Assessment of hydrological alterations from 1961 to 2000 in the Yarlung Zangbo River, Tibet

Hydrological regime that is primarily described by combinations of its magnitude, duration, frequency, timing, and rate of change, is the main driving force in river ecosystems. The Yarlung Zangbo River is the largest river in Tibet and the highest river in the world. Data from 1961 to 2000 together with Range of Variability Approach (RVA) analysis were used to calculate hydrological regime characteristics. The hydrologic regime of the Yarlung Zangbo River has been altered over the studied period and the annual flow decreased more than 10% and even 30%. The extreme low flow duration increased more than 200%. The low pulse duration and the high pulse duration increased even more than 1000%. Extreme water conditions, including extreme low or high flow pulse, may cause severe habitat alterations and should be keep in an appropriate range.