A COMPUTERISED water monitoring system used to check river levels across the state, has shown serious inaccuracies in the recent floods, with some measurements being wrong by as much as two metres.
In the Horsham district the system was installed about three years ago during the prolonged drought, but with the floods the local Wimmera Catchment Management Authority has resorted to sending inspectors to physically check river levels to get reliable information.
Problems with what is known as the Event Radio Tracking System have been variously blamed on a computer software malfunction or on the fact the monitoring points could not be properly calibrated when they were installed because of low water flows.
Council chairman of the city's Emergency Disaster Committee, Bernard Gross, said some of the measurements were so far out they had probably affected the city's preparations and in some cases had possibly created a sense that the flooding was going to be worse than it was.
Unlike cities and towns in Victoria's north-east, Horsham has avoided serious inundation despite expectations on Monday of serious flooding in the city centre.
Cr Gross who was Horsham's mayor last year, said the system had been installed to allow accurate information on river flows to be sent to centralised co-ordinating bodies.
The monitoring points are solar powered and are supposed to do away with the need for manual monitoring.
But Cr Gross said that on Monday the monitor at the town of Glenorchy upstream form Horsham showed the river level to be two metres higher than it was. ''A few houses in the town were flooded, but not that much.''
He said that further downstream, at Drung, near his own property, the automated meter had registered levels almost a metre above the true height.
''I believe they will get it operating properly eventually. In the early days of settlement people used to ride their horses into the river once a day and measure it with a stick,'' he said.
Wimmera Catchment Management Authority spokesman Paul Fennell said similar technology was in place on rivers all around the state and that at times a computer glitch meant they gave inaccurate readings.
Mr Fennell disagreed that the computer glitch had caused serious problems. ''When it happens we are able to interpret it and make corrections.''
But the City of Horsham's general manager of technical services, David Eltringham, said he believed the problem with the system had been caused by it being installed when the rivers were dry.
''There have been no significant water flows to allow us to properly calibrate it. The floods will now probably allow us to do that,'' he said.
Email a friend