 It was constructed by the consulting engineers Sir William Halcrow & Partners between 1955–59 at an estimated cost of £5,515,000.It has a capacity of 120 million gallons per day (6.3 m3/s).The Metropolitan Water Board and other local Water Boards (the Thames Conservancy, the Lee Conservancy Catchment Board and parts of the Essex River Authority and parts of the Kent River Authority) were combined into the Thames Water Authority from 1 April 1974.