William Girling Reservoir

and the William Girling Reservoir in background]] The reservoir was conceived as part of an overall plan for the Lea Valley and laid before the Royal Commission on Water Supply (Balfour Committee) in 1893. At the time the responsible authority was the East London Waterworks Company. However, under the provisions of the Metropolis Water Act 1902, the undertakings of this and seven other companies were transferred to the Metropolitan Water Board (MWB). Work began in 1936 when the tender of John Mowlem (for £682,156) was accepted. The project was led by civil engineer, Robert Wynne-Edwards. Due to the use of mechanical scrapers and bulldozers, which were being used for the first time in…

The geology of the site is alluvium underlain by river terrace gravels and in turn overlying the London Clay formation. The reservoir is formed by a continuous earthen embankment that encloses the basin. The embankments consist of a central puddle clay core with a selected material adjacent to the core forming a filter. The core is a maximum of 12 ft wide at the base and tapers to 5 ft wide at the crest. The core typically extends 3 ft into the London Clay to form a watertight cut off. The embankment shoulders consist of zones of ballast and filling material. The upper embankments slopes are 1 in 2.5 externally, whilst the lower slopes to the berm were constructed at a bank slope of 1 in 8.…