以贺江干流信都和古榄两控制性水文站长系列水文数据为基础,采用水文学方法,开展贺江河道生态流量研究。经过对不同计算方法的结果做分析比较,选择90%保证率最枯月平均值法、年内展布计算法的计算结果分别作为河道基本生态流量的生态基...以贺江干流信都和古榄两控制性水文站长系列水文数据为基础,采用水文学方法,开展贺江河道生态流量研究。经过对不同计算方法的结果做分析比较,选择90%保证率最枯月平均值法、年内展布计算法的计算结果分别作为河道基本生态流量的生态基流和全年流量,信都站和古榄站的生态基流为26.5、34.6 m 3/s,全年流量为58.8、87.0 m 3/s;采纳频率曲线法的计算结果作为河道目标生态流量,信都站和古榄站的全年流量为83.9、121.0 m 3/s。研究成果旨在为今后贺江流域管理与保护提供理论支撑,同时为完善区域水资源合理配置提供参考依据。展开更多
Effective management of a river reach requires a sound understanding of flow and sediment transport generated by varying natural and artificial runoff conditions. Flow and sediment transport within the Ning-Meng reach...Effective management of a river reach requires a sound understanding of flow and sediment transport generated by varying natural and artificial runoff conditions. Flow and sediment transport within the Ning-Meng reach of the Yellow River（NMRYR）, northern China are controlled by a complex set of factors/processes, mainly including four sets of factors：（1） aeolian sediments from deserts bordering the main stream;（2） inflow of water and sediment from numerous tributaries;（3） impoundment of water by reservoir/hydro-junction; and（4） complex diversion and return of irrigation water. In this study, the 1-D flow ＆ sediment transport model developed by the Yellow River Institute of Hydraulic Research was used to simulate the flow and sediment transport within the NMRYR from 2001 to 2012. All four sets of factors that primarily control the flow and sediment transport mentioned above were considered in this model. Compared to the measured data collected from the hydrological stations along the NMRYR, the simulated flow and sediment transport values were generally acceptable, with relative mean deviation between measured and simulated values of 〈15%. However, simulated sediment concentration and siltation values within two sub-reaches（i.e., Qingtongxia Reservoir to Bayan Gol Hydrological Station and Bayan Gol Hydrological Station to Toudaoguai Hydrological Station） for some periods exhibited relatively large errors（the relative mean deviations between measured and simulated values of 18% and 25%, respectively）. These errors are presumably related to the inability to accurately determine the quantity of aeolian sediment influx to the river reach and the inflow of water from the ten ephemeral tributaries. This study may provide some valuable insights into the numerical simulations of flow and sediment transport in large watersheds and also provide a useful model for the effective management of the NMRYR.展开更多
This study considered whether the narrowing of the upper （broad and wandering） reaches of the Lower Yellow River could result in a reduction in sedimentation and even an increase in channel erosion in both the upper...This study considered whether the narrowing of the upper （broad and wandering） reaches of the Lower Yellow River could result in a reduction in sedimentation and even an increase in channel erosion in both the upper and the lower （narrow and meandering） reaches. Analysis of field data and numerical modeling results both justify the proposal to narrow the channel. A positive correlation was found between channel eroded-area and the channel width. Therefore narrowing under conditions of low flow will reduce the amount of erosion in the reach, which, in turn, will reduce the amount of sediment transported into the lower channel. This will reduce the amount of siltation in the lower reaches of the river. However, narrowing under conditions of high flow with a low concentration of sediment will reduce both the extent of flood attenuation along the narrowed channel and the amount of lateral channel bank collapse, which results in increased flows and less sedimentation in the lower channel, leading to increased erosion. When flows with a high concentration of sediment are released from the Xiaolangdi Reservoir, both the lower narrow channel and the upper channel can transport a large amount of the sediment load. It is concluded that the narrowing of the upper broad channel will result in a reduction in sedimentation, or even in channel erosion, in both the upper and the lower channels if the reservoir is operated such that the volume of sediment added during low flows is balanced by the volume eroded during high flows with a low concentration of sediment.展开更多
文摘以贺江干流信都和古榄两控制性水文站长系列水文数据为基础,采用水文学方法,开展贺江河道生态流量研究。经过对不同计算方法的结果做分析比较,选择90%保证率最枯月平均值法、年内展布计算法的计算结果分别作为河道基本生态流量的生态基流和全年流量,信都站和古榄站的生态基流为26.5、34.6 m 3/s,全年流量为58.8、87.0 m 3/s;采纳频率曲线法的计算结果作为河道目标生态流量,信都站和古榄站的全年流量为83.9、121.0 m 3/s。研究成果旨在为今后贺江流域管理与保护提供理论支撑,同时为完善区域水资源合理配置提供参考依据。
基金financially supported by the National Natural Science Foundation of China(51579113,51309111,51309113)
文摘Effective management of a river reach requires a sound understanding of flow and sediment transport generated by varying natural and artificial runoff conditions. Flow and sediment transport within the Ning-Meng reach of the Yellow River（NMRYR）, northern China are controlled by a complex set of factors/processes, mainly including four sets of factors：（1） aeolian sediments from deserts bordering the main stream;（2） inflow of water and sediment from numerous tributaries;（3） impoundment of water by reservoir/hydro-junction; and（4） complex diversion and return of irrigation water. In this study, the 1-D flow ＆ sediment transport model developed by the Yellow River Institute of Hydraulic Research was used to simulate the flow and sediment transport within the NMRYR from 2001 to 2012. All four sets of factors that primarily control the flow and sediment transport mentioned above were considered in this model. Compared to the measured data collected from the hydrological stations along the NMRYR, the simulated flow and sediment transport values were generally acceptable, with relative mean deviation between measured and simulated values of 〈15%. However, simulated sediment concentration and siltation values within two sub-reaches（i.e., Qingtongxia Reservoir to Bayan Gol Hydrological Station and Bayan Gol Hydrological Station to Toudaoguai Hydrological Station） for some periods exhibited relatively large errors（the relative mean deviations between measured and simulated values of 18% and 25%, respectively）. These errors are presumably related to the inability to accurately determine the quantity of aeolian sediment influx to the river reach and the inflow of water from the ten ephemeral tributaries. This study may provide some valuable insights into the numerical simulations of flow and sediment transport in large watersheds and also provide a useful model for the effective management of the NMRYR.
文摘This study considered whether the narrowing of the upper （broad and wandering） reaches of the Lower Yellow River could result in a reduction in sedimentation and even an increase in channel erosion in both the upper and the lower （narrow and meandering） reaches. Analysis of field data and numerical modeling results both justify the proposal to narrow the channel. A positive correlation was found between channel eroded-area and the channel width. Therefore narrowing under conditions of low flow will reduce the amount of erosion in the reach, which, in turn, will reduce the amount of sediment transported into the lower channel. This will reduce the amount of siltation in the lower reaches of the river. However, narrowing under conditions of high flow with a low concentration of sediment will reduce both the extent of flood attenuation along the narrowed channel and the amount of lateral channel bank collapse, which results in increased flows and less sedimentation in the lower channel, leading to increased erosion. When flows with a high concentration of sediment are released from the Xiaolangdi Reservoir, both the lower narrow channel and the upper channel can transport a large amount of the sediment load. It is concluded that the narrowing of the upper broad channel will result in a reduction in sedimentation, or even in channel erosion, in both the upper and the lower channels if the reservoir is operated such that the volume of sediment added during low flows is balanced by the volume eroded during high flows with a low concentration of sediment.
