九龙江径流Flashiness指数时空变化分析

Analysis of Spatiotemporal Variability of Runoff Flashiness Index for Jiulongjiang River

通过分析河流Flashiness指数的时空变异,进而评估水电开发、土地利用变化等人类活动对河流径流时空变异特征的影响.本研究选取地处东南沿海的中尺度流域——九龙江流域,基于1967～2007年近40年的水文资料,利用Flashiness指数、基流指数等重要水文指数,并借助GIS、多元统计分析的方法来识别九龙江北溪与西溪两大干流流域近40年来径流时空变化特征及其影响因素.研究结果表明,九龙江流域近40年来径流特征发生显著的变化,流域面积是影响九龙西溪和北溪径流时空变化的自然因素,大坝建设、水电开发改变了九龙江流域的水文条件,进而影响了径流量的年内分布规律及泥沙输出特征,土地利用变化是影响流域径流特征变化的潜在因子.研究结果可为流域水资源管理提供科学依据.

Spatiotemporal variability of the runoff flashiness index was explored and thereby used to evaluate the effect of human activities including dam construction and land use change on runoff variation. The Jiulongjiang River Basin, the medium-sized coastal watershed located in SE China, was chosen to analyze the characteristics of the runoff variation with Flashiness Index （FI） and Baseflow Index （BFI） for the north reach and west fiver of the Jiulongjiang River, based on the forty-year hydrologic data from 1967 to 2007. The geographical information system and multivariate analysis were coupled to characterize the spatiotemporal varia- tion of the runoff and identify its influencing factor. The results show that the hydrological condition in the Jiulongjiang River Basin was altered significantly in the past 40 year, represented by a decreasing tend for FI and an increasing trend for BFI. Furthermore, the watershed area is the major natural factor leading to spatiotemporal variability of the runoff flashiness index for the north reach and west reach of the Jiulongjiang River. The Dam construction and hydropower development made the hydrological condition changed in the Jiulongjiang River Basin, which greatly influenced the seasonal variability of the runoff and sediment discharge. The land use change was identified as a potential factor influencing the runoff variation of the Jiulong River Basin.