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Indoor imitation experimental study on driving factors of rainfall-runoff process

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Science china Earth Sciences 2005年第3期48卷 417-428页

作者： ZHANG Shifeng1, LIU Changming 1, XIA Jun1, TAN Ge 1, LI Lin1, LIU Caitang1, ZHOU Changqing 1 & GUO Lei2.1. Institute of Geographic Sciences and Natural resources Research, Chinese Academy of Sciences, Beijing 100101, china {2., wuhan university, wuhan 43.072. china 1. Institute of Geographic Sciences and Natural resources Research Chinese Academy of Sciences 100101 Beijing China 2. college of water resources and hydropower engineering Wuhan University 430072 Wuhan China

The driving actions of rainfall-runoff process can be attributed to two aspects. The first is the influence of precipitation process, and the second is that of the ground pad. The re- search results of 179 indoor experiments conducted to imitate rainfall-runoff process indicate that both precipitation duration and intensity play important roles in affecting confluence lag time, which is obviously inconsistent with the traditional hypotheses. The nonlinear relationship is of great significance to the confluence curve especially when the precipitation duration is less than the total confluence time or the precipitation intensity is small. Therefore it can be concluded that the unit hydrograph (UH) can be applied to rainfall-runoff process imitation in the humid areas in the south china region. However, the UH application should be strictly modified in accordance with precipitation conditions in the arid and semiarid region of north china where the precipitation duration is short and the intensity is unstable. It will be hard to get ideal imitation results if the UH is applied blindly without considering specific conditions in the north china region. This also explains the unsatisfactory imitation results caused by using various hydrological models in the north china region. When the precipitation duration is short, and the watershed has not reached total watershed concentration, the characteristics of confluence change greatly, which reflects the actual situation in the north china region. Therefore necessary nonlinear corrections should be made when UH is applied. If the duration is longer than the total confluence time and the balance between pondage and discharge is stricken, the imitation research results will be applicable to both rainfall-runoff relation with longer duration in the south china region and the basic theoreti- cal research on runoff generation and concentration. On conditions of adequate rainfall, peak discharge is in linear relationship with inten

关键词： rainfall-runoff, driving factors, indoor imitation, experiment.

THE UNITED METHOD FOR THE CALCULATION OF SEEPAGE CONTROL BY ADOPTING WEIGHTING SOIL LAYER ON THE BACK SIDE OF DIKE

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Journal of Hydrodynamics 2001年第4期13卷 92-97页

作者： Liu Chuan-shun, Yang Jin-zhong college of water Conservancy and {2. engineering, wuhan university, wuhan 43.072. china wuhan Univ. Wuhan 430072 China

Constructing a weighting soil layer at the downstream toe of dike on layered ground is an effective measure to prevent the foundation from blowout failures. In this paper, a series of differential equations describing the seepage flow in layered dike foundation were established, and a united method combining analytic method with one-dimensional finite difference method was proposed for solving the equations. The case study shows that the results calculated by the united method are considerably identical to the computational results of Finite Element Method (FEM), and the united method is very simple and easy compared to the FEM.

关键词： dike weighting soil layer seepage calculation seepage control united method

A SIMPLIFIED NUMERICAL MODEL OF 3-D GROUNDwater AND SOLUTE TRANSPORT AT LARGE SCALE AREA

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Journal of Hydrodynamics 2010年第3期22卷 319-328页

作者： LIN Lin YANG Jin-Zhong ZHANG Bin ZHU Yan State Key Laboratory of water resources and {2. engineering Wuhan University Wuhan 430072China Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China

A simplified numerical model of groundwater and solute transport is developed. At large scale area there exists a big spatial scale difference between horizontal and vertical length scales. In the resultant model, the seepage region is particularly divided into several virtual layers along the z direction and vertical 1-D columns covering x-y 2.D area according to stratum properties. The numerical algorithm is replacing the full 3-D water and mass balance analysis as the 2.D Galerkin finite element method in x- and y-directions and 1-D finite differential approach in the z direction. The reasonable method of giving minimum thickness is successfully used to handle transient change of water table, drying cells and problem of rewetting. The solution of the simplified model is preconditioned conjugate gradient and ORTHOMIN method. The validity of the developed 3-D groundwater model is tested with the typical pumping and backwater scenarios. Results of water balance of the computed example reveal the model computation reliability. Based on a representative 3-D pollution case, the solute transport module is tested against computing results using the MT3DMS. The capability and high efficiency to predict non-stationary situations of free groundwater surface and solute plume in regional scale problem is quantitatively investigated. It is shown that the proposed model is computationally effective.

