Optimum approach to determine the coefficients in sediment-carrying capability formula

The numerical model to simulate sediment transport and bed erosion or deposition in rivers, estuaries and coastal waters has become an important approach in sediment research. Because sediment transport is very complex and unstable, different mathematical models have been established based on different principles, such as viewpoints of sheer stress and energy of water flow. In China, the sediment-carrying capability formula based on the view of water flow energy equilibrium is widely applied in sediment numerical simulation to solve sediment problems in many important prajects such as the Three Gorge Project and the Regulation Project of the Deep Navigation Waterway in the Yangtze River Estuary. Sediment-carrying capability of water flow means the maximum capability of water flow to carry sediment. It is very important to obtain the sediment-carrying capability formula for developing sediment numerical models, and the key problem is to determine its coefficients in the best way. Based on the least square method directly, a new method called enumeration method is developed in this paper. This method is different from the normal method, which makes a regression analysis after logarithm. The error analysis and result comparison show the coefficients determined by the enumeration method are of more reasonability and that the results of the formula are more accurate in calculating the natural sediment-carrying capability of water flow. At present this method is simple and practical, thus it is the most optimum approach to determine the coefficients in the sediment-carrying capability formula.