Water

15 pages, 7776 KiB

Open AccessArticle

Characteristics of Transient Flow in Rapidly Filled Closed Pipeline

by Kan Wang, You Fu and Jin Jiang

Water 2024, 16(17), 2377; https://doi.org/10.3390/w16172377 (registering DOI) - 24 Aug 2024

Viewed by 85

In this study, a one-dimensional mathematical model based on rigid theory is developed to evaluate the maximum water filling flow rate and filling time of closed pipeline water supply systems during rapid-filling processes. Polynomial fitting is utilized for prediction, and numerical simulation results [...] Read more.

In this study, a one-dimensional mathematical model based on rigid theory is developed to evaluate the maximum water filling flow rate and filling time of closed pipeline water supply systems during rapid-filling processes. Polynomial fitting is utilized for prediction, and numerical simulation results are analyzed to understand the variations in maximum water filling flow rate, filling time, and pressure with respect to opening valve time, air valve area, filling head, and segmented filling pipe length. The findings highlight the significant impact of the filling head on the maximum water filling flow rate, while the filling time is predominantly influenced by the gas discharge coefficient. Rapid changes occur only at the initial stage of rapid filling, reaching the maximum value with a very high acceleration (around t = 4 s). It is observed that pressure fluctuations in the gas–liquid two-phase flow inside the pipeline lead to velocity differences and periodic changes in gas pressure opposite to the filling head. When the gas discharge coefficient reaches approximately 0.3, pressure variation within the water supply system diminishes, and the time and flow rate required for pipeline filling become independent of the discharge coefficient. This study suggests the use of a segmented filling approach to ensure the effectiveness and stability of pipeline filling. Full article

(This article belongs to the Special Issue Hydraulics and Hydrodynamics in Fluid Machinery)

► Show Figures

Figure 1

21 pages, 21660 KiB

Open AccessArticle

Modelling High Resolution Agricultural Nitrogen Budgets: A Case Study for Germany

by Maximilian Zinnbauer, Elke Brandes, Max Eysholdt, Martin Henseler and Philipp Löw

Water 2024, 16(17), 2376; https://doi.org/10.3390/w16172376 (registering DOI) - 24 Aug 2024

Viewed by 92

Abstract

Water pollution with nitrogen (N) from agriculture constitutes a persisting environmental problem in intensive farming regions worldwide. Understanding the spatio-temporal interconnection between agricultural N emissions and N inputs to water bodies is key to evaluating and improving existing mitigation policies. Nitrogen flux models [...] Read more.

Water pollution with nitrogen (N) from agriculture constitutes a persisting environmental problem in intensive farming regions worldwide. Understanding the spatio-temporal interconnection between agricultural N emissions and N inputs to water bodies is key to evaluating and improving existing mitigation policies. Nitrogen flux models are an indispensable tool for addressing these complex research questions in the land use–water nexus, requiring adequate data on agricultural N surpluses. However, high-resolution farm management data are not readily available to the scientific community. We develop a municipality-level agricultural N budget model for Germany based on farm-level administration data from the Integrated Administration and Control System (IACS) and regional expert knowledge. We estimate a total agricultural N surplus of 58 kg N ha⁻¹ of utilised agricultural area as the three-year average for 2014–2016. About 90% of municipalities exhibit N surpluses between 21 and 99 kg N ha⁻¹. Evaluation with collected farm accountancy data revealed a good fit of the modelled (with observed) mineral N quantities applied. Our results highlight the potential of farm-level data for N flux models. Due to the ubiquitous reporting of land use and farming structures in the IACS, our approach can be adapted in other countries of the EU to serve as a harmonised backbone of monitoring and policy impact assessments. Full article

(This article belongs to the Special Issue Agricultural Water Protection in Europe under Pressure: Current State of Nutrient Flux Modeling and Assessment of the Impact of Mitigation Measures at National Level)

► Show Figures

Figure 1

30 pages, 6125 KiB

Open AccessArticle

Spatial Mapping and Prediction of Groundwater Quality Using Ensemble Learning Models and SHapley Additive exPlanations with Spatial Uncertainty Analysis

by Shilong Yang, Danyuan Luo, Jiayao Tan, Shuyi Li, Xiaoqing Song, Ruihan Xiong, Jinghan Wang, Chuanming Ma and Hanxiang Xiong

Water 2024, 16(17), 2375; https://doi.org/10.3390/w16172375 (registering DOI) - 24 Aug 2024

Viewed by 116

Abstract

The spatial mapping and prediction of groundwater quality (GWQ) is important for sustainable groundwater management, but several research gaps remain unexplored, including the inaccuracy of spatial interpolation, limited consideration of the geological environment and human activity effects, limitation to specific pollutants, and unsystematic [...] Read more.

