• 全国中文核心期刊
  • 中国科技核心期刊
  • 美国工程索引(EI)收录期刊

2014 Vol. 25, No. 4

Display Method:
Influence of sediment trapping in reservoirs on runoff and sediment discharge variations in Yangtze River
WANG Yangui, SHI Hongling, LIU Xi
2014, 25(4): 467-476.
Abstract:
In order to understand the influence of reservoir construction on the runoff and sediment discharge variations, relationships between water and sediment parameters and reservoir capacity parameters in the trunk stream and tributaries of the Yangtze River were deeply studied through using the incoming sediment coefficient (ISC), the sediment transport modulus (STM) and the reservoir regulation coefficient in the basin (RCB). Annual sediment discharge in the typical hydrologic stations gradually reduces with increase of the cumulative reservoir capacity in the basin, and the ISC and the STM of the rivers decrease in an exponential form with the RCB, which shows that water storage and sediment trapping of the reservoir is a main influence factor on the runoff and sediment discharge variations. The attenuation laws of the sediment discharge in the trunk stream are some differences from that in tributaries. For the tributaries, the ISC and STM attenuation laws are relatively independent with each other. For the trunk stream, the ISC and STM attenuating ranges in the upper stations are greater than that in the lower stations, and it is near same for the STM attenuation laws in all typical hydrologic stations.
A theoretical investigation of the hydrodynamic conditions for equilibrium island morphology in anabranching rivers
LIU Xiaofang, HUANG Heqing, DENG Caiyun
2014, 25(4): 477-483.
Abstract:
The equilibrium condition of island morphology is of great importance to the understanding of the self-adjusting mechanism of anabranching rivers. Based on the basic flow relationships of continuity, resistance, sediment transport and energy conservation, the equilibrium condition of a two-channel anabranching system with the island planform of approximately a triangular form is derived theoretically by applying a variational approach. The results show that when the anabranching river achieves stationary equilibrium, the main channel with a larger carrying capacity takes a larger proportion of sediment load than the proportion of flow discharge. The shape of island morphology in equilibrium varies with the proportions of flow discharge and sediment load passing into the two channels. The smaller the discrepancy between the proportions of flow discharge and sediment load, the slenderer the island shows. In addition, for Jianli anabranching reach located in the middle Yangtze River, it is demonstrated that the theoretically computed morphologies of the island are highly consistent with the field observations, with a relative error of about 9.0%.
Temporal and spatial variations of snow depth in regions of the upper reaches of Yangtze River under future climate change scenarios:A study based on CMIP5 multi-model ensemble projections
LU Guihua, YANG Ye, WU Zhiyong, HE Hai, XIAO Heng
2014, 25(4): 484-493.
Abstract:
Based on multi-model ensemble projections for the period 2011-2040 under climate change scenarios, the temporal and spatial variations of snow depth in regions of the upper reaches of the Yangtze River are investigated in this study. The ensemble projections of future snow conditions are obtained using a coupled modeling approach involving 21 global climate models in the phase 5 of the Coupled Model Intercomparison Project (CMIP5) and the VIC (Variable Infiltration Capacity) model. The climate change scenarios considered include the Representative Concentration Pathways (RCPs) 2.6, 4.5 and 8.5. Results show that both multi-annual and monthly mean temperatures for the next three decades are projected to rise by 1 to 2℃ relative to the base period (from 1970 to 1999), with obvious increase in winter and spring seasons. The average annual precipitation would increase by 3% to 4%, while a slight decrease in autumns and winters. The multi-annual mean snow depth for the next three decades is projected to decrease by about 37.8% relative to the base period. The time of maximum snow accumulation should be similar to that in the base period, while the starting time of snow melting would be slightly lagged behind. For the spatial extent of snow cover, the snow depth in most regions of the upper reaches of the Yangtze River would be reduced, and the reduction could be more than 50% in some areas.
Research on temporal and spatial change of 400 mm and 800 mm rainfall contours of China in 1961-2000
YUAN Zhe, YAN Denghua, YANG Zhiyong, YIN Jun, YUAN Yong
2014, 25(4): 494-502.
