Extreme Weather Flood Relief:
Morningside Stormwater Upgrade

Ongoing flooding in Whangārei's CBD, drove the construction of a one kilometer-long flood relief channel, to protect residents and the foundations of the city's rail infrastructure.

United Civil was awarded the Morningside Flood Relief Drain contract, to reduce the risk of flooding in Whangārei during extreme weather events.

Over a four month period, a 1000 metre flood relief channel was constructed between the Morningside Basin and Limeburner’s Creek. This was within the existing KiwiRail corridor, including a Rail Possession to facilitate culvert construction under rail infrastructure.

The works included site clearance, service diversions, bulk earthworks and construction of twin box culverts underneath the railway lines over the Christmas holiday period (which we completed ahead of schedule and to KiwiRail standards). We also did drainage, gabion wall construction, fencing, bespoke guardrail and anti-access covers, reinstatement and landscaping.

Key features included:

  • close liaison with KiwiRail to ensure there was no unplanned disruption to the rail service
  • manufacture of the precast box culvert units weighing 13 tonne each, precast concrete wall panels and insitu concrete works to form the culvert crossing and inlet/outlet structures in the KiwiRail yard
  • service diversions were required to facilitate construction of the new flood channel – all traffic management, erosion and sediment control measures were planned and managed by us.

This was a challenging project with all works undertaken in close proximity to existing KiwiRail infrastructure.