As tensions between dam development and river ecosystem conservation intensify globally, a key challenge arises with regard to how dam projects can be steered toward greater ecological compatibility without compromising their societal functions. From the perspective of river ethics, this study clarifies the concept and connotation of ecological dams, and proposes a life-cycle analytical framework for their construction and governance. An ecological dam is defined as a dam whose overall ecological effects are positive, whose adverse ecological impacts remain acceptable and controllable, and whose ecological benefits can be realized in a responsible manner. Employing conceptual analysis and policy-oriented synthesis, the article examines the connotation of ecological dams across the planning, design, construction, impoundment, operation, and maintenance stages. It argues that this transformation should be guided by two interrelated principles: controllable ecological impacts and significant ecological benefits. On this basis, the study identifies key developmental pathways of ecological dams, including whole-process ecological risk management, ecological operation, and adaptive management, integrated monitoring & evaluation, as well as improvement of technical standards and pilot demonstration systems. The study thus provides a coherent analytical framework for ecological dam development.

Continuous monitoring, analysis, and mapping of groundwater depth (GD) and electrical conductivity (EC) are critical for sustainable water management in irrigated agricultural regions. This study evaluates spatiotemporal variations in GD and EC within the Aksu Irrigation System (Türkiye) over 2005–2024 using Mann–Kendall trend analysis and geographic information systems (GIS)-based geostatistical methods. The results indicate that groundwater depth (GD) trends are generally relatively favorable across the study area, despite relatively unfavorable initial conditions. In contrast, increasing EC trends were identified in 38% of the study area, mainly concentrated in the central and northern zones, whereas the remaining areas exhibited relatively favorable conditions. In terms of baseline salinity conditions, no areas exceeded the critical threshold for EC initial values, indicating acceptable groundwater salinity levels at the beginning of the study period. Groundwater-related risk was assessed based on combined GD and EC characteristics influencing root zone conditions, including waterlogging potential and salinity development. The integrated risk map, based on the 2005–2024 assessment period, indicates that 25% of the study area is relatively unfavorable, while 75% is relatively favorable. The proposed approach provides a practical and spatially explicit tool for groundwater risk evaluation, supporting improved water management in large-scale irrigation systems.

Periphyton in aquatic ecosystems plays vital roles in the elemental cycle process and is vulnerable to anthropogenic interference. However, few studies have explored the elemental cycles of carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) in the natural and artificial rivers using functional genes and microbial interactions in periphyton. In this study, the DNA metabarcoding and the quantitative microbial element cycling smart chip were employed to investigate the differences in the microbial-mediated CNPS cycling processes between the Feng and Zao Rivers, representing natural and artificial rivers, respectively. Compared with the more C-fixation (7.55 × 10⁴ ± 2.12 × 10⁴ copies/ng) and nitrification (4.75 × 10³ ± 2.95 × 10³ copies/ng) gene abundance in the artificial river, the C-degradation (2.98 × 10⁴ ± 1.31 × 10⁴ copies/ng), denitrification (3.62 × 10⁴ ± 7.25 × 10³ copies/ng), and S-reduction (6.66 × 10³ ± 4.26 × 10³ copies/ng) gene abundance were more in the natural river. In the natural river, the low levels of TN (5.37 ± 0.40 mg/L), DO (3.27 ± 0.32 mg/L), NH₄⁺ (0.05 ± 0.05 mg/L), and NO₃⁻ (4.36 ± 0.88 mg/L) could support C-degradation, denitrification, and S-reduction. Conversely, higher NO₃⁻ levels (8.47 ± 2.13 mg/L) promoted nitrification in the artificial river. Moreover, more bacterial genera were involved in the CNPS cycling in the artificial river, whereas the bacterial-algal relationship was more complex in the natural river. This study could provide insights into the biodiversity and ecological functions of periphyton in different river types.

This study describes the effect of electromagnetic field (EMF) treatment on the chemical and electrical properties of tap water. It also contributes to a better understanding of the influence of this technique on the physicochemical properties of water exposed to different treatment times by an EMF generated by the Aqua 4D. The magnetized water was analyzed, and its physical and chemical properties were evaluated after a 30-min magnetization cycle via impedance spectroscopy using the electrical and dielectric properties. Increasing the EMF circulation time led to a change in the properties of water. The results showed an increase in pH, electrical conductivity, and certain chemical properties. The optimal change in water properties was obtained with an EMF treatment duration of 5 min. However, the evaluation of the water quality improvement induced by the magnetization process revealed an increase in pH, electrical conductivity, and certain chemical properties. To assess the impact of the magnetization process on water quality, the results were compared with other scientific studies. To reduce treatment costs and increase the long-term viability of the process, the study's results suggest that water magnetization is an effective treatment technology that reduces energy and material consumption (green technology). The importance of key parameters such as pH, oxidation-reduction potential (ORP), and dissolved oxygen (DO), water quality monitoring, and treatment are highlighted. In particular, changes in these parameters are related to the electron density in water. Recent research indicates that magnetic effects can significantly affect pH, ORP, and DO levels. Accordingly, this study provides a comprehensive analysis of the unique properties of magnetized water and explores its potential applications as a smart and environmentally friendly solution in the oil industry, particularly as an injection fluid in enhanced oil recovery operations. In addition, the findings may have implications for advances in aquaculture, water quality control, and the treatment of cancers associated with free radical-induced oxidative stress. By advancing the understanding of magnetized water, this research aims to contribute to innovative applications in various water applications.

Extreme snowfall events have frequently occurred across parts of Eurasia, causing substantial economic losses and severe societal impacts. As global warming intensifies, assessing its potential effect on population exposure to such extremes becomes increasingly crucial. This study employed CMIP6 model datasets and future population projections to predict changes in population exposure to snowfall extremes over Eurasia under SSP2-4.5 and SSP5-8.5 scenarios, and attributed the drivers behind these changes. Results indicate that, on average across Eurasia, both extreme snowfall days and the associated population exposure increase until the mid-21st century (2041–2060). Specifically, population exposure to snowstorm days will increase by 4.1% in the near term (2021–2040) and by 1.8% in the medium term, with particularly pronounced increases over Central Asia, East Asia, and the Mediterranean. Population change is identified as the dominant factor influencing exposure changes across Eurasia, followed by climate change and climate-population synergistic effects. Toward the end of the century, as both snowstorm days and population size decline markedly, the corresponding population exposure decreases further. Thus, climate adaptation policies should account for the heightened population risks linked to increasing snowfall extremes in Eurasia up to the mid-21st century.

Soil erosion is a major global environmental and socio-economic challenge, with impacts particularly severe in tropical, monsoon-dominated mountainous regions, where heavy rainfall, steep terrain, and unsustainable land-use practices accelerate land degradation. The Chalakkudy River Basin in central Kerala represents an ecologically sensitive landscape of the Western Ghats, highly vulnerable to soil erosion due to its diverse physiography, intense monsoonal climate, and increasing anthropogenic pressures. This study evaluates current soil loss and projects potential future soil losses under changing climatic conditions using geospatial techniques integrated with the Revised Universal Soil Loss Equation (RUSLE). Future erosion risks were assessed by analyzing projected trends in rainfall erosivity under three Representative Concentration Pathways (RCP 2.6, 4.5, and 8.5). The results reveal pronounced spatial variability in soil loss across the watershed, with higher erosion rates concentrated in areas of steep slopes, reduced vegetation cover, and disturbed land uses such as deforested hillslopes and plantation zones. In contrast, forested regions and gentle slopes exhibited comparatively lower erosion susceptibility. Under the high-emission scenario (RCP 8.5), soil erosion is projected to increase substantially, with the upper and midland regions of the basin emerging as critical hotspots, driven by intensifying rainfall erosivity and the heightened sensitivity of disturbed landscapes to climate forcing. Erosion hotspots were predominantly identified in deforested highlands, plantation belts along the Western Ghats slopes, and lowland catchments lacking adequate conservation measures. The findings demonstrate that climate change is likely to intensify soil erosion risk across the Chalakkudy Basin, particularly under scenarios associated with greater warming and increased rainfall extremes. These results underscore the insistent requirement of targeted soil and water conservation interventions, including site-specific measures in erosion-prone hotspots, to minimize nutrient-rich topsoil loss and its associated carbon depletion under evolving climatic conditions. This study provides climate-sensitive erosion projections for a highly vulnerable tropical monsoon-dominated basin, offering critical insights for climate-resilient land-use planning, watershed management, and sustainable soil conservation in Kerala and other comparable tropical regions.

Understanding unsteady flow regimes in river channels downstream of a reservoir, is essential for predicting and regulating water level and flow velocity in the lower basin. Using hourly observations of discharge and water level at Xiangjiaba Station from 2018 to 2022, an evaluation indicator was proposed to analyze unsteady flow regimes downstream of Xiangjiaba Reservoir. The redistributive effects were quantified using the governing equations of unsteady flow. A new governing equation for unsteady flow was derived from the conservation of gravitational potential energy flux variation.

