There are three main creeks in the Blacktown area that flow north into Cattai Creek. Cattai Creek flows into the Hawkesbury River. These creeks include First Ponds Creek, Second Ponds Creek and Caddies Creek.
First Ponds Creek
The main land use in the catchment (or drainage area) for First Ponds Creek is open space and farmland helping this creek to remain in a relatively natural state.
Second Ponds Creek
The main land use in the catchment (or drainage area) for Second Ponds Creek is open space and farmland helping this creek to remain in a relatively natural state. Approximately 5 hectares along Second Ponds Creek was salt affected in 1947. Unfortunately, Salvinia does exist in this creek system; Alligator Weed and Water Hyacinth have also been identified.
Wastewater from industries in Rouse Hill is treated to a high standard, which allows it to be reused for another activity (recycled). Water that cannot be reused or recycled is released into the constructed wetland on Second Ponds Creek. The larger water plants (macrophytes) in wetlands and waterways help to remove the nutrients in the wastewater by absorbing them. The Sewage Treatment Plants at Rouse Hill and Castle Hill discharge treated sewage into Second Ponds Creek.
There are many early Aboriginal artefacts along Second Ponds Creek to the north of the Blacktown area.
The catchment (or drainage area) for Caddies Creek is mainly urban. Humans have changed this creek quite significantly; in some sections the base of the creek has been cemented. There has been a loss of local native vegetation and natural rock features from the area and development upstream has led to further vegetation loss. The water in this creek is poor and thick waterweeds choke the creek banks. Fish have not been seen in the creek for many years.
There are several sites along this creek of early Aboriginal and European significance. For example a line of stones on the edge of a pond are believed to be either an early Aboriginal fishing trap or a stone feature built by early Europeans to stop animals from entering the pond. A number of bones have been found near collapsed rock ledges large enough to shelter humans.