鄱阳湖流域抚河径流特征及变化趋势分析

抚河是鄱阳湖流域第二大河流,其径流变化研究对揭示鄱阳湖水文情势演变规律和鄱阳湖生态环境保护具有重要的科学意义。本文采用鄱阳湖流域抚河上、中、下游8个主要水文站的实测资料,分析了抚河径流年内分配特征及变化规律;应用Mann-Kendall非参数检验与回归分析等方法,研究了近几十年内抚河年、月径流变化规律及与降雨的关系。结果表明:(1)抚河径流年内分配不均,但不均匀性在流域内空间差异较小;(2)受水利工程调蓄影响,径流年内分配越来越均匀;(3)不同年代年径流特性存在差异,20世纪70年代至90年代初,径流相对稳定,90年代中期到2002年,呈较明显上升趋势,2002年后,表现为下降趋势;(4)月径流变化有增有减,基本规律为枯水期(11月~次年3月)月径流量基本呈上升趋势,洪水期(4~6月)月径流基本呈下降趋势;(5)抚河的年降水量在2002年附近发生突变减少,与年径流量突变时间基本吻合,说明气候变化降雨量减少对近10年鄱阳湖流域抚河入湖径流的减少影响显著。

Characteristics and Variation Tendency of Runoff in Fuhe River of Poyang Lake Basin

The Fuhe River is the second largest river in Poyang Lake Basin.Study on variation tendency of runoff in the Fuhe River plays an important role in revealing the hydrological regime evolution law and eco-environment protection in the Poyang Lake.Based on the observed data from the 8 stations on the Fuhe River,the annual runoff distributing characteristics and variation characteristics was analyzed,and a non-parametric statistical(Mann—Kendall trend test) and regression analysis methods were employed to detect the trend of the runoff and relationship with rainfall in the Fuhe River Basin during the recent decades.The research results show that:(1) The annual runoff distribution is uneven,but there is no obvious difference in space;(2) In the regulation effect of water structures,the annual runoff distribution is more and more uniform;(3) There exists difference of the annual runoff characteristics in various decades,the runoff was stable from 1970s to early 1990s,there was an obvious upward trend from middle 1990s to 2002,and there was a downward trend from 2003 to 2009;(4) The monthly runoff change demonstrates increasing or decreasing,with increasing trend in dry period(from November to March of following year),and decreasing in flood season(from April to June);(5) Mutation decrease of annual precipitation in the Fuhe River Basin occurred near 2002,and its mutation time basically coincide with that time of the annual runoff,which indicates that rainfall decrease has a major influence on runoff reduction in the Fuhe River of the Poyang Lake Basin in the past 10 years.