Abstract: As an important tributary of the upper Yangtze River, Minjiang River provides a pivotal support for the social economic development in western Sichuan and Chengdu plain. The overall hydropower development in the Minjiang River basin took place slightly later than that in other major tributaries of the Yangtze River. In recent years, reservoir construction project increases unceasingly in the Minjiang River basin, giving rise to variations in the water and sediment condition. In this paper, the characteristics of reservoir construction and water-sediment transport as well as their interrelations are preliminary examined according to flow-sediment process lines and accumulative runoff-sediment load curves based on measured data. Results demonstrated that the number of reservoirs and the total storage capacity have surged since 1970 and 2005, respectively. Reservoirs are constructed from the mainstream to tributaries, with the number of reservoirs under construction declining while high dams and large reservoirs increasing. As dam construction technology improves, earth dam which is easy to construct is gradually changed into other dam types with high difficulty. Moreover, due to the enhancement of reservoirs’ regulation ability and sediment holding function, the runoff and sediment transport in main flood season of the basin have been flattening. Annual runoff and annual sediment transport both saw a downward trend after 1990, of which the annual sediment transport has been decreasing more obviously. Recently, the change of annual sediment transport volume at Gaochang station is in a negative correlation with reservoir construction. Such correlation intensifies with the further increase in the total capacity of reservoir in Minjiang River basin, and is more evident in flood season.

Key words: water and sediment transport, sediment discharge, volume of runoff, accumulative runoff-sediment load curves method, Minjiang river basin, reservoir construction, Gaochang station