关键词：
Water storage capacity;Dongting Lake;Hydrodynamic modeling;Multiple linear regression;Remote sensing
摘要：
Study region: Dongting Lake, China Study focus Water storage capacity (WSC) of a large lake system plays a crucial role in flood control decisionmaking during the flood season. Dongting Lake, located downstream of Three Gorges Dam, has a significant influence over flood control in the middle and lower reaches of the Yangtze River (MLYR). To have a better WSC estimation of Dongting Lake, a multiple linear regression model was developed based on hydrodynamic simulation data of the typical flood processes in the past 3 decades. New hydrological insights for the region The multiple linear regression (MLR) model is developed by integrating of hydrodynamic simulation. Also, the effect of the water level (WL) at Chenglingji station and the WL difference in the lake (Yangliutan-Chenglingji) were investigated. The model can accurately estimate the WSC of Dongting Lake with an R2 of 0.984. The observation indicates that the WL difference within the lake has a great influence on the WSC and the flood regulation capacity ability with the same WL at Chenglingji station. The results of the study can provide a real-time estimation of the WSC of Dongting Lake which can provide useful information for flood control management.
关键词：
Hemispherical bed surface;Observed particle;Interference particle;Dispersive pressure;Incipient velocity
摘要：
The sediment particles play a huge role in shaping the bed load transport. In this research, 240 watertunnel experiments are carried out to investigate the incipient velocity of the observation particles in two particle arrangements. To accurately predict the incipient velocity of the observation particles, the equation is conceived by the rolling instability mechanism. The incipient velocity equations and experimental data are used to analyze the trend of dispersive pressure and the effect of arrangement position on velocity. We find that it is appropriate to choose the coefficient of drag as 0.261 and the coefficient of lift as 0.198 for the incipient velocity equation of spherical particles on the hemispherical bed surface. Furthermore, the dispersive pressure is closely related to the flow state, particle size, and particle arrangement, which leads to the incipient velocity of the observation particle being at a minimum when the interference particle angle is 45 degrees. Finally, the particle spacing and the projected area changed with the arrangements, directly affecting the incipient velocity of the observed particle. The analysis of four aspects for the coefficients, dispersive pressure, different particle spacing, and projected area will facilitate the prediction of particle incipient velocity, especially on hemispherical beds. (c) 2023 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.
通讯机构：
[Chen, J ] C;Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Changsha 410114, Peoples R China.;Key Lab Dongting Lake Aquat Ecoenvironm Control &, Changsha 410114, Peoples R China.;Key Lab Water Sediment Sci & Water Disaster Preven, Changsha 410114, Peoples R China.
关键词：
reef islands;coral sand beach;equilibrium beach profile;coral sand bar
摘要：
This study utilized 50 laboratory experiments to document the evolution of coral beaches under varying regular wave conditions, including five distinct wave periods and ten wave heights. Both the type of equilibrium beach and the shape of sand bars were used to represent beach evolution. The evolution of coral sand beaches was then compared to quartz sand beaches. The experimental results show that the predicted (modeled) equilibrium profile of a quartz sand beach was not applicable to coral sand beaches. Compared to sand bars on quartz sand beaches, the distance from bar crests to the beach berm in coral sand beaches was greater, whereas the erosional depth of sand troughs was deeper. However, the grain size distribution of sand associated with the coral sand beach under wave action was consistent with Celikoglu’s law. Both an equilibrium beach profile classification model and a sand bar shape prediction model for coral sand beaches were developed based on the experimental data.
摘要：
基于气液两相流模型建立二维数值风浪水槽，采用VOF（Volume of Fluid）模型捕捉自由液面，研究了风作用下规则波在岸礁地形上的水动力特性。将计算结果与实验数据对比，证明了该模型计算风作用下波浪传播的准确性，并进一步分析了不同风速对规则波在岸礁地形上水动力特性影响。结果表明：有风作用时，破碎区的波峰高于无风作用时，冲泻区的波峰低于无风作用时，在风速0～8 m/s范围内，风的作用不会改变波浪在岸礁地形上的破碎类型，但会导致波浪提前破碎并影响破碎波形态变化过程。风的作用会改变波浪在岸礁地形上传播时各断面水平时均流速沿水深分布结构，并且会导致水气交界面附近水质点的速度增大，影响范围随着风速的增大而增大。
作者机构：
[Yao, Zhen; Bian, Cheng; Jiang, Changbo; Wu, Zhiyuan; Chen, Jie; Liu, Jiaxiang] Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Changsha 410114, Peoples R China.;[Jiang, Changbo; Wu, Zhiyuan; Chen, Jie] Key Lab Dongting Lake Aquat Ecoenvironm Control &, Changsha 410114, Peoples R China.;[Jiang, Changbo; Wu, Zhiyuan; Chen, Jie] Key Lab Water Sediment Sci & Water Disaster Preven, Changsha 410114, Peoples R China.
