Thirlmere Aqueduct Over the River Irwell

The Thirlmere Aqueduct over the River Irwell is a water supply aqueduct built in 1892 for the Manchester Corporation Water Works. It was designed by engineers J F Bateman and G Hill. The structure features cast iron arches, spandrels, and parapet balustrading, all rising from ashlar and coursed squared gritstone block abutments and intermediate piers. It is a triple-arched design, with decorative pierced spandrels connecting the arches through pierced transverse girders.

Above the arches, there is a broad band of triangular strutting, followed by a shallow band of similar design, and then the arcaded parapet balustrading topped with a moulded handrail. In the center of the balustrade on the central arch, there is a plaque displaying the coat of arms of the Manchester Corporation along with the inscription 'Manchester Corporation Water Works - 1892'. The intermediate piers are faced with ashlar and feature carved and domed cutwaters on the north-west side.

The structure includes springing stones for the cast iron arches above, a projecting cornice at the level of the parapet base, and projecting moulded caps. The ashlar-faced abutments have a cornice that matches those on the piers, and the aqueduct deck is divided into three longitudinal bays by intermediate metal strutting, supporting two large-section water supply pipes along with subsidiary piping in the third bay. This carefully-proportioned aqueduct was designed to harmonise with the adjacent road bridge and is a significant part of one of the most ambitious late-19th century civic water supply projects, intended to deliver water from the Lake District to Manchester.