Waitara Soon to See Pipeline Construction

Construction of the Waitara to New Plymouth sewage pipeline will enter Waitara’s urban area soon.

Some properties along the pipeline’s route may have no vehicle access for up to four days, but foot access will remain at all times. Roads and intersections will be either closed or down to one lane during the installation.

“Unfortunately there will be a lot of disruption for residents along the pipeline’s route. We’ll try to minimise this as much as we possibly can but it’s important that people are aware of the impact the work will have,” says Manager Operations Graeme Pool.

“We are organising letterbox drops and door-knocks along the route, and there will be an information display in the Waitara Library and Service Centre. We’ll also have the latest information on the project’s schedule on our website at newplymouthnz.com/WaitaraPipeline – we encourage people to check that webpage regularly during the construction period.”

Work is currently taking place on the section of Brown Road from Tate Road to Te Rangitahi Heritage Walkway (formerly the Waitara West Walkway). The pipeline’s installation on the walkway itself is scheduled to start on 19 October, and will then take place on Norman Street, Broadway, High Street West and across Queen Street to the Waitara Wastewater Treatment Plant.

The installation is due for completion by Christmas.

The pipeline will be laid in 90m-100m sections at a time on the following schedule. (These dates may change depending on the weather, ground conditions and underground services that are encountered.)

• Along Te Rangitahi Heritage Walkway – from 19 to 26 October.
• Norman Street from Te Rangitahi Heritage Walkway to Broadway – from 27 October to 9 November.
• Broadway from Norman Street to High Street West – from 10 to 27 November.
• High Street West from Broadway to Queen Street – from 28 November to 14 December.
• Queen Street to the Waitara Wastewater Treatment Plant (WWWTP): A couple of days from 15 December.

The construction will be noisy from 7am to 7pm from Monday to Saturday. There will not be work outside these hours unless there is an emergency.

Vehicle access may be blocked for up to four days to each property on the side of the road where the pipeline is laid. Residents will be able to get into their homes by foot only during this time. “We encourage residents to consider where they’ll park their cars during that period,” says Mr Pool.

Traffic flows on the pipeline route will be disrupted when work is taking place in the following blocks:

• Norman Street up to Mould Street, one lane with two-way traffic (with delays); Norman Street from Mould Street to Broadway, consecutive blocks will be closed to through-traffic during construction. (Note: There will be vehicle access to those properties on the side opposite the pipeline’s installation.)
• Broadway from Norman Street to High Street West: One lane will be closed during construction with only one-way traffic available. (Note: Work may switch to the opposite lane depending on the services beneath the road.)
• High Street West from Broadway to Queen: One-way traffic (east-bound).
• Queen Street to the WWWTP: The intersection will be closed during construction.
• Intersections: All intersections will be closed for up to three days. Please keep an eye out for detours.

“Residents will see pipes being stacked on a nearby section or grass berm, ready for welding,” says Mr Pool. “One day before the pipeline trench is dug, topsoil will be stripped to check for items of archaeological interest under the supervision of a cultural monitor from Otaraoa hapu.

“An excavator will dig a trench for the pipeline, 90m-100m at a time. Some excavated soil will be stockpiled beside the open trench and the rest will be trucked off-site. Once the pipe is laid, the trench will be back-filled and the next section will have the topsoil stripped.

“This entire process may take up to four days depending on weather conditions, ground conditions and the number of underground services encountered.”

Full reinstatement of roads and entranceways may take up to two weeks, and the full reinstatement of grass berms up to four weeks, following the pipe installation – however vehicle access to homes should only be blocked for up to four days at a time.

Excavations at air valve chambers and certain welds may remain open for up to four weeks until testing of the pipeline is completed. These excavations will be fenced off and made secure.

This pipeline will connect the Waitara sewerage system to the New Plymouth Wastewater Treatment Plant (NPWWTP), where the sewage will be treated and discharged to sea via the Waiwhakaiho outfall and the excess sludge biomass dried in the thermal drying unit.

Projected to cost about $4.45 million (about $2.8 million under budget), installation of the Waitara to New Plymouth sewage pipeline is part of a larger $12.8m project that includes converting the WWWTP into a pumping station (which has yet to be tendered).

Running alongside this is an upgrade of the NPWWTP, which has a budget of $22.2m. This involves improving the efficiency and capacity of the sewage treatment (to meet the district’s anticipated needs until 2040), as well as improvements to the sludge processing and inlet structures, and additional ancillary work.