Yeah, it's 2 feet deep. I should have dug deeper but I was tired of digging. ; ) That was a real bitch to do by hand. Basically all tree roots from that big maple with a little dirt holding them together. Milwaukee Sawzall with big puning blades became my favorite tool.
Kind of funny... Like a lot of things go it's an example of massive plan escalation. Started out as a simple thought that I should get one of those little self-contained fountains to put outside for the cats to drink from. Then I thought, well, if I'm going to make a fountain might as well have a little pool around it. Then I thought if I'm going to make a pool, I could just make it a little bigger. Made it a little bigger and just kept digging. lol
But I like it a lot. Completely changed the yard and all of the wildlife it attracts.