small to moderate trench created to channel water
For use of the ditch as obstacles for horses, see ditch (obstacle)

A ditch is created to channel water and can be described as a small or moderate depression. A ditch can be used for drainage, to drain water from low-lying areas, alongside roadways or fields, or to channel water from a more distant source for plant irrigation. A trench can be defined as a long narrow ditch.

Ditch for drainage in Netherlands
Ditch for drainage in northern Germany

Ditches are commonly seen around farmland, especially in areas that have required drainage, such as The Fens in the UK and the pro-water management The Netherlands.

Roadside ditches can provide a hazard to motorists, especially in poor weather conditions.

Fortification change

World War I trench works and shrapnel shelter
Ditch as obstacle at Uffington Castle, England

In military engineering and fortification, a distinction is made between a ditch and a trench. A ditch is a barrier, designed to slow down or break up an attacking force, while a trench is a cover, intended to provide protection to the defenders. In Medieval fortification, a ditch was often constructed in front of a defensive wall. When filled with water, such a defensive ditch is called a moat. Today ditches are of no importance as an obstacle for persons, but are still often used as anti-vehicle obstacles.