Flood-damaged Mt Crosby Weir repaired & ready for wet season

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Flood-damaged Mt Crosby Weir repaired & ready for wet season
1 November 2013 - text & images - SEQWater

Essential repairs to Mt Crosby Weir, a critical link in Brisbane and Ipswich’s water supply chain, have been completed in time for the summer wet season.

Mt Crosby Weir is one of the most important assets in South East Queensland’s bulk water supply system. Water from the weir is pumped to the region’s largest water treatment plants, which supply most of Brisbane and Ipswich’s drinking water.

A diver sent in to inspect the weir and associated infrastructure following Ex-Tropical Cyclone Oswald in January discovered significant damage to the structure, most likely caused by the huge volume of water and debris that flowed down the Brisbane River as a result of the wild weather.

 Work at the weir included hauling out a 22-tonne log, which was wedged in one of the two intake pipelines to the Mt Crosby East Bank Water Treatment Plant.

Once the log was removed, about 300 tonnes of rock and sediment that had accumulated in the intake pipeline had to be cleared away.

Numerous sections at the toe of the weir had been severely undermined and immediate action was taken to shore up the structure while a new concrete toe block was constructed to support the toe of the weir.

The repairs began in late June 2013 and, despite a number of challenges including the need to build a coffer dam to confine the flow of the Brisbane River to allow for a detailed inspection of the structure to be carried out, the works were completed in less than five months.

Originally built in 1926, the remediation works were the first major maintenance works at the weir since it was transferred to Seqwater in 2008.

While every effort was made by Seqwater and its contractor to reduce noise and community disruption during the works, Seqwater thanks the Mt Crosby community for their patience and understanding during this important project to ensure a safe, secure, resilient and reliable water supply for the cities of Brisbane and Ipswich.

The Mt Crosby project is part of an extensive program of works Seqwater is undertaking to prepare for the 2013-14 wet season.