 The North Mere is 5.6-acres (2.25 ha) large, and is blocked off on its northern end by a sod-cast bank, adjacent to the site of the North Gate.The southern half takes the form of a 331-foot (101 m) long moat, which was recorded as being 18-foot (5.5 m) deep in the medieval period, terminating in the West Gate.The northern part of this mere occasionally floods in the 21st century, creating a temporary lake, and the moated section usually still contains some standing water.