Each time you size or resize a circuit of lateral pipes, the spray coverage regions for that circuit are appearing on an Xref layer, such as the site base.
The active layer in your drawing is most likely locked.
You cannot have a locked layer active while you size your pipes. When the system is sizing the laterals, it needs to create a temporary region to calculate the area of coverage. Once it has verified that the zone has a proper precipitation rate, the temporary regions will be deleted. However, if the active layer is locked, it cannot create and delete these regions properly.
To get rid of the extra region(s) in your Xref layer, unlock the Xref layer and delete the coverage region objects manually. How to unlock layers
To prevent this issue from happening, you can either:
- Keep your Xref layer unlocked while sizing your pipes, or
- Switch the active layer to layer 0