This next step covers reducing the number of your common computation points (CCPs). Each Common Computation Point must be associated with exactly one Holdout Area. Additional Holdout Areas allow for Reservoir Benefits to be allocated at a finer spatial resolution.
- The HEC-ResSim model extent may not match RAS model extent. If this is the case, there might be more computation points from the HEC-ResSim model that fall outside of the HEC-FIA study area. To delete unneeded Common Computation Points select Select by Location and then enter the following:
- Input Features: Computation_Points
- Relationship: Intersect
- Selecting Features: StudyArea
- Check the Invert spatial relationship checkbox
- Apply. This will select all points that are outside your RAS geometry region.
- Go to the Edit tab, select Delete, then Save your edits.
- Next reduce the number of CCPs to only desired locations, starting with any points that are not directly downstream of a reservoir (like an uncontrolled tributary because there would not be any holdout data).
- If the reservoir locations are not obvious, label them by selecting the shapefile, and then selecting the Labeling tab. Make sure that the Field is on the names, that the Label Features in This Class is checked, and then select the Label button.
- Turn on your river centerlines, and cross sections and/or 2D Areas.
- From this example, there is one CCP that is outside of the RAS 2D Area. Delete that point.
- Lastly, determine how many holdout areas to include in the model. Each holdout area will need ONE computation point associated with it. While this model has 14 computation points, there are only 3 Holdout Areas. Make sure to identify 1 computation point for each holdout area and then delete the rest. The final CCP layer for HEC-FIA will have 3 CCPs and then use ArcGIS Pro Join and Relates to link the Computation Point names to the Holdout Areas.