bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Connectivity of Sediment Affected by Check Dams in Loess Hilly-Gully Region, China
Authors: Bai Leichao , Jiao Juying , Wang Nan , Chen Yulan
Published: September 2021

Check dams play an irreplaceable role in soil and water conservation in the Chinese Loess Plateau region. However, there are few analyses on the connection between check dams and the downstream channel and the impact on structural connectivity and sediment interception efficiency. Based on a field survey, this study classified the connection mode between check dams and the downstream channel, and the actual control area percentage by discharge canal in dam land was used to quantitatively evaluate the degree of the structural connectivity of sediment between the check dam and the downstream channel. The analysis results show that the connection mode can be divided into eleven categories with different structural connectivity. The different connection modes and its combination mode of check dams and downstream channels in dam systems have a large difference, and the structural connectivity of the dam system is less than or equal to that of the sum of single check dams in a watershed. The degree of structural connectivity of a dam system will be greatly reduced if there is a main control check dam with no discharge canal in the lower reaches of the watershed. Compared with a single check dam, the structural connectivity of a dam system is reduced by 0–42.38%, with an average of 11.18%. According to the difference in connection mode and structural connectivity of check dams and dam systems in the four typical small watersheds, the optimization methods for connection mode in series, parallel and hybrid dam systems were proposed. The research results can provide a reference for the impact of a check dam on the sediment connectivity and the sediment interception efficiency in a watershed and can also guide the layout of a dam system and the arrangement of drainage facilities.
New Evidence of MIS 3 Relative Sea Level Changes from the Messina Strait, Calabria (Italy)
Authors: Antonioli Fabrizio , Calcagnile Lucio , Ferranti Luigi , Mastronuzzi Giuseppe , Monaco Carmelo , Orrù Paolo , Quarta Gianluca , Pepe Fabrizio , Scardino Giovanni , Scicchitano Giovanni , Stocchi Paolo , Taviani Marco
Published: September 2021

Investigation of sea-level positions during the highly-dynamic Marine Isotope Stage 3 (MIS 3: 29–61 kyrs BP) proves difficult because: (i) in stable and subsiding areas, coeval coastal sediments are currently submerged at depths of few to several tens of meters below the present sea level; (ii) in uplifting areas, the preservation of geomorphic features and sedimentary records is limited due to the erosion occurred during the Last Glacial Maximum (LGM) with sea level at a depth of −130 m, followed by marine transgression that determined the development of ravinement surfaces. This study discusses previous research in the Mediterranean and elsewhere, and describes new fossiliferous marine deposits overlaying the metamorphic bedrock at Cannitello (Calabria, Italy). Radiocarbon ages of marine shells (about 43 kyrs cal BP) indicate that these deposits, presently between 28 and 30 m above sea level, formed during MIS 3.1. Elevation correction of the Cannitello outcrops (considered in an intermediate-to-far-field position with respect to the ice sheet) with the local vertical tectonic rate and Glacial Isostatic Adjustment (GIA) rate allows the proposal of a revision of the eustatic depth for this highstand. Our results are consistent with recently proposed estimates based on a novel ice sheet modelling technique.
A New Multi-Objective Optimization Model of Water Resources Considering Fairness and Water Shortage Risk
Authors: Tang Xiaoyu , He Ying , Qi Peng , Chang Zehua , Jiang Ming , Dai Zhongbin
Published: September 2021

Assessing the fairness of water resource allocation and structural water shortage risks is an urgent problem that needs to be solved for the optimal allocation of water resources. In this study, we established a new multi-objective optimization model of water resources based on structural water shortage risks and fairness. We propose an improved NSGA-III based on the reference point selection strategy (ARNSGA-III) to solve the optimization model. The superiority of this method was proven by comparing it with three other methods, namely, NSGA-III, MOSPO, and MOEA/D. The model was applied to optimize the allocation of water resources in Wusu City in China. The results show that the new multi-objective optimization model provides reasonable and feasible solutions for solving water conflicts. The convergence and stability of ARNSGA-III are better than those of the other three algorithms. Allocation schemes of water resources for Wusu City in normal years, dry years, and extremely dry years are proposed. In normal years, the structural water shortage risk index is reduced by 50.1%, economic benefits increased by 0.2%, and fairness is reduced by 60.5%. This study can provide new ideas for solving the multi-objective optimization of regional water resources.
Insights from Water Quality of High Andean Springs for Human Consumption in Peru
Authors: Choque-Quispe David , Froehner Sandro , Ligarda-Samanez Carlos A. , Ramos-Pacheco Betsy S. , Peralta-Guevara Diego Elio , Palomino-Rincón Henry , Choque-Quispe Yudith , Solano-Reynoso Aydeé M. , Barboza-Palomino Gloria I. , Taipe-Pardo Fredy , Zamalloa-Puma L. Magali
Published: September 2021

