A culvert is a structure that channels water past an obstacle or to a subterranean waterway. Typically embedded so as to be surrounded by soil, a culvert may be made from a pipe, reinforced concrete or other material. In the United Kingdom, the word can also be used for a longer artificially buried watercourse.
Culvert with secure headwall in Bromsgrove, England
Stone culvert in Haapsalu, Estonia
Steel culvert with a plunge pool below
A multiple culvert assembly in Italy
A ditch is a small to moderate trench created to channel water. 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. Ditches are commonly seen around farmland, especially in areas that have required drainage, such as The Fens in eastern England and much of the Netherlands.
A ditch in the Netherlands
Ditches at the Ouse Washes nature reserve.
Waterplants growing in a ditch in the Netherlands, showing Sagittaria sagittifolia to the right.
Major ditch of Sueca, Valencian Community