Describes a hydraulic flood routing model developed to accurately model the open water river discharge on the Peace and Slave rivers. The model is capable of modelling the discharge at sites where no discharge data exist. The document includes description of the development of the database for the model, including the geometric database (channel distances, surface slopes, bed profiles, channel widths and resistances) and the hydrologic data. The appendix includes a user manual for the user-friendly microcomputer program that has been set up to run historical flows (1961-93) and to simulate naturalised flows on the Peace River (1969-91).