River ecosystems face challenges due to environmental degradation and alterations in flow and sediment transport resulting from climate change and other anthropogenic impacts. These changes may substantially affect river morphology, nutrient dynamics, wetland vegetation, aquatic habitats, and river ecological stability. This highlights the urgent need for systematic and quantitative studies on the interactions and feedback between changes in flow, sediment transport, and river ecology. In this study, we reviewed flow and sediment transport changes in major Chinese rivers, along with their resulting ecological impacts. We propose conducting eco-fluvial dynamic studies, a potential solution that can guide the evaluation and restoration of ecological health impacted by physical processes. These studies can provide major benefits in balancing human and environmental needs in large river systems, which is crucial for the healthy and sustainable development of rivers.
To have effective water resource management, the distributed hydrological models are commonly applied for supporting the decision-making processes. Among different inputs, the spatial distributed rainfall plays significant role in those model simulations. Many interpolation methods have been developed for generating distributed rainfall based on measurement samples. However, depending on the catchment characteristics and data availability, the suitable interpolation algorithm is case-dependent. This paper presents one operational approach for determining the resonable interpolation algorithm in a complex large catchment (Var catchment, France). Based on the daily rainfall data (2008–2014) collected from 16 stations in the Var catchment, six different interpolation approaches including: inverse distance weight (IDW), spline, kriging with linear and spherical semi-variogram models and geographically weighted regression considering elevation effects and the combined impacts of elevation and distance to the sea were tested. Integrated the results of statistical and modeling assessments, the 400m resolution distributed rainfall generated by IDW algorithm shows high preference in generating distributed rainfall in the Var catchment. Moreover, the strategy described in the article also shows promising acceptability for other catchments.
This study applied the interaction of social vulnerability and hazard to assess flood risk in three urbanized areas within the Pasig-Marikina-Laguna-Lake catchment: Manila, Marikina, and Parañaque in Metro Manila, Philippines. This study examined risk patterns across different flood return periods (5, 50, and 100 years) in these urban river environments and provided both city-wide and localized risk assessments. The social vulnerability to flood index (SVFI) was calculated using socioeconomic indicators, while the hazard index was derived from flood depth categories. Results show that city-level risk indices are low to moderate, with Marikina consistently having the highest risk, followed by Manila and Parañaque. However, localized assessments reveal high-risk areas within cities, with Manila being the most vulnerable to frequent floods (5-year return period) and Marikina to less frequent but extreme events (50- and 100-year return periods). Parañaque maintains the lowest risk profile across all scenarios. This study highlights the importance of considering both citywide trends and localized high-risk areas in flood risk management. It provides valuable insights for disaster management planners and policymakers, enabling the development of targeted strategies for sustainable urban river management and flood risk reduction in rapidly urbanizing river systems. The methodology presented applies to other urban areas that face similar flood risks.
The widespread use of antibiotics has significantly increased their presence in aquatic environments, particularly in sensitive Karst River systems. In this study, the distribution and ecological, human health, and resistance selection risk assessment of 44 antibiotics in the typical Karst River, Lijiang River, were investigated during the influenza season, a period marked by heightened antibiotic usage. 27 antibiotics could be found in the water of Lijiang River, among which azithromycin showing the highest concentrations. The concentrations of total antibiotics were in the range 171.70–2003.75 ng/L, with an average value of 704.76 ng/L. Macrolide was the predominant class, constituting an average of 57.65% of the total antibiotic concentrations. Risk assessments revealed that certain antibiotics, especially macrolides, posed moderate to high ecological risks to algae, displayed potential human health risks at low levels and contributed to antimicrobial resistance. Among all the antibiotics, azithromycin was the only one could cause ecological risk to algae, human health risk towards infants and antimicrobial resistance selection risk, which should be identified as the priority antibiotic for control in the Lijiang River during the influenza season. There was no difference in the concentrations, human health and antimicrobial resistance selection risk of antibiotics between mainstream and tributaries of The widespread use of antibiotics has significantly increased their presence in aquatic environments, particularly in sensitive Karst River systems. In this study, the distribution and ecological, human health, and resistance selection risk assessment of 44 antibiotics in the typical Karst River, Lijiang River, were investigated during the influenza season, a period marked by heightened antibiotic usage. 27 antibiotics could be found in the water of Lijiang River, among which azithromycin showing the highest concentrations. The concentrations of total antibiotics were in the range 171.70–2003.75 ng/L, with an average value of 704.76 ng/L. Macrolide was the predominant class, constituting an average of 57.65% of the total antibiotic concentrations. Risk assessments revealed that certain antibiotics, especially macrolides, posed moderate to high ecological risks to algae, displayed potential human health risks at low levels and contributed to antimicrobial resistance. Among all the antibiotics, azithromycin was the only one could cause ecological risk to algae, human health risk towards infants and antimicrobial resistance selection risk, which should be identified as the priority antibiotic for control in the Lijiang River during the influenza season. There was no difference in the concentrations, human health and antimicrobial resistance selection risk of antibiotics between mainstream and tributaries of Lijiang River. This study contributes to a better understanding of antibiotic pollution and provides insights into potential risk management practices in vulnerable aquatic systems worldwide.
