当代珠江三角洲网河同步水沙时空变化特征
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摘要
珠江三角洲网河水沙形式复杂,河口的同步水沙分配特征对研究河口水沙输运以及泄洪排放路径的理解至关重要。分别于2016年12月枯季大小潮与2017年7月洪季大小潮,通过4个航次对珠江三角洲16个站位进行了同步水文观测。观测结果显示,洪枯季西江都为珠江三角洲水沙的主要来源,网河区流量输送存在3条通道,最终经由磨刀门(枯季26%,洪季33%)、洪奇沥(枯季18%,洪季20%)、虎门(枯季20%,洪季16%)三口门入海,三口门枯季总流量占八大口门的64%,洪季占69%。泥沙输运存在2条主要通道,最终经由磨刀门(枯季34%,洪季43%)与洪奇沥(枯季16%,洪季26%)入海,两口门枯、洪季泥沙量约占八大口门的50%、69%。16站位流量与输沙率季节性差异显著,网河区流量季节性差异北江大于西江大于东江,八大口门季节性差异由中间口门向两侧口门递减;网河区输沙率季节性差异西江大于东江大于北江,八大口门季节性差异也由中间口门向两侧口门递减,含沙量的季节变化与输沙率相似,受潮流作用影响,洪枯季大潮含沙量一般大于小潮含沙量。
The water and sediment movement in the Pearl River Delta is rather complicated.The simultaneous distribution of water and sediment in the estuary is essential for study of water and sediment budget.Synchronous hydrological observation was carried out by the authors at 16 stations for 4 voyages in the Pearl River Delta in December 2016(dry season)and July 2017(flood season).Our results show that the Xijiang River is the major source of both water and sediment of the Pearl River Delta.There are three channels flowing through the Modao estuary(26%in dry season,33%in flood season),the Hu estuary(20%in dry season,18%in flood season),and the Hongqili estuary(16%in dry season,21%in dry season)respectively into the ocean.The total flow charge of the three estuaries reaches 69%in flood season and 65%in dry season.There are two major channels for sediment transportation:the Modao estuary(34%in dry season,43%in wet season),and the Hongqili estuary(16%in dry season,26%in wet season).The total sediment discharge of the three estuaries occupies 50%in flood season and 69%in dry season respectively.The seasonal difference in flow and sediment charge is rather significant in a decreasing order of the Beijiang,Xijiang and Dongjiang,and decreases from the middle of estuary to the sides.Seasonal variation in sediment concentration is similar to the sediment transport rate.Sediment concentration is tide dependant.It is higher in spring tide,but lower in neap tide.
The water and sediment movement in the Pearl River Delta is rather complicated.The simultaneous distribution of water and sediment in the estuary is essential for study of water and sediment budget.Synchronous hydrological observation was carried out by the authors at 16 stations for 4 voyages in the Pearl River Delta in December 2016(dry season)and July 2017(flood season).Our results show that the Xijiang River is the major source of both water and sediment of the Pearl River Delta.There are three channels flowing through the Modao estuary(26%in dry season,33%in flood season),the Hu estuary(20%in dry season,18%in flood season),and the Hongqili estuary(16%in dry season,21%in dry season)respectively into the ocean.The total flow charge of the three estuaries reaches 69%in flood season and 65%in dry season.There are two major channels for sediment transportation:the Modao estuary(34%in dry season,43%in wet season),and the Hongqili estuary(16%in dry season,26%in wet season).The total sediment discharge of the three estuaries occupies 50%in flood season and 69%in dry season respectively.The seasonal difference in flow and sediment charge is rather significant in a decreasing order of the Beijiang,Xijiang and Dongjiang,and decreases from the middle of estuary to the sides.Seasonal variation in sediment concentration is similar to the sediment transport rate.Sediment concentration is tide dependant.It is higher in spring tide,but lower in neap tide.
引文
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[15]陈晓宏,陈永勤.珠江三角洲网河区水文与地貌特征变异及其成因[J].地理学报,2012,57(4):429-436.
[2]倪培桐,闻平,刘剑宇.珠江三角洲水沙年际变化趋势分析[J].人民珠江,2016,37(1):19-24.
[3] S.B.Dai a,S.L.Yang,A.M.Cai.Impacts of dams on the sediment flux of the Pearl River,southern China[J].Catena,2008,76(1):36-43.
[4] Chuang Shou Wu,Shilun Yang,Shichang Huang,et al.Delta changes in the Pearl River estuary and its response to human activities(1954—2008)[J].Quaternary International,2016(392):147-154.
[5]杜文印.珠江三角洲近30年水沙分配变化分析[J].广东水利水电,2012(6):5-9.
[6]胡嘉镗,李适宇.珠江三角洲河网与河口夏季水沙通量的模拟[J].水利学报,2009,40(11):1290-1298.
[7]范中亚,林澍,曾凡棠,等.珠江口门枯季动力过程及盐度分布特征[J].热带地理,2013,33(4):400-406.
[8]杨清书,罗章仁,沈焕庭,等.珠江三角洲网河区顶点分水分沙变化及神经网络模型预测[J].水利学报,2003(6):56-60.
[9]姚章民,王永勇,李爱鸣.珠江三角洲主要河道水量分配比变化初步分析[J].人民珠江,2009(2):43-45.
[10]杨明远,严以新,孔俊,等.珠江口水流泥沙运动模拟研究[M].北京:海军出版社,2008.
[11]黄镇国,张伟强.珠江三角洲近期水沙分配的变化及其影响与对策[J].云南地理环境研究,2006,18(2):21-27.
[12]陈小红.珠江三角洲干流汊道泥沙分配及变化—以西、北江三角洲为例[J].热带地理,2000,20(1):22-26.
[13]莫思平.广州港深水出海航道伶仃航段回淤规律分析[J].水利水运工程学报.2008(1):42-46.
[14]邓智瑞,何青,杨清书,等.珠江口磨刀门泥沙絮凝特征[J].海洋学报.2015,37(9):152-160.
[15]陈晓宏,陈永勤.珠江三角洲网河区水文与地貌特征变异及其成因[J].地理学报,2012,57(4):429-436.