Search Results (954)

The combined effects of climate change and socio-economic development have intensified the risk of water supply–demand imbalance in China. To project future trends, this study develops a multi-scenario coupled prediction framework integrating climate, socio-economic, and human activity drivers, combining data-driven and physically based modeling approaches to assess terrestrial water storage imbalance in nine major river basins under six representative SSP–RCP scenarios through the end of the 21st century. Using ISIMIP multi-model runoff outputs along with GDP and population projections, agricultural, industrial, and domestic water demands were estimated. A Water Conflict Index was proposed by integrating the Water Supply–Demand Stress Index and the Standardized Hydrological Runoff Index to identify high-risk basins. Results show that under high-emission scenarios, the WCI in the Yellow River, Hai River, and Northwest Rivers remains high, peaking during 2040–2069, while low-emission scenarios significantly alleviate stress in most basins. Water allocation inequity is mainly driven by insufficient supply in arid northern regions and limited redistribution capacity in resource-rich southern basins. Targeted strategies are recommended for different risk types, including inter-basin water transfer, optimization of water use structure and pricing policies, and the development of resilient management systems, providing scenario-based quantitative support for future water security and policy-making in China. Full article

Gut microbial community assembly involves a critical bioenergetic trade-off, yet the gut microbes with roles in influencing intestinal metabolic homeostasis remain poorly understood in pelagic ecosystems. A central unresolved question is whether microbiome structure is primarily governed by stochastic geographic drift or by deterministic metabolic filters imposed by diet. Here, we test the metabolic release hypothesis, which posits that access to high-quality prey physiologically “releases” the host from obligate dependence on diverse fermentative symbionts. By integrating δ15N analysis with 16S rRNA metabarcoding in the anchoveta from the South Pacific waters (Engraulis ringens), we reveal a profound, diet-induced restructuring of the gut ecosystem. We demonstrate that trophic ascent triggers a deterministic collapse in microbial alpha diversity (rs = −0.683), driven by the near-complete competitive exclusion of fermentative bacteria (rs = −0.874) and the resulting dominance of a specialized proteolytic core. Mechanistically, the bioavailability of zooplankton-derived protein favors efficient endogenous hydrolysis over costly microbial fermentation, rendering functional redundancy obsolete. Crucially, we find that while metabolic function converges, taxonomic identity remains geographically structured (r = 0.532), suggesting that local environments supply the specific taxa to fulfill universal metabolic roles. These findings establish a link between δ15N as a nutritional physiology proxy of anchoveta and its gut for microbial functional state, bridging the gap between nutritional physiology and ecosystem modeling to better inform the management of global forage fish stocks. Full article

The uncoordinated water–sediment relationship, fragile eco-environment and unbalanced economic development in the Wei River Basin (WRB) pose serious challenges to its high-quality development. Most existing studies focus on static structures or single elements, making it difficult to systematically reveal the complex interrelationships among ecosystem services (ESs) supply, transmission and demand. To address this issue, this paper innovatively combines the “system perspective” with the “flow network model”. From the perspective of flood-sediment transport, eco-environmental and socio-economic (FES) subsystems, we take the WRB as its research object and systematically analyzes the supply–demand relationship of ESs, the pathways of the ESs flows and ecological compensation (EC) strategies at multiple scales. By constructing a supply–demand assessment model for six types of ESs combined with the water-related flows model, the enhanced two-step floating catchment area method and the gravity model, this paper simulates the ESs flows driven by different transmission media (water, road and atmosphere). The results showed the following: (1) a significant spatial mismatch was observed between the high-supply areas at the northern foothills of the Qinling Mountains and the high-demand areas in the Guanzhong Plains. Furthermore, the degree of this mismatch increased with decreasing scale. (2) The pathways of different ESs flows were influenced by their respective transmission media. The water-related flows passed through areas along the Wei River and the Jing River. The carbon sequestration flows were identified in the upper reaches of the Luo River and between the core urban agglomerations of the Guanzhong Plains. The crop production flows were significantly influenced by the scale of urban crop demand, radiating outward from Xi’an City. (3) At the county and watershed scales, The EC fund pools of 7.5 billion yuan and 2.6 billion yuan were formed, respectively. These EC funds covered over 90% of the areas. These findings verify the applicability of the “FES subsystems” framework for multi-scale EC and provide a theoretical basis for developing an integrated EC mechanism across the entire basin. Full article

Complex water networks face prominent contradictions among flood control, water supply, and ecological protection, and traditional scheduling models struggle to address multi-dimensional water security challenges. To solve this problem, this study proposes a multi-objective coordinated water resources scheduling model for complex water networks, taking the Taihu Lake Basin as a typical case. First, a multi-objective optimization indicator system covering flood control, water supply, and aquatic ecological environment was constructed, including 12 key indicators such as drainage efficiency of key outflow hubs and water supply guarantee rate. Second, a dynamic variable weighting strategy was adopted to convert the multi-objective optimization problem into a single-objective one by adjusting indicator weights according to different scheduling periods. Finally, a combined solving mode integrating a basin water quantity-quality model and a joint scheduling decision model was established, optimized using the particle swarm optimization (PSO) algorithm. Under the 1991-Type 100-Year Return Period Rainfall scenario, three scheduling schemes were designed: a basic scheduling scheme and two enhanced discharge schemes modified by lowering the drainage threshold of the Xinmeng River Project. Simulation and decision results show that the enhanced discharge scheme with the lowest drainage threshold achieves the optimal performance with an objective function value of 98.8. Compared with the basic scheme, it extends the flood season drainage days of the Jiepai Hub from 32 to 43 days, increases the average flood season discharge of the Xinmeng River to the Yangtze River by 9.5%, and reduces the maximum water levels of Wangmuguan, Fangqian, Jintan, and Changzhou (III) stations by 5 cm, 5 cm, 4 cm, and 4 cm, respectively. This model effectively overcomes technical bottlenecks such as conflicting multi-objectives and complex water system structures, providing theoretical and technical support for multi-objective coordinated scheduling of water resources in complex water networks. Full article

Sierra Leone’s water sector faces a “paradox of scarcity in abundance”: despite plentiful natural water resources, access to safe, reliable, and affordable supply remains limited, particularly for vulnerable populations. This paper investigates the governance dynamics and stakeholder relationships that underpin these challenges, drawing on a mixed-methods approach combining desktop research, surveys, and 37 semi-structured interviews. Using stakeholder and social network analysis, the study identifies key actors and their roles, interests, influence, and interdependencies, while also examining systemic barriers across social, technical, economic, environmental, and political dimensions. The findings reveal a highly fragmented governance landscape, characterised by overlapping mandates, donor dependency, weak enforcement, and the marginalisation of community voices. Although recent reforms—including new regulatory institutions, donor-funded infrastructure projects, and community-based initiatives—represent progress, they remain largely piecemeal, reactive, and insufficient to address entrenched structural deficiencies. The paper concludes that Sierra Leone’s water crisis is less a problem of resource scarcity than one of governance. Achieving sustainable water security requires integrated, system-wide reforms that strengthen institutional capacity, enhance coordination, enforce accountability, and embed inclusive stakeholder participation. Full article

The Rocky Desertification area has high sensitivity and poor anti-interference ability in the ecosystem. It is challenging to achieve sustainable development in a rocky desertification area. Given this issue, the System Dynamics model, the Future Land Use Simulation (FlUS) model, the Integrated Valuation and Trade-offs of ESs (InVEST) model, and the Structural Equation Model (SEM) were integrated in this study to analyze future ecosystem service change in Wenshan Prefecture under SSP1-1.9, SSP2-4.5, and SSP5-8.5 scenarios. The following results are obtained. (1) The area of cultivated land, construction land, forest land, and grassland increased in SSP1-1.9; the area of forest land and grassland decreased in SSP2-4.5 scenario and SSP5-8.5 scenario. (2) The water supply (WS), carbon sequestration (CS), and soil conservation power (SDR) under the three different scenarios were improved compared with 2020. Among them, habitat quality (HQ) demonstrated a slight increase trend under the SSP1-1.9 scenario but decreased under the other two scenarios. (3) WS, CS, and HQ exhibited a tradeoff relationship in the three scenarios compared with 2020. (4) In the SSP1-1.9 and SSP2-4.5 scenarios, the synergistic relationships among CS, HQ, SDR, and WS were particularly detected in the northern, southern, and central parts of the study area. Additionally, climate change and vegetation-dominated ecological environment are the main driving mechanisms affecting ES changes. This paper summarizes the spatial differences in the change trend and synergistic tradeoff and lays a crucial scientific foundation for the ecological protection of karst landform areas. Full article

High-pressure water jet technology is widely utilized for cleaning marine artificial structures due to its portability, efficiency, and environmental friendliness, yet traditional jets underperform in submerged environments. Gas-assisted water jet technology has predominantly been applied to rock breaking—where vertical forces are prioritized—with insufficient research into flow regime evolution, limiting its utility for cleaning applications. This study introduces a supercavitating high-pressure water jet aimed at improving underwater cleaning efficiency while lowering economic costs. Employing ANSYS Fluent—with the RNG k-ε turbulence model and mixture model—validated via high-speed camera experiments, we explored the flow regime evolution of both unconstrained and semi-constrained impinging jets. The key findings of this paper are as follows: The cavity evolves with a periodic “necking-bubbling” pattern, whose intensity correlates positively with gas outlet velocity and supply rate; moderate gas supply—with 120 L/min identified as optimal through orthogonal analysis—effectively delays water jet breakup. For semi-constrained jets, the wall-adjacent gas flow also exhibits “necking-bubbling”; small-angle impact (30° versus 60°) reduces near-wall shear vortices, enhancing gas cavity stability on the target plate. This study bridges the gap between gas-assisted jet technology and underwater cleaning requirements, offering theoretical insights and optimized parameters for efficient, low-cost marine structure cleaning. It thereby supports the sustainable exploitation of marine resources and the stable operation of key marine facilities. Full article

This study aimed to assess various social–ecological traps of hilsa shad (Tenualosa ilisha) fisheries and to investigate the factors that significantly impact livelihood adaptation strategies during the ban period, based on fieldwork in coastal fishing communities. To collect empirical data, a total of 247 in-depth interviews were conducted using a semi-structured questionnaire along with six focus group discussions, oral history, and ten key informant interviews in the Chattogram and Patuakhali districts of Bangladesh. A conceptual framework derived from a strategy for reducing poverty, known as the Sustainable Livelihood Approach (SLA), is applied to determine the livelihood outcomes of hilsa fishers. The results showed that low income (<5000 BDT/month), high interest in loans from dadondar (lender) (10–12%) and aratdar (lessor of the vessel) (5%), high harvesting costs, an increasing number of hilsa fishermen, and intergenerational traps (81.78%) are creating social–ecological traps (SETs) in the hilsa fishery. The significant factors affecting the choice of adaptation strategies include family members, training facilities, home ownership, and belonging to a formal society. Apart from fighting against some extreme climate events, negative feedback comes from the absence of cold storage facilities, illegal use of fishing nets, frequent ban seasons, ignorance of conservation laws, limited opportunities for alternative occupations, and poor supply of drinking water. Hilsa fishermen in these regions depended on aratdar and dadondar for their financial support, which resulted in lower prices than the prevailing market prices. To escape from the SETs, this study identifies potential alternatives, such as government–community finance schemes, the promotion of alternative livelihoods, opportunities for technical education of their children, improvement of the local framework, and strong cooperation between local stakeholders and management authorities that are necessary to maintain the sustainability of hilsa fisheries. Full article

Proton exchange membrane fuel cells (PEMFCs) represent a new generation of clean and efficient energy conversion devices, demonstrating broad application prospects in transportation, distributed power generation, and other fields. The geometric configuration of the cathode gas channel (GC) and the surface microstructure of the gas diffusion layer (GDL) are core factors influencing the efficiency of reactant gas transport and water management performance. However, conventional rectangular flow channels suffer from insufficient convective enhancement and restricted oxygen supply beneath the fins. Furthermore, homogeneous GDLs exhibit limited diffusion and drainage capabilities, often leading to oxygen depletion and flooding downstream of the cathode, significantly limiting overall cell performance. To address these challenges, this study designs a novel centrally positioned fin-type barrier block. A three-dimensional multiphysics numerical model integrating GDL surface microporosity with the internal barrier block flow channels is constructed to systematically investigate the synergistic mechanisms of microporous topology and flow channel structure on two-phase flow distribution, oxygen mass transfer, and electrochemical performance. The results demonstrate that this model accurately captures the dynamic evolution of flow fields within the GDL. Compared to conventional structures, significant coupling effects exist between the GDL microporous structure and the novel barrier block. Their synergistic interaction forms multi-scale mass transfer enhancement and dewatering pathways, providing quantifiable optimization pathways and structural parameter references for high-power-density PEMFC cathode design. Full article

