Abstract: Some formulas have been used to calculate the siltation ratio in offshore waterway.Each formula and its parameters should be set according to the actual conditions of flow and sediment in certain water areas.In sandy coast area,the siltation ratio of waterway should consist of both bed load and suspended load.The method of combining different formulas,which are deduced from different theories and limited in kinds of conditions,is discussed in this paper.The semi-theoretical and semi-empirical formulas,Liu J...