The Lower Clarence has experienced its biggest rainfall event since the start of record keeping in 1877, following the sizeable rainfall totals received in February and March this year.
Yamba’s cumulative total for February and March was 1267 millimetres with a total of 549mm recorded in February and a total of 718mm recorded during March.
Yamba received 274.4mm in one day alone on 28 February – the highest daily recording for the month of February since record keeping began. On 1 March the following day Yamba received 258.2mm, for a total of 532mm in 48 hours.
Clarence Valley Council has examined rainfall data from the Bureau of Meteorology’s Yamba Pilot Hill gauge as part of a review into the cause of ponding in some areas in Iluka following the major rainfall events.
“The significant rainfall has led to a saturated catchment and high water table, exacerbating the time taken for water to disperse,” Clarence Valley Council Director Works and Civil Jamie Fleeting said.
“There has been no event or combination of events since records began that comes close to the rainfall totals recorded at Yamba in February and March. Yamba’s rainfall to the end of March (1435.6mm) is higher than Yamba’s median annual rainfall (1407.3mm).
“We need to be aware that the most efficiently designed drainage systems are not built to cope with rainfall totals equal to that experienced in the recent flooding events.
“One of the issues is there are some properties at Iluka that are quite low relative to the road causing ponding. However, there are no simple solutions to this problem.”
Mr Fleeting said stage one of the Hickey Street development, including road and stormwater infrastructure, has been completed and that the development meets design control and design guidelines. He said a detailed geotechnical investigation had been carried out to examine soil permeability at the site.
“Clarence Valley Council is currently reviewing the drainage network and assets in Iluka, as well as investigating the potential to raise the concrete levee at Marandowie Drive in Iluka,” Clarence Valley Council Mayor Ian Tiley said.
Mayor Tiley said he had been in touch with the community and was aware of their concerns and was pleased to receive the detailed report from Council’s Works and Civil team.
“There is no denying these floods have had a major impact on the Valley,” Mayor Tiley said.
“When we compare the cumulative totals of rainfall data with historical flood events in January, February and March, the increase is 73 per cent above the 1974 flood event and there has been no combined event like this in 145 years of record keeping.
“We are working on providing solutions to all affected areas. Council is assessing the damage caused by the floods and determining a way forward to manage issues in the community and revitalise its assets. Please be patient while we are working on getting things fixed.”