The 4.5 kilometre existing Birkdale wastewater main sewer from Highbury to Beach Haven, near Auckland, serves a population of 10,000 people and has reached capacity. The old pipe is currently being replaced with a much larger pipeline able to meet current and future population projections.
In November 2006, a moratorium was imposed on development in the Birkdale catchment in reaction to continuing dry weather sewer overflows which flowed into the Eskdale stream.
With the completion of the first stage of the program (Birkdale A), the new trunk sewer in the lower end of the catchment has now been commissioned. This means more than 3,600 properties contributing flow to this section of line have had development restrictions lifted.
The remaining 922 properties at the top of the catchment still have the moratorium in place until the next section of work is completed.
The upgrade is being carried out in three stages – A, B and C. Stages A and C will upgrade the existing pipes at the lower and upper ends of the catchment. Stage B will join these two sections in the middle.
Birkdale A, consisting of 1,400 metres of predominantly 1,050 mm diameter pipe installed by microtunnelling, has been completed.
Birkdale B is currently in the consent phase and construction works are planned to start in September/October 2009. This will involve the installation of a new 525 mm diameter, 1,100 metre long sewer and two smaller length sewers.
Work on Birkdale C is underway. This stage includes the installation of a new 960 metre, 450 mm diameter sewer and four smaller length sewers in War Memorial Park, Birkdale. Most of the sewer will be horizontally drilled, which means minimum disruption to residents, road and park users.
The $NZ19 million project is on track to be completed in late 2010.