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Evaluation of soil loss severity and ecological restoration approach for sustainable agriculture in the Hindu Kush, Karakoram and Himalaya region

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Journal of Mountain Science 2024年第5期21卷 1509-1521页

作者： Arshad ASHRAF Imran AHMAD Climate Energy and Water Research InstituteNational Agricultural Research Centre(NARC)Islamabad 44000Pakistan

Soil erosion has resulted in removal of the topsoils containing fine soil particles and plant nutrients, causing decrease in soil fertility in the Hindu Kush, Karakoram and Himalaya(HKH) region. The existing production of cereal crop grains has been reduced to one third of the potential crop grains production owing to land degradation and poor farming practices. It is necessary to assess risk of soil loss and identify appropriate controlling measures to address issues of low agriculture productivity and water insecurity in the region. In the present study, severity of soil loss was predicted using Revised Universal Loss Equation(RUSLE) and ecological measures were identified for sustainable mountain agriculture in the HKH region of Upper Indus Basin, Pakistan. Overall 62.6% area was found to have very low risk of soil loss, i.e., 100 t/(ha·yr) in about 6.8% and 7.4% areas respectively. The mean rate of soil loss was about 41.9 t/(ha·yr) in the Hindu Kush, 31.1 t/(ha·yr) in the Himalayas, 18.8 t/(ha·yr) in the Karakoram and overall 29.7 t/(ha·yr) in the three HKH ranges. As such no considerable measures have been adopted by the communities for restoration of the degraded areas except raising fruit/farm trees and supporting limited social forestry for their livelihoods. The slopes cleared for cultivation and susceptible to erosion may be stabilized through sowing/planting of multi-purpose plant species and formation of proper bench terraces. The conservation of forest ecosystem and pastures at higher elevations would help in reducing overland water flow, risk of flash flood hazard and minimizing sediment loads in the downstream. It is essential to adopt site-specific resource conservation techniques and restore possible ecosystem health for sustainable agriculture and economic development in the region in future.

关键词： Climate change Erodibility Indus basin land degradation Slope stabilization

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Health diagnosis of ultrahigh arch dam performance using heterogeneous spatial panel vector model

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water Science and Engineering 2024年第2期17卷 177-186页

作者： Er-feng Zhao Xin Li Chong-shi Gu The national Key Laboratory of water Disaster Prevention Hohai UniversityNanjing 210098China nationalEngineering research Centerof water Resources Eficient Utilization and Engineering Safety Hohai UniversityNanjing 20098China

Currently,more than ten ultrahigh arch dams have been constructed or are being constructed in China.Safety control is essential to long-term operation of these dams.This study employed the flexibility coefficient and plastic complementary energy norm to assess the structural safety of arch dams.A comprehensive analysis was conducted,focusing on differences among conventional methods in characterizing the structural behavior of the Xiaowan arch dam in China.Subsequently,the spatiotemporal characteristics of the measured performance of the Xiaowan dam were explored,including periodicity,convergence,and time-effect characteristics.These findings revealed the governing mechanism of main factors.Furthermore,a heterogeneous spatial panel vector model was developed,considering both common factors and specific factors affecting the safety and performance of arch dams.This model aims to comprehensively illustrate spatial heterogeneity between the entire structure and local regions,introducing a specific effect quantity to characterize local deformation differences.Ultimately,the proposed model was applied to the Xiaowan arch dam,accurately quantifying the spatiotemporal heterogeneity of dam performance.Additionally,the spatiotemporal distri-bution characteristics of environmental load effects on different parts of the dam were reasonably interpreted.Validation of the model prediction enhances its credibility,leading to the formulation of health diagnosis criteria for future long-term operation of the Xiaowan dam.The findings not only enhance the predictive ability and timely control of ultrahigh arch dams'performance but also provide a crucial basis for assessing the effectiveness of engineering treatment measures.

