, 2005). At Xiaodeshi in the Yalong River, a tributary of YTR, the GDC-0941 molecular weight June–October discharge is 77% of the annual total (Chen et al., 2012). Rainfall contributes the most to the annual total streamflow at Zhimenda, Shigu and Xiaodeshi (Table 2). Annual flow showed slightly increasing trends at Zhimenda during 1961–2011 (Li et al., 2012a and Li et al., 2012b), at Xiaodeshi during 1956–2004 (Cao et al., 2005 and Chen et al., 2012),
and at Shigu in the lower reach during 1953–2005 (Xu et al., 2010 and Zhao and Gao, 2011) (Table 3). The negative trends in annual total are noted at Yushu during 1956-2000 (Table 3) and the reason is unknown (Zhou et al., 2005). The Tuotuo River, the headwater of YTR and located above Yushu, exhibited an increasing trend in streamflow during
the late 1950s–2000 (Table 3; Yang et al., 2003, Jin et al., 2005, Zhang et al., 2008, Liu et al., 2009 and Bing et al., 2011), indicating that the main contributor to the Tuotuo River is melt water that is enhanced by increasing temperature. The difference in streamflow change between Tuotuo River and Yushu implies that as the basin expands to the lower elevation, melt water contribution diminishes and the other influence becomes more important. In MKR, the June–September discharge accounts for 70% of the annual total at Changdu, with combined melt water and groundwater contributing much more than rainfall (Table 2; Wang, 2007 and Lu et al., 2009). Streamflow change at Xiangda during 1956–2000 showed decreasing trends before 1980 but increasing trends after 1980, though the trends GSK458 clinical trial were not statistically significant (Table HAS1 3; Zhou et al., 2005). Also, the date of the mid-point of yearly flow shifted earlier at Xiangda during recent decades (Xu et al., 2004 and Lu et al., 2009). At Changdu that is located below Xiangda, Cao et al. (2005) found statistically insignificant increasing trends in streamflow during 1968–2000 (Table 3); on the other hand, Zhang et al., 2012a and Zhang et al., 2012b showed that during 1958–2005 streamflow at Changdu exhibited statistically
insignificant decreasing trends in annual, flood and non-flood seasonal flows. The differences between Cao et al. (2005) and Zhang et al., 2012a and Zhang et al., 2012b are due to the different datasets, methods and study periods used. It is possible that Cao et al. (2005) only showed a partial change of streamflow over a longer period 1958–2005. For IDR, Senge Zangbu and Langqin Zangbu are the headwaters that are fed primarily by groundwater and melt water (Table 2). In Senge Zangbu groundwater and melt water together account for about 84% of the annual streamflow, with 55% of the annual flow occurring in July–September (Guan and Chen, 1980). Due to lack of reports on IDR within China, streamflow change is virtually unknown. In BPR, the June–September flow accounts for 65–75% of the annual total at stations located along the main branch (Liu, 1999).