关键词： groundwater movement solute transport simplified model 3-D mass balance numerical simulation

Differential Hydrological Grey Model (DHGM) with self-memory function and its application to flood forecasting

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Science china(Technological Sciences) 2009年第4期52卷 1039-1049页

作者： CHEN XiangDong1, XIA Jun1,2.& XU Qian3 1 Key Laboratory of water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural resources Research, Chinese Academy of Sciences, Beijing 100101, {2. 2.State Key Laboratory of water resources and hydropower engineering Science, wuhan university, wuhan 43.072. china 3 School of Hydrology and water resources, Hohai university, Nanjing 2.0098, {2. 1. Key Laboratory of water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China 2. State Key Laboratory of water resources and {2. engineering Science Wuhan University Wuhan 430072 China 3. School of Hydrology and water resources Hohai University Nanjing 210098 China

This paper addresses a problem of flood forecasting with the self-memory function. Considering flood forecasting’s uncertainty and updating demand, a hybrid hydrological model, namely Differential Hy- drological Grey Model with self-memory function (DHGM-SM), is developed. The model has two fold features. One is to establish a self-memorization equation linked with DHGM, that could extract useful information from past data series and realize updating of hydrological dynamic process. The other is that this model has higher efficiency relative to original hydrological model without self-memory func- tion. This approach was applied to river flow forecasting of two representative basins in Tunxi of South china and Daqinggou of North china. It is shown that this hybrid method has satisfactory forecasting accuracy by examination of both calibration and validation.

关键词： differential grey model the self-memorization principle real-time forecasting faded-memory recursive least square method

QUALIFICATION OF UNCERTAINTY FOR SIMULATING SOLUTE TRANSPORT IN THE HETEROGENEOUS MEDIA WITH SPARSE GRID COLLOCATION METHOD

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Journal of Hydrodynamics 2009年第6期21卷 779-789页

作者： SHI Liang-sheng YANG Jin-zhong State Key Laboratory of water resources and {2. engineering Science Wuhan University Wuhan 430072 China The Sonny Astani Department of Civil and Environmental engineering University of Southern California Los Angeles CA 90089 USA

The sparse grid collocation method is discussed to qualify the uncertainty of solute transport. The Karhunen-Loeve （KL） expansion is employed to decompose the log transformed hydraulic conductivity. The head, velocity and concentration fields are represented by the Lagrange polynomial expansion. A sparse grid collocation method is then used to reduce the original stochastic partial differential equations to a set of deterministic equations which is collocated at selected interpolation （collocation） points. The collocation points are constructed by the Smolyak algorithm. The accuracy, efficiency and convergence property of sparse grid collocation method are investigated by numerical experiments. The analysis shows that stochastic collocation strategy helps to decouple stochastic computations, and all the numerical computation is possible to be implemented by existing deterministic finite element codes. The proposed method provides an efficient way to evaluate the uncertainty of the solute transport in the heterogeneous media.

关键词： stochastic partial differential equations collocation method solute transport uncertainty

MODELING UNCONFINED SEEPAGE FLOW USING THREE-DIMENSIONAL NUMERICAL MANIFOLD METHOD

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Journal of Hydrodynamics 2010年第4期22卷 554-561页

作者： JIANG Qing-hui DENG Shu-shen ZHOU Chuang-bing LU Wen-bo School of Civil engineering Wuhan University Wuhan 430072 China State Key Laboratory of water resources and {2. engineering Science Wuhan University Wuhan 430072 China

Three-dimensional numerical manifold method for unconfined seepage analysis is proposed in this *** constructing hydraulic potential functions of the manifold element,the element conductivity matrix and the global simultaneous equations for unconfined seepage analysis are derived in *** algorithm of locating the free surface and the formula for seepage forces are also ***-dimensional manifold method employs the tetrahedral mathematical meshes to cover the whole material *** the iterative process for locating the free surface,the manifold method can achieve an accurate seepage analysis of the saturated domain below the free surface with mathematical meshes *** the shape of manifold elements can be arbitrary,the disadvantage of changing the permeability of transitional elements cut by the free surface in the conventional Finite Element Method（FEM） is removed,and the accuracy of locating the free surface can be ***,the seepage force acting on the transitional elements can be accurately calculated by the simplex *** results for a typical example demonstrate the validity of the proposed method.