The headwaters of the high Andean basin in Peru accumulate water from the mist, rain, snow, and hail, and it is transported superficially and underground to low-lying areas, mostly used for drinkable purposes. The natural water in these areas might be altered due to legal and illegal mining extraction. The aim of the study was to evaluate the water quality for human consumption. Seventeen water samples were examined from Andahuaylas (A), San Jerónimo (S), Talavera (T), and Chiara (CH) districts located between 2813 and 4004 m altitude in the Andes. We used physicochemical, microbiological, and metal parameters, and the results were compared to permissible levels established by the WHO and ECA-Peru to examine samples collected in the dry and rainy seasons in 2019. Application of principal component analysis (PCA) identified areas and conditioning parameters. Extractive mining activity influences the quality of springs due to the presence of metals, especially antimony (Sb), arsenic (As), cadmium (Cd), and lead (Pb), values of which are higher than values permissible for human consumption, being higher in the dry season (p < 0.05). In addition, the presence of cations and particulate matter affects physico-chemical parameters, for example turbidity. PCA showed that parameters for water characterization are season-independent, and water quality in the springs would be conditioned by the presence of metals, especially in Andahuaylas and Talavera zones, as well as the parameters that are associated with dissolved solids in the water (turbidity and fluorides). A frequent monitoring program of springs and groundwater is recommended, with the purpose to protect water from contamination and guarantee safe water availability in low-lying and urbanized areas.
Regulation of Vegetation and Evapotranspiration by Water Level Fluctuation in Shallow Lakes
Authors: Liu Qiang , Liang Liqiao , Yuan Xiaomin , Yan Sirui , Li Miao , Li Shuzhen , Wang Xuan , Li Chunhui
Published: September 2021

Water level fluctuations play a critical role in regulating vegetation distribution, composition, cover and richness, which ultimately affect evapotranspiration. In this study, we first explore water level fluctuations and associated impacts on vegetation, after which we assess evapotranspiration (ET) under different water levels. The normalized difference vegetation index (NDVI) was used to estimate the fractional vegetation cover (Fv), while topography- and vegetation-based surface-energy partitioning algorithms (TVET model) and potential evaporation (Ev) were used to calculate ET and water evaporation (Ep). Results show that: (1) water levels were dramatically affected by the combined effect of ecological water transfer and climate change and exhibited significant decreasing trends with a slope of −0.011 m a−2; and (2) as predicted, there was a correlation between water level fluctuation at an annual scale with Phragmites australis (P. australis) cover and open-water area. Water levels also had a controlling effect on Fv values, an increase in annual water levels first increasing and then decreasing Fv. However, a negative correlation was found between Fv values and water levels during initial plant growth stages. (iii) ET, which varied under different water levels at an annual scale, showed different partition into transpiration from P. australis and evaporation from open-water area and soil with alterations between vegetation and open water. All findings indicated that water level fluctuations controlled biological and ecological processes, and their structural and functional characteristics. This study consequently recommends that specifically-focused ecological water regulations (e.g., duration, timing, frequency) should be enacted to maintain the integrity of wetland ecosystems for wetland restoration.
Spatial Heterogeneity and Driving Factors of Soil Moisture in Alpine Desert Using the Geographical Detector Method
Authors: Zhang Zhiwei , Yin Huiyan , Zhao Ying , Wang Shaoping , Han Jiahua , Yu Bo , Xue Jie
Published: September 2021

Soil moisture is a vital factor affecting the hydrological cycle and the evolution of soil and geomorphology, determining the formation and development of the vegetation ecosystem. The previous studies mainly focused on the effects of different land use patterns and vegetation types on soil hydrological changes worldwide. However, the spatial heterogeneity and driving factors of soil gravimetric water content in alpine regions are seldom studied. On the basis of soil sample collection, combined with geostatistical analysis and the geographical detector method, this study examines the spatial heterogeneity and driving factors of soil gravimetric water content in the typical alpine valley desert of the Qinghai–Tibet Plateau. Results show that the average value of soil gravimetric water content at different depths ranges from 3.68% to 7.84%. The optimal theoretical models of soil gravimetric water content in 0–50 cm layers of the dune are different. The nugget coefficient shows that the soil gravimetric water content in the dune has a strong spatial correlation at different depths, and the range of the optimal theoretical model of semi-variance function is 31.23–63.38 m, which is much larger than the 15 m spacing used for sampling. The ranking of the influence of each evaluation factor on the alpine dune is elevation > slope > location > vegetation > aspect. The interaction detection of factors indicates that an interaction exists among evaluation factors, and no factors are independent of one another. In each soil layer of 0–50 cm, the interaction among evaluation factors has a two-factor enhancement and a nonlinear enhancement effect on soil gravimetric water content. This study contributes to the understanding of spatial heterogeneity and driving factors of soil moisture in alpine deserts, and guidance of artificial vegetation restoration and soil structure analysis of different desert types in alpine cold desert regions.
Effect of Chemical Oxygen Demand Concentration on Nutrient Removal in Simultaneous Nitrification, Denitrification and Phosphorus Removal System in High-Altitude Areas
Authors: Zhao Yani , Zhang Liling , Zhang Meng , Wu Jingya , Li Shuping , Ran Douzhi , Sun Liwei , Zhu Guangcan
Published: September 2021