关键词： Ultrahigh arch dam Structural performance Deformation behavior Diagnosis criterion Panel data model

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Assessing gully erosion and rehabilitation using multi temporal LiDAR DEMs:Case study from the Great Barrier Reef catchments,Australia

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International Soil and water Conservation research 2024年第1期12卷 184-199页

作者： Sana Khan Rebecca Bartley Anne Kinsey-Henderson Aaron Hawdon The Commonwealth Scientific and Industrial research Organisation(csiro) Environment1 James Cook DrDouglas4814Australia The Commonwealth Scientific and Industrial research Organisation(csiro) EnvironmentGPO Box 2583BrisbaneQLD4001Australia

Millions of dollars are being spent on gully rehabilitation to help reduce excess fine sediment delivery to the Great Barrier Reef(GBR).There is an urgent need for(i)prioritisation of active gullies for rehabilitation and(ii)the development of methodologies to inform the effectiveness of remediation.In this study we analyse DEMs of Difference derived from 0.5 m resolution 2-3 year interval multi-temporal LiDAR data collected pre and post rehabilitation at three variable gully morphologies in the Burdekin catchment.Our analysis indicates that the highest annual average fine sediment erosion rates for the untreated control gullies occur at the linear gully(53.38 t ha^(-1)y^(-1))followed by linear-alluvial gully(34.24 t ha^(-1)y^(-1))and least at the alluvial gully(14.41 t ha^(-1)y^(-1)).The proportional loss or export of fine sediment from the gullies in their un-treated condition ranges from∼68 to 90%of what is eroded,and when the gullies are treated the proportion of fine sediment that is retained in the gully proportional to what is eroded increases to∼60%at all sites.Without pre-treatment baseline erosion rates,and additional post treatment LiDAR captures,it is difficult to quantify the treatment effectiveness.Our results offer insights in the erosion mechanisms within different geomorphic gully morphologies and rehabilitation effects in these erosional landforms.This study provides crucial knowledge of gully dynamics that can be coupled with other lines of evidence for better prioritisation of rehabilitation in the GBR catchments.

关键词： Digital elevation models (dis)connectivity Restoration Geomorphic change detection Geomorphic effectiveness GIS

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Response of runoff and its components to climate change in the Manas River of the Tian Shan Mountains

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Advances in Climate Change research 2024年第1期15卷 62-74页

作者： Ze-Long YANG Peng BAI Key Laboratory of water Cycle and Related land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 10010lChina University of Chinese Academy of Sciences Beijing 100049China

A warming-wetting climate trend has led to increased runoff in most watersheds in the Tian Shan Mountains over the past few decades.However,it remains unclear how runoff components,that is,rainfall runoff(Rrain),snowmelt runoff(Rsnow),and glacier meltwater(Rglacier),responded to historical climate change and how they will evolve under future climate change scenarios.Here,we used a modified Hydrologiska Byrans Vattenbalansavdelning(HBV)model and a detrending method to quantify the impact of precipitation and temperature changes on runoff components in the largest river(Manas River)on the northern slope of the Tian Shan Mountains from 1982 to 2015.A multivariate calibration strategy,including snow cover,glacier area,and runoff was implemented to constrain model parameters associated with runoff components.The downscaled outputs of 12 general circulation models(GCMs)from the Sixth Coupled Model Intercomparison Project(CMIP6)were also used to force the modified HBV model to project the response of runoff and its components to future(2016-2100)climate change under three common socio-economic pathways(SSP126,SSP245,and SSP585).The results indicate that Rrain dominates mean annual runoff with a proportion of 42%,followed by Rsnow(37%)and Rglacier(21%).In terms of inter-annual variation,Rrain and Rsnow show increasing trends(0.93(p0.05)mm per year),while Rglacier exhibits an insignificant(p>0.05)decreasing trend(-0.12 mm per year),leading to an increasing trend in total runoff(1.12 mm per year,p>0.05).The attribution analysis indicates that changes in precipitation and temperature contribute 8.16 and 10.37 mm,respectively,to the increase in runoff at the mean annual scale.Climate wetting(increased precipitation)increases Rrain(5.03 mm)and Rsnow(3.19 mm)but has a limited effect on Rglacier(-0.06 mm),while warming increases Rrain(10.69 mm)and Rglacier(5.79 mm)but decreases Rsnow(-6.12 mm).The negative effect of glacier shrinkage on Rglacier has outweighed the positive effect of warming on Rglaciers resulti

