(9.940 ha). It`s situated in Guatuso Lowlands, in Alajuela Province. It protects one of the most important wetlands regions in
Costa Rica. It houses Cano Negro Lake- a shallow, seasonal , freshwater lake
extending over 800 ha that during the dry season almost completely dried up.
It`s made up of net system of rivers, canals and
lagoons. The main river of it is Barra del Colorado. It`s a meander of natural
border-river of San Juan. The birds population includes species such as the osprey,
keel-billed toucan, cormorants, great blue herons, white hawks, great tinamou,
curassowa. The area is home to endangered West Indian manatee, caymans,
crocodiles, gars, and numerous schools of tarpons. During the flow of the tides in San Juan river, many
tarpons start moving upwards the river. It shelters also the biggest number of
Bellons fishes in the world.