The application of biological nitrogen and phosphorus removal processes in high-altitude areas faces severe challenges due to low temperature, low atmosphere pressure and low oxygen concentration. In this study, a simultaneous nitrification, denitrification and phosphorus removal (SNDPR) system was operated under low atmosphere pressure. The chemical oxygen demand (COD) concentrations in influent were decreased from 300 mg/L (stage I) to 200 mg/L (stage II), corresponding to the low COD concentration of sewage in high-altitude areas. The removal of COD and total phosphate was efficient at the H1 reactor (72 kPa). The removal rates of COD and total phosphate were 94.08% (stage I), 90.66% (stage II) and 98.43% (stage I), 99.34% (stage II), respectively, which were similar to L1 (100 kPa). The removal rates of total inorganic nitrogen and simulation nitrification and denitrification were from 81.21% (stage I) and 59.48% (stage I) to 72.86% (stage II) and 31.95% (stage II), respectively, which were also improved compared to L1. Cycle experiment results indicated that the activity of phosphorus accumulating organisms was enhanced, while the ammonia oxidation process was inhibited under low atmosphere pressure.
Spatial Pattern Analysis of a Water-Related Ecosystem Service and Evaluation of the Grassland-Carrying Capacity of the Heihe River Basin under Land Use Change
Authors: Luo Rui , Yang Shiliang , Zhou Yang , Gao Pengqun , Zhang Tianming
Published: September 2021

A key challenge to the sustainability and security of grassland capacity is the protection of water-related ecosystem services (WESs). With the change of land use, the supply of aquatic ecosystem services has changed, and the grassland-carrying capacity has been affected. However, the correlation mechanism between WESs and the grassland-carrying capacity is not clear. In this study, we used the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) model to evaluate the impact of land-use change on WESs, and made a tradeoff analysis between WESs and grassland-carrying capacity. Considering that the Heihe River Basin (HRB) was an important grassland vegetation zone, which was a milestone for the development of animal husbandry in China, HRB was taken as a case. The main findings are as follows: (1) the spatial distribution of WESs shows the dissimilation rule, the upper reaches are the main water yield area, the soil retention is weakening in the middle and lower reaches, and the pollution has further increased in the middle and upper reaches. (2) The carrying capacity of animal husbandry decreased in the upper reaches, increased in Shandan County and Zhangye City in the middle reaches, and decreased sharply in other regions. (3) There was a positive correlation between the livestock-carrying capacity and nitrogen export in 2018, which was increasing. As the change of land use has changed the evapotranspiration structure, WESs have undergone irreversible changes. Meanwhile, the development of large-scale irrigated farmland and human activities would be the source of a further intensification of regional soil erosion and water pollution. Therefore, it is necessary to trade off the WESs and animal husbandry under land-use change. This paper revealed how WESs changed from 2000 to 2018, the characteristics of the changes in the spatial and temporal distribution, and the carrying capacity. It aims to provide a scientific basis for coordinating the contradiction between grassland and livestock resources, improving the regional ecological security situation, and carrying out ecosystem management.
Heavy Metals Removal from Water by Efficient Adsorbents
Authors: Zaimee Muhammad Zaim Anaqi , Sarjadi Mohd Sani , Rahman Md Lutfor
Published: September 2021

Natural occurrence and anthropogenic practices contribute to the release of pollutants, specifically heavy metals, in water over the years. Therefore, this leads to a demand of proper water treatment to minimize the harmful effects of the toxic heavy metals in water, so that a supply of clean water can be distributed into the environment or household. This review highlights several water treatment methods that can be used in removing heavy metal from water. Among various treatment methods, the adsorption process is considered as one of the highly effective treatments of heavy metals and the functionalization of adsorbents can fully enhance the adsorption process. Therefore, four classes of adsorbent sources are highlighted: polymeric, natural mineral, industrial by-product, and carbon nanomaterial adsorbent. The major purpose of this review is to gather up-to-date information on research and development on various adsorbents in the treatment of heavy metal from water by emphasizing the adsorption capability, effect of pH, isotherm and kinetic model, removal efficiency and the contact of time of every adsorbent.
Comparison of Deterministic and Statistical Models for Water Quality Compliance Forecasting in the San Joaquin River Basin, California
Authors: Quinn Nigel W. T. , Tansey Michael K. , Lu James
Published: September 2021

