Harvey's dam runneth over

After record rainfall in winter and spring, Harvey Dam overflowed at the weekend.

What began as a trickle on Friday was definitely flowing on Saturday as water ran over the spillway.

This is the first time water has overflowed at the 11-year-old structure since the Water Corporation extended the old Harvey Weir in 2002.

Harvey Water operations manager Stephen Cook said the company was pleased to see the dam overflowing after three years of low allocation levels.

“Given that our water resource is climate dependent, Harvey Water has to adopt a conservative approach to the management of water,” he said.

“Our objective is to reduce exposure to peaks and troughs of supply by sensible management of the dams.”

He said allocation levels would have to remain steady because water levels were down at other Harvey Water dams.

“While the Harvey Dam, with its large catchment area plus the inflow from Wokalup Pipehead Dam, performed very well, Logue Brook Dam and Waroona Dam performed poorly and were both at less than 50 per cent of capacity,” he said.

“There is still pressure to manage the water wisely because the Harvey Weir is only one dam.

“For the long-term interest of irrigators we must consider all the dams together and we have to work to be equal for everyone.”

Bureau of Meteorology technical officer Michelle Dalpozzo said Harvey had received above average rainfall in the past few months.

Harvey’s July, August and September averages are 154mm, 137mm and 121mm, respectively.

But 209mm of rain fell this July, followed by 213mm in August and 211mm in September.

Miss Dalpozoo said the constant daily rain had kept the soil moist and caused rain to run off into the dam instead of soaking into the soil.

She said rainfall was expected to return to average in the coming months.