A borrow ditch, is a roadside channel dug for drainage purposes. Typically, the dirt is "borrowed" from the ditch, and used to crown the road. It is a variation of a Bar (borrow) Pit, in construction, when dirt is removed and used for construction purposes, and later left to fill with water, forming ponds or lakes. 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, ISBN978-0-306-41433-6