The spatial mapping and prediction of groundwater quality (GWQ) is important for sustainable groundwater management, but several research gaps remain unexplored, including the inaccuracy of spatial interpolation, limited consideration of the geological environment and human activity effects, limitation to specific pollutants, and unsystematic indicator selection. This study utilized the entropy-weighted water quality index (EWQI), the LightGBM model, the pressure-state-response (PSR) framework and SHapley Additive exPlanations (SHAP) analysis to address the above research gaps. The normalized importance (NI) shows that NO₃⁻ (0.208), Mg²⁺ (0.143), SO₄²⁻ (0.110), Cr⁶⁺ (0.109) and Na⁺ (0.095) should be prioritized as parameters for remediation, and the skewness EWQI distribution indicates that although most sampled locations have acceptable GWQ, a few areas suffer from severely poor GWQ. The PSR framework identifies 13 indicators from geological environments and human activities for the SMP of GWQ. Despite high AUROCs (0.9074, 0.8981, 0.8885, 0.9043) across four random training and testing sets, it was surprising that significant spatial uncertainty was observed, with Pearson correlation coefficients (PCCs) from 0.5365 to 0.8066. We addressed this issue by using the spatial-grid average probabilities of four maps. Additionally, population and nighttime light are key indicators, while net recharge, land use and cover (LULC), and the degree of urbanization have the lowest importance. SHAP analysis highlights both positive and negative impacts of human activities on GWQ, identifying point-source pollution as the main cause of the poor GWQ in the study area. Due to the limited research on this field, future studies should focus on six key aspects: multi-method GWQ assessment, quantitative relationships between indicators and GWQ, comparisons of various spatial mapping and prediction models, the application of the PSR framework for indicator selection, the development of methods to reduce spatial uncertainty, and the use of explainable machine learning techniques in groundwater management. Full article

(This article belongs to the Special Issue Application of Smart Technologies in Integrated Water Quality Modeling)

► Show Figures

Figure 1

14 pages, 4957 KiB

Open AccessArticle

Manganese Oxide Enhanced Gravity-Driven Membrane (GDM) Filtration in Treating Iron- and Manganese-Containing Surface Water

by Jiaoying Luo, Yaru Zhang, Hailin Chang, Chenghai Lin, Yating Hu, Haochun Wang, Yanrui Wang and Xiaobin Tang

Water 2024, 16(17), 2374; https://doi.org/10.3390/w16172374 - 23 Aug 2024

Viewed by 212

Abstract

Manganese pollution in surface water has been a new concern in decentralized drinking water treatment. The dissolved manganese cannot be effectively removed by the traditional ultrafiltration (UF) process, but will cause severe membrane fouling. To address such issues, an innovative gravity-driven membrane (GDM) [...] Read more.

Manganese pollution in surface water has been a new concern in decentralized drinking water treatment. The dissolved manganese cannot be effectively removed by the traditional ultrafiltration (UF) process, but will cause severe membrane fouling. To address such issues, an innovative gravity-driven membrane (GDM) coupled with a dynamic manganese oxide (MnOx) film on the membrane surface was proposed, with hopes of enhancing manganese removal and alleviating membrane fouling. The results demonstrated that pre-coating a dynamic MnOx film on the membrane surface of a GDM system would effectively reduce start-up time for removing iron and manganese pollutants, without affecting the flux stabilization of the GDM. Effective manganese removal (~80%) primarily depended on the adsorption and auto-catalytic oxidation facilitated by the pre-coating of MnOx. Furthermore, the MnOx film notably enhanced organic pollutant removal efficiency. Additionally, the MnOx coated on the membrane surface acted as a skeleton, promoting the gradual formation of a biocake layer with a heterogeneous and porous structure, which benefited the flux stabilization of the GDM. In particular, the fine and homogeneous MnOx-M derived from the backflushing water of the mature manganese sand filter exhibited precise and uniform coating on the membrane surface, effectively mitigating the irreversible pore plugging caused by organic matter penetration and thereby enhancing stable flux by ~16.3% compared to the control. This study offered a novel strategy to enhance the purification efficiency of GDM system treating manganese pollution and was expected to contribute to the technological advancement of decentralized water supply scenarios. Full article

(This article belongs to the Special Issue Application of Membrane-Based Technology in Water Treatment)

20 pages, 2869 KiB

Open AccessArticle

Runoff Control Performance of Three Typical Low-Impact Development Facilities: A Case Study of a Community in Beijing

by Jiayi Xiao, Zhiwei Zhou, Zhiyu Yang, Zhili Li, Xiaolong Li, Jinjun Zhou and Hao Wang

Water 2024, 16(17), 2373; https://doi.org/10.3390/w16172373 - 23 Aug 2024

Viewed by 196

Abstract

The development of sponge cities advocates for sustainable urban rainwater management, effectively alleviating urban flood disasters, reducing non-point-source pollution, and promoting the recycling of rainwater resources. Low-Impact Development (LID) serves as a key strategy in this context, providing essential support for urban rainwater [...] Read more.

The development of sponge cities advocates for sustainable urban rainwater management, effectively alleviating urban flood disasters, reducing non-point-source pollution, and promoting the recycling of rainwater resources. Low-Impact Development (LID) serves as a key strategy in this context, providing essential support for urban rainwater control and pollution reduction. To investigate the runoff control effects of LID measures and to reveal the relationship between facility runoff control performance and installation scale, this study focuses on a sponge community in Beijing. A SWMM model was constructed to analyze the rainwater flood control and pollutant load reduction effects of different LID facilities, including bio-retention cells, green roofs, and permeable pavements. Using evaluation indicators such as surface runoff, node overflow, and pollutant control rates, this study examined how facility performance varies with installation scale under different rainfall conditions. The combination scheme of LID equipment optimal configuration is designed by using multiple criteria decision analysis (MCDA) and cost–benefit theory. The results indicate significant differences in performance among the various LID facilities across different rainfall scenarios. Specifically, the optimal installation proportion for runoff and overflow control of permeable pavements were found to be between 30% and 70%. Green roofs demonstrate superior performance in handling extreme rainfall events, while bio-retention cells exhibit significant effectiveness in controlling Total Suspended Solids (TSSs). Through comprehensive performance evaluation, this study identified the optimal combination scale under a 3-year rainfall recurrence interval as 30% permeable pavements, 20% green roof, and 60% bio-retention cells. This combination effectively leverages the strengths of each facility, ensuring system stability and efficiency while also demonstrating optimal management efficiency in cost–benefit analyses. The findings of this research provide valuable insights for future urban water management and infrastructure development. Full article

