Point source pollution influences water quality of Patagonian streams more than land cover

Abstract

Understanding how anthropogenic activities affect water quality is crucial for water resource management and protection. We explored the relationship between land cover variables, point sources of pollution, and water quality in north-western Patagonian streams during the summer of 2019. We measured eight water quality parameters at 103 sampling sites, and used a self-organizing map to cluster, analyse, and visualize our data. We also used boosted regression trees to model the relationship between land cover, position with respect to the nearest point source of pollution, and each water quality parameter. We found that water quality was generally good, with just 15 sites showing signs of severe anthropogenic degradation. Boosted regression trees revealed that the spatial variation in water quality was mainly driven by the presence of point sources of pollution, whereas land cover variables generally had a modest effect. The overall good condition of the streams in the study area indicates that in contrast with more impacted regions of the world, water quality management in Patagonia should focus on water quality preservation, not water quality restoration.