Models of stream-channel development typically focus on the effects of discharge and sediment. Missing from the traditional models is an explicit representation of the mechanism through which channel cross-section elements interact and adjust. The multiple-equations model presented here includes the effects of mutual adjustment of channel characteristics, as well as of discharge and sediment. It incorporates both channel shape and size as endogenous variables. The results of analysis indicate that discharge has primarily direct effects on the channel, whereas sediment appears to have primarily indirect effects. Given that the adjustment mechanism is represented as a set of indirect effects, these results imply that the channel adjustment process is dependent principally on sediment rather than on discharge. The utility of this type of model in an impact assessment context is also discussed.