Johnston's Creek Sewer Aqueduct, Sewerage aqueduct in Annandale, Sydney, Australia

Johnston's Creek Sewer Aqueduct consists of eight reinforced concrete arches, each with a clear span of 75 feet (23 m), carrying a U-shaped sewer carrier 3 ft 6 in by 4 ft 6 in (1.07 by 1.37 m) across Hogan Park in Annandale. The arches rest on mass concrete piers, and the total length is 924 feet (281.6 m). The western end has a concrete retaining wall and public stairs at Nelson Street; the eastern end is near Taylor Street.

William Julius Baltzer designed this component of the Northern Main Sewer expansion, built by the Public Works Department in 1897. The project was part of efforts to serve Sydney's growing population with proper sewage systems.

The aqueduct is associated with engineer W. J. Baltzer and the firm Carter Gummow & Co., early advocates of the Monier system of reinforced concrete in Australia. It is listed by the National Trust of Australia (NSW), the Australian Heritage Commission and the Institution of Engineers (Australia), and remains a landmark of Leichhardt and Forest Lodge.

The aqueduct crosses Hogan Park between Nelson Street and Taylor Street in Annandale; public stairs and a concrete retaining wall stand at the Nelson Street end. The structure is seen from the park's footpaths, and a mature fig near a central span partly hides the carrier. The flume is closed and not open to visitors.

A large fig tree grows near one of the middle arches, creating an unexpected blend between industrial structure and nature. This natural element gives the facility a different appearance than typical sewerage infrastructure.