Data pooling on beach sand
COTTESLOE Council’s beach study has found that sand continues to cause erosion in North Cottesloe, with data being used to determine if sea rises will affect any proposed ocean pools.
“Absolutely it will have to be taken into consideration, and the possibility of any future coastal erosion will be taken into account,” Mayor Jo Dawkins said.
The third annual Cottesloe Coastal Monitoring study from April 2016 to March this year also recommended the council consider how much sand would be needed for replacement sand dumping.
Surveys for the study found erosion at 15 of 18 sites at North Cottesloe Beach, where estate agent Chris Shellabear has mooted an ocean pool.
There was less sand at two of the 10 sites from Cottesloe Beach south to the Dutch Inn Groyne but at only three of the nine sites south of the groyne.
It was noted there was a net overall loss of sand on the town’s 4.5km of coast, mostly north of Cottesloe Groyne, when seasonal changes between winter and summer beach patterns were studied in November last year and April this year.
However, in March there was an unseasonal summer storm that undermined beach steps at Cottesloe Groyne.
Unseasonal and more powerful seasonal storms are climate change predictions, with effects amplified by any sea rises.
However, the study’s 2016-17 report said comparisons of seasonal beach patterns over several years indicated similar results and there was confidence the patterns had not been “heavily influenced” by any changes in the seasons.
Engineering services manager Nick Woodhouse said the overall erosion was in the “general area” of that previously recorded, but a minimum of 3-5 years of data was still needed.
A decision will be made on whether the groyne’s steps are repaired, replaced or renovated for universal access, he said.
Town engineer Nick Woodhouse and Cottesloe Mayor Jo Dawkins where the study found ongoing erosion at North Cottesloe.