I can't speak for Texas, but we normally think of oil or gas when we think of mineral rights in my area of Illinois. You need to check out legal issues there; but the risks you would run around here by not owning the mineral rights is that someone may drill an oil well near your pond (on your property) with potential contamination to your pond. Probably not a huge risk, but I understand it could happen. If that is the case there too, I don't think building the pond would be much of an issue. It might be a lot different down there. Any buried dinosaurs?

[Linked Image from i108.photobucket.com]