Area Q Wastewater Infrastructure-Tie Ins Construction

Bell Block, New Plymouth, Taranaki

New Plymouth District council



This project was divided into 3 sites. The first stage was the Inglewood diversion which involved installing 3 new manholes with a new sewer line running through them and containing knifegate valve, mag flow metre and Ballcentric valve, two of which were 3 and a half metres below ground level and needed steel caging and confined space entry to complete the works. Re instatement required new Kerb and channel and small amount of new pavement. The main Challenges faced on this site was underground services which came from every angle as well as overhead power as well and working at a depth that we were in ground water.

The second stage was at Hickford Park, where we installed a 2300mm manhole over the existing 600mm sewer main and removing the top section of pipe. We then connected on to an existing HDPE pipe installing a gate valve and tying it into the manhole so it would flow into the 600mm pipe. This process involved planning and careful timing to tie in as there was only a small window of time that the sewer pump station could be shut down.

The 3rd stage was in the middle of the New Plymouth Golf Course, this involved laying a new 600mm pipe line through the middle section of the golf course. Fill was brought in to the site from a borrow area on the course to build up the section of course the pipe was going through. This involved constructing gabion baskets along the edge of the ponds to allow us to build up. The pipe was then laid between 2 new manholes. The tie in process involved over pumping the live sewer between a manhole before the job and a manhole after the job to allow tie in works to go ahead without stopping the flow of the sewer. This again involved careful planning and timing around flow rates and the weather as well as storage at the Inglewood plant. During the job there was the construction of a new access track pathway which was built over the new pipe line, the end result speaks for itself. The challenges involved on this site was working in a live golf course with golf balls flying around, Planning work around any competitions the course had and working around the weather.