Search Results (20)

The hydrodynamics characteristics of artificial water diversion canals with long-distance and inter-basin multi-stage sluice gate regulations are prone to sudden increases and decreases, and sluice gate discharge differs from that of natural rivers. Research on the change characteristics of hydrological elements in artificial canals under the control of sluice gates is lacking, as are scientifically accurate calculations of sluice gate discharge. Therefore, addressing these gaps in long-distance artificial water transfer is of great importance. In this study, real-time operation data of 61 sluice gates, pertaining to the period from May 2019 to July 2021, including data on water levels, flow discharge, velocity, and sluice gate openings in the main canal of the Middle Route of the South-to-North Water Diversion Project of China, were analyzed. The discharge coefficient of each sluice gate was calculated by the dimensional analysis method, and the unit-width discharge was modeled as a function of gate opening ($e$), gravity acceleration ($g$), and energy difference ($H$). Through logarithmic transformation of the Buckingham Pi theorem-derived equation, a linear regression model was used. Data within the relative opening orifice flow regime were selected for fitting, yielding the discharge coefficients and stage–discharge relationships. The results demonstrate that during the study period, the water level, discharge, and velocity of the main canal showed an increasing trend year by year. The dimensional analysis results indicate that the stage–discharge response relationship followed a power function ($Q\propto {(\frac{H}{e})}^{constant}$) and that there was a good linear relationship between $l{g}^{(\frac{H}{e})}$ and $l{g}^{(\frac{K}{e})}$ (R² > 0.95, $K={(q^2/g)}^{1/3}$). By integrating geometric, operational, and hydraulic parameters, the proposed method provides a practical tool and a scientific reference for analyzing sluice gates’ regulation and hydrological response characteristics, optimizing water allocation, enhancing ecological management, and improving operational safety in long-distance inter-basin water diversion projects. Full article

Understanding the contribution of macroinvertebrate diversity indices to community stability in urban rivers is critical for developing more effective strategies to manage and conserve the ecological health of urban rivers and to maintain sustainable regional economic and social development. However, knowledge regarding the relationship between environmental factors, multidimensional biodiversity, and community stability in urban rivers remains limited. In this study, we investigated the relationships among macroinvertebrate multidimensional diversity, secondary productivity-to-biomass ratio (SP/B), and average variation degree (AVD) in a typical urban river—the North Canal River basin in Beijing—to identify which biodiversity metric best indicates community stability. Macroinvertebrates were extensively sampled from September to October 2020 in the North Canal River basin (BYH), a typical urban river in Beijing. We comparatively analyzed the spatial variation in different types of diversity—species diversity (SD), functional diversity (FD), and phylogenetic diversity (PD)—as well as SP/B and AVD between the upstream and midstream–downstream reaches of the river under varying degrees of urbanization and human disturbance. Partial Least Squares Structural Equation Modeling (PLS-SEM) was used to assess the relationships among multidimensional diversity, SP/B, and AVD. The results showed that upstream environmental factors and diversity indices together explained 52.9% and 52.0% of the variance in SP/B and AVD, respectively, while midstream–downstream factors explained 65.9% and 84.2%, respectively. These findings suggest that both SP/B and AVD are suitable indicators for examining the relationships between macroinvertebrate community stability, diversity indices, and environmental factors in the BYH. In the upstream region, total phosphorus (TP), FD, and PD were more indicative of SP/B in the central urban area, while SD and PD were more indicative of AVD. In contrast, in the midstream–downstream suburban areas, dissolved oxygen (DO), SD, and PD were more indicative of SP/B, while FD and PD were more indicative of AVD. These findings demonstrate that PD is a stronger indicator of both SP/B and AVD under varying anthropogenic disturbances and environmental conditions. The PLS-SEM results also indicated differences in the specific effects of FD and SD on community stability across the upstream and midstream–downstream sections, as well as differences in the direct effects of environmental factors such as TP and DO. These results suggest that PD is more sensitive than FD and SD in detecting the impacts of anthropogenic disturbances and environmental fluctuations on macroinvertebrate community stability in urban rivers. Our study provides evidence that PD outperforms FD and SD in predicting macroinvertebrate community stability in urban river ecosystems and that the combined use of SP/B and AVD better reveals the complex interactions between biodiversity and environmental factors influencing community stability. This combination can thus enhance our understanding of how biodiversity affects macroinvertebrate community stability in urban rivers. Full article

