Development of a mixed solution technique for a dynamic river quality model

This paper describes the solution methods used in the development of a simple, mixed solution technique river impact model. The model routes a flood wave down a river reach using an Eulerian reference frame. A simple velocity/flow relationship is used to obtain a velocity field from the derived flow field. A Lagrangian reference frame is superimposed upon the derived velocity field and this is then used to route a pollutant wave down the reach. Tests indicated that the model maintaines conservation of flow and pollutant mass. The solution was shown to provide a stable solution method for a wide range of input values.