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Environmental concerns prompt stockwater plan

Rural Case Study

The quality of our natural water sources has been in the news. Stricter regional council water plans and tighter controls are among the reasons father and son John and Tom Latta are looking to install a reticulated stockwater system on their property in Owaka Valley, South Otago.

 “A reticulated stockwater system provides surety of supply and quality of water delivered and can be designed to accommodate any potential future changes in livestock farming practice,” John says.

Stock excreting in rivers and creeks, causing nutrient and pathogen issues downstream, is well understood. Perhaps less understood is the harm that sediment causes through stock pugging the banks and beds of creeks, causing slumping and erosion, siltation and water turbidity (muddy looking).

Sediment not only contains nutrients, pathogens and bacteria, it also adversely affects the habitat for instream invertebrates and native fish, reducing feed availability for trout and salmon and their ability to see prey. While pugging-induced sedimentation can be mitigated by adequate riparian buffer zones, leaving margins uncultivated and planting unstable banks, excluding stock from waterways is the best option.

With these thoughts in mind, John contacted Invercargill-based Farmlands Technical Field Officer and water systems specialist, Ken Stewart. “John and Tom’s property is rolling to hilly country, currently carrying 5,000 sheep and 500 cattle, with future-proofing plans to allow a dairy support operation or to carry up to 2,500 cattle,” Ken says. “A natural spring at height delivering enough flow allowed the design of a gravity system, with negligible on-going running costs.

This development will see the use of 22 kilometres of high-flow metric Greenline pipe, with 13 break pressure tanks managing the water pressure to 100 troughs,” he says. Paul McDonald, owner of Blue Sky Excavation, has been contracted for the development. “Paul is a great fan of the new Plasson Series 1 push-fit compression fittings and will be using them on this job,” Ken says, “as he values their quick and positive jointing system.”

In Ken’s 9 years as a designer he’s heard many favourable comments about his systems, with many focusing on the increased efficiency and short pay-back time. “It’s rewarding to hear things like that in regard to productivity”, Ken says, “and even more satisfying to know for John and Tom it’s an environmentally sustainable solution as well.”