Friday, 27 November 2009

The London/Essex border- King George V

TQ 37 98
The London/ Enfield/Essex boundary goes south on an eccentric course (presumably the course of the original river) down the reservoir

The Lea  Navigation and the Flood Relief Channel flow south

Post to the north Enfield Lock
Post to the south George V Reservoir

Sites on the London, Enfield, side of the border

Lea Navigation.
Enfield Cut which follows the line of the earlier Enfield Millstream. Built Thomas Yeoman 1770

George V Reservoir
Site of common marsh used for Pasturage by Chingford Commoners from to 1906. Cattle marked by Marsh Reeve. Grass cutting rights.
Built by the East London Water Co. In 1898.. It is formed by a continuous embankment on the floodplain of the Lea. An mighty earth embankment divides it into two compartments connected by three large diameter culverts. The external grassed embankment consists of a central puddle clay core with shoulder filling comprising a mixture of river terraced gravels and alluvial deposits. opened in 1913, by the Metropolitan Water Board, covering 420 acres it is the largest in London. It holds 2,729 galls and has a 4 ½ mile perimeter. Water from the Lee is pumped in at the northern end and the for outlet tower is at the southern end. The water goes into a tunnel under the embankment to an open channel to the basin at Chingford Mill.
channel for surface water drainage,
The water is a Site of Special Scientific Interest. It is a major wintering ground for wildfowl and wetland birds, including nationally important numbers of some species. The water also forms a moult refuge for a large population of wildfowl during the late summer months. A total of 85 wetland species have been recorded here in recent years.
King George V Pumping Station. Built in an individual classical mannerist style, in red brick and Portland stone, by W. S. Bryan. Opened with great publicity by George V on 13th March 1913. Contains the world prototype installation of Herbert Humphrey's thermally efficient pumps patented in 1906. These devices dispense with piston, connecting rod, crank, flywheel and gearing and are powered by producer gas. A Humphrey pump is basically a large U-tube with a combustion chamber at the closed end and a delivery outlet at the other. Water in the U-tube is made to oscillate by combustion of the producer gas at the closed end and water spills out at the other. Thus at the closed end the surface of the water in the tube acts as the piston. Five pumps, made by Siemens of Stafford, were originally installed and three are in situ underground. One was by Coppermill - gone by 1993. Gas came from a Dowson producer gas plant with a small gas holder.
The surge towers of the Humphrey Pumps are surrounded by an elegant brick screen wall with coupled Portland stone Doric columns.

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