赣江流域水沙变化特征分析

发布时间：2018-08-30 14:47

【摘要】：赣江是鄱阳湖最大水系,流域面积约占鄱阳湖流域面积50%。近60年来,赣江流域实施了诸多植树造林、水土流失治理项目,为保护流域生态环境提供了坚实保障,另一方面,为满足农业、工业和城市用水需求,在赣江干支流兴建了许多水利工程。这些强烈人类活动给赣江水沙带来新的变化。本文基于赣江上游4站(干流贡水峡山站、支流章江坝上站、桃江居龙滩站、平水翰林桥站)、中游吉安站、下游外洲站近60年的流量、含沙量实测资料,采用水文过程线、流量历时曲线、水沙双累积曲线以及Mann-Kendall检验、Sen坡度估计、Pettitt突变检测等方法,系统分析了上中下游水沙变化特征,结合流域15个气象站的降雨资料粗略探讨了影响水沙变化的主要因素。结果表明:(1)赣江上游各支流和赣江干流水沙年内分配极不均匀,呈现前凸后凹、以6月为峰值的单峰型,主汛期4~6月径流量约占全年的49%,主汛期4~6月输沙量约占全年的65%;(2)近60年赣江各站径流均表现为丰枯交替的波动变化,各站年径流变化趋势微小,不存在显著突变点,上游4站、吉安站、外洲站年径流的Sen斜率估计值为0.73×108m3、0.67×108m3、0.73×108m3,仅占多年平均年径流的0.26%、0.14%、0.10%;(3)近60年赣江各站输沙量年际变化大,变差系数0.46~0.62,1990s之后输沙量锐减;上游4站、吉安站、外洲站年输沙序列的突变点(Pettitt方法)分别在1998年、1990年、1990年,泥沙相对变化幅度为47%、67%、62%;(4)近60年输沙量呈现显著变化的直接原因是高流量成分(相对历时小于5%的流量值)的减少和日均含沙量的锐减,其中含沙量是输沙量变化的主要因素;(5)近60年赣江流域降水变化与外洲站径流变化特征较一致,降水对径流起到了增加的效应,人类活动总体起辅助作用;水土保持综合治理、水利工程均极大的减少了赣江河道输沙量。在变化环境下,近20年赣江水沙演变规律与1990s之前已有显著差异。一方面水土流失治理、植树造林等减少了坡地土壤侵蚀和流失,另一方面水利工程尤其是大型水利工程建设与运行极大的影响了坝下游河道泥沙输移,这种工程措施对河流水沙的影响是及时和快速的。总体上赣江各站年径流量并没有显著的趋势和突变性,而年输沙量已经出现大幅度锐减,导致近20年径流-输沙量的关系偏离了1990s之前的水沙关系。本文研究结论可以为流域管理、生态环境研究提供参考。
[Abstract]:Ganjiang River is the largest water system in Poyang Lake. In the past 60 years, many afforestation and soil erosion control projects have been implemented in the Ganjiang River basin, which have provided a solid guarantee for the protection of the ecological environment of the basin, and on the other hand, to meet the water needs of agriculture, industry and cities, Many water conservancy projects have been built in the main tributaries of the Ganjiang River. These strong human activities have brought new changes to the water and sediment of the Ganjiang River. Based on the measured data of discharge and sediment content in the upper reaches of Ganjiang River (Gongshuixiashan Station, Zhangjiang River, Taojiang Julongtan Station, Hanlin Bridge Station in Pingshui), Ji'an Station in the middle reaches and Waizhou Station in the lower reaches, the hydrological process line is used in this paper. The characteristics of water and sediment variation in upper middle and lower reaches are systematically analyzed by means of flow duration curve, double accumulation curve of water and sediment, and Pettitt mutation detection method of Mann-Kendall test Sen slope estimation. Based on the rainfall data of 15 meteorological stations in the basin, the main factors affecting the change of water and sediment are discussed. The results are as follows: (1) the distribution of water and sand in the upper reaches of Ganjiang River and the main stream of Ganjiang River is extremely uneven in the year, and the distribution of water and sand is extremely uneven, with the peak value of June being a single peak. The runoff in the main flood season from April to June accounts for about 49 percent of the whole year, and the sediment discharge from April to June in the main flood season accounts for about 65 percent of the whole year. (2) in the last 60 years, the runoff of every station in the Ganjiang River is fluctuating alternately, the change trend of the annual runoff of each station is small, there is no significant abrupt point, and the upper four stations are upstream. The Sen slope of annual runoff at Ji'an Station and Wai Zhou Station is estimated to be 0.73 脳 10 ~ 8m ~ 3 / 0.67 脳 10 ~ 8m ~ 3 / 0.73 脳 10 ~ 8m ~ 3, which accounts for only 0.26 ~ 0.14 ~ 0.14 ~ 0.10m ~ 3 of the annual average annual runoff. (3) the annual variation of sediment transport capacity of Ganjiang station in the last 60 years has changed greatly and the coefficient of variation has decreased sharply after 0.46 ~ 0.62C ~ (2) 1990s; the upstream station, Ji'an Station, The abrupt point (Pettitt method) of the annual sediment transport sequence at Wai Chau Station was used in 1998, 1990, 1990, respectively. The relative variation of sediment is 47 / 67 / 62. (4) the direct reason for the significant change in sediment discharge in the last 60 years is the decrease of high discharge components (discharge value of less than 5% relative duration) and the sharp decrease of daily sediment content. Among them, sediment content is the main factor of sediment transport. (5) the variation of precipitation in Ganjiang River basin is consistent with that of runoff in outer continent station in the past 60 years, precipitation plays an increasing role in runoff, human activities generally play an auxiliary role, comprehensive control of soil and water conservation, water and soil conservation, Water conservancy projects have greatly reduced the amount of sediment transport along the Ganjiang River. In the changing environment, the evolution of water and sediment in the Ganjiang River in the past 20 years has been significantly different from that before 1990's. On the one hand, soil erosion and loss are reduced by soil erosion control, afforestation and so on. On the other hand, the construction and operation of water conservancy projects, especially large scale water conservancy projects, greatly affect the sediment transport in the lower reaches of the dam. The effect of such engineering measures on river water and sediment is timely and rapid. On the whole, there is no obvious trend and abrupt change in the annual runoff of every station in Ganjiang River, and the annual sediment discharge has been greatly reduced, which leads to the deviation of the relationship between runoff and sediment discharge in the last 20 years, which deviates from the relationship between water and sediment before 1990's. The conclusion of this paper can provide reference for watershed management and ecological environment research.
【学位授予单位】：江西师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P333

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