Water

11 pages, 410 KiB

Open AccessArticle

Survival and Swimming Performance of Small-Sized Gobiidae Implanted with Mini Passive Integrated Transponders (PIT-Tags)

by Daniel Nyqvist, Alfredo Schiavon, Muhammad Usama Ashraf, Alessandro Candiotto, Adriano Palazzi, Marco Parolini and Claudio Comoglio

Water 2024, 16(19), 2745; https://doi.org/10.3390/w16192745 (registering DOI) - 26 Sep 2024

Abstract

Telemetry techniques are important tools in freshwater fish ecology but are limited by the size of the fish in relation to the size of the electronic tags. The emergence of very small PIT tags (8 mm, mini PIT tags) opens the door to [...] Read more.

Telemetry techniques are important tools in freshwater fish ecology but are limited by the size of the fish in relation to the size of the electronic tags. The emergence of very small PIT tags (8 mm, mini PIT tags) opens the door to study the individual movement and behavior of small-sized fish species and life stages previously outside the scope of fish telemetry. Although high survival from mini PIT tags have been shown in some groups of fish, suitability assessments are lacking for many taxa, and potential behavioral effects have rarely been evaluated. Here, we evaluate the survival tagging effects in small-sized (35–76 mm) Padanian goby (Padogobius bonelli) implanted with mini PIT tags. PIT-tagging was associated with high survival and tag retention in the tagged fish. No effects of PIT-tagging on volitional swimming activity nor on maximum swimming speed were found. Similar results were obtained implanting larger tags (12 mm) in gobies down to 50 mm in length. Our results indicate that PIT telemetry—using mini PIT tags—is applicable for the study of behavior and movement in small-sized gobies. Full article

(This article belongs to the Section Biodiversity and Functionality of Aquatic Ecosystems)

17 pages, 846 KiB

Open AccessArticle

Uncertainty Quantification in Rate Transient Analysis of Multi-Fractured Tight Gas Wells Exhibiting Gas–Water Two-Phase Flow

by Yonghui Wu, Rongchen Zheng, Liqiang Ma and Xiujuan Feng

Water 2024, 16(19), 2744; https://doi.org/10.3390/w16192744 (registering DOI) - 26 Sep 2024

Abstract

The production performances of fractured tight gas wells are closely related to several complex and unknown factors, including the formation properties, fracture parameters, gas–water two-phase flow, and other nonlinear flow mechanisms. The rate transient analysis (RTA) results have significant uncertainties, which should be [...] Read more.

The production performances of fractured tight gas wells are closely related to several complex and unknown factors, including the formation properties, fracture parameters, gas–water two-phase flow, and other nonlinear flow mechanisms. The rate transient analysis (RTA) results have significant uncertainties, which should be quantified to evaluate the formation and fracturing treatment better. This paper provides an efficient method for uncertainty quantification in the RTA of fractured tight gas wells with multiple unknown factors incorporated. The theoretical model for making forward predictions is based on a trilinear flow model, which incorporates the effects of two-phase flow and other nonlinear flow mechanisms. The normalized rates and material balance times of both water and gas phases are regarded as observations and matched with the theoretical model. The unknowns in the model are calibrated using the ensemble Kalman filter (EnKF), which applies an ensemble of multiple realizations to match the observations and updates the unknown parameters step by step. Finally, a comprehensive field case from Northwestern China is implemented to benchmark the proposed method. The results show that the parameters and rate transient responses have wide ranges and significant uncertainties before history matching, while all the realizations in the ensemble can have good matches to the field data after calibration. The posterior distribution of each unknown parameter in the model can be obtained after history matching, which can be used to quantify the uncertainties in the RTA of the fractured tight gas wells. The ranges and uncertainties of the parameters are significantly narrowed down, but the parameters are still with significant uncertainties. The main contribution of the paper is the provision of an efficient integrated workflow to quantify the uncertainties in RTA. It can be readily used in field applications of multi-fractured horizontal wells from tight gas reservoirs. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

20 pages, 1189 KiB

Open AccessArticle

Assessment of Surface Water Availability in the Riyadh Region Using Integrated Satellite Data and Field Measurements (2001 to 2024)

by Raied Saad Alharbi

Water 2024, 16(19), 2743; https://doi.org/10.3390/w16192743 - 26 Sep 2024

Abstract

Surface water availability in arid regions like the Riyadh region of Saudi Arabia is a significant concern due to its low and highly variable rainfall. This study represents the first comprehensive attempt to estimate surface runoff in the Riyadh region by integrating satellite [...] Read more.

Surface water availability in arid regions like the Riyadh region of Saudi Arabia is a significant concern due to its low and highly variable rainfall. This study represents the first comprehensive attempt to estimate surface runoff in the Riyadh region by integrating satellite data with field measurements, including dam observations, for enhanced accuracy. Utilizing the advanced Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks–Dynamic Infrared Rain Rate near-real-time (PDIR-Now) dataset, the study covers a 23-year period from 2001 to 2023. The research aimed to determine runoff coefficients, which are critical for predicting how much rainfall contributes to surface runoff. Analysis of annual runoff volumes and rainfall data from 39 dams, divided into calibration and validation sets, led to a runoff coefficient of 0.059, indicating that 5.9% of rainfall contributes to runoff. The calibration process, validated by statistical measures such as mean bias (0.23 mm) and RMSE (0.94 mm), showed reasonable model accuracy but also highlighted areas for refinement. With an average annual rainfall of 89.6 mm, resulting in 1733.1 million cubic meters (mil. m³) of runoff, the study underscores the importance of localized calibration and ongoing model refinement to ensure sustainable water management in the face of environmental and climatic challenges. Full article

21 pages, 8332 KiB

Open AccessArticle

Effects of Alternative Stress of Drought–Flood on Summer Maize Growth and Yield

by Hongwei Yuan, Ziwei Peng, Jiwei Yang, Jia Liu, Hui Zhao, Shaowei Ning, Xiaoyan Xu, Rong A. and Huimin Li

Water 2024, 16(19), 2742; https://doi.org/10.3390/w16192742 (registering DOI) - 26 Sep 2024

Abstract

The present study aims to assess the responses of growth, development, and yield of summer maize to the effects of drought–flood abrupt alternation through comparative tests under single flood, single-drought, and drought–flood abrupt alternation treatments with varying degrees from the elongation to the [...] Read more.

The present study aims to assess the responses of growth, development, and yield of summer maize to the effects of drought–flood abrupt alternation through comparative tests under single flood, single-drought, and drought–flood abrupt alternation treatments with varying degrees from the elongation to the tasseling stage during the 2021 and 2022 growing seasons. In addition, a water production function model for summer maize was preliminarily established based on the results obtained under the drought–flood abrupt alternation scenarios. The results indicated that drought–flood abrupt alternation with early moderate drought had a certain restricting effect on summer maize, while early moderate drought followed by waterlogging had a compensation effect on the cultivated summer maize. Furthermore, both mild and severe drought followed by waterlogging exert a significant combined constraint on the normal growth and development of summer maize, leading to a sharp decline in maize yield, necessitating a shorter timeframe for mitigating and reducing the effects of waterlogging. Additionally, the water production function model established through a multiple linear regression equation exhibits a high degree of fit and demonstrates a strong linear relationship. This study provides crucial insights for agricultural practices and water resource management strategies, particularly in the evaluation of the integrated impacts of drought and waterlogging on crop yields and the formulation of effective disaster risk reduction and mitigation measures in response to these impacts. Full article

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19 pages, 6366 KiB

Open AccessArticle

Study on Transient Flow Characteristics of Pump Turbines during No-Load Condition in Turbine Mode Startup

by Xianliang Li, Haiyang Dong, Yonggang Lu, Xiji Li and Zhengwei Wang

Water 2024, 16(19), 2741; https://doi.org/10.3390/w16192741 (registering DOI) - 26 Sep 2024

Abstract

To address the escalating demand for power grid load regulation, pumped storage power stations must frequently switch between operational modes. As a key component of such stations, the pump turbine has seen extensive research on its steady-state flow behavior. However, the intricate dynamics [...] Read more.