通讯机构：
[Jie Chen] S;School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha, 410114, China<&wdkj&>Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, 410114, China<&wdkj&>Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha, 410114, China
关键词：
Coral sediment;Oscillatory flow;Threshold of motion;Shields parameters;Critical near-bottom peak velocity
摘要：
In this study, the incipient motion thresholds of coral sediment with the action of oscillatory currents were experimentally recorded by conducting a total of 405 laboratory experiments, including an analysis of nine sieve median diameters, five water depths, and four wave periods. The coral sediment Shields parameters for oscillatory flow were compared to those for unidirectional flow and to those of shell Shields parameters for oscillatory flow. The results showed that there was an extensive scatter range in the Shields parameter for oscillatory flow of coral sediments. Additionally, the coral sediment Shields parameter for oscillatory flow was slightly different from that for unidirectional flow. The use of the Shields curve form to represent the coral sediment threshold for oscillatory flow was not appropriate. Using the critical near-bottom peak velocity to represent the incipient motion threshold of coral sediment for oscillatory flow was a better option. The use of experimental particle data analyses and the equation for the critical near-bottom peak velocity of quartz sand for oscillatory flow was modified to obtain a critical near-bottom peak velocity equation for coral sediment. This equation adds the influence of shape through the median Corey shape factor.
作者机构：
[Tao, He; Xie, Yanwu; Jiang, Changbo; Deng, Bin] Changsha Univ Sci & Technol, Sch Hydraul Engn, Changsha 410114, Peoples R China.;[Tang, Hansong] CUNY City Coll, Civil Engn Dept, Unitetd Sates, New York, NY 10031 USA.;[Jiang, Changbo; Deng, Bin] Key Lab Water Sediment Sci & Water Disaster Preven, Changsha 410114, Peoples R China.
通讯机构：
[Hansong Tang] C;Civil Engineering Department, City College of New York, New York, 10031, NY, Unitetd Sates
关键词：
Solitary wave;Sandy beach;Breakwater;Spill hole;Deposition and erosion;Scour
摘要：
This paper presents a numerical study on erosion and deposition of a sandy beach installed with a breakwater bearing spill holes, aiming to understand its performance in erosion reduction. The two-dimensional (2D) governing equations for the water-sand mixture are solved by the VOF method and other techniques. The numerical approaches are validated against experimental data for wave propagation on an impermeable beach with a breakwater, scour underneath a pipeline, scour in front of a breakwater, and erosion and deposition of a sandy beach. On these bases, numerical simulations are made for three scenarios: a sandy beach, a sandy beach with a breakwater, and a sandy beach with a breakwater with spill holes. Then, the study proceeds to a detailed investigation of the third scenario with different breakwater locations, spill hole sizes, water depths, and wave heights. The results indicate that the breakwater indeed reduces beach erosion, and the breakwater location and wave height have a pronounced influence on the erosion. The breakwater's performance in reducing beach erosion achieves a maximum at a specific size of the hole opening. It is anticipated that the understanding revealed in this study sheds light on the design and application of breakwaters.
通讯机构：
[Long, YN ] C;Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Changsha 410114, Peoples R China.;Key Lab Dongting Lake Aquat Ecoenvironm Control &, Changsha 410114, Peoples R China.;Key Lab Water Sediment Sci & Water Disaster Preven, Changsha 410114, Peoples R China.
关键词：
water level;discharge;Dongting Lake;water surface slope
摘要：
Abstract: The hydrological characteristics of the river–lake connecting section are determined by their interaction and studying them can help to understand the changing relationship between these two water bodies over time. The Lujiao–Luosan section is the connecting section of Dongting Lake and the Yangtze River, and the hydrological data for this section over the past 70 years has been analyzed. It has been found that the lowest water level is consistently rising at the same discharge at Chenglingji station, which is the joint point of Dongting Lake and the Yangtze River. While this could alleviate the drought situation in the Dongting Lake area during dry seasons, it could pose a more significant flood-control challenge during high water levels in the flood season. The water surface slope shows a decreasing trend especially during the dry season, except for the high flood period (July–September), which indicates that the water slope in the connecting section of Dongting Lake has become flatter. The backwater effect of the Yangtze River on Dongting Lake becomes increasingly stronger as the water surface slope difference between the Chenglingji–Luoshan section and the Lujiao–Chenglingji section changes from negative to positive between January and April. Keywords: water level; discharge; Dongting Lake; water surface slope
通讯机构：
[Long, YN ] ;Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Changsha 410114, Peoples R China.
