Simple audit saves water
A simple “catch-can” test has identified how one Hunter Valley vineyard can improve its water use efficiency by more than 10 per cent.
The test was part of a standard irrigation system audit conducted by the vineyard’s management with NSW Department of Primary Industries (DPI) irrigation officer, Gary Creighton.
“Irrigators who have undertaken the Introduction to Irrigation Management Course and developed irrigation and drainage management plans will understand the benefits of an audit of their irrigation system,” he said.
The audit of “Adina”, near Cessnock, a 53-hectare property with 11.8ha of grapes and 5.3ha of olives, checked the vineyard’s pump, mains and the uniformity of its distribution system.
Mr Creighton said the recently refurbished pumping unit was delivering good flow rates and mains pressures.
“But a catch-can test found that distribution uniformity on the vineyard’s 10 irrigation blocks ranged from 81.5 to 94.5pc.
“The test measures how evenly the irrigation system is delivering water across an irrigation block.
“The result indicated the need to plan an upgrade of the drip lines which are now up to 16 years old.”
The property owner, Peter O’Mera, was delighted with the quality of fruit harvested at “Adina” this year, but was looking forward to the results of the audit to feed into his five-year planning for the property.
Mr Creighton said the pump performance was checked using an ultrasonic flow meter.
“A check of the shut-off head before the pumping unit revealed that it was performing as predicted on the performance curves with a shut-off head of 740kPa,” he said.
“Checks on irrigation mainlines with a portable pressure-testing kit confirmed they were also performing within system specifications.
“The next task was to assess the irrigation performance and distribution uniformity (DU) across each of the vineyard’s irrigation blocks,” Mr Creighton said.
“We did this with the catch-can test outlined in WaterWise on the Farm’s Introduction to Irrigation Management manual.
“This test is a timed physical measurement of the water output in representative sections in each irrigation block.
“Exact times were noted as four containers were placed in the first and last row of each block, and in two mid rows.
“The containers were emptied into a measuring flask after about 30 minutes, with the volume of water and exact time noted.
“The DUs on the 10 blocks ranged from 81.5 to 94.5pc, with the lower DUs recorded mainly on the older irrigation blocks.
“The management strategy for “Adina” in the next seven years is expected to include an upgrade of the drip-irrigation system on the blocks which recorded the lowest rates of DU,” Mr Creighton said.
Contact Gary Creighton, Grafton, (02) 6640 1600.