For several years,  we have been taking clients down to the lagoon at Cerro Chato in Fortuna and many of them have even swim in the lagoon (water-filled crater). However, it has been brought to our attention that this behavior may not be sustainable or healthy.  We contacted a volcanologist and expert in order to get his input about this:

“In the past years, Cerro Chato volcano has become a tourist attraction.  Visitors climb up from the south and north faces, by routes that have been eroded because of the high rain precipitation in the area.  In the volcano’s crater, a lagoon has formed. The water in the lagoon has an average temperature of 20 degree Celsius and a pH of 5.

The lagoon is a closed basin and it does not have any streams that exit the lagoon.  The walls of the lagoon are vertical and suffer of erosion as vegetation has been cut to make a route to the lagoon. It is common to see that the waters of the lagoon are brown because of the erosion.  Precipitation in the area may be above 5 meters per year. Alternative descending routes have also caused erosion into the lagoon, causing a negative impact.

Some visitors bathe at the lagoon contaminating the waters.

No studies have been made of the waters to find out if the waters are safe to swim in for the visitors. It is forgotten that the lagoon is an inactive crater.  At the bottom of the lagoon and the walls there exists volcanic rocks that contaminate the water with chemicals that give the pH of 5.

We must question, “Are the waters of the lagoon drinkable?”  To give a realistic answer, chemical analysis must be made from an acidity stand point. Drinkable water must not be lower than pH 5.6. (pH 5.6 to 0 is the most acidic).  It is possible that some swimmers may suffer from allergies caused by the acidity.  Many swimmers may have swallowed the water while swimming or decided to drink it to quench their thirst after a walk.

To be noted:

  • Visitors must not swim in the lagoon of Cerro Chato to avoid health issues and to protect the beautiful waters from contamination.
  • Maintenance must be given to the access routes at the top of Cerro Chato to protect the area and the visitor from any accident.
  • We must recommend visitors not to descend to the lagoon as nature will not be able to regenerate.”

Based on the above observations we have decided that we will no longer climb down to the lagoon during the Cerro Chato Hike with our clients.


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