The catchment of Botany Bay is approx 1,165km² in area, bounded by the Parramatta River and Sydney Harbour catchments in the North. The Hawkesbury-Nepean catchment in the west and the Hacking River catchment in the south. The catchment extends from Prospect Reservoir in the North-West, and South through the local government areas of Liverpool, Campbelltown and Fairfield. The lowridge between Port Hacking and Botany Bay forms the south-eastern boundary of the catchment. The two main sub catchments within Botany Bay catchment are the Georges River and the Cooks River.

Botany Bay and its catchment are significant, being home to many endangered species and communities, Ramsar wetlands including Towra Point Nature Reserve, migratory species, recreational, water based activities and cultural heritage.

• Towra Point Nature Reserve Ramsar site information 
  (search for site number 23)
• Towra Point Nature Reserve further information 

Botany Bay and its catchment waterways are subject to ongoing threats due to nutrient and sediment-laden run-off from various non-agricultural land uses. A substantial part of the catchment is highly developed with almost 40% of its area being used for urban, industrial or commercial purposes.

Pollutants of concern are nitrogen, phosphorus and total suspended solids.
Development pressure is contributing to degradation of bushland and recreational areas which is increasing sediment loads within the catchment.

• Barriers and opportunities to Water Sensitive Urban Design Adoption in Botany Bay catchment.
• Pollutant Load Modelling Report 

• Sydney Metropolitan CMA
• Department Environment and Climate Change

The Great Lakes of the NSW lower North Coast include Myall, Wallis and Smith Lakes.

The Great Lakes system provides habitat for a diverse number of native flora and fauna species, including large numbers of waterbirds, and is an important drought refuge. It also supports significant oyster, fishing, tourism and recreation industries.

It is estimated the area produces one third of Australia's oyster harvest.

• Myall Lakes Ramsar Site information 
  (search for site number 52)
• Myall Lakes National Park further information 

Algal blooms have been identified from time to time in the estuarine lakes, and there has been a health related water quality issue affecting the oyster industry. Water quality is affected by continued urban expansion, with urban diffuse, rural point and diffuse pollution.

Increased nutrients and sediments from catchment runoff disturbs the ecology of the lakes system and contribute to excessive growth of algae. Sediments smother or shade-out seagrasses, macrophytes (aquatic plants) and other benthic organisms.

• Projects contributing to the development of water quality improvement plan 

• Great Lakes Council
• Department Environment and Climate Change