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Response of erosion reduction effect of typical soil and water conservation measures in cropland to rainfall and slope gradient changes and their applicable range in the Chinese Mollisols Region,Northeast China

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International Soil and water Conservation research 2023年第2期11卷 251-262页

作者： Qin Zhang Wei Qin Wenhong Cao jian Jiao Zhe Yin Haichao Xu State Key Laboratory of Simulation and Regulation of water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBejing100048PR China research center on Soil and water Conservation of the Ministry of water resources Beijing100048PR China

Mollisols are rich in organic matter,which makes them suitable for cultivation and for enhancing global food security.Mollisols are experiencing severe soil erosion due to overfarming and a lack of mainte-nance.Thus,suitable soil and water conservation measures(SWCMs)are needed to protect Mollisols.However,how SWCMs respond to changes in slope gradient and rainfall and their effective application area remain ambiguous.Using a long-term field observation dataset,meta-analysis,and statistical test methods,we reveal the typical erosion reduction effect of SWCMs and their responses to changes in slope gradient and rainfall.Next,we calculated a coupling factor,P.S,by slope gradient and rainfall in flood season to determine the effective SWCMs application threshold.Compared with bare land,no-tillage(NT),contour ridge tillage(CT),ridge hedgerows(RH),and terraced fields(TF)had an average erosion reduction coefficient of 91.5%.There was a significant exponential increase in the correlation between P.S and the soil erosion amount in plots with typical measures.According to this correlation and soil loss tolerance(200 t/km^(2)),the upper limits of PS(NT:564 mm;CT:885 mm;RH:1135 mm)were determined and utilized to determine the effective application areas(NT:311.40103 km^(2);CT:320.86103 km^(2);RH:323.72103 km^(2))at the plot scale.In wet years,the applicable area of SWCMs declined toward the low-elevation foothills and flat terrain.All the results are applicable when slope length within 20 m.These results provide a basis for the precise allocation of SWCMs in Mollisols area and promote the scientific utilization of Mollisols resources.

关键词： Mollisols region watererosion in cropland Soil and water conservationmeasures Erosionreductioncoefficient Effective range

Occurrence of bed load transport in the presence of stable clast

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International Journal of Sediment research 2017年第2期32卷 195-209页

作者： Mohd Sofiyan Sulaiman Shanker Kumar Sinnakaudan Set Foong Ng Kyle Strom I-Geo Disaster research center Faculty of Engineering & Technology Infrastructure(FETI)Infrastructure University Kuala Lumpur(IUKL) water resources Engineering & Management research center(WAREM) Universiti Teknologi MARA Faculty of Computer & Mathematical Sciences Universiti Teknologi MARA Department of Civil and Environmental Engineering Virginia Tech

It is well-versed that transport occurrence is vital for in stream rehabilitation,river restoration and installment of sediment sampler on river beds.Current practice emulates the use of continuous prediction using reach-averaged approach.However,prediction of transport occurrence entails the use of binary model through the execution of logistic regression analysis.Bed load and turbulence data were physically measured at mountainous region with divergent surface bedform in its presence.The parameterization and statistical approaches are treated in the similar fashion with multiple regression except for the test for model fit and model selection criterion.The parameters on near-bed turbulence characteristics at the entrainment threshold were assigned as independent variables containing 15 predictors.Almost 80 models were generated by selecting the best possible combination in accordance with the statistical precaution of alleviating multicollinearity issue.It is postulated that the model containing shields stress in the form of turbulent kinetic energy(IKE) at vertical direction and fractional time for second quadrant provides better estimation of potential location for greatest sediment-entrainment;hence a high possibility for transport occurrence.