关键词： three-dimensional seepage numerical manifold method free surface mathematical mesh manifold element

Characterization of Pozzolanic Reaction and Its Effect on the C-S-H Gel in Fly Ash-cement Paste

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Journal of wuhan university of Technology(Materials Science) 2011年第2期26卷 320-325页

作者：王磊何真 State Key Laboratory of water resources and {2. engineering Science Wuhan University

High resolution solid-state 2.Si MAS NMR,combined with XRD,SEM and FTIR were used to characterize the pozzolanic activity of FA,type of main pozzolanic reaction products,and the effect of pozzolanic reaction on the C-S-H microstructure in fly ash-cement （FC） *** experimental results indicate that in the hydrated FC paste with 30% dosage of FA at 3 d,FA partially participated in the pozzolanic reaction,while,at 12. d,FA largely *** the hydration of FC paste at laboratory temperature,the pozzolanic reaction products are C-S-H gel rather than zeolitic ***,after the covalent bonds of Si-O-Si,Si-O-Al and Al-O-Al in the structure of FA are broken,monosilicates Si-OH and Al-OH groups form,these chemical species can connect C-S-H dimers,thus producing more Al-free C-S-H and aluminous C-S-H than in the plain cement *** increased content of Al for Si substitution in the bridging tetrahedra of C-S-H may decrease the stability of C-S-H,which results in a rather obvious loss in the mechanical strength of hardened FC paste.

关键词： NMR C-S-H microstructure dimer polymerization

Coupling the hydrological and ecological process to implement the sustainable water resources management in Hanjiang River Basin

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Science china(Technological Sciences) 2009年第11期52卷 3240-3248页

作者： ZHANG Xiang1 & XIA Jun2.1 State Key Laboratory of water resources and {2. engineering Science, wuhan university, wuhan 43.072. china 2.Key Laboratory of water Cycle and Related Land Surface Processes, IGSNRR, Chinese Academy of Sciences, Beijing 100101, china 1. State Key Laboratory of water resources and {2. engineering Science Wuhan University Wuhan 430072 China 2. Key Laboratory of water Cycle and Related Land Surface Processes IGSNRR Chinese Academy of Sciences Beijing 100101 China

Research on the combination of hydrological variation and ecological demands plays an important role in water availability assessment and sustainable management on basin scale. An integrative frame, consisting of hydrological regime modelling, ecological water demands estimation and renewable {2. management, is given in this paper in order to support the implementation of the sustainable water {2. management. The suggested integrative frame has been used to study the integrated water {2. management in southern Hanjiang River Basin which is the water source of South-toNorth water Transportation Project in china. SWAT (soil and water assessment tool) model was used to simulate the monthly averaging streamflow and the amounts of ecological water demands in stream were also estimated in order to evaluate the available water {2. for the local users and the transportation project. Then we formed the developing scenarioes by coupling the available water {2., the recovering rate of water {2. in natural water cycle, the local water use rate and the amounts of the water transported to North, and used the Scheafer model to analyze their evolving trajectories. Eventually, the sustainable water {2. management measures were assembled by the comprehensive evaluation of the scenarioes. The research indicates that the integrative frame provided a new way for the integrated water {2. management in river basin.

关键词： SWAT (soil and water assessment tool) Scheafer model ecological water demands water resources availability sustainable water resources management

Influence of the impounding process of the Three Gorges Reservoir up to water level 172.5m on water eutrophication in the Xiangxi Bay

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Science china(Technological Sciences) 2010年第4期53卷 1114-1125页

作者： YANG ZhengJian1,LIU DeFu1,JI DaoBin1,2.& XIAO ShangBin1,3 1 college of Civil & Hydroelectric engineering,{2. Three Gorges university,Yichang 443002.{2. 2.School of water resources & hydropower engineering,wuhan university,wuhan {12.{2. 3 Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710075,{2. 1. college of Civil & Hydroelectric engineering China Three Gorges University Yichang 443002 China2. School of Water Resources & Hydropower Engineering Wuhan University Wuhan 430072 China3. Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China

The water level of the Three Gorges Reservoir(TGR) rose to 172.5 m in two stages from September to November,*** hydrodynamic parameters and water quality parameters(*** velocity,temperature,turbidity and nutrient content) had been continuously monitored to reveal the influence of the impounding process of the TGR on the water eutrophication in the Xiangxi Bay(XXB).The maximal daily rise of the water level of the TGR was about 2.38 *** water exchange between the mainstream(the Changjiang River) and the XXB of the TGR was enhanced by density current,and its main characteristics were a density-stratified flow in different *** water exchange reduced the differences of the water quality parameters(for example,temperature,turbidity,nutrient level,pH,etc.) between the mainstream and the XXB during the impounding ***,the water stability index in the mainstream remained small but it was lowered in the *** main causes included the dilution by water of lower concentration of the chlorophyll a(Chl.a) entering from the mainstream,the decline of the water stability,and the increase of suspended silt,which induced the Chl.a to decrease in the XXB during the impounding *** grade of the water eutrophication changed from middle eutrophic level to mesotrophic state in the ***,as available nutrients were imported into the XXB from the mainstream during the impounding process the risk of water eutrophication increases in the XXB in the future.

关键词： impounding density current eutrophication the Xiangxi Bay the Three Gorges Reservoir