Abstract:
Based on daily precipitation data from 1961 to 2010, the spatial location of 400 mm and 800 mm rainfall contours were quantitatively analyzed via weighted contour line average location. Time series analysis methods such as Kendall, Morlet wavelet, moving t test and Yamamoto method were utilized to systematically reveal the spatial shift feature of 400 mm and 800 mm rainfall contours of China in the recent 50 years: During 1961 to 2010, weighted 400 mm and 800 mm rainfall contours average location were 106°07'12"E, 39°25'13"N and 110°16'31"E, 34°12'04"N. The trendy results showed that 400 mm and 800 mm rainfall contours of China had a shifting trend toward west and south, of which 400 mm rainfall contour had a significant shifting trend toward west and 800 mm rainfall contour had a significant shifting trend toward south. Periodic results indicated that primary period of 400 mm rainfall contour's radical and zonal shift were 9 a and 12 a respectively in China, while that of 800 mm rainfall contour's radical and zonal shift were both 7 a. The breakpoint of 400 mm rainfall contour's spatial location were 1995 to 1996 (zonal) and that of 800mm rainfall contour's spatial location were 1975 and 2002 (radical) and 1980, 1982, 1987(zonal).
Characteristics of flood and drought events of the last half millennium in Huaihe River basin
YANG Chuanguo, CHEN Xi, ZHANG Runrun, HU Qi, YU Zhongbo, HAO Zhenchun, LIN Zhaohui
2014, 25(4): 503-510.
Abstract:
This study identifies characteristics of flood and drought occurrence of the last half millennium and their evolution to the past years in the Huaihe River basin based on various sources of data recording historical flood and drought events and disasters, including observed rainfall data, reconstructed wet season rainfall data, historical flood/drought index, history documentary record of floods and droughts, and history flood survey. The reconstructed wet season rainfall and historical flood/drought index are primarily applied to investigate spatial and temporal characteristics of flood/drought events of the last half millennium using the methods of smoothing average, frequency analysis, wavelet analysis and Mann-Kendall tests. Results indicate that over the past half millennium period, flood and drought events were most severe in the 17th century, but occurrence of extreme flood/drought events was most frequent in the 20th century. It is found there was a relatively stable periodic variation of about 40 years over the past half millennium, and the periodic term had been shortened, from 15-20 years before the 18th century to 5 years in the 19th century, and even 2-3 years in recent 20 years. This increasing tendency indicates that the floods and droughts would severely threaten the economic and social development in the study basin.
Numerical model of water consumption of Populus euphratica in the lower reaches of Tarim River
SU Litan, GUAN Donghai, WANG Xingyong, ZHAO Tianyu
2014, 25(4): 511-517.
Abstract:
Water consumption of vegetation is the core of SPAC (Soil-Plant-Atmosphere Continuum) research; it's also the precondition on the research of water requirements by natural vegetation. This paper simulated the water consumption of riparian Populus euphratica forests, the representative natural vegetation in the lower reaches of Tarim River, in a relatively small time scale based on the SHAW(Simultaneous Heat and Water) model. Conventional weather elements, vegetation parameter and hydrothermal data of soil profile were adopted as initial inputs of the model. The results show that there is a deviation between the simulated value and observed value of water consumption by Populus euphratica forests. To further improve the appropriateness of the SHAW model application in arid regions, we established a modified SHAW model by introducing the groundwater level factor GSI (Groundwater-Soil water Interaction). We comparatively analyzed the water consumption of Populus euphratica by the two models of SHAW and GSI-SHAW. The results show that the correlation coefficients between simulated and observed water consumption are 0.8533 and 0.9075 by SHAW model and GSI-SHAW model, respectively. The relative errors of simulated values by SHAW model and GSI-SHAW model are respectively 21.4% and 16.9% against observed water consumption rates. It can be seen that the simulated values of the modified GSI-SHAW model are more approximate to the measured values. We conclude that the integration of GSI model further improves the simulation accuracy of SHAW model, providing a new method and scientific proof for the calculation of water consumption by natural vegetations in arid areas.
Changes of representative glaciers in Xinjiang Hami and their impact to water resources
WANG Puyu, LI Zhongqin, ZHOU Ping, JIN Shuang, CHEN Hui
2014, 25(4): 518-525.
