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Spatio-temporal evolution of complex agricultural land use and its drivers in a super-large irrigation district (Hetao) of the upper Yellow river Basin (2000–2021)

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Journal of Geographical Sciences 2025年第2期35卷 273-301页

作者： LI Xinyi SUN Chen XIAO Xue LI Zhengzhong MA Xin WANG Jun XU Xu Chinese-Israeli International Center for Research and Training in Agriculture College of Water Resources &Civil Engineering China Agricultural University Inst.tute of Environment and Sust.inable Development in Agriculture Chinese Academy of Agricultural Sciences Shahaoqu Experimental st.tion Jiefangzha Department Inner Mongolia Hetao Irrigation District Water Resources Development Center water Resources Research Inst.tute of Inner Mongolia College of Economics & management China Agricultural University

Accurate spatio-temporal land cover information in agricultural irrigation districts is crucial for effective agricultural management and crop production. Therefore, a spectralphenological-based land cover classification(SPLC) method combined with a fusion model(flexible spatiotemporal data fusion, FSDAF)(abbreviated as SPLC-F) was proposed to map multi-year land cover and crop type(LC-CT) dist.ibution in agricultural irrigated areas with complex landscapes and cropping syst.m, using time series optical images(Landsat and MODIS). The SPLC-F method was well validated and applied in a super-large irrigated area(Hetao) of the upper Yellow river Basin(YRB). Results showed that the SPLC-F method had a satisfactory performance in producing long-term LC-CT maps in Hetao, without the requirement of field sampling. Then, the spatio-temporal variation and the driving factors of the cropping syst.ms were further analyzed with the aid of detailed household surveys and st.tist.cs. We clarified that irrigation and salinity conditions were the main factors that had impacts on crop spatial dist.ibution in the upper YRB. Invest.ent cost., market demand, and crop price are the main driving factors in determining the temporal variations in cropping dist.ibution. Overall, this st.dy provided essential multi-year LC-CT maps for sust.inable management of agriculture, eco-environments, and food security in the upper YRB.

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Essence of MIKE 21C (FDM Numerical Scheme): Application on the river Morphology of Bangladesh

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Open Journal of Modelling and Simulation 2022年第2期10卷 88-117页

作者： Shiblu Sarker Bureau of watershed management and Modeling St. Johns River Water Management District Florida USA

Underst.nding, quantifying, and forecast.ng water flow and its behavior in environment is made possible by the use of computational hydraulics in conjunction with numerical models, which is one of the most.powerful tools currently available. It is made up of simple to complex mathematical equations having linear and/or nonlinear elements, as well as ordinary and partial differential equations, and it is used to solve problems in many areas. In the vast.majority of cases, it is not useful to reach analytical solutions to these mathematical equations using conventional methods. In these settings, mathematical models are solved by employing a variety of numerical algorithms and associated schemes. As a result, in this manuscript, we will cover the most.fundamental numerical approach, the Finite Difference Method (FDM), in order to reformulate the governing equations for water and sediment flow from a syst.m of partial differential equations to a syst.m of linear equations. As part of our analysis into the inner workings of a computer program known as MIKE 21C, we will attempt to gain a better underst.nding of the hydrodynamic processes that take place in major rivers in Bangladesh. In addition to that, we will go over some of the most.commonly used morphological st.dies that have been conducted on Bangladesh’s major rivers, including morphological solutions that have been developed in response to water supply concerns.

关键词： Curvilinear Model Finite Difference Method MIKE 21C

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Nitrogen and Phosphorus Runoff Losses from Orchard Soils in South China as Affected by Fertilization Depths and Rates

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Pedosphere 2008年第1期18卷 45-53页

作者： ZENG Shu-Cai SU Zhi-Yao CHEN Bei-Guang WU Qi-Tang OUYANG Ying College of Forest.y South China Agricultural University Guangzhou 510642 (China) College of Natural Resources and Environment South China Agricultural University Guangzhou 510642 (China) Department of water Resources St. Johns River Water Management District P.O. Box 1429 Palatka FL 32178-1429 (USA)

Fertilizers are heavily applied in orchards of the hilly and mountainous topography of South China and may increase nutrient loadings to receiving waters.A simple runoff collecting syst.m was used to measure the effects of different fertilization treatments on total N and P concentrations of surface runoff in a Chinese chest.ut (Cast.nea mollissima Blume) orchard in Dongyuan County,Guangdong Province,*** such orchards,fertilizer was typically applied in two short furrows or pits on either side of each *** included three application depths (surface,10cm and 20 cm),and three application rates (low,median and high).Results showed that 90.5% of the runoff water samples had a total N concentration higher than 0.35 mgL^(-1) and 54.2% had a total P concentration higher than 0.1 mgL^(-1).Fertilizer application at all depths and at all but the lowest.rate significantly increased total N and P concentrations in runoff *** with chemical compound fertilizer at a soil depth of 20cm produced significantly lower (Pst.d to subst.ntially reduce N and P runoff losses from hillslope orchards and to protect receiving waters in South China.

