Engineering in a natural world

I last visited Florida’s Blue Spring State Park about ten years ago. At that time, it was one of these places that really only locals knew about. I only knew about it because I’d read about in the local paper! Blue Spring is really only known for two things: manatees and the (rather appropriately named) Blue Spring.

In winter, Blue Spring becomes home to hundreds of West Indian manatees (the park is actually designated as a manatee refuge). Manatees are one of those wonderful creatures which I think inspire a bit of jealously in most people. After all, they are fat and lazy but generally seem pretty happy and laid-back and spend all of their lives eating and floating in warm water. Yes, that doesn't sound too bad.

But the point of this post is not to talk about manatees. I want to talk about the Blue Spring. The spring bubbles out 104 million gallons (400 million liters) of water each day. That’s just over 1,200 gallons per second - each and every second of each and every day… enough to fill 24 average-sized bath tubs. The water is also a pleasant 72°F (22°C) – maybe not quite bath temperature, but certainly not unpleasant on a warm summer’s day.

The other thing that makes Blue Spring interesting is that we still don’t know where its source is. Some of you may know that Florida has a myriad of limestone caverns underneath it. Sometimes this creates problems (they can lead to sinkholes) and sometimes it creates tourist attractions (such as cave diving in Gainesville). So why don’t we know where the source of Blue Spring is? Surely we can just send divers down there? Well, it’s not that simple – you see there is a problem. That problem is a great big rock called “Cork Rock” which is lodged in the throat of the spring and stops divers from going further down the spring (unfortunately I can’t post pictures in this post, but maybe I’ll re-post this article onto my blog with a pic).

Now, I don’t know about you, but even as a fully-qualified SCUBA diver I would still be extremely scared to dive towards a rock called “Cork Rock” – after all, the word “cork” inspires images of champagne and of “popping corks”. And when the Blue Spring “cork” pops, anything (or anyone) in the way is going to have a really bad day. And rest assured – it’s a geological certainty that one day the erosion is going to be just enough to release “Cork Rock” up that chute. That day could be tomorrow or next week or next century. What that will do for the spring, no one knows.