Monthly streamflow simulation for the Upper Changjiang basin above the Three Gorges in China

The Upper Changjiang is an important water supply source for the densely populated Sichuan basin and for the reservoir at the Three Gorges. The SLURP (Semi-distributed Land Use-based Runoff Process) macro-scale hydrological model, and temperature and precipitation data from ERA40 (European Re-analysis of Global Atmospheric) were used to simulate flow of the main river and its major tributaries. Simulated monthly discharge compares well with the flow recorded at Chongqing, with a pronounced seasonal rhythm that reflects the monsoon influence. Simulation of a long flow series (1957-2002) indicates high discharges in the 1960s followed by a decline in the 1970s and a subsequent increase at the end of the 20th century. Streamflow is strongly related to precipitation, both seasonally and interannually, but the flow of the Changjiang at Chongqing lags precipitation by about a month. Spring and early summer flow of the Upper Changjiang comes mainly from the eastern sector while the west contributes half of the flow between August and November. Copyright © 2008 IAHS Press.