Nepal's vast hydropower potential is central to its long-term economic development; however, it exhibits pronounced spatial heterogeneity and is increasingly vulnerable to climate-induced risks. This study employs an integrated, Basin-scale analytical framework to evaluate the hydrological productivity and economic viability of major river Basins, explicitly linking these indicators to climate resilience. The results reveal a strong spatial concentration of water and energy resources, with the Koshi, Gandaki (Narayani), and Karnali Basins collectively contributing over 68% of the national runoff and accounting for more than 94% of the country's economically feasible hydropower potential. A key finding is the decoupling of Basin size from hydrological efficiency. The Mahakali Basin demonstrates the highest runoff intensity (4.07 million m³/km²/year), whereas the much larger Karnali Basin exhibits the lowest (1.08 million m³/km²/year). While theoretical and economic hydropower potentials are strongly correlated (R² = 0.94), conversion efficiencies vary substantially across Basins due to site-specific topographic, geological, and infrastructural constraints. Climate projections further indicate significant threats to hydropower reliability, including Basin-specific reductions in mean annual flow of up to 48%, accelerated glacier retreat, and increased sediment loads. These risks are particularly acute given Nepal's heavy reliance on run-of-river hydropower projects. The study concludes that realizing hydropower potential in Nepal under a changing climate requires a strategic shift toward climate-adaptive, Basin-specific planning, emphasizing storage-based hydropower, diversification of renewable energy sources, and strengthened transboundary water governance to ensure resilient and sustainable development.

Optimizing reservoir refill operation rules is crucial for enhancing reservoir sustainability and resilience. This study proposes a refill operation model designed to derive optimal refill guide curves by considering flood risk prevention, maximum storage levels, and the combined benefits of hydropower generation and energy storage. The proposed model was applied to the Longtan Reservoir in China. The results indicate that employing various optimal refill guide curves, tailored to wet, normal, and dry hydrological conditions, yields better outcomes than using a single refill guide curve. In wet years, the maximum annual combined benefits of hydropower generation and energy storage increased by 2.88%. In normal and dry years, the average annual water level at the end of the water storage period was significantly raised by 0.71 and 1.9 m, respectively. Correspondingly, the reservoir storage volume increased by 2.53 × 10⁸ m³ and 6.19 × 10⁸ m³, respectively. These findings demonstrate that the proposed approach can enhance the benefits of refill operations at the Longtan Reservoir under varying hydrological conditions.

This study quantifies and interprets the hydro-morphometric characteristics of the Dayi River Basin to evaluate process-based controls on runoff generation, erosion susceptibility, and groundwater recharge in an ungauged tropical crystalline river system in Ghana. Using a 30 m resolution ASTER Digital Elevation Model (ASTER DEM), hydro-morphometric parameters encompassing linear, areal, and relief characteristics were derived. The results revealed an elongated basin with a dendritic drainage pattern, as indicated by a low elongation ratio (0.46), form factor (0.17), and circularity ratio (0.26). The basin further exhibited low drainage density (0.79 km km⁻²), coarse drainage texture (0.32), long length of overland flow (0.63 km), and high infiltration potential, collectively reflecting a structurally controlled hydro-geomorphic river system with enhanced groundwater recharge. These characteristics regulate runoff distribution, erosion, and groundwater recharge within a dual-aquifer system, enhancing the basin′s hydro-geomorphic resilience. The basin-scale hydrological storage coefficient (1.6) indicates a high storage potential, resulting in attenuated runoff peaks, reduced flow erosivity, and enhanced groundwater recharge through subsurface percolation. Such a storage-dominated hydrological response indicates that a substantial proportion of rainfall is partitioned into infiltration and subsurface storage, resulting in enhanced groundwater recharge, sustained baseflow contributions, and reduced flash-flood potential in ungauged tropical crystalline river basins. Watersheds such as Tsatsadu, Tafi, Tsibu, and Tsidje exhibit higher infiltration and reduced erosion, indicating suitability for inland valley rice cultivation, whereas Ahava, Aflabo, Hava, and Koloe show elevated runoff, shorter overland flow, and increased flood and erosion risk. Targeted interventions, including check dams, terraces, afforestation, and sustainable cropping systems, are recommended to mitigate hydrological hazards. By linking DEM-derived morphometric indices with dual aquifer characteristics, this study provides a transferable framework for watershed assessment and sustainable water management in data-scarce tropical dual aquifer basins, with applicability to Sub-Saharan Africa, South Asia, and other tropical regions. The findings contribute to global efforts toward sustainable water management and climate resilience (SDGs 6 and 13), with implications for agricultural water security (SDG 2) in data-scarce tropical basins.