080172 - 17 Aug 2023

Abstract

The expansion of urban areas and the increasing frequency and magnitude of intense rainfall events are anticipated to contribute to the widespread escalation of urban flood risk across the globe. To effectively mitigate future flood risks, it is crucial to combine a comprehensive examination of intense rainfall events in urban areas with the utilization of detailed hydrodynamic models. This study combines extreme value analysis techniques applied to rainfall data ranging from sub-hourly to daily durations with a high-resolution flood modelling analysis at the building level in the centre of Thessaloniki, Greece. A scaling procedure is employed to rainfall return levels assessed by applying the generalised extreme value (GEV) distribution to annual maximum fine-temporal-scale data, and these scaling laws are then applied to more reliable daily rainfall return levels estimated by means of the generalised Pareto distribution (GPD), in order to develop storm profiles with durations of 1 h and 2 h. The advanced flood model, CityCAT, is then used for the simulation of pluvial flooding, providing reliable assessments of building-level exposure to flooding hazards. The results of the analysis conducted provide insights into flood depths and water flowpaths in the city centre of Thessaloniki, identifying major flowpaths along certain main streets resulting in localised flooding, and identifying around 165 and 186 buildings highly exposed to inundation risk in the study area for 50-year storm events with durations of 1 h and 2 h, respectively. For the first time in this study area, a detailed analysis of extreme rainfall events is combined with a high-resolution Digital Terrain Model (DTM), used as an input into the advanced and fully featured CityCAT hydrodynamic model, to assess critical flowpaths and buildings at high flood risk. The results of this study can aid in the planning and design of resilient solutions to combat urban flash floods, as well as contribute to targeted flood damage mitigation and flood risk reduction. Full article

(This article belongs to the Special Issue Urban Hydrology and Urban Water Works under Rapid Urbanisation and Climate Change Conditions in Metropolitan Areas and Mega Cities)

► Show Figures

Figure 1

Open AccessArticle

Identification of the Groundwater Quality and Potential Noncarcinogenic Health Risk Assessment of Nitrate in the Groundwater of El Milia Plain, Kebir Rhumel Basin, Algeria

and

Hydrology 2023, 10(8), 171; https://doi.org/10.3390/hydrology10080171 - 14 Aug 2023

Abstract

In this study, we analyzed the quality and the potential noncarcinogenic health risk of nitrate in groundwater in the El Milia plain, Kebir Rhumel Basin, Algeria. Moran’s I and the ordinary kriging (OK) interpolation technique were used to examine the spatial distribution pattern of the hydrochemical parameters in the groundwater. It was found that the hydrochemical parameters Ca, Cl, and HCO₃ showed strong spatial autocorrelation in the El Milia plain, indicating a spatial dependence and clustering of these parameters in the groundwater. The groundwater quality was evaluated using the entropy water quality index (EWQI). The results showed that approximately 86% of the total groundwater samples in the study area fall within the moderate groundwater quality category. The spatial map of the EWQI values indicated an increasing trend from the south-west to the northeast, following the direction of groundwater flow. The highest EWQI values were observed near El Milia city in the center of the plain. This spatial pattern suggests variations in groundwater quality across the study area, with potentially higher risks near the city center. The potential noncarcinogenic health risks associated with nitrate contamination in groundwater for adults and children through the drinking water pathway were assessed using the hazard quotient (HQ). The results revealed that approximately 5.7% of the total groundwater samples exceeded the HQ limit for adults, indicating potential health risks. Moreover, a higher percentage, 14.28%, of the total groundwater samples exceeded the HQ limit for children, highlighting their increased vulnerability to noncarcinogenic health hazards associated with nitrate contamination in the study area. Taking timely action and ensuring strict compliance with regulations in groundwater management are crucial for protecting public health, preserving the environment, addressing water scarcity, and achieving sustainable development goals. Full article

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

► Show Figures

Figure 1

Journal Menu

Journal Browser

► Journal Browser

Highly Accessed Articles

Latest Books

More Books and Reprints...

E-Mail Alert

News

13 September 2023
Meet Us at the AGU Fall Meeting 2023, 11–15 December 2023, Online or On-Site in San Francisco, CA, USA

6 September 2023
Recap of Awards Granted to Scholars in 2022

31 August 2023
Meet Us at the XVIII World Water Congress, 11–15 September 2023, Beijing, China

More News & Announcements...

Topics

Propose a Topic

Topic in Hydrology, Remote Sensing, Soil Systems, Sustainability, Water

Hydrology and Water Resources in Agriculture and Ecology Topic Editors: Songhao Shang, Qianqian Zhang, Dongqin Yin, Hamza Gabriel, Magdy Mohssen
Deadline: 30 September 2023

Topic in Geosciences, Hydrology, IJERPH, Remote Sensing, Water

Groundwater Pollution Control and Groundwater Management Topic Editors: Yunhui Zhang, Qili Hu, Liting Hao
Deadline: 31 October 2023

Topic in Energies, Hydrology, Remote Sensing, Sustainability, Water

Human Impact on Groundwater Environment Topic Editors: Zongjun Gao, Jiutan Liu
Deadline: 15 November 2023

Topic in Energies, Environments, Hydrology, IJERPH, Remote Sensing, Sustainability

Green Technology, Environmental Management and Corporate Social Responsibility from a Global Perspective Topic Editors: Pingping Luo, Guangwei Huang, Binaya Kumar Mishra, Mohd Remy Rozainy Bin Mohd Arif Zainol
Deadline: 31 December 2023

Conferences

Announce Your Conference

More Conferences...

Special Issues

Propose a Special Issue

Special Issue in Hydrology

Advances in Evaporation and Evaporative Demand: Part II Guest Editors: Aristoteles Tegos, Nikolaos Malamos
Deadline: 30 September 2023

Special Issue in Hydrology

Recent Advances in Hydrological Modeling Guest Editors: Minxue He, Seong Jin Noh, Haksu Lee
Deadline: 31 October 2023

Special Issue in Hydrology

Flood Inundation Mapping in Hydrological Systems Guest Editors: Robert Szczepanek, Ibrahim Demir
Deadline: 15 November 2023

Special Issue in Hydrology

Soil–Water–City Nexus in Urban Environment: Experimental Investigations and Numerical Analysis in Urban Hydrology Science Guest Editors: Patrizia Piro, Michele Turco, Stefania Anna Palermo, Behrouz Pirouz
Deadline: 20 November 2023

More Special Issues

Topical Collections

Topical Collection in Hydrology

Feature Papers of Hydrology Collection Editors: Ezio Todini, Tammo Steenhuis

Journal Description

Hydrology

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Topical Collections

Further Information

Guidelines

MDPI Initiatives

Follow MDPI