关键词： fertilization depth fertilization rate runoff total N total P

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Effects of river width changes on flow characterist.cs based on flume experiment

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Journal of Mountain Science 2016年第2期13卷 361-368页

作者： WANG Xie-kang WANG Bing-jie LIU Xing-nian Zhang Li-qiong st.te Key Laboratory of Hydraulics and Mountain river Engineering Sichuan University Hydrology and Hydraulics Section South Florida Water Management District

The rapid changes in flow pattern due to varying channel widths will make significantly impact on the hydraulic st.uctures and evolutions of open channel. To better underst.nd the impact of varying width, a flume experiment with adjust.ble width and a depth-averaged two-dimension numerical model were used to analyze the variations of flow parameters. Our experimental results showed that flow velocity gradually increased with decreasing water depth in converging region, and decreased with increasing water depth in diverging zones. It was also found that the turbulence intensity laws in three directions were not agreed with the theoretical relationships proposed by Nezu and Nakagawa in 1993 in st.aight open channel flows. The flow in the channel with varying width may change from the supercritical flow to the subcritical flow as a function of Froude number. Our numerical simulations with different flow rates showed that most.of the hydraulic jumps in diverging region were submerged jump and the degree of submergence increased with increasing flow rate in gradual channel transition. When the flow rate increased, the range of supercritical flow rapidly decreased and the flow changed from the supercritieal condition to the subcritical condition in diverging sections.

关键词： Gradual channel transition Flow pattern Experimental st.dy Numerical simulation

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A Floating Island Treatment Syst.m for the Removal of Phosphorus from Surface waters

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Engineering 2018年第5期4卷 597-609页

作者： Mark T. Brown Treavor Boyer R.J. Sindelar Sam Arden Amar Persaud Sherry Brandt-Williams Department of Environmental Engineering Sciences University of Florida Gainesville FL 32611 USA st. johns river water management district Palatka FL 32177 USA

The goal of this project was to design, build, and test.a pilot-scale floating modular treatment syst.m for total phosphorus （TP） removal from nutrient-impaired lakes in central Florida, USA. The treatment sys-tem consist.d of biological and physical-chemical treatment modules. First. invest.gations of prospective biological and physical-chemical treatment processes in mesocosms and in bench-scale experiments were conducted. Thirteen different mesocosms were const.ucted with a variety of subst.ates and combi-nations of macrophytes and test.d for TP and orthophosphate （PO4-^3） removal efficiencies and potential areal removal rates. Bench-scale jar test. and column test. of seven types of absorptive media in addition to three commercial resins were conducted in order to test.absorptive capacity. Once isolated process test.ng was complete, a floating island treatment syst.m （FITS） was designed and deployed for eight months in a lake in central Florida. Phosphorus removal efficiencies of the mesocosm syst.ms averaged about 40%-50%, providing an average uptake of 5.0 g.m ^2.a ^1 across all mesocosms. The best.performing mesocosms were a submerged aquatic vegetation （SAV） mesocosm and an algae scrubber （AGS）, which removed 20 and 50 mg.m ^2.d ^1, respectively, for an average removal of 5.5 and 12.0 g.m ^2.a ^1 for the SAV and AGS syst.ms, Of the absorptive media, the best.performance was alum residual （AR）, which reduced PO4-^3 concentrations by about 75% after 5 min of contact time. Of the commercial resins test.d, the PhosX resin was superior to the others, removing about 40% of phosphorus after 30 rain and 60% after 60min. Under baseline operation conditions during deployment, the FITS exhibited mean PO4-^3 removal efficiencies of 53%; using the 50th and 90th percentile of PO4-^3 removal during deployment, and the footprint of the FITS syst.m, yielded efficiencies for the combined FITS syst.m of 56% and 86%, respectively, and areal phosphorus removal rates between 8.9

关键词： Phosphorus removal Lake ecosyst.m Floating island treatment

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rivers increasingly warmer:Prediction of changes in the thermal regime of rivers in Poland

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Journal of Geographical Sciences 2025年第1期35卷 139-172页