To address the escalating demand for power grid load regulation, pumped storage power stations must frequently switch between operational modes. As a key component of such stations, the pump turbine has seen extensive research on its steady-state flow behavior. However, the intricate dynamics of its transient flow have not yet been thoroughly examined. Notably, the no-load condition represents a quintessential transient state, the instability of which poses challenges for grid integration. Under certain extreme conditions, this could result in the impairment of the unit’s elements, interruption of its functioning, and endangerment of the security of the power station’s output as well as the stability of the power network’s operations. Thus, investigating the flow characteristics of pump turbines under no-load conditions is of significant practical importance. This paper focuses on the transient flow characteristics of a Weifang hydro-generator unit under no-load conditions, exploring the internal unsteady flow features and their underlying mechanisms. The study reveals that under no-load conditions, the runner channel is obstructed by a multitude of vortices, disrupting the normal pressure gradient within the runner and resulting in substantial hydraulic losses. Within the draft tube, a substantial reverse flow zone is present, predominantly along the walls. This irregular flow pattern within the tube generates a potent, stochastic pressure fluctuation. In addition to the interference frequencies of dynamic and static origins, the pressure pulsation frequency at each measurement point also encompasses a substantial portion of low-frequency, high-amplitude components. Full article

(This article belongs to the Special Issue Hydrodynamic Science Experiments and Simulations)

19 pages, 6463 KiB

Open AccessArticle

Biogeochemical Fe-Redox Cycling in Oligotrophic Deep-Sea Sediment

by Di Zhan, Qingyin Xia, Gaoyuan Li, Xinyu Li, Yang Li, Dafu Hu, Jinglong Hu, Ziqi Zhou and Yizhi Sheng

Water 2024, 16(19), 2740; https://doi.org/10.3390/w16192740 (registering DOI) - 26 Sep 2024

Abstract

Biogeochemical redox cycling of iron (Fe) essentially governs various geochemical processes in nature. However, the mechanistic underpinnings of Fe-redox cycling in deep-sea sediments remain poorly understood, due to the limited access to the deep-sea environment. Here, abyssal sediment collected from a depth of [...] Read more.

Biogeochemical redox cycling of iron (Fe) essentially governs various geochemical processes in nature. However, the mechanistic underpinnings of Fe-redox cycling in deep-sea sediments remain poorly understood, due to the limited access to the deep-sea environment. Here, abyssal sediment collected from a depth of 5800 m in the Pacific Ocean was characterized for its elemental, mineralogical, and biological properties. The sedimentary environment was determined to be oligotrophic with limited nutrition, yet contained a considerable amount of trace elements. Fe-redox reactions in sediment progressed through an initial lag phase, followed by a fast Fe(II) reduction and an extended period of Fe(III) oxidation before achieving equilibrium after 58 days. The presence of an external H₂ electron donor significantly increased the extent of Fe(III) bio-reduction by 7.73% relative to an amendment-free control under high pressure of 58 MPa. A similar enhancement of 11.20% was observed following lactate amendment under atmospheric pressure. Fe(II) bio-oxidation occurred after 16 days’ anaerobic culturing, coupled with nitrate reduction. During Fe bio-redox reactions, microbial community composition was significantly shaped by the presence/absence of an electron donor, while the hydrostatic pressure levels were the controlling factor. Shewanella spp. emerged as the primary Fe(III)-reducing microorganisms, and were stimulated by supplemented lactate. Marinobacter hydrocarbonoclasticus was the predominant Fe(II)-oxidizing microorganism across all conditions. Our findings illustrate continuous Fe-redox reactions occurring in the deep-sea environment, with coexisting Fe-redox microorganisms determining the oscillation of Fe valence states within the abyssal sediment. Full article

(This article belongs to the Special Issue Soil and Groundwater Quality and Resources Assessment)

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19 pages, 5237 KiB

Open AccessArticle

Integrated Basin-Scale Modelling for Sustainable Water Management Using MIKE HYDRO Basin Model: A Case Study of Parvati Basin, India

by Abhishek Agrawal, Mahesh Kothari, R. K. Jaiswal, Vinay Kumar Gautam, Chaitanya Baliram Pande, Kaywan Othman Ahmed, Samyah Salem Refadah, Mohd Yawar Ali Khan, Tuhami Jamil Abdulqadim and Bojan Đurin

Water 2024, 16(19), 2739; https://doi.org/10.3390/w16192739 (registering DOI) - 26 Sep 2024

Abstract

Modelling at the basin scale offers crucial insights for policymakers as they make decisions regarding the optimal utilization of water resources. This study employed the MIKE HYDRO Basin model to analyse water demand and supply dynamics in the Parvati Basin of Rajasthan, India, [...] Read more.

Modelling at the basin scale offers crucial insights for policymakers as they make decisions regarding the optimal utilization of water resources. This study employed the MIKE HYDRO Basin model to analyse water demand and supply dynamics in the Parvati Basin of Rajasthan, India, for the period 2005–2020. The MIKE11 NAM model showcased strong alignment between simulated and observed runoff during both the calibration (NSE = 0.79, PBIAS = −2%, R² = 0.79, RMSE = 4.95, RSR = 0.5, and KGE = 0.84) and validation (NSE = 0.67, PBIAS = −12.4%, R² = 0.68, RMSE = 8.3, RSR = 0.62, and KGE = 0.67) phases. The MIKE HYDRO Basin model also exhibited excellent agreement between observed and simulated reservoir water levels, with R², NSE, RMSE, PBIAS, RSR, and KGE values of 0.86, 0.81, 3.87, −2.30%, 0.43, and 0.88, respectively. The MIKE HYDRO Basin model was employed to create six distinct scenarios, considering conveyance efficiency, irrigation method, and conjunctive water use, to assess irrigation demands and deficits within the basin. In the initial simulation, featuring a conveyance efficiency of 45%, flood irrigation, and no groundwater utilization, the average water demand and deficit throughout the study period were estimated as 43.15 MCM and 3.45 MCM, respectively, resulting in a sustainability index of 0.506. Enhancing conveyance efficiency to 75% under flood irrigation and 5% conjunctive use could elevate the sustainability index to 0.92. Transitioning to sprinkler irrigation and a lift irrigation system could raise the system’s sustainability index to 1. These developed models hold promise for real-time reservoir operation and irrigation planning across diverse climatic conditions and varying cropping patterns. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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19 pages, 3524 KiB

Open AccessArticle

Enhancing the Growth and Quality of Alfalfa Fodder in Aridisols through Wise Utilization of Saline Water Irrigation, Adopting a Strategic Leaching Fraction Technique

by Ghulam Sarwar, Noor Us Sabah, Mukkram Ali Tahir, Muhammad Zeeshan Manzoor, Mahmoud F. Seleiman, Muhammad Amir Zia, Hemat Mahmood, Johar Jamil, Ismail Shah, Sumaira Salahuddin Lodhi, Gulnaz Parveen, Hamid Ali and Ikram Ullah

Water 2024, 16(19), 2738; https://doi.org/10.3390/w16192738 - 26 Sep 2024

Abstract

An experiment was conducted to investigate the optimal use of high-salt water for alfalfa fodder growth and quality in Aridisol. The experiment included five treatments and was performed using a completely randomized design (CRD) as factorial design with three replications. We used a [...] Read more.

