on the New South Wales State Heritage Register on 23 March 2012 having satisfied the following criteria. The place has a strong or special association with a person, or group of persons, of importance of cultural or natural history of New South Wales's history. Lake Parramatta Dam is associated with four persons of state significance in the mid to late nineteenth century colony of NSW: Captain Percy Simpson, Edward Orpen Moriarty, Cecil West Darley and William Randle (Randall). Captain Percy Simpson (1789-1877), surveyor, engineer and administrator. Simpson was initially appointed engineer for the dam works and is believed to be the designer. As a free migrant to NSW in 1822, Simpson gained experience managing convicts as the commandant of the convict agricultural settlement at Wellington (1823). In 1828 he was appointed as an assistant surveyor of roads and bridges and from 1828-32 he supervised the construction of the Devine's Hill section of the technically challenging Great North Road at Wisemans Ferry where he developed his skills in the use of ashlar retaining walls. This section of the Great North Road is testament to Simpson's engineering skills and his supervision of convict labour (some working in irons) to a very high standard of construction. Simpson's ability to manage convict labour and his administrative and engineering skills were recognised by successive governors. Surveyor General Sir Thomas Mitchell knew of "no other officer in the Colony to whom I could with better expectation as to the results, intrust any work connected with the formation of roads, bridges and streets.". The challenging road from Lapstone Hill to Mitchell's Pass in the Blue Mountains, bridges at Wollombi, Lansdowne and Duck Creek and the Queens Wharf at Sydney Cove are all attributed to Simpson. Following colonial administrative positions in the 1830s, Simpson returned to Ireland in the 1840s to work on railways. He returned to Sydney in 1850 as a civil engineer and was involved in the radical new design and construction of Lake Parramatta Dam. He remained in Parramatta in the 1850s and 1860s serving as a district registrar. Edward Orpen Moriarty (1824-1896), consulting engineer and surveyor About 1849 Moriarty commenced private practice in Sydney as a civil engineer, carrying out various schemes including the development of coal mines at Wollongong; design of the first Pyrmont bridge across Darling Harbour, timber bridges over the Murrumbidgee at Wagga Wagga and the Nepean at Richmond, and supervision