The Western Treatment Plant is Melbourne's largest wastewater treatment plant. Created in the 1890s in response to the problem of sewage in the gold rush growing 'Marvelous Smellbourne' It is a created landscape of enormous productivity. The town of Cocoroc supplied workers for the Western Sewage Farm into the 1970s and the lagoon treatment system through which the water is filtered before being released into the bay is a RAMSAR wetland and regarded bird watching facility - with an incredible biodiversity of over 300 recorded species.