Whangarei's drought-busting pipe

Everyone stands clear when United Civil contractors get a wriggle on.
It's an impressive sight as the contractors use a fleet of diggers to lift 150m-long sections of polyethylene pipe into a trench they have dug at the side of Whau Valley Rd in Whangarei.
It's a tricky manoeuvre with the 300mm-diameter pipe lurching along like an ailing anaconda and workmen, footpath pedestrians and rubbernecking residents from homes along the road keeping well back so they don't get clipped by a writhing coil.
The pipe will more than double the amount of water the Whangarei District Council can extract from the Hatea River and put through the water treatment plant on the corner of Whau Valley Rd and Fairway Drive.
The $1.2 million pipeline from a pumping station by the river near the AH Reed Memorial Kauri Park in Whareora Rd will increase the amount of river water which can be used for city supply from 4000 cubic metres a day to 9000 cubic metres.
As a result, less water will need to be drawn from the Whau Valley Dam, keeping it well topped up to deal with a drought like the one which dried out the North earlier this year.
The polyethylene pipe will take over from a 225mm fibrolite pipe installed along the same route in the 1950s and now ready for replacement. The old pipe will stay in the ground, but won't be used once the new one is completed. Council water services manager Andrew Venmore said the new pipe would not take the maximum volume of water all the time, but would allow the council to take as much river water as its resource consent allowed during dry weather.
"It is part of our long-term strategy to ensure an adequate supply of potable water as the district grows," he said.
"The strategy includes treatment plant, reservoir, pumping station and pipeline upgrades as well as new works like the Wilson's dam."
About 1km of pipe has been laid from the pumping station to the site of the Kamo bypass extension. Once the pipe from the water treatment plant to Kamo Rd is installed, the contractors will look at connecting the two sections with a link along the bypass extension route which will connect with Western Hills Drive.
Mr Venmore said the 2.5km pipeline was due to be completed in January, and a pump station upgrade was to take place in February.
The council was monitoring the water situation closely after two dry months in a row this spring.
"We had 92mm of rain in the Whau Valley catchment in September compared to the 38-year September average of 145mm, and only 62mm in October compared to a monthly average of 117mm.
"The dam is 96 per cent full, which is slightly better than the November average of 94 per cent."
Mr Venmore said 25 of the past 35 months had been drier than average.