Exploring Rio Celeste and its Turquoise Waters

Rio Celeste is a spectacular blue river (that's right, blue) in Tenorio Volcano National Park of Costa Rica featuring a huge waterfall plummeting into a blue pool below.

The Rio Celeste is a truly breathtaking and mudderefic hike (meaning pretty damn muddy), and you’ll probably get rained on because you are in the rainforest after all. The trail is well-maintained and winds through a lush, tropical rainforest. Along the way, we encountered an abundance of flora and a set of tapir tracks.

How did the Rio Celeste get blue? Local folklore says Rio Celeste is blue because god dipped his paintbrush in the water after he got done painting the sky, and the paint was washed downstream.

The real story of the Rio Celeste and its turquoise blue color is a unique tale of chemistry and physics when two colorless rivers, the Río Buenavista and Quebrada Agria, merge into one another. The Río Buenavista carries a large concentration of aluminosilicate particles, while Quebrada Agria, as its name implies, has high levels of acidity and sulfur due to volcanic activity.

When these two streams mix to form the Celeste River, the drop in pH causes the aluminosilicate particles to aggregate and enlarge. These suspended particles produce what is called “Mie scattering” which gives the river its strong turquoise color.

Let’s get technical.
Río Buenavista (aluminosilicate particles = 184nm and pH = 6.8) + Quebrada Agria (pH = 3.1) = Rio Celeste (aluminosilicate particles = 570nm because pH = 5)

Cool beans? Are you not glad you took chemistry back in school?

The turquoise-blue color of the river is truly a sight to behold and makes for a spectacular and unforgettable hike experience.

#CostaRica #RioCeleste