Intangible cultural heritage (ICH) reflects a region’s history and culture, serving as a significant indicator of regional identity and cohesion. The Grand Canal Basin in China is rich in historical traditions, containing a rich array of ICH resources. Analyzing the spatiotemporal distribution characteristics and influencing factors of ICH within the Grand Canal Basin of China can provide a scientific basis for developing cultural industries and promoting sustainable regional economic growth. This study employed GIS-based spatial analysis methods, including kernel density estimation, the mean nearest neighbor index, and standard deviation ellipse, to investigate the spatiotemporal distribution of 504 national-level ICH items (including extensions) in the Grand Canal Basin of China. The results demonstrate the significant spatial clustering of ICH, with concentrations in high-density regions, particularly at the northern and southern ends of the canal. There is significant regional disparity in the distribution of ICH, with an uneven quantity and structure, predominantly featuring traditional skills and traditional drama categories. The average centroid shift of ICH exhibits a north-to-south oscillatory trajectory. However, overall, it demonstrates a southward-moving trend. This study also underscores the impacts of urbanization, population density, economic development, and transportation infrastructure on ICH distribution. Among these factors, urbanization exerts the strongest influence on the spatial distribution of ICH. The impact of the natural environment is relatively minor; however, it remains a significant element that cannot be overlooked during development. This research offers valuable data and insights for local governments and institutions to formulate evidence-based strategies for the protection and sustainable utilization of ICH resources, promoting sustainable cultural and economic development in the Grand Canal Basin. Full article

Rapid urbanization and its associated human activities have facilitated the colonization and spread of non-native species, rendering urban ecosystems, particularly in megacities such as Beijing, highly susceptible to biological invasions. This study employed environmental DNA (eDNA) metabarcoding to evaluate the biodiversity and geographical distribution of non-native fish, as well as their interactions with native fish species, across three river basins in Beijing pertaining to the Daqing River, the North Canal, and the Ji Canal. Across all the 67 sampling sites, we identified 60 fish taxa, representing 11 orders, 23 families, and 40 genera, with an average of 33.0 taxa per site. Of these, 40 taxa were native, accounting for only 47.1% of the historically recorded native fish species. Additionally, we detected 20 non-native fish taxa, spanning 11 orders, 13 families, and 17 genera. Native fish exhibited geographical homogenization across the basins, while non-native taxa displayed varied geographical distributions. Non-metric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM) revealed no significant variation in the non-native communities across the river basins. Although most of the non-native taxa were widespread, some were restricted to specific sites or basins. The North Canal exhibited significantly lower non-native biodiversity compared with the Ji Canal across all alpha diversity indices. Simple linear regression analyses indicated positive correlations between the number of taxa and species richness for both native and non-native taxa. Interestingly, species co-occurrence analyses revealed predominantly positive interactions among both native and non-native species pairs, with only two negative relationships involving one native and two non-native taxa. This study provides insights into the biodiversity and geographical distribution of non-native fish in Beijing and establishes a baseline for future biomonitoring and conservation efforts. The findings underscore the need for further investigation into the mechanisms and dynamics of biological invasions within urban environments in Beijing. Full article

The South-to-North Water Diversion Project in China is an extensive inter-basin water transfer project, for which ensuring the safe operation and maintenance of infrastructure poses a fundamental challenge. In this context, structural health monitoring is crucial for the safe and efficient operation of hydraulic infrastructure. Currently, most health monitoring systems for hydraulic infrastructure rely on commercial software or algorithms that only run on desktop computers. This study developed for the first time a lightweight convolutional neural network (CNN) model specifically for early detection of structural damage in water supply canals and deployed it as a tiny machine learning (TinyML) application on a low-power microcontroller unit (MCU). The model uses damage images of the supply canals that we collected as input and the damage types as output. With data augmentation techniques to enhance the training dataset, the deployed model is only 7.57 KB in size and demonstrates an accuracy of 94.17 ± 1.67% and a precision of 94.47 ± 1.46%, outperforming other commonly used CNN models in terms of performance and energy efficiency. Moreover, each inference consumes only 5610.18 $\mathsf{\mu }$J of energy, allowing a standard 225 mAh button cell to run continuously for nearly 11 years and perform approximately 4,945,055 inferences. This research not only confirms the feasibility of deploying real-time supply canal surface condition monitoring on low-power, resource-constrained devices but also provides practical technical solutions for improving infrastructure security. Full article

Remote sensing technology plays a crucial role in the rapid and wide-scale monitoring of water quality, which is of great significance for water pollution prevention and control. In this study, the downstream and nearshore areas of the Huaihe River Basin were selected as the study area. By utilizing spectral information from standard solution measurements in the laboratory and in situ water quality data matched with satellite spatiotemporal data, inversion models for total phosphorus (TP) and ammonia nitrogen (NH₃-N) water quality parameters were developed. The validation results using field measurements demonstrated that the inversion models performed well, with coefficients of determination (R²) of 0.7302 and 0.8024 and root mean square errors of 0.02614 mg/L and 0.0368 mg/L for total phosphorus and ammonia nitrogen, respectively. By applying the models to Sentinel-2 satellite images from 2022, the temporal and spatial distribution characteristics of total phosphorus and ammonia nitrogen concentrations in the study area were obtained. The ammonia nitrogen concentration ranged from 0.05 to 0.30 mg/L, while the total phosphorus concentration ranged from 0.10 to 0.40 mg/L. Overall, the distribution appeared to be stable. The southern region of the Guan River estuary showed slightly higher water quality parameter concentrations compared to the northern region, while the North Jiangsu Irrigation Main Canal estuary was affected by the dilution of river water, resulting in lower concentrations in the estuarine area. Full article

Various studies have shown that the heavy use of pharmaceuticals poses serious ecological risks, especially in metropolitan areas with intensive human activities. In this study, the spatial distribution, sources, and ecological risks of 29 pharmaceuticals in 82 surface waters collected from the North Canal Basin in Beijing were studied. The results showed that the pharmaceutical concentrations ranged from not detected to 193 ng/L, with ampicillin being undetected while ofloxacin had a 100% detection frequency, which indicates the widespread occurrence of pharmaceutical pollution in the North Canal Basin. In comparison with other freshwater study areas, concentrations of pharmaceuticals in the North Canal Basin were generally at moderate levels. It was found that pharmaceutical concentrations were always higher in rivers that directly received wastewater effluents. Source analysis was conducted using the positive matrix factorization model. Combining the spatial pollution patterns of pharmaceuticals, it has been found that wastewater effluents contributed the most to the loads of pharmaceuticals in the studied basin, while in suburban areas, a possible contribution of untreated wastewater was demonstrated. Risk assessment indicated that approximately 55% of the pharmaceuticals posed low-to-high ecological risks, and combining the results of risk analyses, it is advised that controlling WWTP effluent is probably the most cost-effective measure in treating pharmaceutical pollution. Full article

The world’s largest water diversion, the South-to-North Water Transfer Project (SNWTP) in China, has created an “invasion highway” to introduce invasive golden mussels (Limnoperna fortunei) from the Yangtze River basin to Beijing. To examine the spread and colonization patterns of this newly introduced invasive species, we conducted comprehensive environmental DNA (eDNA)-based early detection and conventional field surveys across all water bodies in five river basins in Beijing from 2020 to 2023. Our results indicated a rapid spread over the past four years. Among the 130 tested sites, the number of sites with positive signals from eDNA analysis exhibited an annual increase: Commencing with four infested sites identified through field surveys in 2019, eDNA analysis detected an additional 13, 11, and 10 positive sites in 2020, 2021, and 2022, respectively, and a substantial rise comprising an additional 28 sites in 2023. Conventional field surveys detected mussels 1–3 years later than eDNA-based analysis at 16 sites. Across all 16 sites, we detected a low population density ranging from 1 to 30 individuals/m². These findings collectively indicate that the invasions by golden mussels in Beijing are still in their early stages. To date, golden mussels have successfully colonized four out of the five investigated river basins, including the Jiyun River (22.2% positive sites), North Canal River (59.6% positive sites), Chaobai River (40% positive sites), and Yongding River (63.6% positive sites), with the North Canal River and Yongding River being the most heavily infested. Currently, only the Daqing River basin remains uninfested. Given the significant number of infested sites and the ongoing transport of large new propagules via SNWTP, further rapid spread and colonization are anticipated across aquatic ecosystems in Beijing and beyond. Consequently, we call for the proper implementation of effective management strategies, encompassing early detection, risk assessment, and the use of appropriate control measures to mitigate the potential ecological and economic damages in invaded ecosystems. Full article

Sedimentation processes have negative socioeconomic and environmental consequences. The Compound-Specific Stable Isotopes (CSSI) technique allows for the evaluation of sediment inputs associated with different land use changes in a study region. In the present work, this technique was used in the Alhajuela Lake sub-basin, within the Panama Canal Watershed. The role of the main soil contributors to the landscape (land uses, river, runoff, slope) relevant to the sediment load within the sub-basin of Alhajuela Lake was evaluated, and the relevant indicators in the landscape were selected in order to obtain the best representative sample. The contribution levels of three (3) representative land uses (Forest, Pasture and Sediment) in the study area were evaluated for the sediments present in sixteen (16) selected mixing points. The samples collected were subjected to the standard laboratory process to obtain the carbon chain isotopic values present in the fatty acids. The results of the determinations of the carbon chain fatty acid isotope ratios were evaluated using a Bayesian mixing model that takes into account the uncertainty present in the identified source values. According to the results obtained, the source identified as Sediment has a prominent contribution in most of the mixing points. The contributions of Forest land use are important in the mixing points located north of the study area. The contributions associated with Pasture land use are relevant in the points located in the proximity of this land use. The results suggest that landslides caused by high rainfalls events (Forest and Pasture sources) cause strong sedimentation to the north of Alhajuela Lake. At the same time, a high distribution of soils deposition is observed in the area surrounding Alhajuela Lake due to the strong presence of soils with Sediment source in these places. The results obtained are consistent with observations and measurements of the sediments accumulated in Alhajuela Lake between the years 2008 and 2012. Full article

The Beijing–Hangzhou Grand Canal is renowned for being one of the longest and largest canals in the world. Running from Beijing to Hangzhou (north to south), it connects China’s five major water systems and has an important impact on the ecological environment and economy of northern and southern China. It also boasts a large quantity of intangible cultural heritage (ICH). Clarifying the spatio-temporal distribution pattern of ICH in the Beijing–Hangzhou Grand Canal Basin and its influencing factors is essential for the protection and utilization of heritage resources and the formulation of management policies. In this study, 977 national ICH items in the Beijing–Hangzhou Grand Canal Basin are analyzed with the help of ArcGIS spatial analysis technology, SPSS regression analysis, and human geography research methods. The results show that the national ICH in the Beijing–Hangzhou Grand Canal Basin has complete categories but varies in provincial scale, particularly between the north and south parts. According to the analysis using tools such as kernel density estimation, standard deviation ellipse, and the center-of-gravity model, it is clear that the ICH in the Beijing–Hangzhou Grand Canal Basin shows different degrees of sub-type aggregation, varying directional characteristics of each batch of ICH, and a centre of gravity of ICH with a tendency to shift in multiple directions. The main factors affecting the spatio-temporal distribution pattern of ICH in the Beijing–Hangzhou Grand Canal Basin are natural geographical factors, socioeconomic factors, and policy environment factors. Moreover, there is a significant positive correlation between ICH resources and the tourism industry that cannot be ignored. This study provides an important reference for planning the reuse of ICH resource systems in northern and southern China. Full article

A big number of Red Sea species have entered the Mediterranean Sea since the opening of the Suez Canal. Some of them quickly establish local populations and increase their abundance, forming a potential threat for local biodiversity and fisheries. Here, we use habitat modeling tools to study the expansion of three alien, demersal fish species that entered the Mediterranean basin at different times: Pterois miles, Siganus luridus and Siganus rivulatus. Georeferenced occurrence data from the eastern Mediterranean over the past ten years were compiled using online sources, published scientific literature and questionnaires and were correlated with environmental and topographic variables. The maximum entropy modeling approach was applied to construct habitat suitability maps for the target species over all of the Greek Seas. Results emphasized the three species’ strong coastal nature and their association with the presence of Posidonia oceanica meadows. Probability maps evidenced that for all species there is a higher likelihood of presence along the southeast and central Aegean and Ionian Sea coasts and a lower likelihood throughout the North Aegean Sea. For Siganus spp., predictions in the Thracian Sea were highlighted as highly uncertain, as the environmental conditions in this area partly fall outside the range of values occurring in locations of their current presence. Full article

According to previous studies, the Lixiahe area in the east of the Jianghuai River was an alternate environment of land and sea in the middle Holocene, and it was not until the late Holocene that the eastern Jianghuai completely became a terrestrial environment. However, recent archaeological studies have found that the extensive Neolithic sites in the Lixiahe area have recorded the rich human activities and cultural connotations of the prehistoric civilization in the Middle Holocene. In this paper, the Gangxi section of Jianhu Lake, Jiangsu Province (GX2) was selected and pollen analysis was fulfilled, then the geomorphic evolution process of the study area from sea to land was investigated according to the palynological assemblages and algae fossils of brackish water, semi-saline water, fresh water and terrestrial in the section strata. During the period of 8500–3800 cal. BP, GX2 was affected by multiple factors such as sea surface fluctuation, ocean flow and sediment deposition carried by seagoing rivers. Since 5800 cal. BP, the area east of the Grand Canal between the Yangtze River and the Huaihe River, and the west of the Yangzhai town, Funing–Longgang town, Yancheng–Dagang town and Yancheng–west of the Dongtai–Hai’an line, have become a terrestrial environment. After the eastern Jianghuai became a land, the Liangzhu culture (5300–4300 cal. BP) in the Taihu Lake basin in the south wing of the Yangtze River delta expanded to the eastern Jianghuai area, and the Longshan culture and Yueshi culture in the Haidai area in the north also migrated south to the eastern Jianghuai area. Admittedly, the main reason in the process of Neolithic cultural development is the internal motivation that the ancient ancestors struggled with nature and pushed forward the continuous development of civilizations. However, our study explains the palaeogeographical origin of Neolithic culture in the eastern and coastal areas of Jianghuai in the middle Holocene, and meanwhile, provides an example for the man–land relationship research on Neolithic culture. Full article

The Wuqing urban section of the North Canal Basin, Tianjin, is a significant gathering place for multisource pollution, showing the characteristics of a stagnant water body supplied by unconventional water sources. With the development of the economy and society, the water quality of the Wuqing urban section of the North Canal Basin, Tianjin, has been seriously polluted due to the discharge of sewage outlets and the influx of nonpoint source pollution from farmland. In this study, based on the results of special water experiments, a two-dimensional hydrodynamic water quality model was constructed. The concentrations of ammonia nitrogen (NH₃-N), total phosphorus (TP), and chemical oxygen demand (COD) in the study area were simulated, and the model parameters were calibrated and verified with the measured values. Based on the model verification, the water quality improvement scheme of the ecological floating bed with different plant ratios was set up to simulate the water quality. The research results showed that the average concentrations of NH₃-N, TP, and COD decreased by 10.4%, 15.7%, and of d 26.3%, respectively, after the ecological floating bed was arranged. During model parameter calibration and validation, the RMSE ranges of NH₃-N, TP, and COD were 0.09~0.22 mg/L, 0.00~0.02 mg/L, and 0.37~2.42 mg/L, respectively. Other statistical indicators are also within a reasonable range, and the model accuracy and reliability are high. The simulation results of different scenarios showed that the optimal ratio of ecological floating bed plants was 700 m² of Scirpus validus Vahl and 700 m² of Canna in zone 1 of the floating bed combination, 430 m² of Scirpus validus Vahl, and 170 m² of Iris in zone 2 of the floating bed combination, and 200 m² of Iris and 200 m² of Lythrum salicaria in zone 3 of the floating bed combination. This study can provide a theoretical basis for the sustainable development of water purification in the North Canal. It can also provide a model approach for the implementation of river water purification schemes, exemplified by the North Canal. Full article

The pollution of water bodies by pharmaceuticals and personal care products (PPCPs) has attracted widespread concern due to their widespread use and pseudo-persistence, but their effects on sediments are less known. In this study, solid-phase extraction-high performance liquid chromatography–tandem mass spectrometry (SPE-LC/MSMS) was used to investigate the occurrence and ecological risks of five typical pharmaceuticals and personal care products (PPCPs) in thirteen key reservoirs, sluices, dams, and estuaries in the Haihe River Basin. At the same time, the PPCP exchanges of surface water, groundwater, and sediments in three typical sections were studied. Finally, the PPCP’s environmental risk is evaluated through the environmental risk quotient. The results showed that the five PPCPs were tri-methoprazine (TMP), sinolamine (SMX), ibuprofen (IBU), triclosan (TCS), and caffeine (CAF). The average concentration of these PPCPs ranged from 0 to 481.19 μg/kg, with relatively high concentrations of TCS and CAF. The relationship between PPCPs in the surface sediments was analyzed to reveal correlations between SMX and TMP, CAF and IBU, CAF and TCS. The risk quotients (RQ) method was used to evaluate the ecological risk of the five detected PPCPs. The major contributors of potential environmental risks were IBU, TCS and CAF, among which all the potential environmental risks at the TCS samples were high risk. This study supplemented the research on the ecological risk of PPCPs in sediments of important reaches of the North Canal to reveal the importance of PPCP control in the North Canal and provided a scientific basis for pollution control and risk prevention of PPCPs. Full article

Flood control risk is one of the main risks affecting the safe operation of large-scale water transfer projects. Systematically identifying the flood control risk in the project and carrying out risk classification and hierarchical management are problems for project managers. Based on the theory of system and risk assessment, this paper starts with the various risk sources and risk events involved in the whole process of the flood disaster chain, the risk of flood disaster factors, the exposure of the disaster-bearing body, and the vulnerability of the disaster-originating environment are combined. Then, we systematically and comprehensively identify the flood control risks of a large-scale water transfer project, which are divided into four types of risk elements: rainfall–runoff; confluence and flow capacity; the geological characteristics of canal section; economic and social layouts. Specific risk factors are identified for each type of risk element, and a flood control risk evaluation index system for a water transfer project is proposed. According to the framework of the analytic hierarchy process (AHP), a quantitative assessment of comprehensive flood control for water transfer projects is carried out. Taking the middle route of the South-to-North Water Transfer Project in China as an example, this paper evaluates the integrated flood control risks of 39 engineering units, identifies six units with higher risk levels, analyzes the causes, and suggests engineering and non-engineering countermeasures to prevent and reduce the occurrence of risk accidents. This method is not only used for comprehensive flood control risk assessment and risk management in the operation and management stage of the large-scale inter-basin water transfer project, but also has a reference value in considering the optimal layout of the project water transmission line from the perspective of flood control in the planning and design stage. Full article