Abstract:

After the impoundment of the Three Gorges Reservoir,the water quality and quantity have been focused seriously.Baseflow separation is regarded as one of the most important and difficult issues in hydrology,so its separation results have great influence on many aspects,such as hydrological analysis and calculation,water resources management,etc.In order to find a reliable baseflow separation method,we chose flow datas in 2007~2009 provided by Xingshan hydrologic station of the Xiangxi River watershed in the Three Gorges Reservoir,used filtered smoothed minima method to have a baseflow separation,and made a comparison with digital filtering and the smoothed minima method.The results showed that the BFI of smoothed minima,digital filtering and filtered smoothed minima were 042,039 and 036,respectively.The results that dealed with filtered smoothed minima were the most smooth,and corresponded with actual converge physical process.Filtered smoothed minima was able to have a better performance for tracing the digital filter method during ascension period and the smoothed minima method during the recession,required only one pass filtering in the forward direction instead of three pass(forwardbackwardforward)in the digital filtering.Therefore,it is the best separation method among this three baseflow separation methods