With or without water it can be used as a barrier, as an alternative for a fence.
A trench is a long narrow ditch.
Types and applications include:
... and 12.7% who are 65 years of age or older. The median age is 39 years. For every 100 females there are 104.2 males. For every 100 females age 18 and over, there are 97.8 ...