Catchment Delineation Command

Description:

Creates watersheds, catchment and flow path polylines from a surface. Discharge points (e.g. inlet structures, headwalls, etc.) can be specified, which are used to determine catchment areas that drain into the discharge points.

Location on Compact Ribbon:

Location on Extended Ribbon:

Major advantage over similar tools

During catchment processing, any cell that forms a depression can be automatically filled, allowing water to overflow and continue flowing downstream until it reaches the boundary of the surface. This enables continuous flow-path generation and prevents interruptions caused by local depressions or sinks.

Performance for different surface types

The Civil 3D API does not provide a direct method for querying elevations from a GRID surface without throwing an exception when the elevation cannot be determined. Since exception handling is computationally expensive, this can negatively impact performance during processing.

For TIN surfaces, however, the Civil 3D API provides a method to verify whether a point lies on the surface before querying its elevation. This avoids unnecessary exceptions and results in more efficient and faster processing of TIN surfaces.

Instructions:

For more details see the video on our Training Videos web site, channel Pipe Networks (General): https://www.devotechgroup.com/storm-water-training

Catchment delineation dialog:

Source objects (a pipe network with final surface boundary):

Result (catchment delineation with flow paths):