Bone dry Bibra Lake awaits rain


More desert than lake: Bibra Lake is now only 5 per cent full.         www.communitypix.com.au   d450992
More desert than lake: Bibra Lake is now only 5 per cent full.        www.communitypix.com.au d450992

The lake, which Cockburn’s parks and environment manager Anton Lees said was less than 5 per cent full, more closely resembling a barren desert than the lush body of water people are used to.

But Mr Lees said the lake’s current state was part of an annual cycle. He said the majority of wetlands on the Swan Coastal Plain are surface expressions of the groundwater table, with the water you can see representing the height of the groundwater table in the area.

With less rain in summer, the groundwater level drops below the base of the wetland and, like Bibra Lake, appears dry.

“Water levels will again rise when we receive our winter rains,” Mr Lees said. “What we are seeing today is more akin to a natural cycle of wetting and drying that our wetlands regularly went through prior to development.

Mr Lees said developments around Perth meant many wetlands were retaining water all year round.

He said this was unnatural.

“The reason they retained water in the past was because of the clearing of the natural bushland,” he said.

“Each large tree acts like a pump and the larger ones would use almost 500 litres of water per day.

“When the vegetation was removed for housing there were fewer pumps and groundwater levels rose.”