Rigs (ridges) were a form of field drainage in which water ran on the surface of the land, off the rigs and the down the furs (furrows) between them.

In medieval times, rigs were typically broad and high. They were also curved, because the teams of as many as 12 animals, usually oxen, had to start turning before they reached the end of the rig.

Smaller iron ploughs replaced them in the late 18th century. Farm land was enclosed, forming fields surrounded by dykes (walls) or hedges. The rigs in these fields were straighter and lower, like the ones in the picture, with effective drainage crop yields.