Workspaces let you change your terrain model and observe the effects on the analyses. This section discusses the subsuface terrain editing tools that, although not directly changing the terrain, allows you to change how water flows in your workspace.
For an overview of the workspace editing process please consult the introduction page.
Some subsurface features use to model water flowing under bridges in the elevation model. Subsurface structure
Creates a subsurface structure between the two end points of
the path. The edit does not change any elevation on the terrain,
but it allows water to be transported between the end points
without affecting the terrain between them. The subsurface
structure will transport an unlimited amount of water, but it
does not store any water itself – it has
zero volume.
Usage example: Model culverts and
underpasses without obstructing flow over the top of the
structure.
Subsurface basin and sewage drains
Creates a sink point on the surface connected to a
subsurface basin with a specified volume. This volume can either
be typed in manually or set to an event-specific runoff volume
from the watershed of the sink point. This runoff volume is
determined by first clicking query runoff next to
the volume input field and then, selecting the sink point
position on the map. The event determining the runoff volume
can be varied by dragging the rain slider which appears when
clicking query runoff.
Usage example: Model the effect of a subsurface
basin or a sewage drain with a guaranteed service level (e.g. a
sewage drain dimensioned to handle the runoff volume for a 15mm
rain event).