(This article belongs to the Special Issue Urban Flood Frequency Analysis and Risk Assessment)

12 pages, 2319 KiB

Open AccessArticle

Effects of Dry Periods on Nitrogen and Phosphorus Removal in Runoff Infiltration Devices and Their Biological Succession Patterns

by Tian He, Chonghua Xue, Junqi Li, Wenhai Wang, Xiaoli Du, Yongwei Gong, Yimeng Zhao, Manman Liang and Yaxin Ren

Water 2024, 16(17), 2372; https://doi.org/10.3390/w16172372 - 23 Aug 2024

Viewed by 227

Abstract

When using runoff infiltration devices to remove nitrogen and phosphorus pollutants from urban runoff, the quality of the effluent is affected by the length of dry spells between rain events. This study presents a novel analysis of how these dry periods impact the [...] Read more.

When using runoff infiltration devices to remove nitrogen and phosphorus pollutants from urban runoff, the quality of the effluent is affected by the length of dry spells between rain events. This study presents a novel analysis of how these dry periods impact the device’s effectiveness in removing pollutants and the resulting biological succession within the filter. Our analysis examines nitrogen and phosphorus removal in a rainwater filtration context, providing new insights into how dry period duration influences infiltration system performance. The results indicate that biological processes have a significant impact on reducing total nitrogen (TN) and total phosphorus (TP) contents under different drying periods. A 3-day drying period is most effective for reducing TN through biological processes, while a 7-day period is best for TP reduction. This suggests that moderately extending the drying period improves TP removal efficiency but does not enhance TN removal. The dominant bacterial phylum responsible for denitrification and phosphorus removal is Proteobacteria, with Pseudomonas and Acinetobacter as the leading genera. As the drying period lengthens, the dominant genera shift from Pseudomonas to Massilia. At a 3-day drying period, denitrification primarily occurs through Pseudomonas on the surfaces of maifanite and zeolite. At a 7-day dry-out period, Acinetobacter is mainly responsible for phosphate removal on maifanite surfaces. However, after a 14-day dry-out period, both biomass and bioactivity of Pseudomonas and Acinetobacter decrease, leading to reduced efficiency in removing nitrogen and phosphorus pollutants from runoff infiltration devices. These results aid in developing runoff infiltration devices for specific scenarios and offer crucial guidance for regulating runoff pollution control technologies. Full article

(This article belongs to the Special Issue Urban Flooding Control and Sponge City Construction)

► Show Figures

Figure 1

12 pages, 2110 KiB

Open AccessArticle

The Formation Mechanism of Soil Interflow in Loess Hill Gully

by Na Lei, Jichang Han, Yang Zhang, Zenghui Sun, Yanan Li and Liheng Xia

Water 2024, 16(17), 2371; https://doi.org/10.3390/w16172371 - 23 Aug 2024

Viewed by 167

Abstract

To address the problems of salinization of the soil in gully control and land-making projects, the formation mechanism of soil interflow from a gully valley on the Loess Plateau was investigated, regarding its interface, water source, and spatial-temporal distribution characteristics, through field location [...] Read more.

To address the problems of salinization of the soil in gully control and land-making projects, the formation mechanism of soil interflow from a gully valley on the Loess Plateau was investigated, regarding its interface, water source, and spatial-temporal distribution characteristics, through field location monitoring and isotope tracer technique. The results showed the following: (1) there are two types of soil interflow in the Loess Plateau, namely soil interflow in slope and in gully, with interflow in gully being the main form; (2) adequate water supply, layered soil structure, and geographic disparity are conditions for the formation of soil interflow in the gully; (3) soil water is recharged by precipitation, surface water, and groundwater. Surface water is an important source of soil water recharge at the 0–100 cm depth, whereas groundwater is an important source of soil water recharge at the 100–200 cm depth. The results provide a basis for the regulation of the soil interflow, resource utilization, and land quality improvement in the Loess Plateau. Full article

(This article belongs to the Special Issue Soil Erosion and Soil and Water Conservation)

21 pages, 3984 KiB

Open AccessArticle

Distribution and Composition of Beach Litter along the Ionian Coastline of Albania

by Alfredo Fernández-Enríquez, Giorgio Anfuso, Francisco Asensio-Montesinos, Aurora Bakaj, Mariola Ismailaj and Geolind Cobaj

Water 2024, 16(17), 2370; https://doi.org/10.3390/w16172370 - 23 Aug 2024

Viewed by 244

Abstract

This paper deals with beach litter presence on the Ionian coast of Albania, i.e., at Vlora Bay and the Albanian Riviera, which is the most famous coastal tourist destination in the country. Along 16 beaches surveyed in November–December 2022 was found a total [...] Read more.

