The Simple River model engine was developed as an example of model migration. The model
engine is programmed in Fortran and is a very simple conceptual river model.
The Simple River consists of nodes and branches, as shown in Figure 4-4. For each timestep,
the inflow to each node is obtained from a boundary-input file. These flow rates are multiplied
by the timestep length and added to the storage in each node. Then, starting from the
upstream end, the water is moved to downstream nodes and the flow rate in each branch is
calculated.
