The combination of poor land and natural disaster (bushfires) may have led Arndell to centre his interests on his Hawkesbury properties at Cattai Creek.

He spent three years in the colony from 1800-1803, as explorer, cartographer, ensign, artillery officer and engineer, aide-de-camp to Governor King, architect and ship designer.

[1] Access to the school was gained from the river by means of a stone jetty and ramped gravel drive that cut into the steep slope.

Rising costs, fewer children at the two institutions and the distance of the boys' school from Sydney led to the amalgamation of the two orphanages at Rydalmere in 1850.

[1] The east wing was largely devoted to the girls' department which had its dining room on the ground floor of the first extension and dormitories above.

[1] Throughout the operational period of the combined orphanage great changes had been made in government policy for both the education and social welfare for destitute children.

During the 1870s integration of orphans into the community at large, particularly through means of "boarding out" with foster parents began to be favoured over the austere environment of the "barrack" system used at Rydalmere.

This hospital took over the Orphan School complex, growing to the north-east and north in an unusual "village" arrangement of buildings, curved around a green, and what is called the "1900 Ward Range precinct".

The period is associated with Walter Liberty Vernon, NSW Government Architect and health care advocates Frederick Manning and Dr Greenup.

[1] After World War I resources were primarily spent on upgrading existing facilities and services, particularly sanitation and safety features, for example fire stairs.

[1] Post World War II facilities were significantly expanded at Rydalmere in line with changing philosophies of patient care and accommodation.

Service aspects such as kitchens, factories, substations and workshops were generally located to the north and new administrative and recreational facilities in the centre of the site.

In June 2012 Prime Minister Julia Gillard announced $7m in federal funding to complete restoration of the Female Orphan School and the Whitlam Institute.

[5][1] The Rydalmere Hospital area is bounded by Victoria Road to the north, James Ruse Drive to the west, Vineyard Creek to the east and Parramatta River to the South.

[1] The original building is a fine symmetrically balanced composition with projecting central bay capped by a simple triangular pediment.

It was designed in the Colonial Georgian style and constructed in face sandstock brickwork with sandstone window sills, quoins and string courses.

It has a simple rectangular plan and hipped, ventilated slate roof which is topped by a finely detailed zinc lantern with an oriental character.

It is notable for the external timber stud framing and diagonal bracing supporting a gabled roof with slate covering.

[1][6]: 59–86 The physical condition of the site was reported as poor as at 28 July 1997, prior to restoration work by the University of Western Sydney.

[1] The Female Orphan School Precinct as a component of the former Rydalmere Hospital is of outstanding cultural significance, primarily for its continued use and development, between 1813 and 1989 as a public welfare institution for the care and management of the disadvantaged.

[1] As the first purpose built orphan school in the colony, it illustrates a milestone in the establishment of national social welfare and education policies.

[1][6] The structure of the built and natural fabric of the place has been conserved despite the constant adaptation by institutional uses and alienation of its peripheral lands.

As a complex of parkland landscape character with gardens, built form and remnant indigenous vegetation it demonstrates the evolution of different attitudes towards institutional care in NSW.

It has been almost continually occupied since the early years of European settlement, initially by farming activities, but more importantly, by successive public welfare institutions for the care and management of disadvantaged members of society.

The actual establishment of the orphanage at Rydalmere is associated with the governorship and development policies of Lachlan Macquarie, with his wife, Elizabeth, who is thought to have provided the design and with Samual Marsden who superintended the construction.

[1][6]: 118 The place is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement in New South Wales.

The extant south elevation, with the symmetrical pavilions, retains a particular clarity of architectural composition, despite subsequent alterations and additions.

The initial adaptations made to the old orphan school buildings to accommodate the Hospital for the Insane in the late 1880s, represented one of the last examples of a long-standing institutional approach in the care of the mentally ill, that of incarceration rather than hospitalisation.

For the potential to interpret the role of the Parramatta River as a major form of inland transport and communication in the early decades of European settlement.

As the first purpose built orphan school in the Colony, it illustrates a milestone in the establishment of national social welfare and education policies.