• 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

2015 Vol. 26, No. 1

Display Method:
Response of runoff to climate change in the Haihe River basin
HE Ruimin, ZHANG Jianyun, BAO Zhenxin, YAN Xiaolin, WANG Guoqing, LIU Cuishan
2015, 26(1): 1-9. doi: 10.14042/j.cnki.32.1309.2015.01.001
Abstract:
The Variable Infiltration Capacity (VIC) model was used to investigate the response of runoff to climate change in the Haihe River basin(HRB). Firstly, the parameters of the VIC model were calibrated in six sub-catchments in the HRB. Secondly, using the parameter regionalization methodology, the model parameters were estimated in other parts of the HRB. Thirdly, The response of runoff to climate change in the HRB was estimated based on the hypothetical climate scenarios. The results indicated that a 2℃ increase of annual mean temperature would lead to a 6.5% decrease of runoff in the HRB. A 10% increase or decrease of annual precipitation would lead to a 26% increase or 23% decrease of runoff, respectively. A 10% increase or decrease of the percentage of precipitation in the flood season would lead to a 12% increase or 7% decrease of runoff, respectively. Spatially, under the change of temperature and/or precipitation, the runoff in the north-western HRB was more sensitive than that in the south-eastern HRB. Otherwise, under the change of the percentage of precipitation in the flood season, the runoff in the south-eastern HRB was more sensitive than that in the north-western HRB. Overall, the more precipitation, the less sensitive of runoff to precipitation and/or temperature, but the more sensitive of runoff to the percentage of precipitation in the flood season.
Prediction of extreme floods of the Feilaixia reservoir in the Beijiang River basin under climate change
HUANG Guoru, WU Chuanhao, LIU Zhiyu, CHEN Zhijing, HU Jianwei, YIN Zhijie
2015, 26(1): 10-19. doi: 10.14042/j.cnki.32.1309.2015.01.002
Abstract:
In this paper, the downscaling results of the multi-model dataset from the Coupled Model Intercomparison Project Phase 5 (CMIP5) were coupled with the Variable Infiltration Capacity (VIC) model to predict future floods of the Feilaixia reservoir in the Beijiang River basin under RCP2.6, RCP4.5, and RCP8.5 scenarios. Credibility of the projected changes in floods is described using an uncertainty expression approach, as recommended by the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). The results indicate that annual maximum flood peak and maximum 7-day and 15-day flood volumes during 2020-2050 would be "about as likely as not" to show an upward trend under the RCP2.6 scenario and "more likely than not" to show an upward trend under the RCP4.5 and RCP8.5 scenarios. Compared with the 1970-2000 historical period, the flood peaks in the 100 a, 50 a, and 20 a return periods are projected to increase under all future scenarios. In contrast, the maximum 7-day and 15-day flood volumes in the 100 a, 50 a, and 20 a return periods would increase under the RCP4.5 scenario and decrease under the RCP2.6 and RCP8.5 scenarios.
Analysis on the joint distribution of low flows between Xijiang River and Beijiang River under a changing environment
CHEN Zishen, HUANG Qiang, LIU Zengmei
2015, 26(1): 20-26. doi: 10.14042/j.cnki.32.1309.2015.01.003
Abstract:
The risk analysis approach based on Clayton copula and Kendall distribution function is used to analyze the joint distribution of low flows between Xijiang River in Makou and Beijiang River in Sanshui, which are connected through the Sixianjiao waterway in Guangdong, China. Using samples with seven consecutive average minimum flows of Makou gauge and the corresponding low flows of Sanshui gauge during the hydrological years 1959-2010, the "OR," "AND," and secondary return period of the joint distributions of low flows between 1959 and 1985 (referred to as sample A) and between 1986 and 2010 (referred to as sample B) of the two rivers were calculated using the Clayton copula and Kendall distribution function, respectively. The main conclusions of this study can be summarized as follows: ① The design quantiles of the low flows of Makou in sample B are less than the design quantiles for the corresponding return periods of sample A, while the design quantiles of low flows significantly increased in Sanshui; ② The encounter probabilities of low flows between Xijiang River and Beijiang River were significantly reduced, with the same frequencies of samples A and B since 1985; ③ The cumulative frequencies calculated using the secondary return period represent the risk possibilities between Xijiang River and Beijiang River low flows with specific design frequencies; ④ The Q7d,T=20a, Q7d,T=10a, and Q7d,T=2a of the most likely design quantiles calculated using the secondary return period for the Makou and Sanshui gauges may be more suitably used as the design reference for water supply planning of the West River Delta during the low water season.
