Velocity Calculations

An approximate formula must be used to calculate nodal velocities if the flood routing model is to be used with the water quality model. These values are then used to determine flow areas which are saved for use in the water quality simulation.

Two options are available to specify velocity as a function of flow:

1. Power Law Function

   V = Vo + a( Q - Qo )b for Q > Qo (1) V = Vo for Q £ Qo (2)

   This formulation is introduced to avoid potential problems in the quality model when the flow dips initially, possibly attaining a negative value; a property associated with the Muskingum algorithm.

2. User Supplied Relationship
   In this case you provide velocity and flow data pairs and Flood Modeller linearly interpolates between these values.