Model selection for water quality forecasting depends on many factors including analyst expertise and cost, stakeholder involvement and expected performance. Water quality forecasting in arid river basins is especially challenging given the importance of protecting beneficial uses in these environments and the livelihood of agricultural communities. In the agriculture-dominated San Joaquin River Basin of California, real-time salinity management (RTSM) is a state-sanctioned program that helps to maximize allowable salt export while protecting existing basin beneficial uses of water supply. The RTSM strategy supplants the federal total maximum daily load (TMDL) approach that could impose fines associated with exceedances of monthly and annual salt load allocations of up to $1 million per year based on average year hydrology and salt load export limits. The essential components of the current program include the establishment of telemetered sensor networks, a web-based information system for sharing data, a basin-scale salt load assimilative capacity forecasting model and institutional entities tasked with performing weekly forecasts of river salt assimilative capacity and scheduling west-side drainage export of salt loads. Web-based information portals have been developed to share model input data and salt assimilative capacity forecasts together with increasing stakeholder awareness and involvement in water quality resource management activities in the river basin. Two modeling approaches have been developed simultaneously. The first relies on a statistical analysis of the relationship between flow and salt concentration at three compliance monitoring sites and the use of these regression relationships for forecasting. The second salt load forecasting approach is a customized application of the Watershed Analysis Risk Management Framework (WARMF), a watershed water quality simulation model that has been configured to estimate daily river salt assimilative capacity and to provide decision support for real-time salinity management at the watershed level. Analysis of the results from both model-based forecasting approaches over a period of five years shows that the regression-based forecasting model, run daily Monday to Friday each week, provided marginally better performance. However, the regression-based forecasting model assumes the same general relationship between flow and salinity which breaks down during extreme weather events such as droughts when water allocation cutbacks among stakeholders are not evenly distributed across the basin. A recent test case shows the utility of both models in dealing with an exceedance event at one compliance monitoring site recently introduced in 2020.
Analysis of Net Erosion Using a Physics-Based Erosion Model for the Doam Dam Basin in Korea
Authors: Yeon Minho , Kim Seongwon , Shin Hongjoon , An Hyunuk , Lee Daeeop , Jung Sungho , Lee Giha
Published: September 2021

In Korea, approximately 70% of the country is mountainous, with steep slopes and heavy rainfall in summer from June to September. Korea is classified as a high-risk country for soil erosion, and the rate of soil erosion is rapidly increasing. In particular, the operation of Doam dam was suspended in 2001 because of water quality issues due to severe soil erosion from the upstream areas. In spite of serious dam sediment problems in this basin, in-depth studies on the origin of sedimentation using physic-based models have not been conducted. This study aims to analyze the spatial distribution of net erosion during typhoon events using a spatially distributed physics-based erosion model and to improve the model based on a field survey. The spatially uniform erodibility constants of the surface flow detachment equation in the original erosion model were replaced by land use erodibility constants based on benchmarking experimental values to reflect the effect of land use on net erosion. The results of the upgraded model considering spatial erodibility show a significant increase in soil erosion in crop fields and bare land, unlike the simulation results before model improvement. The total erosion and deposition for Typhoon Maemi in 2003 were 36,689.0 and 9893.3 m3, respectively, while the total erosion and deposition for Typhoon Rusa in 2002 were 142,476.6 and 44,806.8 m3, respectively, despite about twice as much rainfall and 1.2 times as high rainfall intensity. However, there is a limitation in quantifying the sources of erosion in the study watershed, since direct comparison of the simulated net erosion with observed spatial information from aerial images, etc., is impossible due to nonperiodic image photographing. Therefore, continuous monitoring of not only sediment yield but also periodic spatial detection on erosion and deposition is critical for reducing data uncertainty and improving simulation accuracy.
Comparison between Deep Learning and Tree-Based Machine Learning Approaches for Landslide Susceptibility Mapping
Authors: Saha Sunil , Roy Jagabandhu , Hembram Tusar Kanti , Pradhan Biswajeet , Dikshit Abhirup , Abdul Maulud Khairul Nizam , Alamri Abdullah M.
Published: September 2021

The efficiency of deep learning and tree-based machine learning approaches has gained immense popularity in various fields. One deep learning model viz. convolution neural network (CNN), artificial neural network (ANN) and four tree-based machine learning models, namely, alternative decision tree (ADTree), classification and regression tree (CART), functional tree and logistic model tree (LMT), were used for landslide susceptibility mapping in the East Sikkim Himalaya region of India, and the results were compared. Landslide areas were delimited and mapped as landslide inventory (LIM) after gathering information from historical records and periodic field investigations. In LIM, 91 landslides were plotted and classified into training (64 landslides) and testing (27 landslides) subsets randomly to train and validate the models. A total of 21 landslides conditioning factors (LCFs) were considered as model inputs, and the results of each model were categorised under five susceptibility classes. The receiver operating characteristics curve and 21 statistical measures were used to evaluate and prioritise the models. The CNN deep learning model achieved the priority rank 1 with area under the curve of 0.918 and 0.933 by using the training and testing data, quantifying 23.02% and 14.40% area as very high and highly susceptible followed by ANN, ADtree, CART, FTree and LMT models. This research might be useful in landslide studies, especially in locations with comparable geophysical and climatological characteristics, to aid in decision making for land use planning.
Study on the Water Supply and the Requirements, Yield, and Water Use Efficiency of Maize in Heilongjiang Province Based on the AquaCrop Model
Authors: Nie Tangzhe , Jiao Yang , Tang Yi , Li Na , Wang Tianyi , Du Chong , Zhang Zhongxue , Li Tiecheng , Zhu Shijiang , Sun Zhongyi , Li Fengrui
Published: September 2021