关键词： Logistic regression analysis Transport occurrence Bed load Entrainment Local bed shear

Flash flood hazard mapping: A pilot case study in Xiapu River Basin, China

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water Science and Engineering 2015年第3期8卷 195-204页

作者： Da-wei Zhang Jin Quan Hong-bin Zhang Fan Wang Hong Wang Xiao-yan He China Institute of water resources and Hydropower research research center on Flood and Drought Disaster Reduction Ministry of Water Resources

Flash flood hazard mapping is a supporting component of non-structural measures for flash flood prevention. Pilot case studies are necessary to develop more practicable methods for the technical support systems of flash flood hazard mapping. In this study, the headwater catchment of the Xiapu River Basin in central China was selected as a pilot study area for flash flood hazard mapping. A conceptual distributed hydrological model was developed for flood calculation based on the framework of the Xinanjiang model, which is widely used in humid and semi-humid regions in China. The developed model employs the geomorphological unit hydrograph method, which is extremely valuable when simulating the overland flow process in ungauged catchments, as compared with the original Xinanjiang model. The model was tested in the pilot study area, and the results agree with the measured data on the whole. After calibration and validation, the model is shown to be a useful tool for flash flood calculation. A practicable method for flash flood hazard mapping using the calculated peak discharge and digital elevation model data was presented, and three levels of flood hazards were classified. The resulting flash flood hazard maps indicate that the method successfully predicts the spatial distribution of flash flood hazards, and it can meet the current requirements in China.

关键词： Flash flood hazard mapping Conceptual distributed hydrological model Xinanjiang model Geomorphological unit hydrograph Xiapu River Basin

Urban flood inundation and damage assessment based on numerical simulations of design rainstorms with different characteristics

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Science China(Technological Sciences) 2020年第11期63卷 2292-2304页

作者： MEI Chao LIU JiaHong WANG Hao LI ZeJin YANG ZhiYong SHAO WeiWei DING XiangYi WENG BaiSha YU YingDong YAN DianYi State Key Laboratory of Simulation and Regulation of water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China Engineering and Technology research center for water resources and Hydroecology of the Ministry of water resources Beijing 100044China

In the context of global climate change and urbanization,urban flooding is an important type of natural disaster that affects urban development,especially in China,which is experiencing rapid urbanization.In the past 10 years,urban flooding events have caused huge disaster losses in Chinese cities.This has resulted in significant negative effects on the urban infrastructure,socioeconomic systems,and urban residents,thus causing widespread concern.Studies have confirmed the change in extreme rainstorms is due to the changing environments in many cities globally.Conducting studies on the impact of these rainstorms with different characteristics for urban flooding is valuable for coping with unfavorable situations.In addition,numerical simulations provide an economical and viable means to perform these studies.This paper presents a numerical model of Xiamen Island in China.Simulations were conducted for 12 design rainstorm events with different return periods,rain patterns,and durations.The results indicate that,in the case of an equal rainfall amount,the rainfall intensity is the key factor that affects the inundated area,depth,and damages.However,the rainfall intensity is not the only determining factor;the rainfall pattern also affects the inundations.In regard to the rainfall pattern,a higher rainfall peak coefficient usually leads to severe urban inundation and damage.As a result,the lag time would be shorter,which may further exacerbate the impact of urban flood disasters.The results of this study provide insights into managing flood risks,developing urban flood prevention strategies,and designing flood prevention measures.

关键词： urban flood flood damage assessment flood disaster management numerical simulations design rainstorms

Non-negligible factors in low-pressure sprinkler irrigation:droplet impact angle and shear stress

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Journal of Arid Land 2022年第11期14卷 1293-1316页

作者： HUI Xin ZHENG Yudong MUHAMMAD Rizwan Shoukat TAN Haibin YAN Haijun College of water resources and Civil Engineering China Agricultural UniversityBeijing 100083China Engineering research center of Agricultural water-Saving and water resources Ministry of EducationBeijing 100083China Semi-arid Agriculture Engineering&Technology research center of China Shijiazhuang 050051China