An experiment was conducted to investigate the optimal use of high-salt water for alfalfa fodder growth and quality in Aridisol. The experiment included five treatments and was performed using a completely randomized design (CRD) as factorial design with three replications. We used a leaching fraction technique (LF), which is a mitigating technique (MT). The five treatments were T1 = MT1 as normal irrigation (control), T2 = MT2 as a leaching fraction (LF) of 15% with the same quality of water, T3 = MT3 as a LF of 30% with the same quality of water, T4 = MT4 as a LF of 15% with good-quality water (as percentage of total water), in the form of 2–3 irrigations every 3 months, and T5 = MT5 as a LF of 30% with good-quality water (as percentage of total water), in the form of 2–3 irrigations every 3 months. The duration of the experiment was three years and normal soil (non-saline, non-sodic) was used in the current study. Results showed that saline water irrigation negatively affected the growth traits, but the application of the LF technique with same-quality or good-quality water mitigated such negative effects. The fodder quality traits such as crude protein (CP), crude fiber (CF) and ashes were also affected in a negative way with the use of saline irrigation water. This negative impact was more intensified in the third year as the concentration of salts increased in saline water during the three years of the current investigation. A LF with canal water at 15 or 30% reduced the negative effects of salt stress and improved fodder biomass production and quality traits. For examples, using a LF with canal water at 30% increased the biomass production to 33.30 g and 15.87 g when plants were irrigated with W1 and W5, respectively. In addition, it improved quality traits such as crude protein content (5.54% and 3.73%) and crude fiber content (14.55% and 12.75%) when plants were irrigated with W1 and W5, respectively. It was concluded that the LF technique can be recommended for practice in the case of saline water irrigation for the optimized growth and quality of alfalfa fodder. Full article

(This article belongs to the Special Issue Safe Application of Reclaimed Water in Agriculture)

14 pages, 2387 KiB

Open AccessArticle

A Forecast Heuristic of Back Propagation Neural Network and Particle Swarm Optimization for Annual Runoff Based on Sunspot Number

by Feifei Sun, Xinchuan Lu, Mingwei Yang, Chao Sun, Jinping Xie and Dong Sheng

Water 2024, 16(19), 2737; https://doi.org/10.3390/w16192737 - 26 Sep 2024

Abstract

Runoff prediction is of great importance to water utilization and water-project regulation. Although sun activity has been considered an important factor in runoff, little modeling has been constructed. This study put forward a forecast heuristic combining back propagation neural network (BPNN) and particle [...] Read more.

Runoff prediction is of great importance to water utilization and water-project regulation. Although sun activity has been considered an important factor in runoff, little modeling has been constructed. This study put forward a forecast heuristic combining back propagation neural network (BPNN) and particle swarm optimization (PSO) for annual runoff based on sunspot number and applied it to the Yellow River of China for the period 1956–2016 and assessed the contribution of the sunspot number by placing sole BPNN modeling on the time series as a contrast. First, the heuristic is made up of BPNN calibration and PSO optimization: (1) we use historical data to calibrate BPNN models and obtain a prediction of the sunspot number for training and testing stages; (2) we use the PSO to minimize the difference between the predicted runoff of both BPNN and a linear equation for forecasting stage. Second, the application offers interesting findings: (1) while BPNN calibration obtains first-class forecasting with the ratio >85% with <20% absolute error in training and testing stages, the PSO can achieve similar performance in the forecasting stage; (2) the heuristic can achieve better prediction in years with a lower sunspot number; (3) besides the influence of the sun activity, atmospheric circulation, water usage, and water-project regulation do play important roles on the measured or natural runoff to some extent. This study could provide useful insights into further forecasting of measured and natural runoff under this forecast heuristic in the world. Full article

(This article belongs to the Special Issue Hydrological Simulation and Forecasting Based on Artificial Intelligence)

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17 pages, 1290 KiB

Open AccessArticle

A Method for the Assessment of Underground Renewable Reserves for Large Regions: Its Importance in Water Supply Regulation

by Joaquín Sanz de Ojeda, Eugenio Sanz-Pérez and Juan Carlos Mosquera-Feijóo

Water 2024, 16(19), 2736; https://doi.org/10.3390/w16192736 - 26 Sep 2024

Abstract

The growing interest in groundwater as a sustainable resource for water supply regulation is noteworthy. Just as surface reservoirs in many countries are primarily designed to manage seasonal fluctuations throughout the year, aquifers possess significant reserves, making them particularly well suited for interannual [...] Read more.

The growing interest in groundwater as a sustainable resource for water supply regulation is noteworthy. Just as surface reservoirs in many countries are primarily designed to manage seasonal fluctuations throughout the year, aquifers possess significant reserves, making them particularly well suited for interannual regulation, especially during droughts. In the face of climate change, this form of regulation may increasingly highlight the importance of groundwater resources. For instance, the temporary use of groundwater reserves through intensive pumping in arid or semiarid regions, compensating for seasonal or interannual variations in natural water recharge, can significantly affect aquifers. The exploitation of groundwater reserves may lead to adverse effects over time, eventually being deemed overexploitation and subject to environmental or even legal issues. This work assesses the interannual regulation capacity of aquifers and estimates the groundwater renewal rates and periods for aquifers according to river basins. We first present the mathematical background and development of a method to assess the hydrodynamic volumes (renewable groundwater reserves) in large regions. This method builds on prior knowledge of the distribution functions of spring water contributions based on their discharge and for lithological groups exhibiting similar hydrogeological behavior. Furthermore, it establishes a relationship between spring discharges and hydrodynamic volumes, facilitating the integration of the latter based on discharge. Although proposed for Spain, the method can also be implemented to other regions where data are available. Full article

(This article belongs to the Special Issue The Qualitative and Quantitative Management of Groundwater Resources in Urban Areas)

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15 pages, 2953 KiB

Open AccessArticle

Characteristics of Runoff Changes during the Freeze–Thaw Period and the Response to Environmental Changes in a High-Latitude Water Tower

by Moran Xu, Yongming Chen, Dongmei Liu, Peng Qi, Yingna Sun, Licheng Guo and Guangxin Zhang

Water 2024, 16(19), 2735; https://doi.org/10.3390/w16192735 - 26 Sep 2024

Abstract

Runoff in high-latitude water towers is crucial for ecological and human water demands during freeze–thaw periods but is highly sensitive to climate change and human activities. This study focuses on Changbai Mountain, the source of the Songhua, Tumen, and Yalu rivers, analyzing runoff [...] Read more.

Runoff in high-latitude water towers is crucial for ecological and human water demands during freeze–thaw periods but is highly sensitive to climate change and human activities. This study focuses on Changbai Mountain, the source of the Songhua, Tumen, and Yalu rivers, analyzing runoff variation and its environmental responses using the modified Mann–Kendall method and the water–energy balance equation. The results show significant non-stationarity in runoff trends, with an increasing trend in the Yalu River basin (p < 0.05), a decreasing trend in the Tumen River basin (p < 0.05), and complex trends in the Songhua River basin. Additionally, the relationship between runoff and driving factors during freeze–thaw periods was quantized. When the snowfall, potential evapotranspiration (E0), and subsurface changes increased by 1%, the snowmelt runoff changes were 1.58~1.96%, −0.58~−1.96%, and −0.86~−1.11% in the Yalu River basin; 2.16~2.35%, −1.04~−1.35%, and −1.56~−1.95% in the Tumen River basin; and 1.44~2.41%, −0.44~−1.41%, and −0.72~−1.62% in the Songhua River basin. The increased snowfall was the most prominent reason for the increase in snowmelt runoff during spring. The results of this study will benefit ecosystem conservation and the stability of downstream water supply in this high-latitude water tower. Full article

(This article belongs to the Special Issue Climate Change and Hydrological Processes)

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16 pages, 3673 KiB

Open AccessArticle

Parameters Variation of Natural Gas Hydrate with Thermal Fluid Dissociation Based on Multi-Field Coupling under Pore-Scale Modeling

by Zhengyi Li, Zhiyuan Wang and Hongfei Ji

Water 2024, 16(19), 2734; https://doi.org/10.3390/w16192734 - 26 Sep 2024

Abstract

The permeability, heat conductivity, and reaction rate will be varied with the change of natural gas hydrate saturation when thermal fluid is injected into the natural gas hydrate reservoirs. In order to characterize the variation of the physical field parameters with hydrate saturation, [...] Read more.