Agricultural irrigation depends heavily on freshwater resources. Under the context of increasingly severe water shortages, studying the relationship among crop water requirements (ETc), actual crop evapotranspiration (ETa), irrigation water requirements (Ir), yield, and water use efficiency (WUE) would be beneficial to improve the agricultural application of irrigation water. Based on the daily data of 26 meteorological stations in Heilongjiang Province from 1960 to 2015, this study used the calibrated AquaCrop model to calculate the ETc, ETa, Ir, and yield of maize (Zea mays L.) in different hydrological years (extremely dry years, dry years, normal years, and wet years) along with WUE to evaluate the mass of yield produced per unit mass of crop evapotranspiration (ET) under rainfed and irrigated scenarios. The results showed that ETc and ETa decreased first and then increased from the west to the east during the four types of hydrological years. Ir exhibited a decreasing trend from the west to the east. Compared with the irrigation scenario, the rainfed scenario’s average yield only decreased by 2.18, 0.55, 0.03, and 0.05 ton/ha, while the WUE increased by 0.32, 0.4, 0.33, and 0.21 kg/m3 in the extremely dry years, dry years, normal years, and wet years, respectively. The results indicated that in the normal and wet years, the WUE was high in the central regions, and irrigation did not significantly increase yield; further, we determined that irrigation should not be considered in these two hydrological years in Heilongjiang Province. In the extremely dry and dry years, irrigation was necessary because it increased the yield, even though the WUE decreased. This study provides a theoretical basis for studying the regional irrigation schedule in Heilongjiang Province.
Estimating the Leaf Water Status and Grain Yield of Wheat under Different Irrigation Regimes Using Optimized Two- and Three-Band Hyperspectral Indices and Multivariate Regression Models
Authors: Elsayed Salah , El-Hendawy Salah , Dewir Yaser Hassan , Schmidhalter Urs , Ibrahim Hazem H. , Ibrahim Mohamed M. , Elsherbiny Osama , Farouk Mohamed
Published: September 2021

Spectral reflectance indices (SRIs) often show inconsistency in estimating plant traits across different growth conditions; thus, it is still necessary to develop further optimized SRIs to guarantee the performance of SRIs as a simple and rapid approach to accurately estimate plant traits. The primary goal of this study was to develop optimized two- and three-band vegetation- and water-SRIs and to apply different multivariate regression models based on these SRIs for accurately estimating the relative water content (RWC), gravimetric water content (GWCF), and grain yield (GY) of two wheat cultivars evaluated under three irrigation regimes (100%, 75%, and 50% of crop evapotranspiration (ETc)) for two seasons. Results showed that the three plant traits and all SRIs showed significant differences (p < 0.05) between the three irrigation treatments for each wheat cultivar. The three-band water-SRIs (NWIs-3b) showed the best performance in estimating the three plant traits for both cultivars (R2 > 0.80), and RWC and GWCF under 75% ETc (R2 ≥ 0.65). Four out of six three-band vegetation-SRIs (NDVIs-3b) performed better than any other SRIs for estimating GY under 100% ETc and 50% ETC, and RWC under 100% ETc (R2 ≥ 0.60). All types of SRIs demonstrated excellent performance in estimating the three plant traits (R2 ≥ 0.70) when the data of all growth conditions were combined and analyzed together. The NWIs-3b coupled with Random Forest models predicted the three plant traits with satisfactory accuracy for the calibration (R2 ≥ 0.96) and validation (R2 ≥ 0.93) datasets. The overall results of this study elucidate that extracting an optimized NWIs-3b from the full spectrum data and combined with an appropriate regression technique could be a practical approach for managing deficit irrigation regimes of crops through accurately, timely, and non-destructively monitoring the water status and final potential yield.
Modelling Debris Flow Runout: A Case Study on the Mesilau Watershed, Kundasang, Sabah
Authors: Rosli Muhammad Iylia , Che Ros Faizah , Razak Khamarrul Azahari , Ambran Sumiaty , Kamaruddin Samira Albati , Nor Anuar Aznah , Marto Aminaton , Tobita Tetsuo , Ono Yusuke
Published: September 2021

Debris flows are among the fatal geological hazards in Malaysia, with 23 incidents recorded in the last two decades. To date, very few studies have been carried out to understand the debris flow processes, causes, and runouts nationwide. This study simulated the debris flow at the Mesilau watershed of Kundasang Sabah caused by the prolonged rainfall after the 2015 Ranau earthquake. Several interrelated processing platforms, such as ArcGIS, HEC-HMS, and HyperKANAKO, were used to extract the parameters, model the debris flow, and perform a sensitivity analysis to achieve the best-fit debris flow runout. The debris flow travelled at least 18.6 km to the Liwagu Dam. The best-fit runout suggested that the average velocity was 12.5 m/s and the lead time to arrive at the Mesilau village was 4.5 min. This high debris flow velocity was probably due to the high-water content from the watershed baseflow with a discharge rate of 563.8 m3/s. The flow depth and depositional thickness were both lower than 5.0 m. This study could provide crucial inputs for designing an early warning system, improving risk communication, and strengthening the local disaster risk reduction and resilience strategy in a tectonically active area in Malaysia.
Study of the Overflow Transport of the Nordic Sea
Authors: Shi Wenqi , Li Ning , Lv Xianqing
Published: September 2021