This paper deals with beach litter presence on the Ionian coast of Albania, i.e., at Vlora Bay and the Albanian Riviera, which is the most famous coastal tourist destination in the country. Along 16 beaches surveyed in November–December 2022 was found a total amount of 6621 litter items (or 416 kg) belonging to 114 categories of the EU J−code list. Most of these were plastic fragments and items (82%), mainly linked to local tourist activities. Wastewaters were responsible for bringing different litter items to the urban beaches of Vlora Bay. The most commonly observed litter items were cigarette butts, plastic caps/lids, and medium-sized plastic fragments of non-foamed plastic. The cleanest beaches, quite often, were the ones where beach clubs implemented clean-up programs during and at the end of the summer season. The results of this paper constitute a baseline of the beach litter amount and content along the study coast, which has never been investigated before. Municipalities and beach clubs have to implement more frequent and efficient clean-up activities and educational initiatives to reduce beach pollution, with special attention paid to the presence of cigarette butts and other small plastic items. Full article

(This article belongs to the Section Oceans and Coastal Zones)

► Show Figures

Figure 1

15 pages, 6100 KiB

Open AccessArticle

The Conditions for the Formation of Strontium in the Water of Ancient Silicate Deposits Near the Arctic Coast of Russia

by Alexander I. Malov

Water 2024, 16(17), 2369; https://doi.org/10.3390/w16172369 - 23 Aug 2024

Viewed by 233

Abstract

Strontium is a toxic chemical element widely distributed in groundwater. First of all, its appearance in water is associated with the dissolution of sulfate and carbonate rocks. The aim of this study was to assess the characteristics of strontium concentration in ancient aluminosilicate [...] Read more.

Strontium is a toxic chemical element widely distributed in groundwater. First of all, its appearance in water is associated with the dissolution of sulfate and carbonate rocks. The aim of this study was to assess the characteristics of strontium concentration in ancient aluminosilicate deposits that were filled with sedimentogenic brines and seawater in different geological periods. Studies were conducted on 44 water samples, in which the chemical and isotopic composition was determined with the subsequent assessment of saturation indices in relation to the main rock-forming minerals and the residence time of groundwater in the aquifer. It was found that minimal strontium concentrations are characteristic of the least mineralized waters and arise mainly due to the dissolution of carbonates. After their saturation in relation to calcite, the process of carbonate dissolution was replaced by their precipitation and an increase in silicate dissolution with an increase in strontium concentration in more mineralized waters. The incongruent dissolution of aluminosilicates resulted in the appearance of new clay minerals in the aquifer, which together with iron hydroxides and newly formed calcium carbonates created opportunities for sorption and ion exchange processes. The contribution of seawater consisted of an increase in strontium concentrations by approximately 15–20%. The effect of the duration of the water–rock interaction on strontium concentrations in groundwater was expressed in the fact that over a thousand years they increased by 0.1 mg/L, which is 20–30 times less than in the waters of carbonate deposits located 100 km to the east. An assessment of the non-carcinogenic risk to human health of contact with the groundwater showed the safety of using the studied groundwater for drinking purposes. Full article

(This article belongs to the Special Issue Water Environment Pollution and Control, Volume II)

► Show Figures

Figure 1

18 pages, 10848 KiB

Open AccessArticle

Nitrogen Removal from Polluted Water by an Integrated Constructed Wetland-Microbial Electrolysis Cell System

by Ruina Zhang, Kexin Li, Longqiang Yi, Xin Su, Changyuan Liu, Xinyu Rong, Haoxin Ran, Yingjie Wei, Li Wan, Rui Han and Yinghai Wu

Water 2024, 16(17), 2368; https://doi.org/10.3390/w16172368 - 23 Aug 2024

Viewed by 299

Abstract

An integrated constructed wetland-microbial electrolysis cell (ICW-MEC) system was investigated for nitrogen removal under different pollution loads, hydraulic loads (HLRs), and aeration conditions. The treatment performance of each unit and the microbial community characteristics for nitrogen removal were elucidated. The results showed that, [...] Read more.

An integrated constructed wetland-microbial electrolysis cell (ICW-MEC) system was investigated for nitrogen removal under different pollution loads, hydraulic loads (HLRs), and aeration conditions. The treatment performance of each unit and the microbial community characteristics for nitrogen removal were elucidated. The results showed that, on average, 80% of NH₄⁺-N, around 70% of nitrate nitrogen (NO₃⁻-N), and 70% of total nitrogen (TN) were removed by the system under three pollution loads, with less influence by pollution loads. The high removal efficiencies of NH₄⁺-N (81.8%), NO₃⁻-N (71.4%), and TN (72.8%) indicated tolerable to high HLRs. The intermittent aeration negatively affected NH₄⁺-N removal, while increasing NO₃⁻-N and TN removals by 3.2–13.0% and 3.7–16.7%. The contribution efficiencies of the secondary unit to the removal of NH₄⁺-N, NO₃⁻-N, TN, and total organic carbon (TOC) reached 47.4%, 55.0%, 45.9%, and 38.8%, respectively. The distinct microbial communities existed in various units of the ICW-MEC system, which were strongly affected by environmental factors and shaped by diverse fillers and structures of the system. The dominant bacteria contributed to the efficient nitrogen removal performance of the ICW-MEC system. The three units exerted their advantages to ensure efficient and stable system operation. Full article

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

► Show Figures

Figure 1

15 pages, 5508 KiB

Open AccessArticle

Effect of Stocking Density on Growth Performance of Juvenile Gibel Carp (Carassius gibelio) and Economic Profit of Land-Based Recirculating Aquaculture System

by Huacheng Li, Jieya Liu, Xiao Gu, Luyi Li, Liqin Yu, Rong Tang, Chunfang Wang, Li Li and Dapeng Li

Water 2024, 16(17), 2367; https://doi.org/10.3390/w16172367 - 23 Aug 2024

Viewed by 235

Abstract

The land-based recirculating aquaculture system (RAS) has been widely applied to fish farming as a new eco-friendly culture model. This system consists of circular culture tanks on land integrated with water treatment and recycling systems. This study investigated the growth performance of juvenile [...] Read more.

