The Ensemble Forecast Processor (EFP) is a plugin that was first introduced in CWMS 3.4. The Ensemble Forecast Processor allows you to process various statistical metrics from ensemble flows at specified locations in the watershed, and then use those metrics to influence other model alternatives in the forecast. For example an HEC-ResSim alternative could use a statistical metric from the Ensemble Forecast Processor within a rule in a reservoir's operations to help determine releases. The statistical metrics available to compute from the ensemble time series include the minimum volume, maximum volume, average volume, and percentile volume over a specified number of days.
The EFP plugin is flexible and can be placed throughout the program order of the CAVI forecast to allow for a variety of uses. One possible use case of the EFP is in support of Forecast Informed Reservoir Operations (FIRO). For this example application, ensemble forecasted inflows can be processed by the EFP plugin, and the resulting metrics (e.g., the 75th percentile three-day forecasted volume) can be used to influence the decision rules in the HEC-ResSim alternative to determine potential reservoir operations.
The following sections of the User's Manual will outline how to define input and output locations and how to select specific metrics to compute within a CWMS forecast. The EFP is treated like any other program within the CAVI. Before creating a forecast, a new Program Order containing EFP must be created. Once an EFP Alternative has been developed, it must be assigned a model alternative key and a new Forecast Run must be created.