Changes in the climate system over recent decades have had profound impacts on the mean state and variability of ocean circulation, while the Nordic Sea overflow has remained stable in volume transport during the last two decades. The changes of the overflow flux depend on the pressure difference at the depth of the overflow outlet on both sides of the Greenland-Scotland Ridge (GSR). Combining satellite altimeter data and the reanalysis hydrological data, the analysis found that the barotropic pressure difference and baroclinic pressure difference on both sides of the GSR had a good negative correlation from 1993 to 2015. Both are caused by changes in the properties of the upper water, and the total pressure difference has no trend change. The weakening of deep convection can only change the temperature and salt structure of the Nordic Sea, but cannot reduce the mass of the water column. Therefore, the stable pressure difference drives a stable overflow. The overflow water storage in the Nordic Sea is decreasing, which may be caused by the reduction of local overflow water production and the constant overflow flux. When the upper interface of the overflow water body in the Nordic Sea is close to or below the outlet depth, the overflow is likely to greatly slow down or even experience a hiatus in the future, which deserves more attention.
Improving Indicators of Hydrological Alteration in Regulated and Complex Water Resources Systems: A Case Study in the Duero River Basin
Authors: Pardo-Loaiza Jesús , Solera Abel , Bergillos Rafael J. , Paredes-Arquiola Javier , Andreu Joaquín
Published: September 2021

Assessing the health of hydrological systems is vital for the conservation of river ecosystems. The indicators of hydrologic alteration are among the most widely used parameters. They have been traditionally assessed at the scale of river reaches. However, the use of such indicators at the basin scale is relevant for water resource management since there is an urgent need to meet environmental objectives to mitigate the effects of present and future climatic conditions. This work proposes a methodology to estimate the indicators of hydrological alteration at the basin scale in regulated systems based on simulations with a water allocation model. The methodology is illustrated through a case study in the Iberian Peninsula (the Duero River basin), where different minimum flow scenarios were defined, assessing their effects on both the hydrological alteration and the demand guarantees. The results indicate that it is possible to improve the hydrological status of some subsystems of the basin without affecting the water demand supplies. Thus, the methodology presented in this work will help decision makers to optimize water management while improving the hydrological status of the river basins.
Rain Belt and Flood Peak: A Study of the Extreme Precipitation Event in the Yangtze River Basin in 1849
Authors: Yang Yuda , Xu Zhengrong , Zheng Weiwei , Wang Shuihan , Kang Yibo
Published: September 2021

Floods caused by extreme precipitation events, in the context of climate warming, are one of the most serious natural disasters in monsoon region societies. The great flood in the Yangtze River Basin in 1849, in Eastern China, was a typical extreme flood event. According to historical archives, local chronicles, diaries, and historical hydrological survey data, this study reconstructed the temporal and spatial patterns of extreme precipitation in 1849, and the flood process of the Yangtze River. We found four major precipitation events at the middle and lower reaches of the Yangtze River, from 18 May to 18 July 1849. The torrential rainfall area showed a dumbbell-like structure along the Yangtze River, with two centers distributed separately in the east and west. For the specific flood process of the Yangtze River, many tributaries of the Yangtze River system entered the flood season consecutively since April, and the mainstream of the Yangtze River experienced tremendous pressure on flood prevention with the arrival of multiple rounds of heavy rainfall. In mid-to-late July, the water level and flow rate of many stations along the mainstream and tributaries had reached their record high. The record-breaking peak flow rate at many stations along the mainstream and tributaries in the middle reaches of the Yangtze River indicated intense precipitation in the area. The heavy rainfall disaster in the Yangtze River Basin could be driven by these reasons. First, the cold air in North China was extraordinary active in 1849, which made it difficult for the subtropical high pressure to move northward. Second, the rain belt stagnated in the Yangtze River Basin for a long time, and the Meiyu period reached 42 days, 62% longer than normal years. Third, the onset of a southwest monsoon was earlier and more active, which provided abundant moisture to the Yangtze River Basin. The great flood disaster was caused by heavy precipitation at the middle reaches, which made it quite different from the other three great floods in the Yangtze River in the 20th century. At present, the large water conservancy projects in the Yangtze River are mainly designed for flood problems caused by rainstorms in the upper reaches of the Yangtze River. The middle reaches of the Yangtze River, however, are facing the weakening of flood diversion capacity, caused by social and economic development. Therefore, future flood prevention measures in the Yangtze River should pay great attention to the threat of this flood pattern.
Research on the Influence of Collector Microstructure on the Performance of PEM Electrolyzer
Authors: Ji Wenxuan , Wang Sen , Sun Yongwen , Lv Hong , Shen Xiaojun , Zhang Cunman
Published: September 2021

