High Quality Content by WIKIPEDIA articles! The Brent Reservoir (popularly called the Welsh Harp) is a reservoir which straddles the boundary between the London boroughs of Brent and Barnet and is owned by British Waterways. The reservoir takes its informal name from a public house called The Welsh Harp, which stood nearby until the early 1970s. It is the only Site of Special Scientific Interest in Barnet and Brent.