The permeability, heat conductivity, and reaction rate will be varied with the change of natural gas hydrate saturation when thermal fluid is injected into the natural gas hydrate reservoirs. In order to characterize the variation of the physical field parameters with hydrate saturation, DDF-LBM was applied to simulate the hydrate dissociation process by thermal fluid injection under pore-scale modelling. Based on the forced conjugate heat transfer case, the relaxation frequency of the thermal lattice in the pores is corrected. Based on the P-T phase equilibrium relationship of hydrates and considering the heat absorbed by the hydrate reaction, the solid–liquid state of the hydrate lattice is judged in real time, and the dynamic simulation of the heat flow solidification multi-physics field is realized. The simulation results show that the dissociation rate of the hydrates by thermal fluid injection was higher than that by heating the hydrate surface alone and was positively correlated with the hydrate saturation. On the basis of the above results, this paper provided exponential fitting equations between different hydrate saturations and average permeability, effective thermal conductivity, and inherent reaction rate. The fitting results show that saturation has a negative correlation with relative permeability and effective thermal conductivity, and a positive correlation with the inherent reaction rate. The above results can provide a reference basis for accurately describing the heat and mass transfer of natural gas hydrate under the macroscale. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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22 pages, 6770 KiB

Open AccessArticle

Sediments of Hydropower Plant Water Reservoirs Contaminated with Potentially Toxic Elements as Indicators of Environmental Risk for River Basins

by João Batista Pereira Cabral, Wanderlubio Barbosa Gentil, Fernanda Luisa Ramalho, Assunção Andrade de Barcelos, Valter Antonio Becegato and Alexandre Tadeu Paulino

Water 2024, 16(19), 2733; https://doi.org/10.3390/w16192733 - 26 Sep 2024

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Abstract

The aim of this work was to determine the concentrations, distribution, and fate of potentially toxic elements [lead (Pb), zinc (Zn), nickel (Ni), copper (Cu), mercury (Hg), arsenic (As), and cadmium (Cd)] in sediments of a hydropower plant water reservoir located in the [...] Read more.

The aim of this work was to determine the concentrations, distribution, and fate of potentially toxic elements [lead (Pb), zinc (Zn), nickel (Ni), copper (Cu), mercury (Hg), arsenic (As), and cadmium (Cd)] in sediments of a hydropower plant water reservoir located in the Brazilian Cerrado biome (used as system model). The purpose of this study was achieved with an analysis of the level of contamination based on the geoaccumulation index (Igeo) and factor contamination (FC) and comparisons with values established by environmental legislation. The physical–chemical–biological properties of sediment samples, the distribution, and the fate of potentially toxic elements (PTEs) in the basin of the stream studied were also investigated using Pearson’s correlation coefficient (r) and principal component analysis (PCA). Cu, Hg, and Cd concentrations in the sediment samples from most of the points analyzed were above level II of the categorization stipulated in environmental legislation, characterizing sediments of poor quality. Moreover, Igeo and FC values indicated potential pollution of the water reservoir sediment by Cd. Concentrations of Cd exceeding 0.34 mg kg⁻¹ surpassed the reference values for water quality established by Conama Resolution No. 454/2012, highlighting the urgent need for ongoing sediment quality monitoring strategies. Hence, the study water reservoir was classified as being moderately to extremely polluted due to the fate of potentially toxic metals in the sediment samples. Frequent monitoring of the sediment quality in watersheds with hydropower plants is indispensable for the assessment of water resources, considering the importance of the water supply and power generation for the population. Moreover, water contaminated by PTEs poses potential risks to river basins, as well as to human and animal health. The results of this work can assist in the investigation of other water reservoirs around the world. Full article

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15 pages, 6034 KiB

Open AccessArticle

Risk Management Associated with Surface Sources of Public Water Supply in Urban and Rural Areas in a Developing Country

by Isabel Francisco de Araújo Reis, Hamilton Cristiano Leôncio, Ana Letícia Pilz de Castro and Aníbal da Fonseca Santiago

Water 2024, 16(19), 2732; https://doi.org/10.3390/w16192732 - 26 Sep 2024

Viewed by 199

Abstract

This research aimed to apply a risk management methodology to multiple surface water sources in urban and rural areas of a developing country. The applied methodology enabled the identification of hazards, classification, and the prioritization of risks at 21 collection points in the [...] Read more.

This research aimed to apply a risk management methodology to multiple surface water sources in urban and rural areas of a developing country. The applied methodology enabled the identification of hazards, classification, and the prioritization of risks at 21 collection points in the rural area and 9 collection points in the urban area. Both rural and urban areas exhibited common events with a high-risk level, such as human access (100% in urban areas and 90% in rural areas), climatic events, and inadequate collection structures (100% of points in both urban and rural areas). However, rural areas presented specific risks associated with animal husbandry (70% of points with high risk), a lack of monitoring, limited infrastructure (30% of points with high risk), and wildlife, including birds and worms (50% of points with high risk in rural areas and 10% in urban points). On the other hand, urban areas faced challenges related to vandalism and sabotage (high risk in 40% of points). Understanding these similarities and differences permits integrated risk management among the various stakeholders who can contribute to risk management within a watershed. Full article

(This article belongs to the Section Urban Water Management)

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17 pages, 2873 KiB

Open AccessArticle

Cascading Failure and Resilience of Urban Rail Transit Stations under Flood Conditions: A Case Study of Shanghai Metro

by Dekui Li, Yuru Hou, Shubo Du and Fan Zhou

Water 2024, 16(19), 2731; https://doi.org/10.3390/w16192731 - 25 Sep 2024

Viewed by 228

Abstract

The increasing frequency of urban flooding, driven by global climate change, poses significant threats to the safety and resilience of urban rail transit systems. This study systematically examines the cascading failure processes and resilience of these networks under flood conditions, with a specific [...] Read more.

The increasing frequency of urban flooding, driven by global climate change, poses significant threats to the safety and resilience of urban rail transit systems. This study systematically examines the cascading failure processes and resilience of these networks under flood conditions, with a specific focus on the Shanghai Metro. A comprehensive resilience evaluation model was developed by integrating geographic information, static network characteristics, and dynamic passenger flow indicators. This study employs an improved Coupled Map Lattice (CML) model to simulate cascading failures by considering the coupling effects of station centrality, geographic elevation, and passenger flow dynamics. The results indicate that stations with higher degrees of centrality are more likely to trigger rapid cascading failures across the network. However, incorporating dynamic passenger flow and geographic elevation data helps mitigate these effects, emphasizing the need for multi-dimensional resilience strategies. The findings provide valuable insights for urban transit management, offering a scientific foundation for developing targeted disaster response strategies to enhance network resilience against floods. This study advances our understanding of the vulnerability of urban rail transit systems and offers practical guidance for improving disaster preparedness in urban transportation infrastructure. Full article

(This article belongs to the Special Issue Assessment of Urban Pluvial Flood Risk and Utilization of Rainwater & Flood Resources, 2nd Edition)

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17 pages, 1727 KiB

Open AccessArticle

Zooplankton Index for Shallow Lakes’ Assessment: Elaboration of a New Classification Method for Polish Lakes

by Agnieszka Ochocka

Water 2024, 16(19), 2730; https://doi.org/10.3390/w16192730 - 25 Sep 2024

Viewed by 211

Abstract

Due to its fundamental position in the aquatic food chain linking primary producers (phytoplankton) to higher trophic levels (fish), zooplankton has a crucial influence on the structure and function of lakes. The scientific literature shows that zooplankton is an effective indicator of eutrophication. [...] Read more.

