The Western Sydney Orbital (WSO) is a major development a portions of which lies within the Cabramatta Creek catchment. To mitigate any adverse impacts on flooding patterns in the area three detention basins are proposed: a basin located between Ash Road and west of WSO at Prestons; a basin located on both sides of Illaroo Road and east of WSO at Hoxton Park and Prestons and a basin located between Cowpasture Road and Government Road east of the WSO at Hinchinbrook.