Nepean River - Floods in The Nepean District

Floods in The Nepean District

Early floods

The first flood on record - apparently a small occurrence - was in 1795. Others followed in 1799, 1806 and 1809. In 1810, after a series of major floods on the Hawkesbury, Governor Macquarie proclaimed the ‘Macquarie Towns’ of Windsor, Richmond, Wilberforce, Castlereagh and Pitt Town in an attempt to ensure that development was restricted to higher ground, free of flooding. The devastation caused by flooding in February, 1817 prompted Governor Macquarie to issue a notice exhorting settlers, in the strongest possible terms, to build their residences above the established flood levels.

The most devastating flood occurred in June 1867, the Nepean River being estimated to have reached a height of about 13.4 metres in the river, and 27.47 metres on land, i.e. 27.74 metres AHD (Australian Height Datum). This flood carried away the approaches to the recently rebuilt Victoria Bridge. Emu Plains, Castlereagh and the lower parts of Penrith were all under flood, causing immense loss of property. Many houses were carried into the river by landslides. Many residents were forced to take refuge in public buildings such as the Penrith Hospital and the public schools. A major flood such as that of 1867 caused inundation of over 16,000 dwellings and damage costing in the order of $1.4 billion.

There have been other notable floods since, particularly that of July 1900 and March 1914. Again there was much flooding of streets and loss of houses and property along the river.

1974 was another significant La Niña flood event.