Determining the risk-moderate criterion for flood utilization
WANG Zhongjing, ZHU Jinfeng, SHANG Wenxiu
2015, 26(1): 27-33. doi: 10.14042/j.cnki.32.1309.2015.01.004
Abstract:
Flood utilization can alleviate the shortage in water resources in North China. As an important part of flood utilization criteria, the risk-moderate criterion ensures reasonable and safe exploitation of water resources. For the adjustment of flood limit water levels (FLWL), an analysis method is proposed, which determines risk-moderate criterion by computing flood regulation with the designed floods of different return periods and modeling long-time series water supply with reservoir scheduling model. This method is applied to Miyun Reservoir in Beijing. Results show that the uplift of the major-flood-period FLWL from the initial value of 147.00 m to the current value of 152.00 m is relatively reliable, and its upper threshold can be 153.20 m further. The upper threshold of later-flood-period FLWL for reliable flood utilization is 155.40 m, compared with 154.00 m at present. The water supply assurance rates increase by 0.3% and 0.01% in these two cases, respectively; and the risk rates of the dam and downstream flood control areas are kept within 0.01% and 1%, respectively. These risk rates satisfy the designed standard and risk-moderate criteria of flood utilization.
An hydrology-process based method for antecedent effect rainfall determination in debris flow forecasting
ZHANG Shaojie, JIANG Yuhong, YANG Hongjuan, LIU Dunlong
2015, 26(1): 34-43. doi: 10.14042/j.cnki.32.1309.2015.01.005
Abstract:
Antecedent effect rainfall is a key factor in debris flow forecasting, but the current method used to calculate this factor has the defect that the parameters determination of the method is too subjectively. In order to solve this problem, a hydrology-process (e.g. rainfall interception, rainfall infiltration and evapotranspiration) based method to calculate the antecedent effect rainfall for debris flow forecasting is proposed. Taking the antecedent effect rainfall calculated by the hydrology-process based method and the empirical based method as the initial value, the debris flow forecasting system for Sichuan province based on the water-soil coupling mechanism is employed to forecast debris flow disasters induced by the heavy rainfall on July 9, 2013 in Sichuan province. The forecasting results show that the hydrology-process based method that used to calculate the antecedent effect rainfall is more suitable for debris flow forecasting, because the failure prediction rate of debris flow forecasting is 21.1% lower than the method of the empirical formula of the rainfall attenuation. Consequently, the hydrology-process based method that used to calculate the antecedent effect rainfall can serve the debris flow mitigation better.
Preliminary analysis on evaporation rules of high-salinity phreatic water in arid area
JIA Ruiliang, ZHOU Jinlong, GAO Yexin, ZHOU Yinzhu, LI Yang, LI Xianwen
2015, 26(1): 44-50. doi: 10.14042/j.cnki.32.1309.2015.01.006
Abstract:
In order to analyze the evaporation rules of high-salinity phreatic water in arid area, monitoring of phreatic water evaporation with different total dissolved solids (TDS) (0.8 g/L, 30 g/L and 100 g/L), lithological characteristics of unsaturated zones (fine sand and silty clay) and depth of groundwater (0 m, 0.5 m,1.0 m, 2.0 m and 3.0 m) were carried out at groundwater balance experiment station in Changji, Xinjiang from 1st April, 2012 to 31st March, 2014. The results showed that the influence of lithological characteristics of unsaturated zones on the evaporation of phreatic water with high salinity was basically the same as in freshwater when the groundwater depth was larger than 0.5 m. The influence of variation of lithological characteristics of unsaturated zone on phreatic water evaporation was far less than the common influence of TDS and atmosphere evaporation potential on phreatic water evaporation when the groundwater depth was 0.5 m and TDS was 30 g/L. Annual phreatic water evaporation had an opposite trend as atmospheric evaporation capacity EΦ20 with groundwater depth being 0 m, TDS being 100 g/L and lithological characteristics of unsaturated zones being silty clay. Phreatic water evaporation decreased gradually with the increase of TDS during non-freezing period with groundwater depth being 0.5 to 1.0 m. The inhibition effect of TDS variation on phreatic water evaporation lagged behind with the groundwater depth of 3.0 m.
Evolution and quantization methods of rill morphology on the slope under rainfall simulation
ZHANG Pan, YAO Wenyi, TANG Hongwu, XIAO Peiqing
2015, 26(1): 51-58. doi: 10.14042/j.cnki.32.1309.2015.01.007
Abstract:
The quantitative methods of rill morphology evolution were studied, which employs the indoor soil bin rainfall simulation experiment of two bulk density of loess soil (1.30 g/cm3, 1.05 g/cm3) under the rainfall intensities of 45 mm/h,87 mm/h and 127 mm/h with 20° slope gradient. In the research, the fractal dimension and topological parameters were respectively calculated by different methods. Besides, the parameter of slope geomorphologic comentropy for geomorphology was also applied. Then the sensitivity of the quantization parameters was analyzed. The results show that the fractal dimension as an integrity parameter was not provided sensitively for describing the maturity rill networks. But the slope geomorphologic comentropy was a sensitive method to express erosion degree, and the topological parameters could reflect the diversity of rill network structures with preferable sensitivity.
A method of measuring sediment incipient velocity based on B-scan ultrasound imaging technique
MA Zhimin, ZOU Xianjian, ZHAO Xiaohong, XU Ming, TAO Weiliang
2015, 26(1): 59-65. doi: 10.14042/j.cnki.32.1309.2015.01.008
Abstract:
The measurement of the incipience of sediment particles on the riverbed has been a difficult problem in sediment transport research. For this reason, this paper puts forward a method of measuring sediment incipient velocity based on B-scan ultrasound imaging technique. This method uses B-scan ultrasound imaging device to obtain the underwater topography and ultrasonic moving images of the nearby particles in the model water channel. The image spots of the moving particles near the riverbed are analyzed and counted by means of image processing techniques. The relationship between flow velocity and particle spots is also analyzed. The result shows that particle spots have a mutation during the process of sediment incipient motion, which is corresponding to the sediment incipient motion. It can be used to measure sediment incipient and the corresponding incipient velocity. The measured incipient velocity is verified by changed topographic lines of riverbed. This method is free from flow disturbance and interference, suitable for both clear and muddy flow water and easy to realize automatic measurement.
Experimental study on the interaction between bank collapse and riverbed evolution of homogeneous soil
LI Guomin, YU Minghui, CHEN Xi, HU Chengwei
2015, 26(1): 66-73. doi: 10.14042/j.cnki.32.1309.2015.01.009
Abstract:
Bank collapse is a sudden change of lateral channel migration, along with the riverbed deformation. The paper presents a study on the process and influence factor of bank collapse and bed evolution of homogeneous soil through a series of experiments carried out in a bend flume. Experimental results reveal a repeat process as follows: Bank collapse after accumulative basal erosion, the failed bank soil remaining at the bank-toe temporarily but soon afterwards being disintegrated and transported by intensified turbulent flow nearby, the coarser soil disintegrated from the bank or the fallen block being dragged to the convex bank downstream as bed load while the finer parts being transported by flow as suspended load, near-bank current structure being adjusted due to bank collapse and bed evolution. The research also reveals that the magnitude of the bank collapse or the riverbed erosion are mainly in proportion to the near-bank velocity and scouring duration, but reverse to the cohesion of material. The amount of bank collapse is larger than that of bed erosion when the channel suffers from erosion. The range of the named relative rate of bed erosion is about 0.40~0.92, decreasing as the amount of bank erosion.
One-dimensional coupled model for predicting turbidity currents in reservoirs
WANG Zenghui, XIA Junqiang, LI Tao, GAO Guoming, ZHANG Junhua
2015, 26(1): 74-82. doi: 10.14042/j.cnki.32.1309.2015.01.010
Abstract:
Among traditional depth-averaged models for predicting turbidity currents, it is difficult to take into account the influence of flow and sediment conditions at the plunge point and the gradient of free water surface. Therefore, a one-dimensional unsteady turbidity current model for reservoirs with irregular cross-sections is proposed, and a two-step calculation mode of alternating the calculations of turbidity current and open channel flow is adopted in this model. The proposed calculation mode can dynamically determine the location of the upstream boundary for the turbidity current simulations using the plunge criterion, and can also connect the reach transported in the pattern of open channel flow and the reach transported in the pattern of turbidity current. Three processes of flow movement, sediment transport and bed evolution in a reservoir are solved by a fully coupled approach, with a TVD (Total Variation Diminishing) version of the MUSCL-Hancock scheme being used in this solution. Turbidity current movements in two laboratory experiments were simulated under different setups, including an instantaneous fixed-volume release and a constant-flux input, with the effect of free surface gradient on the model predictions being investigated. The calculations indicate that the proposed model can satisfactorily predict the thickness and sediment concentration of turbidity currents and their propagation processes, which can be used as a tool for the sediment management in reservoirs.
Comprehensive two-dimensional associate hydrodynamic models for overflow and levee-breach flood and its application
YUAN Ximin, TIAN Fuchang, WANG Lina
2015, 26(1): 83-90. doi: 10.14042/j.cnki.32.1309.2015.01.011
Abstract:
In order to better cope with the phenomenon of concurrent activity of peak discharge increase and long duration overflow and levee-breach, a comprehensive two-dimensional associate hydrodynamic model theory was proposed by referring to the theory of comprehensive two-dimensional gas chromatography and the model was developed to simulate overflow and levee-breach flood over river channel. Approximate Riemann solution of Roe was used for numerical simulation of interface flux. In the model, coupling river and irrigated area was realized through weir flow equations of overflow and levee-breach, and with dyke broadening taken into account, levee and river-channel mesh was refined to optimize this model by hot start, dry depth and wet depth theory. Moreover, real terrain method was improved by increasing roughness to reflect the influence of dense villages. In this paper, the model was applied to the case of Ningmeng section of Yellow River to simulate overflow and levee-breach flood routing, the calculation results was proved reasonable and reliable, and the flow fields tend to smooth and well-distributed, which preliminarily validated of the accuracy and reliability of the model. The research results was of great significance to river outburst floods detailed simulation, flood risk analysis and flood control decision in this region.
Distribution of motion scales of vortices in turbulent open channel flow
ZHANG Peng, YANG Shengfa, HU Jiang, CHEN Yang, XING Yun
2015, 26(1): 91-98. doi: 10.14042/j.cnki.32.1309.2015.01.012
Abstract:
To understand the distribution of motion scales of vortices in turbulent open channel flow along water depth. A flume experiment system based on high-resolution particle image velocimetry (PIV) was applied to measure fully developed turbulent open channel flow. Meanwhile, the distribution of motion scale of vortices in turbulent open channel flow along water depth, upwelling, sweep down flow and average swirling strength etc. were analyzed using improved power spectrum estimation. The results indicate that the motion scale of vortices in turbulent open channel flow first increases and then decreases along the water depth. The sweep down flow is more prone than upwelling along the water depth. The swirling strength of prograde vortex is larger than that of ret-rograde vortex at respective water depth. The swirling strength of near-wall region is the greatest. Vortices featured by great swirling strength and small scale occur in the near-wall region, then, the vortex scale becomes greater along the water depth, while it decreases under the inhibitory effect of sweep down flow in surface area.
Impact of Vallisneria natans on flow structure
ZHANG Yinghao, LAI Xijun
2015, 26(1): 99-106. doi: 10.14042/j.cnki.32.1309.2015.01.013
Abstract:
In order to study the impact of submerged vegetation on flow structure, flume experiments were conducted to measure the mean velocity, the Reynolds stress and the turbulence kinetic energy of flow with Vallisneria natans canopy. Influenced by Vallisneria natans canopy, a logarithmic profile is generally presented above the canopy. As a difference exists in the vertical distribution of frontal area, a region with counter velocity gradient and a local velocity maximum appear inside the canopy. The Reynolds stress reaches maximum around the top of canopy and decreases gradually in both upward and downward. Due to the existence of counter velocity gradient, negative stress and a local stress maximum are produced within the canopy. Turbulence produced by shear stress makes turbulence kinetic energy reach maximum around the top of canopy and transmits vertically towards the bed. Restricted by the limited distance of the vertical transportation of turbulence, wake production becomes the major source of turbulence, and the turbulence kinetic energy diminishes dramatically at the bottom of canopy.
Characterization of residual LNAPL and effect of LNAPL entrapment configuration on water flow in a single fracture
LU Bin, WU Shiqiang, TAN Yefei, YU Shuang'en, XIE Xinghua
2015, 26(1): 107-113. doi: 10.14042/j.cnki.32.1309.2015.01.014
Abstract:
The mechanism becomes very difficult to realize when light non-aqueous phase liquid (LNAPL) migrates with residue in the variable-aperture fracture. The immiscible liquids in the 'fracture-water-LNAPL' system can affect and interact with one another. Meanwhile, these liquids are confined and controlled by the fracture surfaces and the aperture. We performed a toulene migration experiment with the use of a transparency replica fracture with a length of 27.4 cm and a width of 20.0 cm. Some LNAPL migration images and entrapment configuration were first acquired. We then analyzed the geometric characteristics of the LNAPL entrapment configuration and clogged aperture. We also compared the water flow in the fracture before and after LNAPL entrapment through numerical modeling. Results show that free phase LNAPL invaded the fracture through a gallery with large aperture, and some isolated LNAPL blobs were entrapped at a tight aperture area. The location of the LNAPL migration and residue is closely related to the aperture, and the frequency of the clogged aperture followed a normal distribution. The range of the clogged aperture is from 0.01 mm to 1.40 mm, whereas the distribution centered at 0.20 mm to 0.30 mm. As the water flow resistance was increased in the entrapment configuration, the pressure difference between the inlet and outlet increased after the entrapment. Residual LNAPL caused water flow velocity redistribution, and changed the distribution and amount of channel flow.
A non-hydrostatic model for water waves in nearshore region
FANG Kezhao, SUN Jiawen, LIU Zhongbo, YIN Jing
2015, 26(1): 114-122. doi: 10.14042/j.cnki.32.1309.2015.01.015
Abstract:
Based on uniform grid, a depth integrated non-hydrostatic model for coastal water flow is presented. The numerical implementation of the model is split into hydrostatic step and non-hydrostatic step. In the hydrostatic step, an efficient finite volume scheme is used to solve the fully nonlinear shallow water equations, where the hydrostatic reconstruction approach and the implicit treatment of the bottom friction are used to ensure the properties of well balance, conservation and non-negative water depth, and moving shoreline is also efficiently handled. In the non-hydrostatic step, the predicted solutions from hydrostatic step are corrected by the contribution of the dynamic pressure, which is obtained by solving Possion equations using finite difference method. A simple criterion is introduced to identify breaking waves and the governing equations are then switched off to the fully nonlinear equations, which admit breaking waves as a shock. Some numerical tests are conducted for model validation.
Experimental study of rip currents by intersecting wave on barred beach
WANG Yan, ZOU Zhili
2015, 26(1): 123-129. doi: 10.14042/j.cnki.32.1309.2015.01.016
Abstract:
To better understanding the characteristics of rip current by intersecting wave, the experimental study of rip currents by intersecting wave on the barred beaches was conducted. The intersecting wave trains in the experiment were created by reflecting of obliquely incident waves on a vertical wall which stands perpendicular to the coastal line. The two intersecting waves are with the same amplitude and frequency, but opposite angle. The results of the distribution of wave heights, set-up of the mean level by wave gauges and velocity measuring by ADVs, are shown for analyzing the characteristics of rip currents on barred beaches. The influence of nodes and antinodes on the location and spacing of rip current is investigated. The effect of wave period to rip current is analyzed by the velocity distribution of rip currents of different periods on the top of sandbar.
Effect of climate warming on lake thermal and dissolved oxygen stratifications: A review
ZHANG Yunlin
2015, 26(1): 130-139. doi: 10.14042/j.cnki.32.1309.2015.01.017
Abstract:
Climate warming has many complex, profound direct and indirect effects on lake physical, chemical, biological processes, and ecosystem. Overall, the response of individual lake to climate change can be very different and shows a great regional difference. Climate warming alters lake thermal and dissolved oxygen stratifications to further affect lake biological processes, and the structure and function of lake ecosystem. This study detailedly reviews the study progresses of this field including lake warming trend, the effects of the long-term slowly rising air temperatures and the extreme heat wave on lake thermal and dissolved oxygen stratifications, and the projected climate scenarios. Many studies show the lake warming with the different slopes is recorded for the globally different regions lakes. The long-term slowly rising air temperatures and the extreme heat wave will result in the earlier onset of stratification, the late mixing and an increase in the length of the thermal stratification duration. In addition, lake warming will cause the descreases of mixing depth and thermocline depth, and the increase of lake thermal stability. Correspondingly, the diffusion depth of dissolved oxygen and oxycline depth significantly decrease, which will aggravate the hypoxic and anoxic environment of lake bottom. In addition, climate warming has some indirect effects on lake thermal and dissolved oxygen stratifications through changing the rainfall, input substances of the catchment, and wind speed. Therefore, much work is needed in many research areas including experimental data evidence, empirical and numerical model to validate and predict the potential effects of climate warming on lake thermal and dissolved oxygen stratifications.
Summary of nitrogen removal in surface runoff by bioretention system
WANG Shumin, HE Qiang, XU Qiang, SONG Li
2015, 26(1): 140-150. doi: 10.14042/j.cnki.32.1309.2015.01.018
Abstract:
Bioretention system is known to be the main technology of the management of nitrogen in urban runoff, which is effective in removing a range of pollutants, including suspended solids, heavy metals, phosphorus, oil and grease, and fecal coliform. Nitrogen removal performance, however, has been highly variable. So, a better understanding of the efficiency and process of denitrification in bioretention system is of crucial importance for the control of nonpoint source pollution in urban area. In this paper, based on data collection and analysis, advances in denitrification processes of bioretention system, including denitrification performance, influence factors and mechanism, were summarized in detail. In the end of the paper, some related advices on future research were put forward in the following aspects: To further study the processes and drivers of nitrogen removal in bioretention system; to further study the coupling response relationship among macroscopic biotope, running performance and microecosystem; and to further carry out some experiments on identifying the key characteristic of function plants with molecular biology method.