The Macquarie Marshes are a semi-permanent inland wetland system in western New South Wales, with 9,850ha Ramsar-listed. It is one of the more important breeding sites in the Murray-Darling Basin and Australia for large wading birds. We investigated relationships between flows, inundation and number of breeding pairs of seven wading bird species (straw-necked ibis Threskiornis spinicollis, Australian white ibis Threskiornis mollucca, glossy ibis Plegadis falcinellus, rufous night herons Nycticorax caledonicus, intermediate egrets Ardea plumifera, great egrets Ardea alba and little black cormorants Phalacrocorax sulcirostris) over a period of 36 years (1986-2022). We also investigated the effect that managed flows for the environment has had on waterbird breeding events over a 26-year period (1996-2022). About a third of regulated river water (334GL, when dams are full) is available in the Macquarie River for the environment. Numbers of breeding pairs estimated within breeding aggregations from ground surveys were also compared to recent estimates from orthomosaics of drone images. Waterbird breeding was positively related to wetland inundation with differing flow requirements among waterbird species and breeding aggregates. Managed environmental flows were beneficial for waterbird breeding events with large breeding events occurring only when Burrendong dam was operating at 100% capacity or above. This project will provide valuable insight into how both managed and unmanaged flows drive waterbird breeding within the Macquarie Marshes on a spatial, temporal and species level, which is essential for ensuring the future success of waterbird breeding events and the conservation status of the Macquarie Marshes.