西辽河源头流域径流变化趋势及影响因素分析

利用1977—2008年老哈河流域与沙拉沐沦河流域水文数据,采用Mann-Kendall检验法、有序聚类分析和线性回归方法分析其降水量、径流量近32 a的年内和年际变化规律及其影响因素.结果表明:1977—2008年2个流域年降水量和径流量均呈现下降的趋势,径流量下降幅度明显高于降水量;沙拉沐沦河流域降水量下降趋势不明显,稳定的泉水补给使得径流量受降水量减少和土地利用/覆被变化影响较小;老哈河流域径流量减少幅度远远高于降水量,在雨季下游有断流现象,该流域1977—1998年降水量是径流量变化的主要影响因素,1999—2008年流域内土地利用/覆被变化和水库水坝修建、河道外取水等人类活动共同作用使得该流域径流量减少了70.3%.

Analysis of trend and influencing factors of runoff variation in headwater basin of West Liaohe River

Based on hydrological data from the Laohahe Basin and Shalamulunhe Basin from 1977 to 2008,the Mann-Kendall test method,the sequential cluster analysis method,and the linear regression method were used to analyze the intra-annual and inter-annual variations and influencing factors of precipitation and runoff over 32 years in the basins.The results show the following: There was an obvious decreasing trend of annual precipitation and runoff in the two basins from 1977 to 2008,and the runoff decreased more significantly than precipitation.The decreasing trend of precipitation was not significant in the Shalamulunhe Basin,and the runoff was slightly influenced by the decrease of precipitation and the variation of land use/cover due to the constant spring feed.In the Laohahe Basin,the runoff decreased much more significantly than precipitation,and the breaking flow occurred in rainy seasons.Precipitation was the main factor influencing the runoff from 1977 to 1998 in the basin.The runoff decreased by 70.3% from 1999 to 2008 due to the effects of human activities,including the variation of land use/cover,construction of reservoirs and dams,and water collection from outside of the river courses in the basin.