Aqueducts are vulnerable to being cut during a siege. What measures have been taken historically either to mitigate the loss of external water sources, or to prevent the damage itself from occurring? | AskHistorians Archive Observer

Aqueducts are vulnerable to being cut during a siege. What measures have been taken historically either to mitigate the loss of external water sources, or to prevent the damage itself from occurring?

by Cataphractoi

Ed__

Followup, does this also apply to rivers? has anyone ever tried to cut off the water supply by rerouting a river.