Is your feature request related to a problem? Please describe.
Activated aqueducts are indistinguishable from inactive when empty. This makes it almost impossible to deactivate a long sequence when water has been entirely drained - particularly as a long line can empty faster than it refills.

Describe the solution you'd like
A modified texture or model for active aqueducts. Something as simple as a tiny black drainage hole at the base of the trough would be enough to allow us to quickly identify where the line is leaking, while also fitting the aesthetic: that's where the extra growth happens because that's where the water is seeping into the soil.