A major landslip, a 2m-wide access corridor and a highly constrained drilling alignment made this stormwater renewal anything but straightforward.
Kerry Drainage & Civil developed a specialist solution to restore the outfall while working around protected trees, unstable ground and nearby residential properties.
The project began after a significant landslip caused irreparable damage to the existing stormwater outfall at Lynbrooke Avenue, Blockhouse Bay. The slip also created a risk of further ground movement close to residential properties and resulted in the closure of the community beach access footpath.
Kerry Drainage & Civil was engaged by Auckland Council to renew the stormwater infrastructure and stabilise the affected area. The highly restricted site presented a significant construction challenge, with all works taking place within an access corridor just 2m wide.
A key component was the installation of approximately 80m of 225mm PE pipe using directional drilling. The alignment required both horizontal and vertical bends to navigate around protected trees, remain within Council property and ensure the new pipe was anchored into stable clay. With pipe bends of less than 100m radius, the drilling required careful planning and precise execution.
The wider works included the construction of two 3m-high, 20m-long timber ground-anchored retaining walls, removal of slip material, construction of a new wingwall and riprap outlet, and reinstatement of the public reserve footpath.
The project combined trenchless technology, ground stabilisation and conventional civil construction to deliver a durable stormwater solution within an exceptionally constrained environment.
