Creating a New EFP Alternative

As with all programs included in HEC-RTS, the first step in using them inside of a watershed is to set up a new alternative. 

This guide will teach you how to create a new EFP Alternative in your HEC-RTS watershed.

Step 1: Create new EFP Alternative

EFP Alternatives are developed within HEC-RTS.

1. Launch HEC-RTS and open your watershed.
2. Navigate to the Setup tab.
3. Right-click on EFP from the Watershed Tree and click New.
4. In the Create New Ensemble Forecast Processor Alternative dialog, enter a Name and optional Description.
5. Click OK to create your new alternative.

Step 2: Configure Input Settings

The Input Settings tab contains two sub-tabs:

• LookBack
• Forecast

LookBack Tab

You only need to enter data in this tab if:

• You have selected the Ensemble Member with Closest Volume to Metric Compute option, and
• You want to merge observed time series data from the Lookback period with the ensemble member selected for the Forecast period.

For more details, refer to the documentation on Ensemble Member with Closest Volume to Metric.

To configure LookBack settings:

1. Click Add to insert a new location in the table.
2. Enter the required information in each of the fields:
   1. Group - The A Part of the pathname
   2. Location - The B Part of the pathname.
   3. Parameter -  The C Part of the pathname.
      1. This must match the Parameter used in the Forecast Period and the Compute Location specified in the Output Settings.
   4. Timestep - Select from the dropdown.
      1. This must match the timestep used in the Forecast Period and Compute Location.
   5. F-Part - The F Part of the pathname.
3. Repeat for each location required.
4. Click Apply to save changes. 

Forecast Tab

This tab is required. Use it to define ensemble collection pathnames used in calculating statistical metrics. Each entry must refer to an ensemble collection in the HEC-DSS file, whether extracted from an external source or generated by a previous program in the forecast sequence.

To configure Forecast settings:

1. Click Add to insert a new location in the table.
2. Enter the required information in each of the fields:
   1. Group - The A Part of the pathname
   2. Location - The B Part of the pathname.
   3. Parameter - The C Part of the pathname.
      1. This must match the Parameter defined in the Compute Location in Output Settings.
   4. Timestep - Select from the dropdown. 
      1. This must match the associated timestep in the Compute Location.
   5. F-Part - The identifier portion of the pathname's F Part (exclude the collection part, e.g., C:000001).
3. Repeat for each location required.
4. Click Apply to save changes. 

Step 3: Configure Output Settings

The Output Settings tab contains two sub-tabs:

• Locations to Compute Metrics
• Cumulative Volume Scalar Decision Metrics

Locations to Compute Metrics Tab

Use this tab to define where metrics will be calculated and what input data to use during the Lookback and Forecast periods.

1. Click Add to insert a new location in the table.
2. Enter the required information into each of the fields:
   1. Group - Select the name of the group. This will become the A part of the output pathname.
   2. Location - Select the name of the location. This will become the B Part of the output pathname.
   3. Parameter - Select the parameter of the time series. This becomes the C Part of the output pathname and must match the parameter used in the Lookback and Forecast inputs.
   4. TimeStep - Select the timestep (E-Part of the pathname). It must be consistent with entries in the Lookback and Forecast periods.
   5. LookBack - Choose the record to use during the Lookback period.

      • Set this field to null if either:

        • The closest volume compute option is not selected, or

        • The Forecast record already covers the full Forecast time window, including the Lookback period (e.g., when linked from another program or an extract).

   6. Forecast - Select the ensemble time series record used to compute metrics during the Forecast period.
3. Click Apply to save changes. 

Cumulative Volume Scalar Decision Metrics

Use this tab to define the specific metrics to calculate during each forecast. Multiple metrics can be computed in a single alternative.

1. Enter at least one value (number of days) in the Cumulative Volume field.
   1. Values are entered as full days. Multiple entries need to be separated by commas.
   2. Values must be less than the length of the forecast time window.
   3. After entering the required number of values, you must hit ENTER to save the data.
2. Check the boxes next to the metric(s) you want to compute:
   1. Min 
   2. Max 
   3. Average 
   4. Standard Deviation 
3. Check the box next to Percentiles to compute percentiles (if needed).
   1. Values are entered as decimals (e.g., 20% would be entered as 0.20). Multiple entries need to be separated by commas.
   2. After entering the required number of values, you must hit ENTER to save the data.
4. Check the box next to Return the Ensemble member that contains the volume closest to each metric if needed.
5. Click Apply to save changes.

Step 4: Finalize the Alternative

1. Review the inputs for all tabs.
2. Make any necessary edits, clicking Apply to save changes before switching tabs.
3. Click OK to finalize the new EFP alternative.