Abstract:
Water scarcity is a big problem in Hami, Xinjiang and glaciers are the major water supply. In order to make reasonable evaluation and forecast of glaciers and water resources in Hami, taking Yushugou Glacier No. 6 and Miaoergou ice cap as representative, the study comprehensively analyzed the recent glacier changes in Hami and their impact on water resources under the background of climate warming based on in-situ observation and previous studies. Results indicated that the thickness of Yushugou Glacier No.6 decreased by 20 m, or 0.51 m/a with the terminus retreat of 254 m, or 6.5 m/a during the period 1972-2011. Due to serious ablation, the surface meltwater runoff of Yushugou Glacier No. 6 was obvious and a moraine lake was formed at the terminus. By comparison, the melting rate of Miaoergou ice cap was smaller than Yushugou Glacier No. 6, which was directly related to the glacier types and the high altitude of Miaoergou ice cap with low sensitivity to climate warming. The comprehensive analysis found that the difference of recent runoff changes in various rivers was directly caused by whether there was any glacier coverage and its ratio in the drainage basins of Hami.
Analyzing hydrological connectivity for a slope-surface on the basis of rainfall simulation experiment
WANG Shengping, YAO Ankun, ZHAO Xiaochan
2014, 25(4): 526-533.
Abstract:
Hydrological connectivity provids a possible way forward to underestand runoff process and mechnisam, which is valuable for soil erosil controling and sustainable watershed management. The research aims to characterize the slope hydrological connectivity when acconuting for infiltration process, and to investigate the impacts of both slope and rainfall intensity on hydrological connectivity development. On the basis of rainfall simulation experiment, we analyzed hydrological connectivity of a simulated slope (size: 150cm×50cm) with various degree (5°,15°, and 25°) and rainfall intensities (25mm/h, 50mm/h, 70mm/h, and 86mm/h) by using a structural indicator (Flowlength,lF) and a functional indicator (relative surface connection function, FRC), respectively. The results suggested that hydrological connection of the surface is mainly composed of short flow paths, lF of 0-100 mm accounting for as high as 90%, whilst lF of 100-500 mm accounting for 3% to 8%. The development of hydrological connectivity is mainly confined to the initial stage of the events, whilst it is difficult to further develop once the infiltration rate is equal to the surface storage rate, and the ratio of surface connected is stablized at a certain range value in the late stage. The increase in slope generally facilitate the development of hydrological connectivity. The ratio of surface connected on 5 degree-slope is generally lower than the others. Due to the increase in surface roughness, the development of hydrological connectivity is limited when the rainfall intensity is increased to a certain degree, which partly explain the insignificant change in hydrological connectivity under the rainfall intensity of between 50 mm/h, 70 mm/h, and 86 mm/h.
Hydrology, hydrodynamics, and water quality model for impounded rivers:I:Theory
CHEN Liangang, SHI Yong, QIAN Xin, LUAN Zhenyu, JIN Qiu
2014, 25(4): 534-541.
Abstract:
In order to satisfy the requirements of water environment daily management on large-scale impounded river network, the Hydrology, Hydrodynamics, and Water Quality Model (DHQM) is designed based on the cross-integration of multiple methods. DHQM adopts a modular structure as well as one- and two-dimensional nesting frameworks. DHQM includes 5 parts: River runoff simulation, sluice scheduling simulation, river water quality simulation, local inflow and river pollution load estimation, and water quality real-time correction. DHQM demonstrates a fair data robustness and flexibility in application, which boosts its applicability for the real-time early warning and regulation of water environments as well as for quantifying the hydrological and environmental effects of dams and sluices.
Application of dual time-step algorithm for 2-D shallow water equations
YU Haijun, HUANG Guoru, WU Chuanhao
2014, 25(4): 542-549.
Abstract:
Aiming at the problem of low efficiency of traditional explicit schemes, an efficient finite volume scheme is proposed by applying an implicit dual time-step algorithm to discretize the two-dimensional shallow water equations on unstructured grids. An implicit non-linear lower-upper symmetric Gauss-Seidel (LU-SGS) solution algorithm is used as the iteration solver for the inner steady problems. The model's accuracy, efficiency, and capability of dealing with practical problems are validated through its application to four typical examples and comparison with an explicit algorithm. In addition, the effects of physical time step and maximum iteration number on the model's accuracy and efficiency are assessed. Numerical results from the test examples show that the dual time-step approach eases the restrictions on the sizes of time steps, which can be more than 10 times that of explicit algorithms, and that the reduction in run-time can be more than 50%. The proposed model is found to be accurate and efficient, thus having a good potential for popularization.
