PM turns first sod on Central Plains Water irrigation scheme

29 April 2014

PRESS RELEASE

PM turns first sod on Central Plains Water irrigation scheme

Prime Minister John Key today turned the first sod of the $375 million Central Plains Irrigation Scheme near Hororata in Canterbury.

First conceived in 2001, Stage 1 of the 60,000 ha scheme is expected to deliver water to 20,000 ha of Central Canterbury in September next year.

Chief executive Derek Crombie said that the first major work on the $140m first stage, comprising the 17km-long headrace canal and bridges, will commence immediately, with construction of the 130km-long pipeline network picking up momentum mid-year.

“We expect to have up to 150 contractors working on a number of sites in the near future and to this end we are heartened by the experience of our two major contractors, Fulton Hogan/John Holland JV on the headrace canal and Downers, supported by subcontractors Aquaduct NZ Ltd, for the pipe network.

“Our plan is to have the headrace canal and bridges substantially finished by the middle of next year, including lining the canal. This means we should be able to fill the canal in July which will give us nearly two months of testing and tidying up before water officially flows in September 2015.

“As for the pipe distribution network, the intention is to build a pipe manufacturing plant in the scheme area. We will start now with laying some of the smaller pipes that can be manufactured locally and look to have the new plant up and running towards the end of winter. The first shipment of pipe plastic for the plant is already on the water,” he said.

Crombie said that while the journey to today’s sod turning has been long, there has always been strong farmer support that kept the project going.

“Firstly I have to acknowledge the farmer shareholders who have invested $40 million in the project so far, as well as the Board and Directors such as former chairman Pat Morrison and present chairman Doug Catherwood. We have also had ongoing support, including financial assistance, from the Selwyn District Council and the Ministry for Primary Industries. “

“All have made significant contributions,” he said.

As well as the Prime Minister, other notables in attendance at today’s ceremony were the Rt Hon David Carter, Hon Nathan Guy and the mayors of Selwyn (Kelvin Coe) and Ashburton (Angus McKay).

Key facts and figures of interest

Headrace

• Contractors will have less than 18 months to build the 17km-long headrace canal and 130km-long pipe distribution network.

• For the headrace and canal we are going to have to move 1.9 million cubic metres of earth, which includes 377,000m3 of topsoil, the equivalent of removing the topsoil from 125 hectares. We also need to install 550,000m3 of HDPE liner.

• We will build 13 bridges spanning approximately 25m each (10 on farm bridges and 3 public road bridges)

• For stage I it is estimated the contractors will use up to four teams of 6 x Cat 627 scrapers to keep to the timetable. The scrapers will work in pairs (push-pull configuration) to scrape off the topsoil layer followed by the subsoil and then the substratum material.

• The topsoil will be scraped off from the corridor and stored in a windrow along the alignment. The subsoil will also be scraped off from the corridor and stored in another windrow next to the topsoil windrow. The substratum is the material that will be used to form the canal.

• From edge to edge, including side roads, the canal will be around 40m wide and 17km long. It will have a capacity of 33m3 per second and is designed to withstand a one-in-100 year flood in the Rakaia River. During construction the canal will look like a highway.

Distribution network

• The pipe distribution network largely consists of a number of pump stations and four main pipelines extending from the headrace canal down the Canterbury Plains to supply the various farms (this may be reduced to three main pipelines as part of the optimisation design stage)

• These main pipelines will be constructed between May 2014 and August 2015, with work on the southernmost pipeline commencing first.

• With 130km of pipe to lay, contractors will eventually be working simultaneously on all main pipe lines at the same time, up to six days per week. We expect to take around three to five working days per km of pipeline depending on the pipe size and nature of the material being excavated.

• The pipes will be buried at a depth of no less than 900mm to prevent pipe floatation and to avoid impact from agricultural activities.

Three-stage programme

• Stage 1 - 23,000 ha - Te Pirita, Sheffield. Construction, April 2014 - September 2015
• Stage 2 - 10,000 ha - Hororata - Greendale – Burnham. Construction, September 2015 - September 2016
• Stage 3 - 27,000 ha - Coalgate - Darfield - Kirwee – Waimakariri. Construction, September 2016 - September 2018

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