What makes waterfalls so mesmerizing? The roar of big waterfalls, the power that pounds and shapes the rocks below; the peaceful trickle of little ones, winding their way through a landscape; even water dripping rhythmically off a leaf. We're drawn to them. Why?
As my mother's daughter, I've had ample opportunity to ponder this question: "... and there's a waterfall nearby!" was a common refrain on vacations growing up. Our highlights list includes Niagara Falls, of course, as well as Bridalveil Fall (Yosemite Park), Zapata Falls (CO), the Damajaqua Cascades (27 natural waterslides, Dominican Republic), and the ones we sought off the beaten path in Kauai and Maui, to name but a few. The Kuang Si Waterfall is a worthy addition.
Our pink Scoopy moped (like this) carried us the 18 miles from Luang Prabang to the Kuang Si falls through the serene, well-signposted countryside. From the first little waterfall, I was struck by the colors: the deep greens of the surrounding jungle, the bright, bright translucent blue of the pools. It's a blue color I'd never seen in nature before, one that immediately made me ask about mineral content.
This blog is called "Rambling Scientist" and, while I've focused more on "rambling" than "science" so far, I looked into the color of the Kuang Si falls. It all comes back to geology and, of course, chemistry. Calcium carbonate, to be be specific. As water cascades through falls, travertine -- a form of calcium carbonate (think limestone) -- precipitates out, coating the bottom and sides of the pools with a layer of white. Light reflecting through the mineral rich water, off the pale bottom, results in the brilliant blue color.
Many of the travertine pools were suitable for swimming; the water was a bit cold for my taste but B. had a blast playing on the rope swing.
The trail ultimately leads to the main fall, which features a 200 ft cascade. Once again, the sun and the water colluded to our photographic delight.