The membrane electrode assembly was prepared by a catalyst coated membrane (CCM) with an effective active area of 10 × 10 cm2 in this work. Porous titanium plates with different diameters were used as anode collectors to study the polarization curve and electrochemical impedance spectroscopy (EIS) of the electrolyzer. The results show that the pore size of a porous titanium plate on the anode side has a significant effect on the performance of the electrolyzer. The best cell performance was obtained when the median diameter of the anode titanium plate was 12.3 um. When the current density is 1 A/cm2, the battery voltage is 2.253 V.
Socio-Economic Barriers to Adoption of Electric Vehicles in South Africa: Case Study of the Gauteng Province
Authors: Moeletsi Mokhele Edmond
Published: September 2021

Electric vehicles (EVs) were introduced into the South African market in 2013, and their adoption rate has been very low. There are limited existing studies covering consumer perceptions towards EVs in Africa and, thus, this study investigated possible socio-economic barriers present in the South African automotive market that impede the adoption or consumer purchase intention of EVs. The survey was conducted in the Gauteng Province in South Africa using questionnaires comprised of Likert-type questions. The analysis was conducted using statistical methods comprising mainly of frequency tables and Chi-squared tests on contingency tables. The findings of the study on barriers to adoption of EVs in the market highlighted the high purchase price, high battery price, and high likelihood for owning a secondary vehicle based on the current circumstances as the main purchase intention barriers that the respondents in the Gauteng Province accentuated. However, generally the willingness to buy EVs was high for a majority of the factors that were presented. With these perceived positive opinions from respondents, it is down to government and private companies to provide a conducive environment for the consumers.
Scenario approach to assessing the prospects for the impact of the COVID-19 pandemic on the economy of countries (using the example of the United States, China and Russia)
Authors: Iordanova Veronika Grigoryevna , Shapor Maria Alexandrovna , Munchinova Buinta Yurievna
Published: September 2021

The article is devoted to the study of the phenomenon of the scenario approach to assess the prospects for the impact of the COVID-19 pandemic on the economies of countries using the example of the largest world leaders: the United States, China, Russia. The emerging global epidemiological problem is a serious constraining factor for the development of the economies of states. From the point of view of scientifi c novelty, the analysis and assessment of development scenarios for the economies of the studied states can become the basis for drawing up an action plan to eliminate the consequences of the COVID-19 pandemic. To this end, within the framework of this work, scenarios of further development were considered for each of the countries. For Russia, the following scenarios were chosen baseline scenario — the pace of development of the world economy will be slow, full recovery will take place at the end of 2023; deflationary scenario — in this scenario, the impact of the COVID-19 pandemic, as well as the current restrictions, will persist for a long time. At the same time, oil prices will reach $ 50 per barrel only after 2023, inflation by 2023 will reach 1.5-2.5 %; pro-inflationary scenario — the effects of the pandemic will subside quickly enough, but the potential level of output in the global economy will fall deeper. At the same time, oil prices by 2023 will be $ 42–43 per barrel; risk scenario — within the framework of this scenario, the possibility of a repeat of the COVID-19 pandemic is allowed and the tightening of restrictive measures, which will negatively affect the economies of states, is not excluded. The choice of the studied states was determined not only by world leadership, but also by the degree of influence of the coronavirus on their economies. During the study, a forecast of key indicators of the economies of the United States, China and Russia for 2021 was carried out, the prospects for their dynamics in the current economic situation were assessed, and the main trends followed by the governments of states were examined and identified.
The procedure for moving goods purchased in foreign online stores
Authors: Nazarova Anna Sergeevna
Published: September 2021

This article discusses possible ways to improve the system of comprehensive prevention of violations of customs legislation, provided for by the Development Strategy of the customs service of the Russian Federation until 2030. Ways to improve the system of comprehensive prevention of violations of customs legislation are qualitative increase in the level of legal literacy of all participants in customs legal relations; development of interactive services for interaction of customs authorities with participants in customs legal relations to clarify issues related to compliance with mandatory requirements and resolve complex legal situations; ensuring information openness and electronic accessibility of mechanisms for pre-trial (out-of-court) dispute settlement. The author considers the possible implementation of each element aimed at improving the comprehensive prevention of violations of mandatory requirements using digital technologies. The article notes that prevention in general and prevention of violations of the requirements of customs legislation in particular is of great importance in the normal functioning of the state and society. The author comes to the conclusion that it is advisable to provide for the remote possibility of consulting in electronic form. It would be especially relevant to conduct remote consultation in the context of a pandemic. A remote method of obtaining advice on customs matters and other issues related to the competence of customs authorities in electronic form would have a number of advantages, such as saving time, efficiency, convenience for foreign trade participants. The article notes that a number of state bodies provide consulting services in electronic form. As an example, we can cite the tax authorities. Currently, digital technologies are widely implemented in the activities of customs authorities, which made it possible to transfer the interaction of customs and business into electronic form, automate a number of customs operations, and reduce the costs of participants in foreign economic activity.
Methodological approaches to determining the impact of barriers on international trade
Authors: Madiyarova Diana Makayevna , Terletskii Maxim Vladimirovich
Published: September 2021

