The San Juan River is a Colombian river that flows into the Pacific Ocean through the Chocó Department. It is approximately 380 km and drains a watershed of 16000 km2. The river drains into a large delta that covers nearly 300 km2. The average discharge of the Rio San Juan is 2,054.67 m3/s.

Geography

The river begins on Cerro Caramanta in the West Andes. The delta is due north of Bahía Málaga and Buenaventura. The mouth of the river has extensive stands of mangroves, part of the Esmeraldas-Pacific Colombia mangroves ecoregion.

Hydrometry

Monthly average flow of San Juan River ( m³/second) measured at Penitas station Data from 25 years

Fauna

Reptiles

A species of snake, Dipsas sanctijoannis, is named after the San Juan River of Colombia, and is native to the watershed.

Fish