Context

The Hawkesbury River is a semi-mature tide dominated drowned river valley located to the north and west of Sydney. It is part of a larger more complex river system known as the Hawkesbury-Nepean Catchment, which is one of the largest coastal basins in NSW. 

The catchment area is approximately 21,400 square kilometres and it includes a number of major rivers and tributaries including the Hawkesbury-Nepean, Colo, Cox, Grose, McDonald, Wollondilly and Warragamba rivers. 

The river system starts south of Goulburn with the Mulwaree River and on inland facing slopes west of Wollongong. A number of tributaries flow out of deep canyons in the Blue Mountains. As the river makes its way north it meanders through flood plains at Richmond and Windsor where it is joined by South Creek, which drains much of the urban run-off from Western Sydney. This run-off includes areas which have only recently been opened up to development in the north-west sector of Sydney. After the rural area of Sackville, the river continues to gradually meander east through steep sandstone country to the estuary at Broken Bay and Pittwater before entering the sea.

The Hawkesbury-Nepean Catchment comprises of a number of major towns including Penrith, Gosford, Goulburn, Camden, Katoomba, Lithgow, Richmond, Windsor, Mittagong and Bowral. 

The Hawkesbury River and its estuary has great social, environmental and economic significance to many communities in the Sydney and Central Coast regions. As well as the ongoing relationship traditional owners have with the river system,  many local people have strong historical and cultural ties to the river dating back to early colonial Australia. The river, estuary and its tributaries support a diverse ecosystem including rainforests, woodlands, grasslands, mangroves, saltmarshes, tidal mudflats and sand bars which provide habitat for a diverse array of flora and fauna. It's used for a variety of recreational pursuits, including fishing, boating, swimming and canoeing/kayaking. The rivers and dams within the catchment provide the majority of Greater Sydney's drinking water and the system supports a 259 million dollar agriculture industry. Other commercial activities occurring within the river system include boat hire and charters, short term holiday rental properties, oyster farming, and commercial fishing. 

Brewongle Environmental Education Centre is located at Sackville North on a ridge above the Hawkesbury River. The fieldwork study site is located on a bend of the Hawkesbury River between two sections known as the reaches. Sackville Reach extends from the south-west and Portland Reach to the south-east of the site. 

The land was originally inhabited by the Dharug Aboriginal Peoples. Since Europeans began settling in the area from the early 19th Century, the natural vegetation of the area has been modified by farming practices, school buildings and rural residential properties.

Today, this section of the river is lined with rural blocks, some of which are used for farming, others as lifestyle properties and water-ski parks.

Sackville North Public School was located on the site from 1878-1972. Brewongle Environmental Education Centre was opened officially in 1979 and is a facility that hosts other schools on day and camp visits.