关键词：
Dongting Lake Basin;Data -scarce area;Coupled hydrological and hydrodynamic;models;Streamflow simulation;Lake water balance
摘要：
Study region: The Dongting Lake Basin is a typical regional study in humid southern China with data-scarce areas. Study focus: This study improved the streamflow simulation by coupling hydrological and hydrodynamic models and considering water yields in data-scarce areas. We constructed a soil and water assessment tool (SWAT) hydrological model of the Dongting Lake Basin to simulate the streamflow in the data-scarce areas, which was further coupled into the MIKE21 hydrodynamic model as additional boundary conditions. New hydrological insights: The results showed that the relative error of streamflow simulation was reduced from 24.64 % to 10.50 % in the coupled hydrological-hydraulic model over the singular hydrodynamic model, which also indirectly verified the results of streamflow simulation in the data-scarce area. Based on the coupled model, the annual water yields in the data-scarce areas were estimated to be 38.95 x 109 m3, representing 15.13 % of the yearly water yields in the basin. The water yields in the data-scarce areas showed a seasonal variation, which was concentrated from April to July. The monthly water balance error of the Dongting Lake Basin was significantly reduced (57.42 %) when considering the water yields in data-scarce areas. The model-coupling approach in this study can be applied to other data-scarce areas to improve streamflow simulation.
作者机构：
[Yao, Zhen; Bian, Cheng; Jiang, Changbo; Wu, Zhiyuan; Chen, Jie] Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Changsha 410114, Peoples R China.;[Jiang, Changbo; Wu, Zhiyuan; Chen, Jie] Key Lab Dongting Lake Aquat Ecoenvironm Control &, Changsha 410114, Peoples R China.;[Jiang, Changbo; Wu, Zhiyuan; Chen, Jie] Key Lab Water Sediment Sci & Water Disaster Preven, Changsha 410114, Peoples R China.
通讯机构：
[Jie Chen; Jie Chen Jie Chen Jie Chen] S;School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha, 410114 China<&wdkj&>Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, 410114 China<&wdkj&>Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha, 410114 China
关键词：
Coral reef sediment;incipient mean velocity;median shape factor;Shields curve band;threshold of motion
摘要：
Abstract This study experimentally documented the thresholds of critical motion for tropical shallow marine carbonate sediments by conducting a total of 225 laboratory experiments that included the analysis of nine median sediment diameters and five water depths. A shape factor, Sf, which quantifies the shape of a single particle, was evaluated during the investigation. Both the critical Shields parameter and the incipient mean velocity were used to represent the critical thresholds of motion. The thresholds of motion for coral reef sediment were then compared with the results from quartz sand. The experimental results show that the critical threshold of motion is smaller for coral reef sediment than for quartz sand of the same median sieve diameter due to differences in particle shape in spite of the coral reef sediment being of higher density. For diameters higher than 1.425 mm, the critical Shields parameters and incipient mean velocities tend to have similar values to quartz sand. The differences between the two increased significantly for median sieve diameters <1.075 mm. Based on the experimental data, Shields curve bands and equations for the incipient mean velocity for sediments of differing shape factors were obtained for tropical shallow marine carbonate sediments as well as marine carbonate grains.
作者机构：
[Jiang, Changbo; Ma, Yuan; Jiang, CB; Li, Shanshan; Li, Chuannan] Changsha Univ Sci & Technol, Sch Hydraul Engn, Changsha 410114, Peoples R China.;[Li, Shanshan] Hunan City Univ, Coll Civil Engn, Yiyang 413002, Peoples R China.;[Jiang, Changbo; Ma, Yuan; Jiang, CB; Li, Chuannan] Key Lab Dongting Lake Aquat Ecoenvironm Control &, Changsha 410114, Peoples R China.
通讯机构：
[Jiang, CB ] C;Changsha Univ Sci & Technol, Sch Hydraul Engn, Changsha 410114, Peoples R China.;Key Lab Dongting Lake Aquat Ecoenvironm Control &, Changsha 410114, Peoples R China.
关键词：
spatiotemporal trend;hydroclimatic variables;the Dongting Lake basin
摘要：
The Dongting Lake basin, located in the middle Yangtze River region, has long been under the threat of climate change. However, there has been a lack of comprehensive analysis and research on the long-term trends and interactions among hydrometeorological factors within the region. To address this gap, this study collected data from 31 meteorological stations in the region and employed statistical analysis methods, including the non-parametric Mann-Kendall test, Sen's slope test, and cross-wavelet analysis. The results revealed significant increases in temperatures, especially in the spring season, while summer, winter, and annual rainfall also exhibited a significant increase. However, spring and autumn rainfall showed a non-significant decrease, and there was a clear decreasing trend in annual streamflow. Interestingly, evaporation demonstrated a significant increasing trend. The annual average temperature and annual runoff exhibited approximately negative correlations in the 6-10-year resonance period and positive correlations in the 4-6-year resonance period. There are significant positive resonance periods in the relationship between annual precipitation and annual runoff within the range of 0-12 years, indicating that precipitation has a substantial impact and serves as the primary source of runoff. Furthermore, there was a transition between "abundance" and "dry" periods in the annual runoff around 4 a, occurring before and after 1973 and 2005. The change points in annual precipitation and runoff were identified as 1993 and 1983.