The land-based recirculating aquaculture system (RAS) has been widely applied to fish farming as a new eco-friendly culture model. This system consists of circular culture tanks on land integrated with water treatment and recycling systems. This study investigated the growth performance of juvenile gibel carp (Carassius gibelio) cultured at high stocking density (HSD, 0.3 kg/m³) and low stocking density (LSD, 0.15 kg/m³) conditions in RAS, and evaluated the comprehensive economic profit of RAS. The body weight, body length, weight gain rate, and condition factor of gibel carp in the LSD group were significantly higher than those in the HSD group (p < 0.05). The feed conversion ratio increased significantly in the HSD group (p < 0.05). A histological analysis revealed a significantly higher density of white muscle fibers in the LSD group (p < 0.05). Relative mRNA expression levels showed that ubiquitin–proteasome system (UPS)-related genes, ub, psma2, and mafbx, were significantly expressed in the HSD group, while the s6k1 expression was elevated in the LSD group (p < 0.05). The mRNA expression levels of keap1 and hsp70 in the dorsal muscle were significantly higher in the HSD group (p < 0.05). Throughout the rearing period, the water temperature remained consistent between the two density groups. The pH value gradually decreased and the dissolved oxygen levels in the HSD group were generally lower than in the LSD group. The nitrite nitrogen (NO₂⁻-N) content was higher in the HSD group. Compared to the LSD group, the return on investment was significantly lower in the HSD group. In conclusion, the water quality and growth rates of juvenile gibel carp were better in the LSD group. An appropriate stocking density improved the growth performance and aquaculture economic efficiency. Full article

► Show Figures

Figure 1

25 pages, 4573 KiB

Open AccessArticle

Modeling and Evaluating the Socio-Economic–Flood Safety–Ecological System of Landong Floodplain Using System Dynamics and the Weighted Coupling Coordination Degree Model

by Ming Li, Chaojie Niu, Xiang Li, Liyu Quan, Wenzhong Li, Chengshuai Liu, Chen Shi, Shan-e-hyder Soomro, Qike Song and Caihong Hu

Water 2024, 16(17), 2366; https://doi.org/10.3390/w16172366 - 23 Aug 2024

Viewed by 214

Abstract

The lower course of the Yellow River is a “hanging river” across the hinterland of China, and the safety of its flood control measures/systems is closely tied to the stability of the nation. Ensuring high-quality, sustainable development of the lower Yellow River floodplain [...] Read more.

The lower course of the Yellow River is a “hanging river” across the hinterland of China, and the safety of its flood control measures/systems is closely tied to the stability of the nation. Ensuring high-quality, sustainable development of the lower Yellow River floodplain while maintaining flood safety is crucial for the entire Yellow River Basin. Previous studies have primarily focused on the overall development of the Yellow River Basin or the economic–ecological coupling development of cities along the river, often neglecting the flood safety development of the floodplain. This study optimizes the socio-economic–flood-safety–ecological (SFE) system of the typical downstream Landong floodplain within the Yellow River Basin. The system dynamics model (SDM) can simulate the dynamic behavior of SFE systems by constructing mathematical models that incorporate feedback loops and time delays. The primary components include causal loop modules and stock-flow modules. Then, a coupling coordination degree model for the Landong floodplain is established using a comprehensive subjective and objective weighting method, assessing the SFE system’s coordination under five scenarios: inertial development, economic development, environmental protection, flood safety, and sustainable development. The results of historical and validity tests indicate that the SDM can effectively simulate the coupling coordination degree of the SFE system. The study results suggest that the coupling coordination degree increases the most under the sustainable development scenario, indicating that the development of the Landong floodplain should not only focus on socio-economic growth, but should also consider flood safety and ecological concerns. In addition, comprehensive regulation from socio-economic, flood safety, and ecological environment indicators are necessary to achieve high-quality, coordinated development. This study has significant implications for policy formulation and management to achieve high-quality and sustainable development in the downstream floodplain of the Yellow River. Full article

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

► Show Figures

Figure 1

20 pages, 3200 KiB

Open AccessArticle

Assessing the Coordination Degree of Coupled Human–Water–Ecosystem in the Tarim River Basin of China

by Mengqiao Li, Jianhua Xu, Ruishan Chen and Abdullah Ahmed Al-Ghamdi

Water 2024, 16(17), 2365; https://doi.org/10.3390/w16172365 - 23 Aug 2024

Viewed by 180

Abstract

To understand the current status of water resource utilization and explore the coordination degree of the coupled human–water–ecosystem in the Tarim River Basin, we used the water shortage rates and index of WUE to analyze the dynamic changes in water shortage and water [...] Read more.

To understand the current status of water resource utilization and explore the coordination degree of the coupled human–water–ecosystem in the Tarim River Basin, we used the water shortage rates and index of WUE to analyze the dynamic changes in water shortage and water use efficiency. We also applied the Gini coefficient to study the evolutionary trend of the degree of matching between water consumption and GDP in each sector. Based on the above analysis, we developed a human–water–ecosystem coupling coordination degree model incorporating various indicators relevant to the three subsystems to quantitatively assess the coupled and coordinated development status of the three subsystems of the human–water–ecosystem in the basin from 2004 to 2020. The main findings are as follows: (1) The Tarim River Basin suffers from water shortage in dry years, with a prominent supply–demand contradiction. In the severe drought years of 2009 and 2014, the water shortage rates reached 10.20% and 10.93%, respectively. (2) From 2004 to 2020, the Tarim River Basin’s water use efficiency (WUE), and its five prefectures showed a clear upward trend. On a multi-year average, Bayingol Mongolian Autonomous Prefecture had the highest WUE, while the Hotan region had the lowest. (3) The multi-year average value of the match between water consumption and GDP for the entire basin is 0.28. By industry, the primary industry’s match between water consumption and GDP is higher, while the secondary and tertiary industries have lower matches. (4) From 2004 to 2020, the coordination degree of coupled human–water–ecosystem in the five prefectures showed different degrees of upward trend, generally developing towards better coordination. In terms of multi-year averages, Bayingol Mongolian Autonomous Prefecture, located in the east, has the highest degree of coupled coordination. Meanwhile, Hotan, in the south, lags significantly behind the remaining four regions. Therefore, the Tarim River Basin should further improve and optimize the development model of sustainable water resource use. Full article

► Show Figures

Figure 1

12 pages, 4137 KiB

Open AccessArticle

Effect of Two Types of Wastewater Treatment Plants on Antibiotic Resistance of Fecal Coliform

by María Elena Pérez-López, Montserrat Miranda-Falcón, Miguel Correa-Ramírez and Araceli Loredo-Treviño

Water 2024, 16(17), 2364; https://doi.org/10.3390/w16172364 - 23 Aug 2024

Viewed by 255

Abstract

The existence of fecal coliform microorganisms (FCs) resistant to antibiotics in the domestic wastewater of an urban and semi-urban locality was determined, along with the effect of two types of treatment plants for wastewater on the resistance of coliform, an aerated lagoon (AL) [...] Read more.

The existence of fecal coliform microorganisms (FCs) resistant to antibiotics in the domestic wastewater of an urban and semi-urban locality was determined, along with the effect of two types of treatment plants for wastewater on the resistance of coliform, an aerated lagoon (AL) and a stabilization lagoon (SL). Samples were taken from the affluent and effluent of each treatment plant. FC content, pH, electrical conductivity, dissolved oxygen, total solids, total volatile solids, and several types of ions were determined. Resistant FCs were quantified by plate count in bright green bile agar with ampicillin, amoxicillin, sulfamethoxazole-trimethoprim, amikacin, gentamicin, cefixime and their mixtures. The isolated strains were evaluated against other antibiotics using antibiograms. The relationship between the variables was validated with an analysis of variance factorial design, and Fisher’s means test (α = 0.05) and Pearson’s correlation were used to establish it. The community that presented more resistant FCs was the urban one, but when the wastewater passed through the systems of AL and SL, this fact changed. The resistance of the FCs to ampicillin, amoxicillin, trimethoprim, sulfamethoxazole and cefixime was higher in the SL, with values of 67, 48, 2 and 25.8%, while those for the AL were 20, 13, 22 and 5.3%, respectively. Full article

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

► Show Figures

Figure 1

14 pages, 4534 KiB

Open AccessArticle

Prediction of Dissolved Oxygen Factor at Oncheon Stream Watershed Using Long Short-Term Memory Algorithm

by Heesung Lim, Hyungjin Shin, Jaenam Lee, Jongwon Do, Inhyeok Song and Youngkyu Jin

Water 2024, 16(17), 2363; https://doi.org/10.3390/w16172363 - 23 Aug 2024

Viewed by 189

Abstract

Rapid urbanization and industrialization have caused water quality issues in urban rivers. Appropriate measures based on water quality monitoring systems and prediction methods are needed for water quality management. While South Korea has operated a water quality monitoring system that measures various environmental [...] Read more.

Rapid urbanization and industrialization have caused water quality issues in urban rivers. Appropriate measures based on water quality monitoring systems and prediction methods are needed for water quality management. While South Korea has operated a water quality monitoring system that measures various environmental factors and has accumulated water quality data, a water quality prediction system is not in place. This study suggests a water quality prediction method based on a long short-term model using water quality and meteorological monitoring data. Additionally, we present a derived input set of the prediction model that can improve the prediction model performance. The prediction model’s performance was evaluated by the coefficient of determination under various conditions, such as the hyperparameters, temporal resolution of input data, and application of upstream and downstream data. As a result, using the temporal resolution of the input data as hourly data improved predictions by an average of 25.6% over three days of the prediction period compared to daily data. Meanwhile, it was analyzed that the hyperparameters and using upstream and downstream data have a minor effect on the model performance. The results of this study underscore the crucial role of the number, duration, and temporal resolution of available monitoring data in water quality management. Full article

(This article belongs to the Special Issue Application of Smart Technologies in Integrated Water Quality Modeling)

► Show Figures

Figure 1

16 pages, 1820 KiB

Open AccessReview

Antibiotic Resistance and Aquatic Systems: Importance in Public Health

by Njomza Lajqi Berisha, Ana Poceva Panovska and Zehra Hajrulai-Musliu

Water 2024, 16(17), 2362; https://doi.org/10.3390/w16172362 - 23 Aug 2024

Viewed by 383

Abstract

This review focuses on the crucial role of aquatic ecosystems in preserving biodiversity and the biosphere, as well as the connection between antimicrobial resistance (AMR) and these ecosystems. It provides an in-depth analysis of the link between ecological well-being and public health, helping [...] Read more.

This review focuses on the crucial role of aquatic ecosystems in preserving biodiversity and the biosphere, as well as the connection between antimicrobial resistance (AMR) and these ecosystems. It provides an in-depth analysis of the link between ecological well-being and public health, helping readers understand this complex subject. Aquatic ecosystems are essential for maintaining biodiversity and ecological balance. Additionally, they act as primary reservoirs and pathways for the spread of antimicrobial resistance (AMR). These ecosystems risk antibiotic contamination through various sources, such as the release of antibiotics from animal and human waste, improper disposal of unused medications, and pharmaceutical industry waste management practices. The presence of antibiotic residues in these environments significantly speeds up the development of bacterial resistance. The global prevalence of antimicrobial resistance (AMR) is evident in freshwater bodies, tributaries, sewage waters, and wastewater treatment facilities. Antimicrobial resistance (AMR) is now a significant public health threat, compromising the effectiveness of many previously successful treatments against various pathogens. One notable and alarming aspect of antimicrobial resistance (AMR) is its rapid development, often occurring within 5–10 years after introducing antimicrobial drugs to the market. This acceleration is closely tied to bacteria’s ability to thrive and adapt in the presence of antimicrobial agents and their residues in the environment. The implications of antimicrobial resistance (AMR) include treatment failures with long-term effects and a continuous increase in healthcare costs. This review comprehensively examines the intricate relationship between aquatic habitats, antibiotics, and the global challenge of antimicrobial resistance (AMR). It emphasizes the critical role of these ecosystems in preserving ecological diversity. It raises awareness about AMR’s urgent public health issue, laying a foundation for understanding its extensive consequences. Full article

► Show Figures

Figure 1

14 pages, 1042 KiB

Open AccessArticle

An Improved Index-Velocity Method for Calculating Discharge in Meandering Rivers

by Kaiyan Liang and Zili Li

Water 2024, 16(17), 2361; https://doi.org/10.3390/w16172361 - 23 Aug 2024

Viewed by 225

Abstract

Accurately measuring river flow is not only crucial for hydrologists monitoring hydrological processes but also important for all professionals involved in hydrological research. The ultrahigh frequency (UHF) band enables the surface flow velocity measurement at a deeper effective water depth, so it is [...] Read more.

Accurately measuring river flow is not only crucial for hydrologists monitoring hydrological processes but also important for all professionals involved in hydrological research. The ultrahigh frequency (UHF) band enables the surface flow velocity measurement at a deeper effective water depth, so it is less susceptible to the influence of wind drift. However, in curved river channels, the spatial variation in surface velocity is caused by the uneven erosion of the water flow, and this variation is influenced by both air shear stress and the curvature of the river. To mitigate the impact of water level on cross-sectional flow velocity estimation and address the nonlinear relationship between cross-sectional area and water level, this paper proposes a model that is independent of river water level. The nonlinear relationship between cross-sectional area and water level is calculated using a Taylor series expansion. The model was validated using experimental data collected from the Xiantao section of the Han River in Hubei, China, from March to July 2018. The data were discussed separately for high-flow and low-flow periods and were divided into training and validation sets in an 8:2 ratio. Compared to the previous method, our improved method reduces the Root Mean Square Error (RMSE) and Mean Absolute Percentage Error (MAPE) by approximately 2%. In the estimation of flow during the dry season, the improved method achieved a correlation coefficient of 0.9523, representing an increase of 0.1243 compared to the original method. The RMSE was 23.0383, and the MAPE was 0.0232, showing reductions of 23.144 and 0.0241, respectively, compared to the original method. In the estimation of discharge during the wet season, the improved method achieved a correlation coefficient of 0.9908, an increase of 0.0575 compared to the original method. The RMSE was 65.4929, and the MAPE was 0.0391, reflecting reductions of 75.1271 and 0.0338, respectively, compared to the original method. This advancement further enhances the application of UHF radar for discharge measurement in meandering rivers. Full article

► Show Figures

Figure 1

42 pages, 16420 KiB

Open AccessArticle

Multi-Objective and Multi-Variable Optimization Models of Hybrid Renewable Energy Solutions for Water–Energy Nexus

by João S. T. Coelho, Maaike van de Loo, Juan Antonio Rodríguez Díaz, Oscar E. Coronado-Hernández, Modesto Perez-Sanchez and Helena M. Ramos

Water 2024, 16(17), 2360; https://doi.org/10.3390/w16172360 - 23 Aug 2024

Viewed by 353

Abstract

A new methodology, called HY4RES models, includes hybrid energy solutions (HESs) based on the availability of renewable sources, for 24 h of water allocation, using WaterGEMS 10.0 and PVGIS 5.2 as auxiliary calculations. The optimization design was achieved using Solver, with GRG nonlinear/evolutionary [...] Read more.

