While we were in Queensland during the holidays, this big flat boat went around the lake out the back of my Nan and Pop’s house and when it came to our house we could see what the machinery on it was doing. It had a digger on board and it scraped the grass away from the edge of the lake until all you could see was sand. Then it would grab scoops of grass off the beach and move it round to the side so it could wash all the sand and dirt out by jiggling it in the water before it tipped the grass and rocks out onto the boat. Another machine packed the pile tighter every so often until the boat got so full they had to go and empty it. When they were finished another machine followed along after it to dredge sand up from the bottom of the lake and cover the beaches. They come around about every 5 years. It was fun to watch.