The Sanxia Reservoir on the Changjiang River stored water from 1 to 10 June and from 25 October to 5 November in 2003, elevating the water level to 135 and 139 m above mean sea level at the dam, respectively. A monthl...The Sanxia Reservoir on the Changjiang River stored water from 1 to 10 June and from 25 October to 5 November in 2003, elevating the water level to 135 and 139 m above mean sea level at the dam, respectively. A monthly dataset of water discharge, suspended sediment concentration （SSC） and sediment load of the Changjiang River from 1953 to 2003 measured at the Datong Hydrological Gauging Station of the downstreammost Changjiang River was mainly used to examine the Changjiang River sediment delivering into the sea in 2003 in response to the Sanxia Reservoir water storages in the same year. The results show that （1） compared with those in 2002, 2001, and the multi-yearly （1953-2000） average, both annual SSC and sediment load at Datong in 2003 were markedly reduced, and they were even smaller than the multi-yearly （1953-2000） minimum, although the annual runoff in 2003 did not change largely; and （2） compared with those in the corresponding months in 2002, 2001 and the multi-monthly average from 1953 to 2000, monthly SSC and sediment load at Datong both in June and November of 2003 were also markedly reduced, and those in June 2003 were even smaller than the multi-monthly minimum from 1953 to 2000. These may indicate that sediment sedimentation in the Sanxia Reservoir resulting from the Sanxia Reservoir water storage should be the main cause of the decreased annual and monthly SSC and sediment load of the Changjiang River into the sea in 2003. Besides, it seems that the Sanxia Reservoir water storage in the early June （flood season） of 2003 had more impacts on the decreased monthly SSC into the sea than that in the late October and early November （approximately non-flood season） of 2003.展开更多
2022年汛期长江流域发生了历史罕见的流域性干旱,大通站9—10月份流量在11000 m 3/s上下浮动。9月份开始,叠加台风的影响,长江口遭遇了严重的盐水入侵事件,威胁上海市供水安全。结合实测流量、风速和盐度数据分析,认为此次盐水入侵由低...2022年汛期长江流域发生了历史罕见的流域性干旱,大通站9—10月份流量在11000 m 3/s上下浮动。9月份开始,叠加台风的影响,长江口遭遇了严重的盐水入侵事件,威胁上海市供水安全。结合实测流量、风速和盐度数据分析,认为此次盐水入侵由低流量和台风导致;基于此,采用三维河口海岸数值模型定量分析三峡水库应急补水的压咸效果。结果表明,应急补水削弱了长江口的盐水入侵,减小了咸潮上溯距离,南支—北港纵断面0.45 psu等盐度线下移了17 km,降低了水库取水口盐度,为青草沙水库争取了约6 h的取水窗口。10月份2次寒潮在一定程度上削弱了此次补水效果,为确保补水效果需加强河口地区水文、潮汐及气象综合监测能力,以保障上海市淡水利用安全。展开更多
文摘The Sanxia Reservoir on the Changjiang River stored water from 1 to 10 June and from 25 October to 5 November in 2003, elevating the water level to 135 and 139 m above mean sea level at the dam, respectively. A monthly dataset of water discharge, suspended sediment concentration （SSC） and sediment load of the Changjiang River from 1953 to 2003 measured at the Datong Hydrological Gauging Station of the downstreammost Changjiang River was mainly used to examine the Changjiang River sediment delivering into the sea in 2003 in response to the Sanxia Reservoir water storages in the same year. The results show that （1） compared with those in 2002, 2001, and the multi-yearly （1953-2000） average, both annual SSC and sediment load at Datong in 2003 were markedly reduced, and they were even smaller than the multi-yearly （1953-2000） minimum, although the annual runoff in 2003 did not change largely; and （2） compared with those in the corresponding months in 2002, 2001 and the multi-monthly average from 1953 to 2000, monthly SSC and sediment load at Datong both in June and November of 2003 were also markedly reduced, and those in June 2003 were even smaller than the multi-monthly minimum from 1953 to 2000. These may indicate that sediment sedimentation in the Sanxia Reservoir resulting from the Sanxia Reservoir water storage should be the main cause of the decreased annual and monthly SSC and sediment load of the Changjiang River into the sea in 2003. Besides, it seems that the Sanxia Reservoir water storage in the early June （flood season） of 2003 had more impacts on the decreased monthly SSC into the sea than that in the late October and early November （approximately non-flood season） of 2003.