Due to its fundamental position in the aquatic food chain linking primary producers (phytoplankton) to higher trophic levels (fish), zooplankton has a crucial influence on the structure and function of lakes. The scientific literature shows that zooplankton is an effective indicator of eutrophication. However, according to the requirements of the Water Framework Directive, zooplankton is still not included as one of the biological components for assessing the ecological status of lakes. In Poland, the zooplankton-based method (ZIPLAs) has been developed to assess the ecological status of deep stratified lakes. Shallow lakes function differently from deep lakes, and literature data show that the response of zooplankton indices to eutrophication parameters is much weaker than in deep lakes. This paper presents the Zooplankton Index for Shallow Lakes’ Assessment (ZISLA), a new method for assessing ecological status based on zooplankton community structure. The ZISLA includes the body size index of Daphnia cucullata (BSI), the percentage share of high trophy-indicating rotifer species (IHTROT), the number of rotifer species (NROT), and the Margalef index (D). The ZISLA shows a strong, significant correlation with total phosphorus and total nitrogen (Spearman’s coefficient (R = −0.77, R = −0.74; p < 0.0001) and slightly weaker with Secchi disk visibility (R = 0.72; p < 0.0001). The ZISLA index shows a statistically significant good/moderate distinction for all water quality parameters. Full article

(This article belongs to the Section Water Quality and Contamination)

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27 pages, 16009 KiB

Open AccessArticle

Numerical Groundwater Model to Assess the Fate of Nitrates in the Coastal Aquifer of Arborea (Sardinia, Italy)

by Gerhard Schäfer, Manon Lincker, Antonio Sessini and Alberto Carletti

Water 2024, 16(19), 2729; https://doi.org/10.3390/w16192729 - 25 Sep 2024

Viewed by 184

Abstract

The Arborea plain in Sardinia (Italy) is classified as a nitrate-vulnerable zone (NVZ). In the present study, the individual work steps that are necessary to progress from the existing 3D hydrogeological model to a 3D numerical groundwater model using the interactive finite-element simulation [...] Read more.

The Arborea plain in Sardinia (Italy) is classified as a nitrate-vulnerable zone (NVZ). In the present study, the individual work steps that are necessary to progress from the existing 3D hydrogeological model to a 3D numerical groundwater model using the interactive finite-element simulation system FEFLOW 7.4 are shown. The results of the transient flow model highlight the influence of the drainage network on the overall groundwater management: the total water volume drained by the ditches accounted for approximately 58% of the annual outflow volume. The numerical transport simulations conducted from 2012 to 2020 using hypothetical field-based nitrate input scenarios globally underestimated the high concentrations that were observed in the NVZ. However, as observed in the field, the computed nitrate concentrations in December 2020 still varied strongly in space, from several mg L⁻¹ to several hundreds of mg L⁻¹. The origin of these remaining local hotspots is not yet known. The modeling of rainfall fluctuations under the influence of climate change revealed a general long-term decline in the groundwater level of several tens of centimeters in the long term and, in conjunction with a zero-nitrate scenario, led to a significant decrease in nitrate pollution. Although hotspots were attenuated, the concentrations at several monitoring wells still exceeded the limit value of 50 mg L⁻¹. Full article

(This article belongs to the Special Issue Water-Related Geoenvironmental Issues, 2nd Edition)

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23 pages, 1745 KiB

Open AccessReview

Morbidity and Water Quality: A Review with a Case Study in Tonosí, Panama

by Natasha A. Gómez Zanetti, Jorge E. Olmos Guevara and Yazmin L. Mack-Vergara

Water 2024, 16(19), 2728; https://doi.org/10.3390/w16192728 - 25 Sep 2024

Viewed by 212

Abstract

Water quality concerns the physical, chemical, and biological factors that could negatively impact human health through its consumption, potentially causing infectious and chronic diseases due to immediate or prolonged exposure. In this context, the objective of this study is to identify diseases that [...] Read more.

Water quality concerns the physical, chemical, and biological factors that could negatively impact human health through its consumption, potentially causing infectious and chronic diseases due to immediate or prolonged exposure. In this context, the objective of this study is to identify diseases that are correlated with the quality of drinking water according to the literature. A systematic review was carried out considering academic and scientific documents from the last 6 years, including peer-reviewed research articles, books, and technical documents, such as standards and regulations related to public health and water quality. Subsequently, these results were applied to a case study from Tonosí (a district in Panama), where a drinking water quality assessment project was developed over the past two years including physicochemical, biological, inorganic chemical, and organic chemical analyses on drinking water during the rainy and dry seasons. Forty-five documents were obtained from the literature review and are presented in tables relating to diseases and water quality parameters. Based on the drinking water quality assessment results from Tonosí, the levels above and below the permissible range—according to the DGNTI-COPANIT 21-2019 Technical Regulation adopted by Panama as a drinking water quality standard—and the diseases associated with the parameters evaluated (in accordance with the literature review) are presented. The results show that there is a possible relationship between some of the water quality parameters and cases of gastrointestinal diseases in the area; however, more in-depth research and statistics at the national level are needed on the health of the population. Full article

(This article belongs to the Special Issue Studies on Water Resource and Environmental Policies)

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18 pages, 4533 KiB

Open AccessReview

Seasonal Variations of Ice-Covered Lake Ecosystems in the Context of Climate Warming: A Review

by Qianqian Wang, Fang Yang, Haiqing Liao, Weiying Feng, Meichen Ji, Zhiming Han, Ting Pan and Dongxia Feng

Water 2024, 16(19), 2727; https://doi.org/10.3390/w16192727 - 25 Sep 2024

Viewed by 231

Abstract

The period of freezing is an important phenological characteristic of lakes in the Northern Hemisphere, exhibiting higher sensitivity to regional climate changes and aiding in the detection of Earth’s response to climate change. This review systematically examines 1141 articles on seasonal frozen lakes [...] Read more.

The period of freezing is an important phenological characteristic of lakes in the Northern Hemisphere, exhibiting higher sensitivity to regional climate changes and aiding in the detection of Earth’s response to climate change. This review systematically examines 1141 articles on seasonal frozen lakes from 1991 to 2021, aiming to understand the seasonal variations and control conditions of ice-covered lakes. For the former, we discussed the physical structure and growth characteristics of seasonal ice cover, changes in water environmental conditions and primary production, accumulation and transformation of CO₂ beneath the ice, and the role of winter lakes as carbon sources or sinks. We also proposed a concept of structural stratification based on the differences in physical properties of ice and solute content. The latter provided an overview of the ice-covered period (−1.2 d decade⁻¹), lake evaporation (+16% by the end of the 21st century), the response of planktonic organisms (earlier spring blooming: 2.17 d year⁻¹) to global climate change, the impact of greenhouse gas emissions on ice-free events, and the influence of individual characteristics such as depth, latitude, and elevation on the seasonal frozen lakes. Finally, future research directions for seasonally ice-covered lakes are discussed. Considering the limited and less systematic research conducted so far, this study aims to use bibliometric methods to synthesize and describe the trends and main research points of seasonal ice-covered lakes so as to lay an important foundation for scholars in this field to better understand the existing research progress and explore future research directions. Full article

(This article belongs to the Special Issue China Water Forum 2024)

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19 pages, 5063 KiB

Open AccessArticle

An Urban Flood Model Development Coupling the 1D and 2D Model with Fixed-Time Synchronization

by Sang-Bo Sim and Hyung-Jun Kim

Water 2024, 16(19), 2726; https://doi.org/10.3390/w16192726 - 25 Sep 2024

Viewed by 274

Abstract

Due to climate change, the frequency and intensity of torrential rainfall in urban areas are increasing, leading to more frequent flood damage. Consequently, there is a need for a rapid and accurate analysis of urban flood response capabilities. The dual-drainage model has been [...] Read more.

Due to climate change, the frequency and intensity of torrential rainfall in urban areas are increasing, leading to more frequent flood damage. Consequently, there is a need for a rapid and accurate analysis of urban flood response capabilities. The dual-drainage model has been widely used for accurate flood analysis, with minimum time step synchronization being commonly adopted. However, this method has limitations in terms of speed. This study applied the hyper-connected solution for an urban flood (HC-SURF) model with fixed-time step flow synchronization, validated its accuracy using laboratory observation data, and tested its effectiveness in real urban watersheds with various synchronization times. Excellent performance was achieved in simulating real phenomena. In actual urban watersheds, as the synchronization time increased, the errors in surcharge and discharge also increased due to the inability to accurately reflect water level changes within the synchronization time; however, overall, they remained minimal. Therefore, the HC-SURF model is demonstrated as a useful tool for urban flood management that can be used to advantage in real-time flood forecasting and decision-making. Full article

(This article belongs to the Topic Urban Hydrogeology Research)

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16 pages, 2262 KiB

Open AccessArticle

Decontamination Potential of Ultraviolet Type C Radiation in Water Treatment Systems: Targeting Microbial Inactivation

by Abayomi Olusegun Adeniyi and Modupe Olufunmilayo Jimoh

Water 2024, 16(19), 2725; https://doi.org/10.3390/w16192725 - 25 Sep 2024

Viewed by 212

Abstract

Access to safe water and sanitation is a critical global challenge, posing significant health risks worldwide due to waterborne diseases. This study investigates the efficacy of ultraviolet type C radiation as a disinfection method for improving water quality. The research elucidates UV-C’s mechanism [...] Read more.

Access to safe water and sanitation is a critical global challenge, posing significant health risks worldwide due to waterborne diseases. This study investigates the efficacy of ultraviolet type C radiation as a disinfection method for improving water quality. The research elucidates UV-C’s mechanism of action, highlighting its ability to disrupt DNA and RNA replication, thereby inactivating pathogens. Furthermore, the study analyses the influence of key factors on UV-C disinfection effectiveness, including water turbidity and the presence of dissolved organic matter, which can attenuate UV-C penetration and reduce treatment efficiency. The experimental results demonstrate a substantial reduction in microbial content following UV-C treatment. River water samples exhibited a 57.143% reduction in microbial load, while well water samples showed a 50% reduction. Notably, Escherichia coli (E. coli) concentrations decreased significantly, with an 83.33% reduction in well water and a 62.5% reduction in borehole water. This study makes a novel contribution to the understanding of UV-C disinfection by identifying the presence of resistant organisms, including Adenoviruses, Bacterial spores, and the Protozoan Acanthamoeba, in water samples. This finding expands the scope of UV-C research beyond easily culturable bacteria. To address this challenge, future investigations should explore synergistic disinfection strategies, such as combining UV-C treatment with advanced oxidation processes. Optimising UV-C system designs and developing robust, real-time monitoring systems capable of detecting and quantifying known and emerging UV-resistant pathogens are crucial for ensuring comprehensive water decontamination. Full article

(This article belongs to the Section Wastewater Treatment and Reuse)

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22 pages, 3600 KiB

Open AccessArticle

Seasonal- and Event-Scale Stream DOC Dynamics in Northern Hardwood-Dominated Headwater Catchments of Contrasting Forest Harvest History

by Annie Gray, Micheal Stone, Kara L. Webster, Jason A. Leach, James M. Buttle and Monica B. Emelko

Water 2024, 16(19), 2724; https://doi.org/10.3390/w16192724 - 25 Sep 2024

Viewed by 191

Abstract

Forests are critical source regions of high-quality drinking water but forest disturbances such as harvesting can alter stream dissolved organic carbon (DOC) concentrations and influence source water treatability. Most stream DOC-centric forest harvesting impact studies report on effects <10 years post-harvest; less is [...] Read more.

Forests are critical source regions of high-quality drinking water but forest disturbances such as harvesting can alter stream dissolved organic carbon (DOC) concentrations and influence source water treatability. Most stream DOC-centric forest harvesting impact studies report on effects <10 years post-harvest; less is known about the legacy effects of forest harvesting on stream DOC. Here, inter- and intra-catchment variability in stream DOC concentration and export were evaluated in two northern hardwood-dominated headwater catchments (unharvested reference and 24 years post-clearcut). The relationship between stream DOC and the concentration, spatial distribution, and hydrologic connectivity of hillslope solute pool DOC was investigated. Stream DOC concentrations in the legacy clearcut catchment exceeded those in the reference catchment for all flow conditions. Inter-catchment differences in DOC export were inconsistent. Hillslope solute pool DOC concentrations decreased with soil depth but were not significantly different between catchments. Concentration–discharge regression analysis indicated that DOC was primarily transport-limited (flushing) in both catchments. Aqueous potassium silica molar ratio data indicate the influence of groundwater on stream chemistry and streamflow was similar in both catchments. Results suggest that while clearcut harvesting can have detectable decadal-scale effects on stream DOC concentrations in northern hardwood-dominated headwater catchments, the effects are limited and likely do not pose a reasonable threat to downstream drinking water treatment operations. Full article

(This article belongs to the Section Water and Climate Change)

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20 pages, 12466 KiB

Open AccessArticle

Status, Sources, and Risks of Heavy Metals in Surface Sediments of Baiyangdian Lake and Inflow Rivers, North China

by Hongwei Liu, Yaonan Bai, Yihang Gao, Bo Han, Jinjie Miao, Yanchao Shi and Fengtian Yang

Water 2024, 16(19), 2723; https://doi.org/10.3390/w16192723 - 25 Sep 2024

Viewed by 232

Abstract

Baiyangdian Lake, recognized as the largest freshwater body in northern China, plays a vital role in maintaining the regional eco-environment. Prior studies have pointed out the contamination of sediments with heavy metals, raising concerns about eco-environmental challenges. Therefore, it is imperative to evaluate [...] Read more.

Baiyangdian Lake, recognized as the largest freshwater body in northern China, plays a vital role in maintaining the regional eco-environment. Prior studies have pointed out the contamination of sediments with heavy metals, raising concerns about eco-environmental challenges. Therefore, it is imperative to evaluate the current pollution levels and ecological threats related to heavy metals found in the sediments of Baiyangdian Lake as well as in its inflow rivers. In May 2022, surface sediments with a depth of less than 20 cm were analyzed for Cu, Zn, Pb, Cr, Ni, As, Cd, and Hg to determine the pollution status, identify sources of pollution, and evaluate potential ecological risks. A range of evaluation methods used by predecessors such as geo-accumulation index (I_geo), enrichment factor (EF), ecological risk index (RI), sediment quality guidelines (SQGs), positive matrix factorization (PMF), absolute principal component score-multiple linear regression model (APCS-MLR), chemical mass balance (CMB), and UNMIX model were analyzed. After comparison, multi-methods including the geo-accumulation index (Igeo), absolute principal component score-multiple linear regression model (APCS-MLR), ecological risk index (RI), and sediment quality guidelines (SQGs) were utilized this time, leading to a better result. Findings reveal that pollution levels are generally low or non-existent, with only 1.64% of sampling sites showing close to moderate pollution levels for Cu, Pb, and Zn, and 4.92% and 1.64% of sites exhibiting close to moderate and moderate pollution levels for Cd, respectively. The main contributors to heavy metal presence are pinpointed as industrial wastewater discharge, particularly Cu, Zn, Pb, Cd, and Hg. The ecological risks are also relatively low, with 4.92%, 1.64%, and 1.64% of sampling sites demonstrating close to moderate, moderate, and strong risks in the inflow rivers, respectively. Additionally, only one site shows moderate potential biological toxicity, while the rest display non-toxicity. These findings will update our cognition and offer a scientific basis for pollution treatment and ecosystem enhancement for government management. Full article

(This article belongs to the Special Issue Soil and Groundwater Quality and Resources Assessment)

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14 pages, 3337 KiB

Open AccessArticle

Innovative Treatment of Urban Wastewater by Flocculation Combined with Ozone Pre-Oxidation and Denitrification

by Weiqi Zhou, Ning Fang, Yali Guo, Fan Yang, Xinyue Liu and Zhujun Luo

Water 2024, 16(19), 2722; https://doi.org/10.3390/w16192722 - 25 Sep 2024

Viewed by 246

Abstract

In this study, urban wastewater was treated by flocculation, ozone pre-oxidation and denitrification for efficient purification. Polymeric aluminum chloride (PAC) and polymeric aluminum ferric sulfate (PAFS) were added to the wastewater at different levels to remove the COD, turbidity, TP and TN of [...] Read more.

In this study, urban wastewater was treated by flocculation, ozone pre-oxidation and denitrification for efficient purification. Polymeric aluminum chloride (PAC) and polymeric aluminum ferric sulfate (PAFS) were added to the wastewater at different levels to remove the COD, turbidity, TP and TN of the wastewater. A better flocculant was selected and its optimum ozone pre-oxidation concentration was determined by changing the ozone concentration and measuring the effluent quality. Denitrification was further enhanced by varying the C/N ratio of the wastewater. The results show that, with the increase in flocculant dosage, the removal rates of COD, turbidity, TP and TN by PAC and PAFS were improved. The purification effect of PAC was better than that of PAFS and the optimum removal of COD, turbidity, TP and TN was obtained at a dosage of 80 mg L⁻¹ by PAC, at 55.9%, 55.6%, 90.0% and 13.3%, respectively. Ozone pre-oxidation enhanced the removal of COD, turbidity and TN by PAC, and the optimal ozone dosage was 1.2 mg L⁻¹, which resulted in 64.8%, 57.1% and 24.8% removal of COD, turbidity and TN, respectively. With the increase in the C/N ratio from 2.0 to 4.0, the NO₃⁻-N concentration of PAC-treated water gradually decreased, but when the C/N ratio was 4.0, the COD concentration increased, so the optimal C/N ratio should be 3.5. Overall, the combination of ozone pre-oxidation, denitrification and flocculation was an effective method to treat urban wastewater, which has a strong application prospect. Full article

(This article belongs to the Section Wastewater Treatment and Reuse)

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20 pages, 1989 KiB

Open AccessArticle

EstuarySAT Database Development of Harmonized Remote Sensing and Water Quality Data for Tidal and Estuarine Systems

by Steven A. Rego, Naomi E. Detenbeck and Xiao Shen

Water 2024, 16(19), 2721; https://doi.org/10.3390/w16192721 - 25 Sep 2024

Viewed by 274

Abstract

Researchers and environmental managers need big datasets spanning long time periods to accurately assess current and historical water quality conditions in fresh and estuarine waters. Using remote sensing data, we can survey many water bodies simultaneously and evaluate water quality conditions with greater [...] Read more.

Researchers and environmental managers need big datasets spanning long time periods to accurately assess current and historical water quality conditions in fresh and estuarine waters. Using remote sensing data, we can survey many water bodies simultaneously and evaluate water quality conditions with greater frequency. The combination of existing and historical water quality data with remote sensing imagery into a unified database allows researchers to improve remote sensing algorithms and improves understanding of mechanisms causing blooms. We report on the development of a water quality database “EstuarySAT” which combines data from the Sentinel-2 multi-spectral instrument (MSI) remote sensing platform and water quality data throughout the coastal USA. EstuarySAT builds upon an existing database and set of methods developed by the creators of AquaSat, whose region of interest is primarily larger freshwater lakes in the USA. Following the same basic methods, EstuarySAT utilizes open-source tools: R v. 3.24+ (statistical software), Python (dynamic programming environment), and Google Earth Engine (GEE) to develop a combined water quality data and remote sensing imagery database (EstuarySAT) for smaller coastal estuarine and freshwater tidal riverine systems. EstuarySAT fills a data gap that exists between freshwater and estuarine water bodies. We are able to evaluate smaller systems due to the higher spatial resolution of Sentinel-2 (10 m pixel image resolution) vs. the Landsat platform used by AquaSat (30 m pixel resolution). Sentinel-2 also has a more frequent revisit (overpass) schedule of every 5 to 10 days vs. Landsat 7 which is every 17 days. EstuarySAT incorporates publicly available water quality data from 23 individual water quality data sources spanning 1984–2021 and spatially matches them with Sentinel-2 imagery from 2015–2021. EstuarySAT currently contains 299,851 matched observations distributed across the coastal USA. EstuarySAT’s primary focus is on collecting chlorophyll data; however, it also contains other ancillary water quality data, including temperature, salinity, pH, dissolved oxygen, dissolved organic carbon, and turbidity (where available). As compared to other ocean color databases used for developing predictive chlorophyll algorithms, this coastal database contains spectral profiles more typical of CDOM-dominated systems. This database can assist researchers and managers in evaluating algal bloom causes and predicting the occurrence of future blooms. Full article

(This article belongs to the Section Water Quality and Contamination)

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39 pages, 21329 KiB

Open AccessArticle

Irrotational Flow over Ogee Spillway Crest: New Solution Method and Flow Geometry Analysis

by Oscar Castro-Orgaz, Willi H. Hager, Yakun Guo, Sebastien Erpicum and Francisco Nicolás Cantero-Chinchilla

Water 2024, 16(19), 2720; https://doi.org/10.3390/w16192720 - 24 Sep 2024

Viewed by 492

Abstract

A spillway is a hydraulic structure of major importance in dam safety, and its current analysis usually involves a hybrid approach combining CFD modeling with experimental research, either using well-known WES design charts or conducting new model experiments in the laboratory. Flow over [...] Read more.

A spillway is a hydraulic structure of major importance in dam safety, and its current analysis usually involves a hybrid approach combining CFD modeling with experimental research, either using well-known WES design charts or conducting new model experiments in the laboratory. Flow over spillway crests involves fluid accelerations, making irrotationality an adequate simplification of the Navier–Stokes (NS) equations. However, an efficient tool using this method is currently lacking for spillway flow, particularly for ogee spillway flow. This work focuses on this aspect of the problem, and a new method for computing irrotational flow solutions over ogee spillways is proposed by developing flow net computational solutions. The proposed method entails a new iterative procedure in the complex potential plane where free surface pressures are exactly set to zero, contrary to other methods, and an automatic determination of the critical point, the unknown energy head, and the free surface profile. The model generates solutions efficiently in only a few seconds on a personal workstation, permitting a fast estimate of spillway flow operation, and is thus an effective complement to experimental and NS-CFD modeling. The solutions produced are compared with observations of a high operational head equal to five times the design head of the ogee crest, resulting in reasonable agreement. The application of the new model to investigate the limitations of analytical equations used in spillway flow, like Jaeger’s theory, establishes limits for its use by relating its curvature parameter to the spillway chute slope. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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17 pages, 3213 KiB

Open AccessArticle

Assessment of Leachate Generated by Sargassum spp. in the Mexican Caribbean: Part 2, Mobility of Metals

by Rosa Maria Leal-Bautista, Juan Carlos Rodríguez-García, Rubi Chablé-Villacis, Gilberto Acosta-González, Jose Epigmenio Bautista-García, Raul Tapia-Tussell, Daniela Ortega-Camacho, Edgar Olguín-Maciel and Gloria González López

Water 2024, 16(19), 2719; https://doi.org/10.3390/w16192719 - 24 Sep 2024

Viewed by 278

Abstract

The spread of sargassum on beaches in Africa, Brazil, Central America, and the Caribbean has increased to become a social, environmental, and economic problem. In recent years, the presence of biomass on the coasts of the Mexican Caribbean has been recorded as ≈2360 [...] Read more.

