For a defined channel boundary material (i.e. known d and ) and water viscosity there are six channel/sediment parameters: Q, Qs, V, B, y0 and S. Three equations (continuity, the Ackers-White transport equation and the White et al. resistance equation) and a fourth one based on the variational principle – minimum stream power, i.e. maximized transport with least energy expenditure – would then facilitate the design procedures it two of the six parameters are stipulated. For further detailed information and design tables based on this more rational method the reader is referred to White et al.32