Droplet shear stress is considered as an important indicator that reflects soil erosion in sprinkler irrigation more accurately than kinetic energy,and the effect of droplet impact angle on the shear stress cannot be ignored.In this study,radial distribution of droplet impact angles,velocities,and shear stresses were investigated using a two-dimensional video disdrometer with three types of low-pressure sprinkler(Nelson D3000,R3000,and Komet KPT)under two operating pressures(103 and 138 kPa)and three nozzle diameters(3.97,5.95,and 7.94 mm).Furthermore,the relationships among these characteristical parameters of droplet were analyzed,and their influencing factors were comprehensively evaluated.For various types of sprinkler,operating pressures,and nozzle diameters,the smaller impact angles and larger velocities of droplets were found to occur closer to the sprinkler,resulting in relatively low droplet shear stresses.The increase in distance from the sprinkler caused the droplet impact angle to decrease and velocity to increase,which contributed to a significant increase in the shear stress that reached the peak value at the end of the jet.Therefore,the end of the jet was the most prone to soil erosion in the radial direction,and the soil erosion in sprinkler irrigation could not only be attributed to the droplet kinetic energy,but also needed to be combined with the analysis of its shear stress.Through comparing the radial distributions of average droplet shear stresses among the three types of sprinklers,D3000 exhibited the largest value(26.94-3313.51 N/m^(2)),followed by R3000(33.34-2650.80 N/m^(2)),and KPT(16.15-2485.69 N/m^(2)).From the perspective of minimizing the risk of soil erosion,KPT sprinkler was more suitable for low-pressure sprinkler irrigation than D3000 and R3000 sprinklers.In addition to selecting the appropriate sprinkler type to reduce the droplet shear stress,a suitable sprinkler spacing could also provide acceptable results,because the distance from the sprinkler exhibited a highly significan

关键词： center pivot irrigation system water droplet universal model soil erosion water-saving irrigation

Effects of patchy distributed Artemisia capillaris on overland flow hydrodynamic characteristics

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International Soil and water Conservation research 2019年第1期7卷 81-88页

作者： Guanhua Zhang Jiajun Hu Soil and water Conservation Department Changjiang River Scientific Research InstituteChina research center on Mountain Torrent&Geologic Disaster Prevention of Ministry of water resources China Changjiang water resources Commission of the Ministry of water resources Wuhan 430010China

Laboratory-simulated rainfall experiments were conducted to quantify the effects of patchy distributed Artemisia capillaris on overland flow hydrodynamics.Rainfall intensities of 60,90,120,and 150 mm h-1 were applied on a bare plot (CK) and four different patched patterns:a checkerboard pattern (CP),a banded pattern perpendicular to slope direction (BP),a single long strip parallel to slope direction (LP),and a pattern with small patches distributed like the letter'X'(XP).Each patterned plot underwent two sets of experiments,intact plant and root (the above-ground parts were removed),respectively.Results showed that flow velocity increased with rainfall intensity,and the lower slope velocity was higher than the upper slope.The removal of grass shoots significantly increased flow velocity.The contributions of grass shoots and roots to the reductions in flow velocity under different rainfall intensities were different.The shoots made greater contribution of 53-97% at 60 and 90 mm h-1,and the roots contributed more (51-81%) at 120 and 150 mm h-1.Mean flow depth increased with rainfall intensity and it declined after the aboveground parts were cleared.Reynold numbers (Re) in this study were 25-80,indicating a laminar flow in the study.Froude numbers (Fr) were ≥ 1 for CK and < 1 for patterned treatments.Fr of the lower slope was higher than the upper ones.Darcy-weisbach (f) and Manning (n) friction coefficient ranked in the order of CK < LP < BP/CP/XP with values of grass sections being higher than the bare sections and upper slope higher than the lower slope,and both decreased after removing the grass shoots.BP,CP,and XP performed more effectively than LP in retarding flow velocity and increasing hydraulic roughness.

关键词： Overland flow Vegetation pattern Hydrodynamics Soil erosion rate Simulated rainfall

Network Structure Optimization Method for Urban Drainage Systems Considering Pipeline Redundancies

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International Journal of Disaster Risk Science 2022年第5期13卷 793-809页

作者： Jiahui Lu Jiahong Liu Yingdong Yu Chuang Liu Xin Su State Key Laboratory of Simulation and Regulation of water Cycle in River Basins China Institute of Water Resources and Hydropower ResearchBeijing 100038China School of Transportation and Civil Engineering&Architecture Foshan UniversityGuangdong 528000China Engineering and Technology research center for water resources and Hydroecology of the Ministry of water resources Beijing 100044China

