You got be kidding me. Look, I enjoy a good joke as much as anyone. But that is too absurd to even think about.
But you are making me laugh, so thanks. No really, this is funny. Like someone asking me to prove there is a sinkhole, and I get a million dollars if I can do it.
Hahahahaha!
But why would anyone take you seriously? See? Its too much. One has to believe you are kidding, or delusional. There is no other option.
Underground Stream: Water that passes through or under the earth's surface in a definite channel is generally known as an "underground stream."
See? Thats a definition, used by lawyers and engineers, in a real document. There are thousands and thousands of those documents. See? They are used by engineers and lawyers and real people over real issues, (almost always involving somebody screwing with somebody else who is downstream of a particular underground stream). See?
Its not hidden knowledge. Its not mysterious at all. That you keep asking for proof is funny.