60 Million Litres per Day Floating Pump Station, Waikato River, New Zealand

Abstract

After drought conditions were experienced across New Zealand in 2019, Watercare determined that the 175 million litres per day (MLD) upgrade to the Waikato River to Redoubt Reservoir (R2R) project should be increased in capacity by including a 50 MLD water treatment plant (WTP) on the Waikato River at a remote location 60 km south of Auckland, New Zealand. Required for urgent drought mitigation, the WTP was designed and commissioned within 12 months, enabling water delivery to Auckland by southern hemisphere Winter 2021. As a conventional pump station could not have been constructed at this remote site within the timeframe, a floating pump station was developed utilising modular Linkflote pontoons to support the equipment, gangways for services and access and tubular piles for restraint. With principal issues of constructability and short programme, the superstructure design incorporated a steel spreader frame to distribute relatively high, concentrated loads over the Linkflote pontoon system.