The rain started in the Lockyer Valley west of Brisbane on Monday 10 January 2011 and rainfall, announced late the next morning by the Bureau of Meteorology, reached rates of 80 mm to 100 mm per hour.
A second rain event occurred on Tuesday when floodwaters from Grantham and Toowoomba started to flow through the Lockyer Creek through Gatton.
"Five minutes of no pump activation at a peak rain event can be a very significant issue," says Allan Dall, divisional manager of Sydney processing operations with Barden Produce.
Submerged pumps
Barden lost $500,000 worth of crops at Gatton, including 200,000 bunches of Asian vegetables at its five-acre hydroponic facility, when two submerged evacuation pumps stopped after energy supplier Energex cut the power supply.
"They were actually working and controlling the flood until they cut the power to the town," says Barden Produce national hydroponics manager Nathan Clackson. "When the power went, the farm went under in like two minutes."
Clackson was at home in Peats Ridge on the NSW Central Coast when the flood event occurred.
"I was down here and I sent the farm manager back to turn [diesel generators] on," says Clackson. "The police turned him around because they shut the road down."
Controllers under water
The pumping sheds, which feed the hydroponic tables, were flooded and recirculating pumps for the facility stopped operating.
"It swamped controllers, pumps, electrics, generators, you name it," says Dall. "Even the actual tables themselves, some of them were underwater."
Barden supplies major supermarkets including Coles, Woolworths and Aldi, as well as independent customers. Produce was shipped from Barden’s Peats Ridge (NSW) hydroponic facility to maintain supply.
"I built the farm, I knew exactly what we were missing, so I went to see my irrigation supplier," says Clackson. His controls supplier is Thinkwater Irrigation.
"They rang up Brown Brothers, who sells the pumps, and they got some flown in from overseas," says Clackson. "I got them landed two days later. They rang up Kenran and Kenran made me six new pump starters."
Replacement gear
Clackson drove to Queensland bringing replacement equipment in his car. "I got in what I could," says Clackson. "What wasn’t in stock we flew in from overseas.
"I got stuff delivered to me that Saturday lunchtime from suppliers and I drove up Sunday night from Sydney to Gatton and basically I reinstalled all the pumps and controllers over the next two days and got the farm running again," he says.
"While I was doing that we had some labourers cleaning the farm down, getting rid of all the mud using pressure cleaners and all that sort of business, to fix it all up," Clackson explains.
"From a capital investment perspective, every hole here in this facility costs us money every day," says Dall. "If there’s nothing in it we’re not making any money.
"From a fulfilment of customer orders [perspective] – commitments that they’ve given us for volumes that we have to deliver – if we’re not planting into these holes in four to six weeks we’re not going to have crop available to supply to those customers, to [meet] those commitments."
Probes in the white box at top right feed pH and EC readings to the Bluelab Dosetronic controller, which controls the Peridoser dosing unit at bottom. There are six tanks and systems like this at Barden’s Gatton facility.
Dosetronic dosing controllers and Peridoser dosing units were flown in from manufacturer Bluelab in New Zealand.
"Bluelab responded pretty quickly to me needing dosers and sent them straight over," says Clackson.
Barden’s flowmeters provide an indication of the volume of tank water – which is dosed with nutrient solution, acid solution and alkali solution – being transferred back to the hydroponic tables.
The tanks hold 5,000 litres each and there are six tanks, three in each shed.
The flowmeter senses whether or not water is moving in the system. "It can alert our farm manager if there is an issue either in partial obstruction to the flow or whole obstruction to the flow," says Dall.
Probes from Bluelab take a measurement of pH and electrical conductivity and the output.
"It’s taken every 30 seconds," says Dall. "Obviously there’s a small delay from the time that you add the dose of nutrient into the tank and when [the reading] comes back to the doser."
Three solutions
The signal is fed to the Dosetronic unit that controls the Peridoser unit, which dispenses the three solutions into the storage tank.
"Our priority was, being that there’s six systems, to get three operational," says Dall. Staff were planting seedlings at the hydroponic facility a week after the flood event.
"I had half the farm going in the first day and the other half the second day," says Clackson. "At the end of the second day we planted a heap of seedlings and caught up on what we missed out on.
"We were harvesting our crops before other farmers could get onto the ground that they had for field growing."
Barden now has a failover system in place in the form of a manual diesel pump that can supplement the two evacuation pumps.
"That gives us the opportunity where, if the pumps and the controls fail on that rainwater evacuation, we’ve got a secondary option to try to maintain that, and reduce the water that’s there before it floods the pumping shed in future," says Dall.
Think Water Peats Ridge
t: 02 4373 1466