The Water Cloud Model (WCM) plays a crucial role in active microwave soil moisture inversion applications. Empirical parameters are important factors affecting the accuracy of WCM simulation, but the current evaluation of empirical parameters only considers the forward simulation process, and insufficient consideration is given to the model inversion problem. This study proposes a new estimation method for vegetation parameters in the WCM by combining the soil backscattering model and the objective function. The effectiveness of the method is then verified using measured data. Simultaneously, this study also analyzes the factors influencing the evaluation of vegetation parameters in the WCM, resulting in the following conclusions. First, blindly utilizing vegetation parameters recommended by previous model studies is not advisable. To ensure the accuracy of the simulation, it is necessary to adjust the vegetation parameters appropriately. Second, to ensure the ability of the WCM solving both forward and inverse problems, it is advisable to consider both soil backscatter and surface backscatter simulations in the construction of the cost function. Third, soil backscatter simulations have an impact on the solution of vegetation parameters, and more accurate soil scattering models provide a better representation of the modeled vegetation. This study presents a dependable method for resolving the vegetation parameters of the WCM, thereby offering a valuable reference for the application of the model in surface parameter inversion research.
The Kolong, a significant distributary of the mighty river Brahmaputra in Assam, India, has experienced significant human-induced alterations aimed basically for flood mitigation. This study investigates the socio-ecological impacts of the course change of the Kolong River done by the local people of Kahargaon village in Nagaon district of Assam, India. Employing a mixed-methods approach, the research integrates field observations, stakeholder interviews, community forums, and secondary data analysis to assess the river’s dynamics and its effects on local livelihoods and ecosystems. The findings reveal that while flood mitigation efforts have provided immediate relief, they have also led to ecological degradation and disrupted traditional livelihoods, particularly those dependent on the river’s natural flow. The left-out channel, once rich in biodiversity, now suffers from reduced water levels and a diminished riverine ecological niche, compelling communities to adapt through alternative agricultural practices and grazing. This study emphasizes the need for integrated management strategies that balance flood control with ecological preservation and livelihood sustainability. Thus, the study promotes community-based conservation initiatives, restoring natural flow patterns, and developing adaptive livelihood strategies. The insights gained so far contribute to the broader understanding of human–river interactions and offer valuable lessons for sustainable river management in similar contexts globally.
The analysis of plastic loosening zone of tunnels with cold condition, high in situ stress, and weak stratum is the key scientific problem of tunnel construction in cold areas. Based on the unified strength theory and considering the coupling effect of high in situ stress and low-temperature field, the analytical model of the plastic loosening zone of tunnel surrounding rocks was proposed, and the influence laws of physical parameters (initial ground stress, freezing temperature, excavation radius, and intermediate principal stress) was explored. The results illustrate that: (1) with the coupling of low temperature and stress fields, the in-situ stress has a more significant effect on the radius of the plastic loosening zone of the tunnel surrounding rocks, showing a nonlinear correlation. When the in situ stress is small, the influence of the temperature field on the radius of the plastic loosening zone is more obvious. (2) The radius of the plastic loosening zone of the tunnel surrounding rocks increases synchronously with the excavation radius and gradually decreases with the increase of the intermediate principal stress. (3) The greater the temperature difference in the low-temperature field, the tunnel stability has a more significant response to the intermediate principal stress and is positively correlated with the coefficient of the intermediate principal stress. (4) In the actual project, the proposed model can well describe the mechanical behavior and deformation characteristics of tunnel surrounding rocks in low-temperature environment, showing applicability. The research results are expected to provide a theoretical basis for the study of tunnel stability in cold areas.
The present study aimed to delineate a robust watershed boundary and extract its morphometric parameters in the Karnaphuli watershed, Bangladesh, using different digital elevation models (DEMs). Two DEMs, the shuttle radar topographic mission (SRTM) and the terra advanced spaceborne thermal emission and reflection radiometer (ASTER), were employed to delineate watershed boundaries and evaluate various morphometric characteristics. Raster data such as fill sinks, flow direction, and flow accumulation were utilized to delineate the watershed. The morphometric analysis included the estimation of linear, areal, and relief parameters. The findings revealed a noticeable difference between the datasets; ASTER delineated a larger watershed area than SRTM. Regarding stream order, there were streams ranging from 1st to 6th order, encompassing numerous small, medium, and main channels of the river. Drainage density was calculated as 0.52 km/km2 for SRTM and 0.51 km/km2 for ASTER, both having a spatial resolution of 30m. The bifurcation ratio ranged from 1.94 for SRTM to 2.45 for ASTER, indicating varying degrees of structural disturbance influenced by geological factors. The form factor indicated an elongated shape of the study area. The overall dimensions of the streams and the watershed extent suggest moderate mean annual rainfall discharge. The watershed exhibited relatively high denudation rates, attributed to the basin relief. A low drainage density indicated the importance of infiltration processes. The findings of this study provide valuable insights into the spatial variability of watershed characteristics, highlighting the need for tailored management strategies for the Karnaphuli River. Implementing targeted conservation measures and watershed management practices based on these morphometric parameters can enhance water resource sustainability and ecological health in the region.
Inland wetlands play a vital role in mitigating non-point source nitrogen loads through denitrification and anammox processes. However, the impact of varying human activities within the same region on these nitrogen removal processes of inland wetlands remains unclear. This study investigated the differences in nitrogen removal rates of wetland sediments under various human activities in Jiashan County, China. 15N isotope tracing was used to determine denitrification and anammox rates. Denitrification was the primary nitrogen removal pathway, with an average contribution of 82.34%. Denitrification and anammox rates varied significantly under different human influences, with the highest rates in residential and agricultural areas. NH4+, chlorophyll a, NO3−, and pH were the main environmental factors. This study highlights the need for targeted wetland management and restoration strategies based on the type and intensity of human activities. Protecting and restoring these “natural purifiers” is crucial for improving regional water quality and maintaining the ecological functions of wetlands in rapidly urbanizing landscapes.