The spread of sargassum on beaches in Africa, Brazil, Central America, and the Caribbean has increased to become a social, environmental, and economic problem. In recent years, the presence of biomass on the coasts of the Mexican Caribbean has been recorded as ≈2360 m³ Km⁻¹, reaching up to 200 m wide in the northern part of the coasts. Its removal from the coast and, later, the continent is one of the strategies implemented to mitigate its impact on land. Several studies have reported the seasonality of and geographic variation in sorbed metals in sargasso. However, it is unknown whether these metals can mobilize or remain in sargassum tissue once they reach accumulation sites. This study included seawater, sargassum tissue as a consortium, and S. natans and S. fluitans, as well as the leachate generated in the process of degradation per se and percolated by rain. Of the 10 metals evaluated (As, B, Fe, Zn, Mn, Cd, Al, Ni, Cu, and Pb for water, tissue, and leachate), only B is recurrent in water from the north of the Mexican Caribbean, in addition to traces of Al and Fe. Meanwhile, in tissue, the results coincide with those of previous studies, where As is recurrent, although its concentration varies with the mentioned variability. The leachate showed that four to eight metals of those present in the tissue were detected, including As, Fe, and Al, which represent a potential impact on coastal systems and infiltration into shallow water table areas. Full article

(This article belongs to the Special Issue Marine Ecological Monitoring, Assessment and Protection)

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23 pages, 2296 KiB

Open AccessArticle

Multivariate Statistical Approach and Assessment of Pollution of Water and Sediments in Karstic Springs of Transboundary Aquifer Žumberak–Samoborsko Gorje Mountain (Croatia/Slovenia)

by Nenad Buzjak, Natalija Matić, Krešimir Maldini and Vinod Jena

Water 2024, 16(19), 2718; https://doi.org/10.3390/w16192718 - 24 Sep 2024

Viewed by 362

Abstract

This study highlights the geochemistry of water and sediments of the karstic springs of the transboundary aquifer (TBA) Žumberak–Samoborsko Gorje Mt. (NW Croatia). After calculating pollution indices, the analysis showed that the sediments are unpolluted. The geo-accumulation index (Igeo) showed only the elements [...] Read more.

This study highlights the geochemistry of water and sediments of the karstic springs of the transboundary aquifer (TBA) Žumberak–Samoborsko Gorje Mt. (NW Croatia). After calculating pollution indices, the analysis showed that the sediments are unpolluted. The geo-accumulation index (Igeo) showed only the elements Ba and Rb, indicating moderate levels of pollution, with the highest values in springs Vapnik and Bistrac. Statistical analysis confirmed their natural origin. The water of these springs is under possible anthropogenic influence as indicated by elevated concentrations of total nitrogen (TN) and total phosphorus (TP). According to a principal component analysis (PCA) for elements in sediments, PC1 described a combined lithogenic and oxidative–reductive influence, PC2 described a combined geological background including total organic carbon (TOC) content and oxidative–reductive influence, while TOC had the greatest influence on PC3. Depending on element composition, the factor scores related to PC1 and PC2 resulted in two different groups of sites, while the factor scores concerning PC1 and PC3 did not show separation in two groups. The hierarchical cluster analysis showed three clusters in relation to the content of the elements. The correlation coefficient between the sediment and related water samples showed that the springs placed in a low-permeability formation (dolomite) had a strong positive coefficient of correlation. Full article

(This article belongs to the Section Hydrogeology)

17 pages, 2199 KiB

Open AccessReview

Stormwater Management in Urban Coastal Areas—A Review

by António Geraldes, Francisco Piqueiro, Cristina Santos and Cristina Matos

Water 2024, 16(19), 2717; https://doi.org/10.3390/w16192717 - 24 Sep 2024

Viewed by 306

Abstract

Stormwater management in coastal urban cities, where drainage networks are influenced by marine dynamics and specific soil and altimetry conditions, has specific challenges that need to be addressed to ensure adequate management in such areas, which are also heavily affected by floods. Their [...] Read more.

Stormwater management in coastal urban cities, where drainage networks are influenced by marine dynamics and specific soil and altimetry conditions, has specific challenges that need to be addressed to ensure adequate management in such areas, which are also heavily affected by floods. Their location downstream of drainage basins and the interaction of network outfalls with current and tidal variability increases the vulnerability of populations and should therefore be the target of specific studies. This article presents a literature review, where publications that focus on stormwater management in coastal urban areas were identified and analyzed. The main objective was to present the key issues related to drainage in coastal areas, the most relevant challenges, the solutions and strategies that reveal the greater potential for application and the challenges for modeling this type of case. It is intended to provide a grounded basis for new ways of optimizing stormwater drainage in coastal areas and promote a sustainable urban water cycle. This review reveals the necessity to implement a multidisciplinary approach to minimize three main issues: urban flooding, stormwater pollution and groundwater salinization, including the adaptation of existing infrastructures, complementing them with control solutions at source, correct urban planning and the involvement of populations. For an effective management of urban stormwater drainage in coastal areas, this approach must be carried out on a watershed scale, duly supported by reliable decision support tools and monitoring systems. Full article

(This article belongs to the Special Issue Urban Drainage Systems and Stormwater Management)

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23 pages, 6058 KiB

Open AccessArticle

Hydraulic Property Estimation of Green Roof Substrates from Soil Moisture Time Series

by Blanca Cuadrado-Alarcón, Tom Vanwalleghem, Ana María Laguna, Antonio Hayas, Adolfo Peña, Gonzalo Martínez, Ángel Lora and Juan Vicente Giráldez

Water 2024, 16(19), 2716; https://doi.org/10.3390/w16192716 - 24 Sep 2024

Viewed by 340

Abstract

The adoption of green roofs is an effective practice for mitigating environmental issues in urban areas caused by extreme weather conditions. However, certain design aspects of green roofs, such as the characterization of the physical properties of their substrates, need a better understanding. [...] Read more.

The adoption of green roofs is an effective practice for mitigating environmental issues in urban areas caused by extreme weather conditions. However, certain design aspects of green roofs, such as the characterization of the physical properties of their substrates, need a better understanding. This study proposes a simple method for estimating two hydraulic properties of green roof substrates based on the evolution of moisture during drying periods, or drydowns, where evaporative processes dominate: the weighted-mean diffusivity and the saturated hydraulic conductivity. Soil moisture was monitored using 12 in situ sensors from 2015 to 2020 in a study involving six different green roof plots composed of various mixtures of demolition-recycled aggregates and organic substrates. A universal parameterization for determining water diffusivity in soils was applied to estimate the weighted-mean hydraulic diffusivity. As a by-product, the saturated hydraulic conductivity was estimated from the evaluated diffusivity and the measured water retention data. The median values obtained for

\bar{D}

and

k_{s}

range from 14.5 to 29.9 cm²d⁻¹ and from 22 to 361 cmd⁻¹, respectively. These values fall within the ranges reported by other research groups using direct measurement methods and supports the validity of Brutsaert’s model for green roof substrates. Furthermore, an increase in

\bar{D}

and a decrease in

k_{s}

were observed as the percentage of recycled aggregates in the substrates increased, which could be considered for design purposes. Full article

(This article belongs to the Section Soil and Water)

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