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:
... 18, 5.1% from 18 to 24, 32.6% from 25 to 44, 31.2% from 45 to 64, and 9.4% who are 65 years of age or older. The median age is 42 years. For every 100 females there are ...