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Water storage problems solved

Water storage problems solved

New water storage reservoir to help Canterbury Plain’s farmer secure water requirements through summer.

Rangitata, Canterbury, New Zealand, 29 July 2009

One of the largest lined dams in the South Island has recently been installed for South Canterbury potato, specialist small seed and cereal farmer, Mr. Murray Turley. Using the latest lining technology from Firestone Building Products, this new storage structure will enable Mr. Turley to bank critical water by storing 400,000m3 of winter water, when aquifers and rivers are high due to abundant winter rainfall and Spring snow melt, which will then provide much needed relief through the ever increasing dry summers, as seen recently in the drought stricken Hawke’s Bay.

This privately funded infrastructure is planned to be part of the region’s much publicised Rangitata South Irrigation Scheme, which is planned to irrigate a total of 12 000Ha of farmland in the area. Like many of the existing and planned schemes, the aim is to provide a reliable water supply utilizing storage ponds, which is seen as the key to future growth in the primary sector for this region by Irrigation New Zealand. This belief from INZ is echoed by Federated Farmers chairman Don Nicolson. 

Mr. Turley plans to irrigate at least 1000Ha, which would have required approximately 250 000m3 storage, however in order to future proof his farming operations, he decided to increase his planned storage capacity to 400 000m3. Traditional dams in Canterbury have tended to be shallow earth dams which take up a very large foot print of valuable land and also have excessive losses associated with evaporation from a large surface area as well as seepage due to gravel sub grade conditions.   To achieve the required 400 000m3 storage from a traditional earth dam design with a depth of 2m, the reservoir would have taken up approximately 25Ha. Water loss due to evaporation alone on a dam of this size can equate to staggering 1000m3 per day in summer. To solve this problem, the client decided to build a 10m deep dam, which would take up less valuable land and have a smaller surface area which is more efficient by minimizing water loss from evaporation. Since water pressure for a 10m water depth would cause unacceptable loss to seepage, the client was presented with a range of impermeable artificial lining membranes including HDPE and EPDM.

Mr. Turley selected an EPDM membrane manufactured by Firestone Building Products due to its durability and Firestone international material warranty of 20 years, but it also satisfied the engineers future-proofing and building consent requirements by having a life expectancy of over 50 years.  Once Rooney Earthmoving of Ashburton completed the excavation and construction, Young Farmer of the year, Tim O’Sullivan, and his Canterbury Environmental Linings business partner Simon Metcalf could move in to begin the liner installation process. Due to one of the wettest May’s in 20 years for this area, installation of the 62 000sqm of Firestone EPDM liner took a little longer than expected. Now that the reservoir is complete, stockpiling of winter water can commence and is expected to take approximately 60 days to fill.  

Mr. Turley has always been an early adopter of new technology and innovative solutions in the farming community, and has again set the bar with this storage scheme. With the growing water scarcity, Mr. Turley through his efficient design to minimize water loss arable land, has planned for the future by safeguarding his water requirements for many years to come. 

Cosio Industries is the New Zealand distributor of Firestone lining products, manufactured by Firestone Building Products USA.
The material is a synthetic rubber waterproofing membrane available in some of the widest standard sizes in the lining industry, namely 15.25m x 61m, and is therefore very quick to install. The product is installed with a Firestone issued warranty on material of 20 years, under most conditions, which is very important considering the cost of this sort of on farm investment.

Facts and figures for this project:

  • Size = 240m x 240m
  • Depth = 10m
  • Maximum storage capacity = 400 000m3 or 40 000 000L
  • Surface area of liner = 62 000sqm
  • The reservoir is large enough to accommodate 8 rugby fields.
  • 60 days to fill. End of press release.