Landslip won't affect quality
SHANNON Creek Dam managers have downplayed concerns the landslip (pictured) at the dam may lead to a reduction in water quality or further embankment problems.
Clarence Valley Council’s water cycle manager Greg Mashiah said the photo, which was taken by a valley resident from a public viewing platform, showed a landslip that occurred in one of the areas from which earth fill was extracted for the main embankment.
“The slip occurred along a downward sloping layer of weak material that had been identified in earlier geolog–ical studies,” Mr Mashiah said.
“As the water level in the dam rose, the weak material became saturated and subject to water uplift pressure.
“Further uplift pressure from the rising water induced downward sliding and the slippage continued over a number of months, but appears to have stabilised over the last 10 months. The slippage has very little effect on the dam.
“The exposed soil areas are likely to erode a little but the eroded material soon settles out and has little or no effect on the water quality.
“Council will continue to monitor the slip but will not take any action unless a much larger slip occurs in the future. This is the only significant slip that has occurred around the dam.”