OK, Juggernaut, have some REP for that bit science on rivers!

My curious question now regards the Yucatan Peninsula, and the Island of Cozomel. I've been to Cancun, Mexico, on vacation a few years ago, having recently (at the time) learning about the propensity of underwater rivers in southern Mexico. The island of Cozomel (largest island off Mexican coast, very near Cancun.

Most of the Yucatan is extremely flat, but there are almost no surface rivers there. Sinkholes everywhere. Underground rivers everywhere.

I visited a "park" that contained a sinkhole right near the coast, about a half mile away from the sea. Fresh water rose from the sinkhole and formed a short surface river called a "Ria" that reached the sea.

Cozomel is really not that big, yet underground rivers course meandering around the reaching the sea.about 5 meters under the surface.

I've always wondered about the science regarding that... Can anyone answer, Juggie or Waldronate?? It seems almost bizzare.

GP