A new methodology, called HY4RES models, includes hybrid energy solutions (HESs) based on the availability of renewable sources, for 24 h of water allocation, using WaterGEMS 10.0 and PVGIS 5.2 as auxiliary calculations. The optimization design was achieved using Solver, with GRG nonlinear/evolutionary programming, and Python, with the non-dominated sorting genetic algorithm (NSGA-II). The study involves the implementation of complex multi-objective and multi-variable algorithms with different renewable sources, such as PV solar energy, pumped hydropower storage (PHS) energy, wind energy, grid connection energy, or battery energy, and also sensitivity analyses and comparisons of optimization models. Higher water allocations relied heavily on grid energy, especially at night when solar power was unavailable. For a case study of irrigation water needs of 800 and 1000 m³/ha, the grid is not needed, but for 3000 and 6000 m³/ha, grid energy rises significantly, reaching 5 and 14 GWh annually, respectively. When wind energy is also integrated, at night, it allows for reducing grid energy use by 60% for 3000 m³/ha of water allocation, yielding a positive lifetime cashflow (EUR 284,781). If the grid is replaced by batteries, it results in a lack of a robust backup and struggles to meet high water and energy needs. Economically, PV + wind + PHS + grid energy is the most attractive solution, reducing the dependence on auxiliary sources and benefiting from sales to the grid. Full article

(This article belongs to the Special Issue Water and Energy Synergies)

► Show Figures

Figure 1

14 pages, 3797 KiB

Open AccessReview

Research Hotspots and Trends in the Environment Condition of the Yellow River Basin (2014–2024): A Bibliometric and Visualization

by Ruoting Gao, Hao Chen, Chunzhong Wei, Yanbo Jiang, Si Zeng, Chunfang Zhang, Yue Jin and Wenjie Zhang

Water 2024, 16(17), 2359; https://doi.org/10.3390/w16172359 - 23 Aug 2024

Viewed by 286

Abstract

The Yellow River holds significant developmental and historical importance for China. Over the past decade, there has been a growing recognition of the river basin’s complexity as a hydrological, ecological, economic, political, and social system. Therefore, analyzing its research hotspots and trends helps [...] Read more.

The Yellow River holds significant developmental and historical importance for China. Over the past decade, there has been a growing recognition of the river basin’s complexity as a hydrological, ecological, economic, political, and social system. Therefore, analyzing its research hotspots and trends helps to anticipate future research directions. This study utilized bibliometric software (such as VOSviewer and CiteSpace) to analyze the articles and research trends related to the ecological environment of the Yellow River Basin over the past 11 years (2014–2024). The results indicate that a total of 2096 articles have been published on this topic, with an almost annual increase in publications. Keyword co-occurrence and clustering network analysis indicate that the middle and lower reaches of the Loess Plateau, the delta, and the water quality and flow changes in the Yellow River Basin have been long-term research focuses. Climate change plays a dominant role in Yellow River runoff variation. In recent years, water quality has steadily improved, although delta erosion issues remain unresolved. Research on the sustainable development and ecosystem services of the Yellow River Basin has become a recent trend. With continuous policy development, refinement, and advancements in research, significant progress has been made in enhancing ecosystem services and achieving sustainable development in the Yellow River Basin. Regarding international collaboration, China, the United States, Australia, the United Kingdom, and Germany rank among the top five, with the most intensive collaborations occurring between China and the US, the UK, and Germany. Full article

► Show Figures

Figure 1

19 pages, 7944 KiB

Open AccessArticle

Experimental Study on the Performance and Internal Flow Characteristics of Liquid–Gas Jet Pump with Square Nozzle

by Zhengqing Cao, Xuelong Yang, Xu Xiao, Chenbing Zhu, Daohang Zou, Qiwei Zhou, Kaiyue Fang, Xinchen Zhang and Jiegang Mou

Water 2024, 16(17), 2358; https://doi.org/10.3390/w16172358 - 23 Aug 2024

Viewed by 216

Abstract

In order to ascertain the impact of working water flow rate and inlet pressure on the performance of the liquid–gas jet pump with square nozzle, the pumping volume ratio and efficiency of the liquid–gas jet pump with square nozzle were experimentally investigated at [...] Read more.

In order to ascertain the impact of working water flow rate and inlet pressure on the performance of the liquid–gas jet pump with square nozzle, the pumping volume ratio and efficiency of the liquid–gas jet pump with square nozzle were experimentally investigated at different inlet pressures and working water flow rates. Furthermore, the internal flow characteristics of the liquid–gas jet pump with square nozzle were explored through the utilization of visualization technology in the self-designed square-nozzle liquid–gas jet pump experimental setup. The findings indicate that the pumping ratio of the liquid–gas jet pump increases in conjunction with an elevation in the inlet pressure. Liquid–gas jet pump efficiency is higher at lower inlet pressures, up to 42.48%, and drops rapidly as inlet pressure increases. The pumping volume ratio of the liquid–gas jet pump increases significantly as the working water flow rate increases, and the working water flow rate exerts a minimal effect on the working efficiency of the liquid–gas jet pump. In the context of extreme vacuum conditions, a considerable number of droplets undergo substantial reflux in the posterior section of the throat, with a notable absence of bubbles in the diffusion tube. The size and number of bubbles diminish gradually along the axial direction. The objective of this paper is to provide a reference point for determining the optimal operational parameters for a square-nozzle liquid–gas jet pump in a practical context. Full article

(This article belongs to the Special Issue Hydraulics and Hydrodynamics in Fluid Machinery)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Water, Volume 16, Issue 17 (September-1 2024) – 20 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI