A bar ditch, also known as a barrow pit, is a roadside pit or channel dug for drainage purposes. Also, adjacent to pasturage, confines cattle keeping livestock from straying onto road [cattle country, western USA][Possibly archaic]  The term is most often used in the Southwestern United States.
^Avis, Walter S. (1984) "Notes on Borrow(ing) Pit" pp. 1–10 In Raphael, Lawrence J. (1984) Language and cognition: essays in honor of Arthur J. Bronstein Plenum Press, New York, page 3, ISBN 978-0-306-41433-6