Time interpolation method used by the model to fill time-varying input at times between data points. Interpolation is needed when the available data are coarser in time (say 1 month steps) than the time step of the model (say, 5 or 15 minutes).
Linear interpolation between closest time series elements. This is the preferred method for instantaneous continuous data such as flow and stage
Use the last value in the time interval of the input data. For instance, if monthly data were input and the model requires values every fifteen minutes, the last value in April would be substituted for every time step in April. The reason for this option is that period averaged data is stamped at the end of the period in HEC-DSS. It is not recommended that you use it for pre-processed inputs that have been disaggregated to instantaneous values. Use linear instead.
No interpolation. For regular series, the simulation will fail if there is no data available at the model time step. For irregular series such as gate ops, the previous good value is used.