关键词： Tian Shan Rainfall runoff Snowmelt runoff Glacier meltwater Warming-wetting Tipping point

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Assessment of runoff changes in the sub-basin of the upper reaches of the Yangtze River basin, China based on multiple methods

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Journal of Arid land 2024年第4期16卷 461-482页

作者： WANG Xingbo ZHANG Shuanghu TIAN Yiman Department of water Resources China Institute of Water Resources and Hydropower ResearchBeijing 100038China College of Hydrology and water Resources Hohai UniversityNanjing 210098China

Quantitative assessment of the impact of climate variability and human activities on runoff plays a pivotal role in water resource management and maintaining ecosystem integrity.This study considered six sub-basins in the upper reaches of the Yangtze River basin,China,to reveal the trend of the runoff evolution and clarify the driving factors of the changes during 1956–2020.Linear regression,Mann-Kendall test,and sliding t-test were used to study the trend of the hydrometeorological elements,while cumulative distance level and ordered clustering methods were applied to identify mutation points.The contributions of climate change and human disturbance to runoff changes were quantitatively assessed using three methods,i.e.,the rainfall-runoff relationship method,slope variation method,and variable infiltration capacity(Budyko)hypothesis method.Then,the availability and stability of the three methods were compared.The results showed that the runoff in the upper reaches of the Yangtze River basin exhibited a decreasing trend from 1956 to 2020,with an abrupt change in 1985.For attribution analysis,the runoff series could be divided into two phases,i.e.,1961–1985(baseline period)and 1986–2020(changing period);and it was found that the rainfall-runoff relationship method with precipitation as the representative of climate factors had limited usability compared with the other two methods,while the slope variation and Budyko hypothesis methods had highly consistent results.Different factors showed different effects in the sub-basins of the upper reaches of the Yangtze River basin.Moreover,human disturbance was the main factor that contributed to the runoff changes,accounting for 53.0%–82.0%;and the contribution of climate factors to the runoff change was 17.0%–47.0%,making it the secondary factor,in which precipitation was the most representative climate factor.These results provide insights into how climate and anthropogenic changes synergistically influence the runoff of the upper reaches of the Yangtze River basin.

关键词： economic belt runoff change influencing assessment climate human activities

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Numerical investigation of hydro-morphodynamic characteristics of a cascading failure of landslide dams

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Journal of Mountain Science 2024年第6期21卷 1868-1885页

作者： ZHONG Qiming CHEN Lingchun MEI Shengyao SHAN Yibo WU Hao ZHAO Kunpeng Department of Geotechnical Engineering Nanjing Hydraulic Research InstituteNanjing 210024China national Key Laboratory of water Disaster Prevention Nanjing 210098China Key Laboratory of Reservoir and Dam Safety of the Ministry of water Resources Nanjing 210029China

A cascading failure of landslide dams caused by strong earthquakes or torrential rains in mountainous river valleys can pose great threats to people’s lives,properties,and infrastructures.In this study,based on the three-dimensional Reynoldsaveraged Navier-Stokes equations(RANS),the renormalization group(RNG)k-εturbulence model,suspended and bed load transport equations,and the instability discriminant formula of dam breach side slope,and the explicit finite volume method(FVM),a detailed numerical simulation model for calculating the hydro-morphodynamic characteristics of cascading dam breach process has been developed.The developed numerical model can simulate the breach hydrograph and the dam breach morphology evolution during the cascading failure process of landslide dams.A model test of the breaches of two cascading landslide dams has been used as the validation case.The comparison of the calculated and measured results indicates that the breach hydrograph and the breach morphology evolution process of the upstream and downstream dams are generally consistent with each other,and the relative errors of the key breaching parameters,i.e.,the peak breach flow and the time to peak of each dam,are less than±5%.Further,the comparison of the breach hydrographs of the upstream and downstream dams shows that there is an amplification effect of the breach flood on the cascading landslide dam failures.Three key parameters,i.e.,the distance between the upstream and the downstream dams,the river channel slope,and the downstream dam height,have been used to study the flood amplification effect.The parameter sensitivity analyses show that the peak breach flow at the downstream dam decreases with increasing distance between the upstream and the downstream dams,and the downstream dam height.Further,the peak breach flow at the downstream dam first increases and then decreases with steepening of the river channel slope.When the flood caused by the upstream dam failure flows to the downstream dam,it can produce a surge wave that

