From field tiles to smooth-wall pipes

The benefits of land drainage are tacitly understood by farmers, who rely on managing their water table to maximise production outcomes. Farm inputs such as fertiliser and herbicides bring incremental benefits. Soil structure is improved with greater worm activity, less soil compaction and better-quality pasture with reduced pugging. Better root system development and warmer soils over winter months increase pasture production, while dryer soils allow stock to graze wetter winter paddocks for longer periods and vehicle access around the farm is improved. The predominant land drainage pipe 50 years ago was field tiles. These short lengths of earthenware pipe had lugs on the end, so when butted together a gap was left for the groundwater to enter the pipe. It was time-consuming, backbreaking work to lay these tiles on grade, so when Novaflo, a lightweight coiled corrugated pipe with slotted holes, became available in the mid 1970s, it quickly became the product of choice. Massey University led the way in New Zealand in assessing the benefits of land drainage and providing practical information on best practice installation. Understanding soil structures, the use of imported backfill material, where mole-drains were effective and the use of laser level technology saw a quantum increase in land drainage effectiveness. In the late 1990s, Iplex Pipelines introduced the next generation of land drainage pipe under the brand name Nexus. Using twin-wall technology, two pipe extruders operated on a single manufacturing line to produce a pipe with a corrugated external wall and smooth inner wall. This was a game changer in many respects for the performance of polyethylene land drainage pipes. With the smooth-bore 110mm Nexus producing a laminar, less turbulent flow of water through the pipe, the water flowed faster, delivering an impressive 49 percent better flow than the 110mm corrugated-bore Novaflo. These test results were confirmed by the then Ag Engineering Department of Massey University. Faster removal of excess water from the soil profile amplified all the benefits of land drainage. Other positives became apparent to land drainage contractors, who took to using Nexus immediately. It could be laid on a much flatter gradient, 1:1,000 rather than 1:400 for 110mm Novaflo. This was a huge benefit on flat land with little fall, allowing longer lateral drainage lines into open culverts, negating the need to use larger bore, more expensive drainage pipe or in some cases the necessity to create more open culverts. The faster water flow through the Nexus also had the effect of flushing out dirt that had entered the pipe, stopping blockages, maintaining the full-bore drainage performance and extending the life of the drainage network. With 160mm Nexus delivering 69 percent greater flow than 160mm corrugated bore Novaflo and the addition of a new 200mm Nexus diameter, land drainage systems became easier to design and install with maximised performance. How times have changed!

| Land drainage has improved considerably with the development of better pipe technology.

For more information on land drainage or other rural pipeline matters, contact your Farmlands Technical Field Officer or the friendly team at your local Farmlands store

| The corrugated walls of the original Novaflo, above, created a turbulent flow. The smooth walls of Nexus produce a faster flow. Article supplied by Iplex