Stone and rocks are ok with a driven point. You usually break them as you pound it from what I've read. As long as it's not bedrock, you're good.
If you know, or have reason to believe where the spring is coming in, you could drive a test point 5' down and see if you can hit it up stream from the watering hole you posted. I'd want it 50'+ laterally from that hole just to keep the chance of surface contamination down. Birds, mice, deer, coon, and every other critter in nature all poop wherever, and I wouldn't want that to infiltrate my water source if I could avoid it. You might need more distance yet. The well code probably specifies distance from a septic drain field, and that's the spec I'd go with. Crystal clear doesn't mean clean by any stretch. You'll want to get it tested before you use it, or before trying to do more than get a source of irrigation water.