关键词： Cascading landslide dams Cascading dam failure process Detailed numerical simulation model Flood amplification effect Parameter sensitivity analyses

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Coupling Coordination Analysis of Cropland Intensification and Agroecosystem Services:Evidence from Loess Plateau in Shaanxi Province,China

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Chinese Geographical Science 2024年第3期34卷 401-419页

作者： FU Shaowu FU Mengyu QIU Menglong Center for land Resource research in Northwest China Shaanxi Normal UniversityXi’an 710119China

One of the greatest challenges in the agroecosystem is to improve cropland intensification while preserving agroecosystem services.While many studies have investigated the effect of cropland intensification on agroecosystem service,the interactive coupling and coordination among these factors remain largely unexplored.In view of this,this study performed a case study of the Loess Plateau in Shaanxi Province,China and constructed comprehensive evaluation models to quantify the cropland intensification and agroecosystem service in this area.Balance analysis and the coupling coordination degree model were used to evaluate the interactive relationship between cropland intensification and agroecosystem service,and statistical analysis and spatial autocorrelation were used to analyze the spatial characteristics and potential mechanism of the coupling coordination.Results show that both the cropland intensification and agroecosystem service in the study area were relatively low yet gradually increased from 2000 to 2020.Agroecosystem service lag was identified as the dominant unbalanced development type.Improving the supply capacity of agroecosystem services plays a key role in the balanced development of cropland in the Loess Plateau.The coupling coordination degree between cropland intensification and agroecosystem service ranges from basic coordination to serious incoordination.Therefore,cropland intensification practices in the area should be optimized to enhance this coordination degree.An upward trend was also observed in the coupling coordination degree from2000 to 2020.The withdrawal of marginal cropland in the Grain for Green program is one of the most important reasons for this trend,especially for the northern region.Around 83.6%of the high-high clusters are concentrated in the southern region of the Loess Plateau,whereas 70.5%of the low-low clusters are distributed in the northern region.These clustering characteristics are mainly attributed to the environmental suitability of these areas for agriculture and

关键词： cropland intensification agroecosystem services balance analysis coupling coordination degree Loess Plateau,China

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Factors hindering the degradation of pharmaceuticals from human urine in an iron-activated persulfate system

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Journal of Environmental Sciences 2024年第1期135卷 130-148页

作者： Yiruiwen Xie Dao Guan Yangfan Deng Yugo Sato Yu Luo Guanghao Chen Department of Civil and Environmental Engineering Water Technology LabHong Kong Branch of Chinese National Engineering Research Center for Control&Treatment of Heavy Metal PollutionThe Hong Kong University of Science&TechnologyHong Kong 999077China

This study investigated the degradation of clofibric acid(CFA),bezafibrate(BZF),and sulfamethoxazole(SMX)in synthetic human urine using a novel mesoporous iron powderactivated persulfate system(mFe-PS system),and identified the factors limiting their degradation in synthetic human urine.A kinetic model was established to expose the radical production in various reaction conditions,and experiments were conducted to verify the modeling results.In the phosphate-containing mFe-PS system,the 120 min removal efficiency of CFA decreased from 95.1%to 76.6%as the phosphate concentration increased from 0.32 to 6.45 mmol/L,but recovered to 90.5%when phosphate concentration increased to 16.10 mmol/L.Meanwhile,the increased concentration of phosphate from 0.32 to 16.10mmol/L reduced the BZF degradation efficacy from 91.5%to 79.0%,whereas SMX removal improved from 37.3%to 62.9%.The m Fe-PS system containing(bi)carbonate,from 4.20 to166.70 mmol/L,reduced CFA and BZF removal efficiencies from 100%to 76.8%and 80.4%,respectively,and SMX from 83.5%to 56.7%within a 120-min reaction time.In addition,alkaline conditions(pH≥8.0)inhibited CFA and BZF degradations,while nonacidic pH(pH≥7.0)remarkably inhibited SMX degradation.Results of the kinetic model indicated the formation of phosphate(H_(2)PO_(4)^(·)/HPO_(4)^(·-))and/or carbonate radicals(CO_(3)^(·-))could limit pharmaceutical removal.The transformation products(TPs)of the pharmaceuticals revealed more incompletely oxidized TPs occurred in the phosphate-and(bi)carbonate-containing m Fe-PS systems,and indicated that H_(2)PO_(4)^(·)/HPO_(4)^(·-)mainly degraded pharmaceuticals via a benzene ring-opening reaction while CO_(3)^(·-)preferentially oxidized pharmaceuticals via a hydroxylation reaction.

