I switch mine off, empty, piling up the frozen stuff so it stays cold, then start scraping the loose ice/frost. I leave for a while, (half hour or so) then come back and scrape more. Soon the ice starts falling off in chunks. It usually takes an hour or so before all ice comes off. At this stage it's all still frozen in bottom of freezer. Then I scoop it up with a dustpan, into a basin, and remove. There's very little water, as I remove as ice. The small amount of water can be soaked up with a towel.
My freezer also has a small drainhole, covered with a plug, but I've never had to use.