Upper Mangatawhiri Dam: Valve Tower Upgrade
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Client: Watercare Services Ltd
Location: Hunua Ranges
Contract Value: $650,000
Completed: Jun 2007
Main Contractor: Brian Perry Civil


The Upper Mangatawhiri Dam is located on land owned and operated by the Auckland Regional Council at the headwaters of the Mangatawhiri River in the Hunua Ranges.

The Dam has supplied an average of 54000³/day of raw water since its commissioning in 1965.

Work Scope:

  • Provision and installation of 10 No. ground anchors 150mm in diameter approximately 16m into the formation rock beneath the valve tower.
  • Installation of a 10m long "dead-man" pile anchor to the abutment of the access bridge.

All access for plant, materials and labour was through a 1.2m² opening and up a 200m tunnel to the base of the Tower.

Throughout the period of the works the Dam supplied raw water into the Watercare network