关键词： Pharmaceutical degradation Human urine Iron-activated persulfate system Phosphate radicals Carbonate radicals Transformation products

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Synthesis of chitosan-based grafting magnetic flocculants for flocculation of kaolin suspensions

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Journal of Environmental Sciences 2024年第5期139卷 193-205页

作者： Chuang Liu Xiaoyu Wang Sicong Du Wenyan Liang Beijing Key Lab for Source Control Technology of water Pollution/Engineering research Center for water Pollution Source Control&Eco-remediation/College of Environmental Science and Engineering Beijing Forestry UniversityBeijing 100083China

A series of novel chitosan-based magnetic flocculants FS@CTS-P(AM-DMC)was prepared by molecular structure control.The characterization results showed that FS@CTS-P(AM-DMC)had a uniform size of about 21.46 nm,featuring a typical core-shell structure,and the average coating layer thickness of CTS-P(AM-DMC)was about 5.03 nm.FS@CTS-P(AM-DMC)exhibited excellent flocculation performance for kaolin suspension,achieved 92.54% turbidity removal efficiency under dosage of 150 mg/L,pH 7.0,even at high turbidity(2000 NTU)with a removal efficiency of 96.96%.The flocculation mechanism was revealed to be dominated by charge neutralization under acidic and neutral conditions,while adsorption and bridging effects play an important role in alkaline environments.The properties of magnetic aggregates during flocculation,breakage,and regeneration were studied at different pH levels and dosages.In the process of magnetophoretic,magnetic particles collide and adsorb with kaolin particles continuously due to magnetic and electrostatic attraction,transform into magnetic chain clusters,and then further form three-dimensional network magnetic aggregates that can capture free kaolin particles and other chain clusters.Particle image velocimetry confirmed the formation of eddy current of magnetic flocs and experienced three stages:acceleration,stabilization,and deceleration.

关键词： Magnetic flocculation Chitosan Fe_(3)O_(4) Graft copolymerization PIV

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Features and formulae of sediment incipient motion in vegetated flow environment

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Journal of Hydrodynamics 2024年第2期36卷 331-339页

作者： Yu-xuan Xu Wei-jie Wang Shi-bao Zhang Han-qing Zhao Xue-kai Chen Hai-ping Zhang School of water Conservancy North China University of Water Resources and Electric PowerZhengzhou450045China State Key Laboratory of Simulation and Regulation of water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing100038China China Three Gorges Corporation Wuhan430010China

Aquatic vegetation is a vital component of natural river ecosystems,playing a crucial role in maintaining ecological balance,providing habitat and improving water quality.However,the presence of vegetation results in increased resistance in vegetated channels compared with non-vegetated channels,rendering traditional sediment movement predictions inadequate for the latter.Consequently,the concept of a vegetation influence factor,denoted by CDah,has been proposed by previous researchers to represent the effect of vegetation on sediment movement in watercourses.In this study,we focus on exploring the vegetation resistance coefficient(CD)among the vegetation influence factors,evaluating two different calculation methods for vegetation resistance coefficient,and presenting two expressions through genetic algorithm analysis to predict the incipient flow velocity of sediment in vegetated watercourses.The predicted values from the new formulae show excellent agreement with measured data,highlighting the high accuracy of the proposed methods in predicting the incipient flow velocity of sediment.Our results provide a solid theoretical basis for understanding the influence of aquatic vegetation on sediment particle movement.

关键词： Vegetation flow vegetation resistance coefficient genetic algorithm sediment initiation

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