Ancient sources of the River Fleet can be found at two different North London sites – In the east originating at Kenwood House and nearby in the west- as a small stream running through the Vale of Health, Hampstead in London NW3.
The western branch runs briefly over ground through the Heath, on through Hampstead ponds only to permanently disappear beneath the tracks at Hampstead Heath railway station, these two underground branches meet near Camden town but in 1826 the Fleet flowed above ground reaching 65 feet wide at flood at this point.
Today, the once over ground River Tyburn runs far below the city through the King’s Scholars Pond sewer - trickling through labyrinthine Victorian arched brick tunnels. Also, in the 1960’s, the overgrown and derelict River Quaggy - a tributary of the River Ravensbourne was completely encased in an underground concrete conduit, making way for the continually changing and developing urban environment.