The Tourism Area Life Cycle shaped tourism research for decades, but its concepts Product Life Cycle and Carrying Capacity remain problematic. We apply a Path Dependence frame under an Urban Growth Machine Theory lens to explore the effects of growth pressure and resource undersupply on the decline and rejuvenation of Japan’s former premier hot spring resort Atami. We conduct structured data collection utilizing sampling and coding methods to collect quantitative and qualitative data from primary and secondary sources, reconstructing Atami’s development paths. Findings suggest that growth pressure conflicted with local supply such as land, water, labor and created negative externalities, most notably high prices. Decision makers’ uncompromising focus on growth aggravated displacement of key actors, disrupting local communities and undermining the human agency needed for small-scale product innovation; empowered associations obstructing promotion and diversification efforts; encouraged extreme specialization depriving Atami of new independent businesses; and drove local opposition to major new projects, thereby stalling product renewal. The framework helped recontextualize Atami’s recovery and demonstrated the value of directly incorporating factors of capacity into analysis. Results link displacement to long-term sustainability risks affecting ‘replaceable’ resorts reliant on innovation. Unencumbered access to local resources for residents (housing, training) is proposed as mitigation. Full article

Torrential flows are hazardous hydro-geomorphological phenomena characterized by sudden water discharge and intense sediment transport. They occur in mountainous areas where hydrometeorological monitoring is often limited or absent. The lack of such data hinders the identification of flow types and sediment transport conditions, reducing the effectiveness of mitigation measures. To address this issue, the current study focuses on geomorphic characteristics of torrential watersheds and identifies indirect indicators of torrential activity. The sedimentological and geomorphic signatures of torrential flows in the lower Damdere River catchment (Eastern Rhodopes Mountains, southern Bulgaria) were characterized. To capture inter-annual variability in torrential activity and differences between the Damdere and its tributary the Duandere, we sampled riverbed deposits. We also sampled areas upstream and downstream of the check dam to assess its influence. Samples were analyzed for grain size distribution, petrography, and mineralogy (X-ray diffraction). Results show contrasting controls on sediment supply and transport: the Duandere delivers relatively coarse material, whereas the Damdere attains higher transport capacity during torrential events. The check dam is largely infilled and exerts only local effects by trapping finer sediments upstream. Downstream, the channel retains its torrential character. Inter-annual comparison upstream of the structure shows sediment fining linked to lower flows. Petrographic and XRD data point to mechanically driven erosion and rapid sediment transfer. The results underline the importance of geological–geomorphological indicators in the lack of long-term monitoring in similar mountain catchments and can support flood risk management. Full article

The observed shortage of water resources in the western and southern regions of the Russian Federation may soon affect the territory of the Republic of Bashkortostan. An increase in the share of groundwaters can help to solve this problem. To provide the population of the republic with water resources, the groundwater of magnesium–bicarbonate-type from the Kraka ophiolite massifs can be used. The massifs occur on the western slope of the Southers Urals. In this work we studied ultramafic rocks and their influence on the formation of the chemical composition of water. The research area is located in the northern part of the Zilair synclinorium, which occurs within the Central Ural megazone. In terms of hydrogeology, of particular importance to the territory of the synclinorium is the Zilair basin of fracture waters of the second order, which is part of the Uralian hydrogeologic folded zone. The ultramafic rocks from the studied area have consistently high CaO/Al₂O₃ ratios (0.4–1.6), which indicates the widespread development of parageneses with participation of clinopyroxene and a low degree of depletion of the primitive mantle source. Because of the complex geological structure of the area, water samples collected from both water points in the Kraka massifs, and the surrounding Early–Middle Paleozoic rocks were analyzed for major ions using a laboratory method to identify possible hydro-geochemical zoning. A statistical analysis was then conducted based on the obtained anion–cation composition data. From the viewpoint of the hydrolytic concept, the formation of the chemical composition of groundwater takes place due to the removal of Mg²⁺ from the rock-forming minerals of ultramafic rocks (olivine and pyroxene) and the supply of Na⁺, K⁺, Ca²⁺, and SO₄²⁻ Cl⁻ from atmospheric precipitations. The bicarbonate anion has a complex nature, where both biochemical processes in the soil and atmospheric precipitation play a significant role. Magnesium–bicarbonate-type of waters, due to low mineralization (to 1 g/L) and the majority of other geochemical parameters (pH of the medium, and content of Na, K, Ca, SO₄, and Cl), whose values that are within the limits set by the World Health Organization (WHO), can be used as drinking water. The increased values of total hardness (0.20–3.39 mmol/L) in accordance with the regulatory document SanPiN 1.2.3685–21, adopted by the Russian Federation, do not exceed the maximum permissible concentrations (up to 7.00 (10.00) mEq/L or 3.50 (5.00) mmol/L). The high magnesium content, in accordance with GOST (state standard) R 54316–2020, allows the magnesium–bicarbonate waters of the Kraka massifs to be classified as table mineral waters for the treatment of various diseases (including hypomagnesemia). Full article

