Wollongong council hopes to clean out Towradgi Rock Pool within the next three weeks but in the meantime has removed 500 tonnes of sand from the pool at Bulli.
Recent weather has pushed more sand onto the city's beaches, leaving Towradgi pool in particular almost entirely filled.
The spokesperson said emptying Towradgi pool of sand was a big job that would take time and extensive resources.
"Looking at the longer-range tidal forecast, we're working to have the pool cleaned in the next three weeks," the council spokesperson said.
They said rock pools were "particularly challenging" to maintain.
"Their location right on the shoreline means you need a combination of low tides, seas and swell to be able to empty, clean and then re-fill the pools," the spokesperson said.
"Plus, we need to make sure the weather forecast doesn't mean a pristine pool would be re-filled with sand or seaweed just hours later."
The pool cleaning crew had three 20-tonne excavators, a backhoe and a bulldozer ready to complete the work at Towradgi as soon as possible, the spokesperson said.
But while most cleans take four to six hours, the significant amount of sand means this time around the job is likely to take several days.
This week the crew has been cleaning the rock pools in Woonona, Bulli and Coledale.
For the first time they had to bring in an excavator at Bulli, a pool that ordinarily does not need this level of machinery.
"It's estimated some 500 tonnes of sand were removed from the pool," the council spokesperson said.
The spokesperson said there had not been any east coast lows, which often washed away large volumes of sand, for some time.
"This means some spaces, like rock pools, can see a build-up of sand," the spokesperson said.
"It also means, however, we've got more space on our beaches for summer."
They said cleaning Woonona's pool was a particular priority this week because a thorough empty and clean was needed to ensure no glass shards were remained following recent vandalism that left broken glass on the concourse.
Meanwhile, Thirroul Pool reopened on the morning of Tuesday, November 7 following water quality issues caused by large swells.
The council publishes its pool cleaning schedule online at wollongong.nsw.gov.au/explore/our-pools.
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