Today, within the framework of the functioning of foreign trade policy, there are two main opposing models: protectionism and free trade. Recently, the situation is developing towards the dominance of the policy of protectionism over the policy of conducting free trade, since there is a continuous increase in the number of non-tariff measures and the manifestation of trade wars. This situation leads to the need for a policy of trade liberalization. Implementing a foreign trade policy aimed at eliminating trade barriers is not a quick process and requires a thoughtful scientific assessment. To analyze the criticality of the situation of the absence of a free trade policy and to reflect its validity, a very wide methodological toolkit is used to study various kinds of trade barriers, ranging from the calculation of the simplest indicators to the construction of complex econometric models. This study provides a comprehensive review of the main methodological approaches to determining the impact of tariff and non-tariff barriers on the international trade activities of countries. In the scientific review work, 4 domestic and 24 foreign sources, formed on the basis of 21 resources, were involved in the search for literature. The results of the review analysis of research papers showed that in the study of tariff and non-tariff barriers, researchers mainly use three econometric models, namely gravity model, partial equilibrium model and general equilibrium model. In addition, the study of non-tariff barriers can be carried out in the context of two other methods besides the econometric one: the implementation of the "price gap" method and the derivation of "incidence indicators".
MEJORAMIENTO DEL SISTEMA DE CAPTACIÓN - ADUCCIÓN - DESARENADOR ACUEDUCTO MUNICIPIO DE CALARCÁ, QUINDÍO
Authors: Monsalve-Durango Elkin Aníbal , García-Reinoso Pedro León , Lozano-Sandoval Gabriel
Published: September 2021

La zona de capación del sistema de acueducto del Municipio de Calarcá en el Departamento del Quindío, localizada en la parte alta del Río Santo Domingo, constantemente quedaba inhabilitada por el alto flujo de material presente en este río de montaña con régimen torrencial. La empresa MULTIPROPÓSITO DE CALARCÁ S.A ESP encargada de prestar entre otros servicios el Acueducto del municipio, solicitó a la Universidad del Quindío, a través del Centro de Extensión de la Facultad de Ingeniería y con el apoyo del grupo de Investigación CIDERA, analizar la situación hidrológica e hidráulica presente, y realizar los estudios que permitieron establecer las acciones de intervención en la zona de captación y la optimización de cada una de las unidades y elementos conexos en captación, canal de aducción y desarenador.
Gerenciamento de resíduos sólidos urbanos no estado de Minas Gerais: uma análise quantitativa de indicadores de sustentabilidade
Authors:   , Canella Cecilia de Mattos
Published: September 2021

Com o aumento dos resíduos sólidos urbanos (RSU), especialmente nos centros urbanos, a demanda por soluções ambientalmente correta se torna cada vez mais necessária. A partir de 2010, com a criação da Política Nacional de Resíduos Sólidos (PNRS), a gestão dos RSU passou a ser fundamentada por uma lei federal. Dessa forma, o presente trabalho propõe uma análise do gerenciamento de RSU nos municípios do estado de Minas Gerais, através de indicadores de sustentabilidade. Em uma primeira etapa, foram selecionados indicadores secundários para avaliação dos Territórios de Desenvolvimento mineiros através dos tratamentos estatísticos análise descritiva, séries temporais e análise em painel. Na análise descritiva, algumas das características dos territórios presentes na literatura foram confirmados pelos indicadores socioeconômicos, enquanto os indicadores de gestão de RSU não apresentaram relação direta com os dados disponíveis dos Territórios. Após isso, foram analisadas as séries temporais dos Territórios de Desenvolvimento para cada indicador, assim como a análise em painel com modelos de dependência e independência entre os indicadores, considerando o estado de Minas Gerais como um todo. Os resultados obtidos através dos tratamentos estatísticos dos dados confirmam pontos relatados na literatura e em outras regiões do país. Por fim, foi realizada uma pesquisa de campo no Território de Desenvolvimento Mata para aplicação do Indicador de Qualidade de Aterro de Resíduos (IQR) em aterros sanitários de quatro municípios (A, B, C e D), obtendo pontuação final 4,3; 9,8; 10,0 e 4,3, respectivamente. Considerando que os AS dos municípios A e D são administrados pela prefeitura, sem apoio da iniciativa privada, percebe-se que o poder público ainda enfrenta dificuldades em função dos altos custos de operação de um aterro sanitário e pela falta de equipe qualificada para administração do mesmo. É notório que problemas como ausência de corpo técnico capacitado, dificuldades de gerir recursos e ausência de educação ambiental nos municípios resultam em indicadores baixos e divergentes entre si. Dada a dificuldade da população de separar e acondicionar adequadamente seus resíduos e das prefeituras de coletar, transportar, tratar e dispor esses resíduos ao mesmo tempo que órgãos federais vão de encontro a natureza das autarquias responsáveis pelas regulamentações do manejo de RSU, percebe-se poucos avanços deste serviço e o cenário ainda é preocupante.