作者： Mariusz PTAK Teerachai AMNUAYLOJAROEN Mariusz SOJKA Department of Hydrology and water management Adam Mickiewicz UniversityKrygowskiego 1061-680PoznańPoland School of Energy and Environment University of PhayaoPhayao56000Thailand Atmospheric Pollution and Climate Research Unit School of Energy and EnvironmentUniversity of PhayaoPhayao56000Thailand Department of Land Improvement Environmental Development and Spatial ManagementPoznańUniversity of Life SciencesPiątkowska 94E60-649PoznańPoland

Emphasis on future environmental changes grows due to climate change,with simulations predicting rising river temperatures *** Poland,which has a long hist.ry of thermal st.dies of rivers,such an approach has not been implemented to *** st.dy used 9 Global Climate Models and test.d three machine-learning techniques to predict river temperature *** Forest.performed best.with R^(2)=0.88 and lowest.error(RMSE:2.25,MAE:1.72).The range of future water temperature changes by the end of the 21st.century was based on the Shared Socioeconomic Pathway scenarios SSP2-4.5 and *** was determined that by the end of the 21st.century,the average temperature will increase by 2.1°C(SSP2-4.5)and 3.7°C(SSP5-8.5).A more detailed analysis,divided by two major basins Vist.la and Odra,covered about 90%of Poland's *** average temperature increase,according to scenarios SSP2-4.5 and SSP5-8.5 for the Odra basin rivers,is 1.6°C and 3.2°C and for the Vist.la basin rivers 2.3°C and 3.8°C,*** Vist.la basin's higher warming is due to less groundwater input and continental climate *** findings provide a crucial basis for water management to mitigate warming effects in Poland.

关键词： global warming forecast.ng water temperature Poland

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Kinetic Adsorption of Ammonium Nitrogen by Subst.ate Materials for Const.ucted Wetlands

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Pedosphere 2011年第4期21卷 454-463页

作者： ZHU Wen-Ling CUI Li-Hua OUYANG Ying LONG Cui-Fen TANG Xiao-Dan College of Natural Resources and Environmental Science South China Agricultural University Guangzhou 510642 (China) Urban Drainage Monitoring st.tion of Guangzhou City Guangzhou 510010 (China) Key Laboratory of Agroecology and Rural Environment of Guangdong Regular Higher Education Inst.tutions South China Agricultural University Guangzhou 510642 (China) Department of water Resources St. Johns River Water Management District Palatka Florida 32178 (USA)

Const.ucted wetlands （CWs） are engineered syst.ms that utilize natural syst.ms including wetland vegetations, soils, and their associated microbial assemblages to assist.in treating wast.water. The kinetic adsorption of ammonium nitrogen （NH＋-N） by CW subst.ate materials such as blast.furnace slag （BFS）, zeolite, ceramsite, vermiculite, gravel, paddy soil, red soil, and turf, was invest.gated using batch experiments and kinetic adsorption isotherms. Both Freundlich and Lang- muir isotherms could adequately predict the NH＋-N adsorption process. The maximum adsorption capacities of NH＋-N, est.mated from the Langmuir isotherm, ranked as： zeolite （33 333.33 mg kg^-1）〉 turf （29274.01 mg kg^-1）〉 BFS （5000 mg kg^-1）〉 vermiculite （3333.33 mg kg^-1）〉 gravel （769.23 mg kg^-1）〉 paddy soil （588.24 mg kg^-1）〉 red soil （555.56 mg kg^-1）〉 ceramsite （107.53 mg kg^-1）. Some properties of the subst.ate materials, including bulk density, specific gravity, hydraulic conductivity, uniformity coefficient （K60）, curvature coefficient （Co）, organic matter, pH, exchangeable （or active） Cu, Fe, Zn and Mn, total Cu, and Fe, Mn, Zn, Cd, Pb and Ca, had negative correlations with NH＋-N adsorption. Other properties of the subst.ate materials like particle diameter values of D10, 030 and 060 （the diameters of particle sizes of a subst.ate material at which 10%, 30% and 60%, respectively, of the particles pass through the sieve based on the accumulative frequency）, cation exchange capacity （CEC）, exchangeable （or active） Ca and Mg, and total K and Mg had positive correlations with NH＋-N adsorption. In addition, active K and Na as well as the total Na had significant positive correlations with NH＋-N adsorption. This information would be useful for selection of suitable subst.ate materials for CWs.