A coupled mathematical model for two-dimensional flow-transport simulation in tidal river network
SONG Lixiang, YANG Fang, HU Xiaozhang, YANG Liling, ZHOU Jianzhong
2014, 25(4): 550-559.
Abstract:
Water flows in tidal river network are governed by channel runoff, tidal power and potential sluices operations, so the corresponding hydrodynamic conditions are very complex. To simulate the flow-mass transport in tidal river network under sluices operations, an integrated solver is proposed for computing flow and mass transport fluxes simultaneously, and then a two-dimensional coupled flow-mass transport model based on unstructured Godunov-type scheme is developed. The MUSCL-Hancock predictor-corrector scheme combined with the slope limiter is adopted to achieve the high-accuracy and high-resolution property. The sloping bottom grid is used to represent the sluice as a linear topography, and the sluice operation is modeled through adjusting the nodal bed elevation. Numerical results of test examples and field application show that the model is accurate, and can efficiently simulate complex flow and mass transport in tidal river network under sluices operations, thus has bright application prospects.
Flood routing model with lateral coupling one-dimensional channel and two-dimensional floodplain simulation
ZHANG Fangxiu, HAN Longxi, WANG Ming, HUANG Rui
2014, 25(4): 560-566.
Abstract:
For the purpose of rapid simulation for bankful flood routing on large scale compound channel, based on previous studies on one-dimensional and two-dimensional flood routing models, one dimensional main channel hydrodynamic model and two dimensional hydrodynamic model were laterally coupled by simplifying and nesting main channel and flood plain with rectangle grids and triangle grids, in which water exchanges between grids, floodplain and main channel were simulated. The model was verified with a measured flood process in the lower reaches of the Yellow River numbered as flood "96·8". The simulation results for flood routing in section between Huayuankou hydrometric station and Jiahetan Hydrometric station indicate that the model performs well for simulating of bankful flood process routing on complex river channel.
Experimental study on scouring characteristics of cohesive bank soil in the Jingjiang reach
ZONG Quanli, XIA Junqiang, ZHANG Yi, XU Quanxi
2014, 25(4): 567-574.
Abstract:
The erosion-resisting capacity of cohesive soil is relatively strong, with its magnitude determining the erosion rate of cohesive riverbank. It is necessary to obtain the incipient condition, erodibility coefficient, and the relationship between them in order to investigate the erosion-resisting capacity of cohesive soil. Therefore, a series of laboratory experiments has been conducted in a closed rectangular flume for the investigation of incipient conditions and scouring characteristics of a cohesive bank soil sampled from the Jingjiang reach. According to experimental results, the relationship was obtained between incipient velocity and the ratio of liquid limit to natural water content, as well as the quantitative relationship between critical shear stress and dry density, critical shear stress and liqidity index, which accounted for the effects of various physical properties on the incipient motion of cohesive soil. In addition, the variation characteristic of erodibility coefficient with the critical shear stress was proposed for the cohesive bank soil in the Jingjiang reach, and it was found that the obtained erodibility coefficient under the same critical shear stress is much higher, as compared with the value calculated using the existing relations obtained from other river basins, which is attributed to a lower clay content in the study reach and the disturbed soil samples. Based on the results of scouring experiment, a quantitative relationship between the erodibility coefficient and critical shear stress of cohesive bank soil was obtained, with a correlation coefficient of 0.90, which can provide a basis for predicting the erosion process of riverbanks in the Jingjiang reach.
General formula derivation of most likely regional composition method for design flood estimation of cascade reservoirs system
LIU Zhangjun, GUO Shenglian, LI Tianyuan, XU Changjiang
2014, 25(4): 575-584.