Contaminated water detoxification remains difficult due to the presence of persistent halo-organic contaminants, such as perfluorooctanoic acid (PFOA) and chlorophenols, which are chemically stable and resist conventional purification methods. Functionalized membrane-based separation and decontamination have garnered immense attention in recent years. Commercially available microfiltration membrane (PVDF) and polymeric non-woven fiber filters (glass and composite) are functionalized with poly(methacrylic acid) (PMAA) that shows outstanding pH-responsive performance and tunable water permeability under ambient conditions perfect for environmental applications. Polymer loading based on weight gain measurements on PMAA–microglass composite fibers (137%) and microglass fibers (116%) confirmed their extent of functionalization, which was significantly greater than that of PVDF (25%) due to its widely effective pore diameter. Presence of chemically active hydrogel within PVDF matrix was validated by FTIR (hydroxyl/carbonyl) stretch peak, substantial decrease in contact angle (68.8° ± 0.5° to 30.8° ± 1.9°), and decrease in pure water flux from 509 to 148 LMH/bar. Nanoparticles are generated both in solution and within PVDF using simple redox reactions. This strategy is extended to PVDF-PMAA membranes, which are loaded with Fe/Pd nanoparticles for catalytic conversion of 4-chlorophenol and PFOA, forming Fe/Pd-PVDF-PMAA systems. A total of 0.25 mg/L Fe/Pd nanoparticles synthesized in solution displayed alloy-type structures and demonstrated a strong catalytic performance, achieving complete hydrogenation of 4-chlorophenol to phenol and 67% hydrogenation of PFOA to its reduced form at 22–23 °C with ultrapure hydrogen gas supply at pH 5.7. These results underscore the potential of hybrid polymer–nanoparticle systems as a novel remediation strategy, integrating tunable separation with catalytic degradation to overcome the limitations of conventional water treatment methods. Full article

The aim of this paper is to investigate the measures adopted by higher education institutions (HEIs) for sustainable water management in university campuses. Rain and storm water harvesting and treatment, rain and storm water reuse, wastewater treatment and reuse and technologies for runoff reduction were found to be frequently undertaken. Sustainable approaches to water supply such as water-efficient appliances, irrigation algorithms and the use of drought-resistant plants have been adopted as well. In support, monitoring of consumed water and of rain and storm waters has been a widespread practice. Important considerations were given to the impact of the identified measures on campuses’ energy consumption and greenhouse gas emissions. Nature-based solutions, employment of renewable energies and sustainable disinfection methods are measures to prioritize. Some wastewater technologies may deserve priority in virtue of their positive contribution to circular economy. Drawbacks such as groundwater and soil contamination due to wastewater reuse and the release of pollutants from fertilized nature-based technologies were identified. Despite their variety, it must be noted that many of these measures have generally involved rather limited portions of campuses, taken more for demonstration or pilot/full-scale research purposes. Additional measures not identified in the current review—for instance the prevention of pollution from micropollutants and waste mismanagement—should be implemented to boost HEIs’ environmental sustainability. The findings of this review pave the way for a more structured implementation of water sustainability measures in university campuses. Full article

Uncontrolled water outflows from water supply pipes can pose a serious threat to human safety and infrastructure due to the washing out of soil particles and the formation of subsurface voids, leading to soil subsidence (suffosion). One way to mitigate these hazards is by determining water outflow zones (WOZ) around underground pipes, within which water may emerge on the soil surface. This paper presents the final stage of a broader study on the use of fractal geometry for determining WOZ. Suffosion hole locations form point structures that exhibit features of probabilistic fractals, and their parameters depend on the number of points in the structure. The objectives of the study were: (1) to determine the minimum number of points required for a structure to be considered representative; (2) to establish a relationship for calculating the WOZ radius; and (3) to empirically verify the theoretical WOZ radius values. Representative structures were identified and used to calculate the R_fr parameter, which, after scaling to real conditions, enabled determination of the WOZ radius, ranging from 3.5 to 5.5 m. Empirical verification confirmed the method’s validity, as theoretical zones covered up to 100% of actual outflow points (96% overall). The developed method can be applied into decision-support systems for sustainable infrastructure planning, and more efficient use of water resources. Full article