Workflow modification: only run delineations per crossing (point group)

[gassc]

Currently, in the culvert capacity workflow, the peak-flow calculation is run for every record in the NAACC table. This calculation includes costly raster operations like delineation and flow length.

In a best-practices data prep workflow, all culverts at a common crossing have been snapped to the same location (flow line) on hydrologically-corrected DEM. That means more every culvert at the same location will have the same peak-flow. We could cut down on geoprocessing time quite a bit for multi-culvert crossing situations if we only run once and then "share" the output with the other culvert records at the same crossing.

There are at least two approaches here:

1. run peak flow for records in NaaccCrossing model (which includes a list of culverts via NaaccCulvert model).

• for this approach to work well, it assumes that all culverts with common Survey_Id have in fact been snapped to the same location. Are there cases where they might not?

2. analyze geographic coincidence of culverts (using say, the resolution of the DEM as a snapping distance), and use those groups to run peak flow, ignoring any association based on the Survey_Id

• this approach potentially would handle situations where there multiple surveys for a crossing

---

Changing this would require a pretty significant refactor to the existing workflows, but not underlying calculators or lower-level geoprocessing workflows. That refactor may best be able to be implemented in parallel with other tools.