Redundancy is an important attribute of a resilient urban drainage system.While there is a lack of knowledge on where to increase redundancy and its contribution to resilience,this study developed a framework for the optimal network structure of urban drainage systems that considers pipeline redundancies.Graph theory and adaptive genetic algorithms were used to obtain the initial layout and design of the urban drainage system.The introduction of additional water paths(in loop)/redundancies is suggested by the results of complex network analysis to increase resilience.The drainage performances of the urban drainage system with pipeline redundancies,and without redundancies,were compared.The proposed method was applied to the study area in Dongying City,Shandong Province,China.The results show that the total overflow volume of the urban drainage system with pipeline redundancies under rainfall exceeding the design standard(5 years) is reduced by 20-30%,which is substantially better than the network without pipeline redundancies.

关键词： China Pipeline redundancies Structure optimization method Urban drainage systems Urban hydrology Urban resilience

Estimation of future water resources of Xiangjiang River Basin with VIC model under multiple climate scenarios

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water Science and Engineering 2017年第2期10卷 87-96页

作者： Guo-qing Wang Jian-yun Zhang Yue-ping Xu Zhen-xin Bao Xin-yue Yang State Key Laboratory of Hydrology-water resources and Hydraulic Engineering Nanjing Hydraulic Research Institute research center for Climate Change Ministry of Water Resources Institute of Hydrology and water resources Civil EngineeringZhejiang University College of Hydrology and water resources Hohai University

Variation trends of water resources in the Xiangjiang River Basin over the coming decades have been investigated using the variable infiltration capacity(VIC) model and 14 general circulation models'(GCMs') projections under the representative concentration pathway(RCP4.5) scenario. Results show that the Xiangjiang River Basin will probably experience temperature rises during the period from 2021 to2050, with precipitation decrease in the 2020 s and increase in the 2030 s. The VIC model performs well for monthly discharge simulations with better performance for hydrometric stations on the main stream of the Xiangjiang River than for tributary catchments. The simulated annual discharges are significantly correlated to the recorded annual discharges for all the eight selected target stations. The Xiangjiang River Basin may experience water shortages induced by climate change. Annual water resources of the Xiangjiang River Basin over the period from 2021 to 2050 are projected to decrease by 2.76% on average within the range from-7.81% to 7.40%. It is essential to consider the potential impact of climate change on water resources in future planning for sustainable utilization of water resources.

关键词： water resources Climate change VIC model Xiangjiang River Basin Climate scenarios Hydrological modeling

Semi-automated detection of rangeland runoff and erosion control berms using high-resolution topography data

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International Soil and water Conservation research 2024年第1期12卷 217-226页

作者： Li Li Changjiang River Scientific research Institute of Changjiang water resources Commission Wuhan430010China research center on Mountain Torrent&Geologic Disaster Prevention Ministry of Water ResourcesWuhan430010China University of Arizona School of Natural Resources and the EnvironmentTucsonAZ85719USA

An inventory of topographic modifications is essential to addressing their impacts on hydrological and morphological processes in human-altered watersheds.However,such inventories are generally lacking.This study presents two workflows for semi-automatic detection of linear earthen runoff and erosion control berms in rangelands using high-resolution topographic data.The workflows consist of initial object identification by applying either morphological grayscale reconstruction(MGR)or the Geomorphon(GEO)method,followed by identification refinements through filters based on objects’horizontal and vertical information.Three sites were selected within the Altar Valley,Arizona,in the southwestern United States.One site was used for developing workflows and optimizing filter thresholds,and the other two sites were used to validate workflows.The results showed that:1)The MGR-based workflow methodology could produce final precision and detection rates of up to 92%and 75%,respectively,and take less than 5 s for a 10.1 km^(2) site;2)The workflow based on the MGR method yielded greater identification accuracy than did the GEO workflow;3)Object length,orientation,and eccentricity were important characteristics for identifying earthen berms,and are sensitive to general channel flow direction and berm shape;4)Manual interrogation of topographic data and imagery can significantly improve identification precision rates.The proposed workflows will be useful for developing inventories of runoff and erosion control structures in support of sustainable rangeland management.

关键词： Earthen berm Rangeland Grayscale morphological reconstruction Geomorphon LiDAR