Influence of Middle Route of South-to-North Water Diversion Project on Hydrological Regime in Middle and Lower Reaches of Hanjiang River

In order to evaluate the influence of the middle route of the south-to-north water diversion project(MR-SNWDP) on water bloom in the middle and lower reaches of the Hanjiang River,the effects on the hydrological regime were analyzed.Based on the flow data of Xiantao Section,both of the fractal feature of flow curve and the variations of hydrological feature values(after the 145×108m3 scheme of MR-SNWDP has been implemented) were calculated,considering if the diversion work from Yangtze River to Hanjiang River(DWYRHR) is built.The results indicate that the hydrological regime in the middle and lower reaches of the Hanjiang River will be obvi-ously changed,mainly in the following ways: The annual runoff distribution will become more uniform,the annual runoff concentration will become lower,relative variation rate will become smaller,which will become more visible under the effects of the DWYRHR;the average flow of different period(year,flood season,dry season) will become smaller,and the minimum flow of ten days will become smaller too,which will be mitigated under the effects of the DWYRHR.Since the outbreak of water bloom in the Hanjiang River concentrates in dry seasons,the decrease of average flow during dry season and the minimum flow of ten days surely will accelerate the outbreak of water bloom in the Hanjiang River.