One-dimensional flow over a plane: Criteria for kinematic wave modelling

Abstract Criteria for using the kinematic wave approximation to the Saint Venant equations for shallow water flow are examined. Attention is focused on the steady-state upstream depth, which, for the condition of zero flow at the upstream boundary, is generally non-zero (proven mathematically) but in the kinematic approximation is implicitly assumed to be zero. Contours of dimensionless steady-state upstream depth over a two-parameter plane are used to obtain a further criterion for kinematic wave modelling. The new criterion is consistent with, and improves upon, the existing criteria. Application of the criteria to catchment modelling is demonstrated and discussed.