Flood levels don't add up
THE accuracy and frequency of river height reporting during the most recent Clarence River flood has come under fire from the SES and farmers alike.
Frustrated sources within the SES complained the Bureau of Meteorology's website, which has access to real-time data from telemetric river gauges, was being updated too infrequently as the river rose on Australia Day and January 27.
This, say farmers, including Lower Southgate cattle/soy/maize farmer Phil Ensbey, led to further delays in reporting on local radio stations.
"Early on we knew that it would be higher that what was predicted ... we spoke to people up river and looked at the local rain and knew it would be closer to five (metres) than four," he said.
The river peaked at Grafton at 5.5m on January 2, but an SES source said this was 0.2m lower than the real level.
Various sources said yesterday some gauge readings on the BOM site were up to six hours old and an SES source said gauge updates were regularly two to three hours old despite telemetric readings being available in real time.
Veteran Southgate farmer, now Grafton resident, Eddie Smith said he had been contacted by several of his former neighbours looking for accurate information.
"Most people were disappointed at the information they got and some said they couldn't get any information at all."
The manager of the Bureau of Meteorology's NSW Flood Warning Centre, Gordon McKay, said as a rule of thumb, gauges below the tidal zone (below Rogan's Bridge in the case of the Clarence) were managed by Manly Hydraulics Laboratory (MHL), a business unit of the NSW Department of Finance and Services, and those above the tidal zone were owned and managed by the NSW Office of Water.
Mr McKay admitted there had been problems with the frequency of uploads and the management of the data supplied by MHL, but he said the BOM was in the middle of an upgrade.
He said the higher-than-expected rainfall led to numerous updates of flood predictions.
Mr McKay said MHL received data updates from the gauges through the Telstra network and in turn updated the BOM.
Other sources said the previous telemetric system, where a gauge could be phoned up for the latest reading, had been abandoned because the phone numbers had gradually filtered out into the community and the public was flattening the onsite batteries from overuse.
MHL water level and rainfall officer Sarah Hesse said MHL updated information to the BOM based on the BOM's request.
Ms Hesse said she had not heard of any problems or inaccuracies in the latest event.
NSW SES director of community safety Steve Opper said there were temporary malfunctions in gauges in almost every flood event and while he recognised this could be a maintenance issue, he said, flood warning was not the main role of many of the gauges.
He said many of the gauges were used for water resource management but had a dual role in flood time and that any increased maintenance schedule was a matter of resource allocation.
Mr Opper said the BOM, SES and local councils worked together to physically check gauges if the figures didn't correlate.
Grafton's Bill Paterson of Paterson Consultants has worked throughout the state on flood issues for four decades.
He expressed frustration at the lack of improvement in flood response despite more frequent flood events and called for better public access to flood gauge information.
"That information needs to be more freely available rather than relying on press releases from the bureau," he said.
Asked about unofficial reports of ants building nests in and around gauges and destroying them, Ms Hesse said she wouldn't be surprised considering ants were attracted to the heat in electronics.
She said sometimes mud on pressure sensors could throw gauges out after a flood.