Abstract:
In this study the joint probability distributions of floods at all sub-basins of cascade reservoirs were established using Copula function and based on the principle of maximizing joint probability density function the general formula of the most likely regional composition (MLRC) method was derived for design flood estimation of downstream reservoirs. The developed procedure was tested and compared with equivalent frequency regional composition (EFRC) method for determination of design flood of the Shuibuya-Geheyan-Gaobazhou cascade reservoirs system located at the Qingjiang River, a tributary of the Yangtze River in China. The results show that the design flood values of the MLRC method are within the range of peak discharges estimated by different EFRC schemes. The design flood reduction rates of the Yidu site are found to be evident due to the regulation of upstream cascade reservoirs, and the 100-year design flood reduction rate estimated by the MLRC method is 30.2%. The findings of the study reveal that the proposed method not only has strong statistical basis, but also has rational results with unique composition scheme, which will provide a new approach for design flood estimation of complex cascade reservoirs system.
Spatial variability of soil moisture and salt content in cotton field on microscales under mulch drip irrigation
SHI Wenjuan, MA Yuan, XU Fei, WANG Quanjiu
2014, 25(4): 585-593.
Abstract:
To explore spatial variability of agricultural soil moisture and salinity on microscales under mulch drip irrigation, we conducted filed experiments and employed classical statistics and geostatistics to investigate the spatial variability of soil moisture and salt content in cotton field on three microscales (0.25 m×0.25 m, 1 m×1 m, and 4 m×4 m) and in different soil depths and determine the reasonable sampling number. The results indicated that the variability of soil moisture was moderate and relatively weak on three microscales, which was enhanced as scale increased and enhanced first and then weakened as depth increased. The variability of soil salinity was moderate and relatively strong, which was enhanced as scale increased and enhanced first and then weakened as depth increased. On three microscales and in different depths, most semi-variograms of soil moisture and salinity could be simulated by Gaussian models with high accuracy and the reasonable sampling number should be 367. The results could provide theoretical guidance for developing monitoring scheme and control measures for soil moisture and salinity under mulch drip irrigation.
Development and challenges of urban hydrology in a changing environment:I:Hydrological response to urbanization
ZHANG Jianyun, SONG Xiaomeng, WANG Guoqing, HE Ruimin, WANG Xiaojun
2014, 25(4): 594-605.
Abstract:
The change in the natural hydrologic processes impacted by global climate change and rapid urban expansion is a hotspot issue in the field of urban hydrology. To understand the evolvement rules of urban water cycle, we discuss the development in urban hydrology, and reveal the response mechanism of hydrological processes in urban environment. Then, we summarize the advances in the effect of urbanization on hydrological regime, including hydrological cycle and water resources management, water quality and environment, and water ecosystem. There have been significant recent advances in the measurement and modeling the hydrological responses to urban expansion, with technologies such as experiments and hydrological models. Despite the advances, many new challenges in urban hydrology remain, especially in a changing environment, which impose a requirement to ensure that sustainable urban development are adaptable and resilient to changes. Further researches into the spatio-temporal dynamics response of urban rainfall, causes of urban extreme storm, quantification of the effects of urbanization on hydrological response and water ecosystem, and urban water management are required to pay more attention to. Urban hydrology will play a critical role in addressing these challenges, to support scientific foundations for establishing eco-city and ensuring water safety for cities.
Advances in the physical simulation experiment on debris flow initiation in China
NI Huayong, TANG Chuan
2014, 25(4): 606-613.
Abstract:
As debris flows usually occur abruptly and rapidly in mountainous areas, it is difficult to observe their initiation and occurrence process. Therefore, the physical simulation experiment has been adopted as an important method to study debris flow initiation mechanism by more and more scientists. In recent years, many physical simulation experiments have been carried out and related phenomenon have played an important role both in mechanism research and in disaster mitigation. However, compared to the complex process of debris flow initiation and occurrence, there usually are some limits in the condition of physical simulation experiments. In this paper, based on data collection and analysis, advances in the physical simulation experiments including runoff type and artificial rainfall type were summarized in detail. And then by comparing the experimental study progress of both nationwide and worldwide, some factors that should be further taken into account in the physical simulation experiments on debris flow initiation were discussed. In the end of this paper, some related advices on future physical simulation experiments on debris flow initiation were put forward in the following aspects: To further improve the similarity of experimental condition, such as runoff density, rainfall type and soil characteristics, to further study the relation between debris flow initiation and the physical and dynamic variation of soil mass, and to further carry out some comprehensive experiments in which all the rainfall process, runoff process and material-supplying process are all involved.
2014, 25(4): 614-616.
Abstract: