Time Step

The incremental time step in hours. The analysis will start from the starting time, incrementally solving the routing process for each incremental time step up through the ending time. Please note that the accuracy and stability of the solution of the finite difference continuity equation depends on the value of the time step. The smaller the time step the more accurate and stable the solution. The user should choose a reasonable time step for the routing problem, typically 0.1 hour to 0.2 hour. If the output hydrograph shows serious oscillations, the solution is unstable and the time step should be reduced. If the discrepancy between the results of any two time steps is less than an acceptable error (say 5%), the analysis may be considered satisfactory.