Barranca del Oro Wastewater Treatment Plant, Nayarit, Mexico

Barranca del Oro is a wastewater treatment plant located in the town of Barranca del Oro, within the municipality of Amatlán de Cañas, Nayarit, Mexico. The plant serves a population of 1,804, making it a small-scale facility in a rural setting. It is situated inland, more than 10 km from the coast, but within 50 km of the Pacific Ocean. The plant provides secondary treatment, which is the standard level required under Mexican regulations (NOM-001-SEMARNAT-1996) for municipal wastewater before discharge. With a designed capacity of 691.20 m³/day and an actual discharge volume of 172.80 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into a local watercourse that ultimately drains into the Pacific Ocean. The region's hydrology is part of the larger Río Grande de Santiago basin, which supports diverse aquatic life and agricultural activities downstream. Proper treatment helps protect these ecosystems from nutrient pollution and pathogens.

The plant's discharge flows into local streams that are part of the Río Grande de Santiago watershed, which drains into the Pacific Ocean via the Santiago River and the Marismas Nacionales system. This coastal wetland complex is ecologically sensitive, supporting migratory birds and mangrove forests. Secondary treatment reduces organic load and suspended solids, helping to maintain water quality in downstream habitats.