Riachuelo

Riachuelo, Spanish for "little river," is a toponym used in several Spanish-speaking countries. In Argentina, the name most often refers to the Matanza–Riachuelo, a tidal river and estuary system in the Buenos Aires metropolitan area. The watercourse runs through the southern part of the region and empties into the Río de la Plata, forming part of the boundary between certain districts and the city of Buenos Aires. The basin has long been associated with heavy industrial activity and dense urban settlement, making it one of the most polluted waterways in the country.

Environmental concerns led to extensive remediation efforts beginning in the late 20th century and continuing into the present. National, provincial, and municipal authorities, together with international partners, have implemented plans to reduce pollutant discharge, relocate or upgrade polluting industries, improve sanitation, and address public health needs for nearby residents. Progress has included infrastructure investments, monitoring programs, and community-led initiatives, though challenges remain in sediment contamination and flood management.

Beyond the river, Riachuelo labels other places and localities in Argentina and elsewhere, reflecting the common usage of the term to denote a small or seasonal river. The term continues to appear in geographic names, literature, and local discourse related to the Buenos Aires region.