Willandra Creek leaves the Lachlan at Willandra Weir approximately 50-km west of Lake Cargelligo and immediately downstream of Lake Brewster. The creek is part of the regulated Lachlan River as far as the Willandra Homestead downstream of which the creek is unregulated. Willandra Creek is a Black Box dominated system with River Cooba and Cumbungi. River regulation and works at the creek off–take mean that the creek now receives more reliable flows that would have occurred naturally, with the consequence that River Red Gum is beginning to establish in the upper reaches of the creek. The creek, particularly the National Park, supports a wide-variety of species and ecological features. Morrison’s Lake, formerly a town water supply, is under the management of NPWS NSW and provides habitat for a variety of wetland-dependent species.