Calculation of Water Volume for Sediment Transport in the Sediment-laden River of the Main Stream of Liaohe River, Northern China

The water volume for sediment transport affects the distribution of sediments in rivers and offers important guidance for river dredging, management and remediation. In this paper, with daily water and sediment data of major hydrological stations of main stream of Liaohe River from 1988 to 2010, we calculated the average water volume and unit water volume for sediment transport of the year with the methods of sediment discharge, sediment concentration and erosion and silting ratio correction that are based on net water volume method. We analyzed the relations between change process of water volume for sediment transport and its impact factors to identify the critical water volume for sediment transport for non-scouring and non-silting situation. The results showed that (1) according to the calculation with the hydrological data from the major hydrological stations in Tongjiangkou, Tieling, Mahushan, Ping’anpu and Liujianfang, the average water volume and the unit water volume for sediment transport during the flood season of the year were 13.88×108m3 and 1136.62m3/t respectively; (2) According to the theoretical calculation, the water demand model for hydraulic sediment dredging in the major reaches of the main stream of Liaohe River was determined and there was linear function relationship between the sediment discharge and the water demand. When the channel kept the sediment from silting, the water demand at Tieling was ≥18.73×108m3, ≥5.49×108m3 at Mahushan, ≥2.90×108m3 at Ping’anpu and ≥10.97×108m3 at Liaozhong. In a word, net water volume method can accurately calculate the amount of sediment transport in sediment-laden rivers with a prospect of broad application.