I can’t think of any place better to help students understand the Edwards Aquifer than Aquarena Springs in San Marcos, Texas.
You can arrange educational field trips or private group tours by phone or through their website, or you might want to take a glass-bottom boat tour. (As a child, I LOVED these. I was admittedly a bit geeky even then, but I think it’s fair to say most children would enjoy the boats that let you look down to see endangered fish species, unique water plants, and underwater springs that bubble up through the sandy bottom.)
Aquarena Springs has been a work-in-progress for a few years, but I’m pleased to see that they have a new website that will let you explore Spring Lake before you go. Here’s a sample: