海流兔河近50年来基流变化特征分析

基流是枯水期河流的主要补给来源,对干旱半干旱区的河流尤其重要.在沙漠半沙漠区,河流基流还对维持脆弱的生态系统中发挥重要作用.对河流基流变化分析,可为流域水资源保护以及合理的利用和开发提供依据.本文基于半干旱风沙滩地区海流兔河1957年到2007年的实测流量资料,采用递归数字滤波法对该站的流量过程进行了基流分割,研究了海流兔河年基流量和基流指数(BFI)的年内、年际变化特征；用M-K非参数检验法分析了基流量和BFI的变化趋势.结果表明,海流兔流域基流占径流比重较大,年均径流、基流都呈减少趋势,径流年内分配均匀、基流则表现为先减少后增加,BFI年际、年内变化都较均匀,没有明显的增加或减少趋势；情势变化指数法(RSI)检测出基流在1966、1986年存在突变点,径流在1968、1989、2001年发生突变.

Analysis of base flow variation characteristic in Hailiutu River in past 50years

Base flow is the main supplement source of stream flow in dry period and especial important to the river in arid and semi-arid area. It plays an important role in maintaining the fragile ecological system in the region. Based on the observed runoff series of Hailiutu river from 1957to 2007, the paper used recursive digital filter method for base flow separation and investigated the trend of annual and inter-annual variations of base flow and BFI (base flow index). The statistical method of nonparametric Mann-Kendall test was used for analyzing the trend of base flow and BFI. Results showed that base flow holds a larger proportion of the runoff, annual base flow and runoff have a significant descending trend; the annual distribution of runoff is even but the base flow first decreased and then increased; BFI both in annual and inter-annual shows even, has no significant increase or decrease trend. The Regime Shift Index (RSI) method was used to measure sudden change point of the base flow in 1966and 1986.The runoff occurred sudden change in 1968,9and 2001.