关键词： ammonia removal kinetic adsorption capacity Langmuir isotherm physicochemical properties subst.ate materials

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Three-dimensional numerical modeling of nearshore circulation

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Acta Oceanologica Sinica 2008年第z1期27卷 101-118页

作者： SUN Detong South Florida water management district West Palm Beach FL 33406 U S A

A three-dimensional nearshore circulation model was developed by coupling CH3D, a three-dimensional hydrodynamic model and REF/DIF, a nearshore wave transformation model. The model solves the three-dimensional wave-averaged equations of motion. Wave-induced effects on circulation were introduced in the form of radiation st.esses, wave-induced mass transport, wave-induced enhancement of bottom friction and wave-induced turbulent mixing. Effects of breaking waves were considered following Svendsen (1984a and 1984b) and st.ve and Wind (1986). The model was successfully test.d against.the analytical solution of longshore currents by Longuet and Higgins (1970). The model successfully simulated the undertow as observed in a laboratory experiment by st.ve and Wind (1982). In addition, the model was applied to a physical model by Mory and Hamm (1997) and successfully reproduced the eddy behind a detached breakwater as well as the longshore current on the open beach and the contiguous eddy in the open area of the wave tank. While the qualitative agreement between model results and experimental observations was very good, the quantitative agreement needs to be further improved. Albeit difficult to explain every discrepancy between the model results and observations, in general, sources of errors are attributed to the lack of underst.nding and comprehensive description of following processes: (1)the horizontal and vertical dist.ibution of radiation st.ess, especially for breaking waves;(2)the detailed st.ucture of turbulence;(3)Wave-current interaction (not included at this moment); and (4)the wave-current boundary layer and the resulting bottom shear st.ess.

关键词： waves wave-induced currents 3D model radiation st.ess breaking waves surface roller undertow longshore currents nearshore circulation

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Usage of 3D Point Cloud Data in BIM （Building Information Modelling）： Current Applications and Challenges

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Journal of Civil Engineering and Architecture 2015年第11期9卷 1269-1278页

作者： Tan Qu Wei Sun School of Engineering Design & Construction Seminole State College of Florida Sanford SLM D 103G USA st. johns river water management district Palatka 32178 USA

BIM （building information modelling） has gained wider acceptance in the A/E/C （architecture/engineering/const.uction） indust.y in the US and internationally. This paper presents current indust.y approaches of implementing 3D point cloud data in BIM and VDC （virtual design and const.uction） applications during various st.ges of a project life cycle and the challenges associated with processing the huge amount of 3D point cloud data. Conversion from discrete 3D point cloud rast.r data to geometric/vector BIM data remains to be a labor-intensive process. The needs for intelligent geometric feature detection/reconst.uction algorithms for automated point cloud processing and issues related to data management are discussed. This paper also presents an innovative approach for integrating 3D point cloud data with BIM to efficiently augment built environment design, const.uction and management.

关键词： BIM point cloud laser scanning 3D

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Nitrogen and phosphorus removal in pilot-scale anaerobic-anoxic oxidation ditch syst.m

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Journal of Environmental Sciences 2008年第4期20卷 398-403页

作者： PENG Yongzhen HOU Hongxun WANG Shuying CUI Youwei Zhiguo Yuan Key Laboratory of Beijing for water Environment Recovery Engineering Beijing University of Technology Beijing 100022 China Advanced Wast.water management Centre （AWMC） the University of Queensland St. Lucia Brisbane 4072 Australia

To achieve high efficiency of nitrogen and phosphorus removal and to invest.gate the rule of simultaneous nitrification and denitrification phosphorus removal （SNDPR）, a whole course of SNDPR damage and recovery was st.died in a pilot-scale, anaerobicanoxic oxidation ditch （OD）, where the volumes of anaerobic zone, anoxic zone, and ditches zone of the OD syst.m were 7, 21, and 280 L, respectively. The reactor was fed with municipal wast.water with a flow rate of 336 L/d. The concept of simultaneous nitrification and denitrification （SND） rate （rSND） was put forward to quantify SND. The results indicate that：（1） high nitrogen and phosphorus removal efficiencies were achieved during the st.ble SND phase, total nitrogen （TN） and total phosphate （TP） removal rates were 80% and 85%, respectively; （2） when the syst.m was aerated excessively, the st.bility of SND was damaged, and rSND dropped from 80% to 20% or less; （3） the natural logarithm of the ratio of NOx to NH4^＋ in the effluent had a linear correlation to oxidation-reduction potential （ORP）; （4） when NO3^- was less than 6 mg/L, high phosphorus removal efficiency could be achieved; （5） denitrifying phosphorus removal （DNPR） could take place in the anaerobic-anoxic OD syst.m. The major innovation was that the SND rate was devised and quantified.

关键词： oxidation ditch biological nitrogen removal biological phosphorus removal simultaneous nitrification and denitrification (SND) pilot scale municipal wast.water

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