YES! This is exactly what I had in mind! Sand box in a kiddie pool with a vinyl tablecloth "shower cap" to keep water and animals out. I like her way of doing the elastic better than what I had had in mind. Perfect!
Mama To Three Chicks: Kiddie Pool Cover - I don't even know how to sew and this still looks easy! I'm thinking to use it as a sandbox cover (made using a kiddie pool similar to this one) To make one that is waterproof, you could start with a really big round vinyl tablecloth.
~The Baby Pool Project~ My husband made this awesome #DIY Baby Kiddie Pool Deck • Step 1 - Measure and build a center base • Step 2 - Build an outer base • Step 3 - Build the platform/deck and drill an umbrella hole • Step 4 - Paint with waterproof deck paint • Step 5 - Fill with water, add a potted palm tree and enjoy your Summer! ☀ (So easy to put away in pieces once Summer ends and you need the space back!)