Streamflow–concentration relationships of surface water in the Choapa basin: historical analysis and projections under climate change

ABSTRACT

The use of concentration–streamflow (C–Q) relationships is presented as a novel approach for studying climate change effects on water quality. Based on data from nine monitoring stations in the Choapa basin, north-central Chile, constituent behaviours were classified as constancy, enrichment or dilution. Constancy was shown for B, As, and Cu. Dilution and enrichment relationships were observed at some sites. Electrical conductivity and major ions showed dilution behaviour, with Na⁺, Mg²⁺, Cl⁻, SO₄⁻² and K⁺ showing greater variability in response to streamflow changes. Fe, Al, Mn and Zn presented enrichment behaviour, with Al and Fe showing greater variability. Based on historical C-Q relationships and available projections of streamflow variations under climate change, the change in constituent concentrations from 2010 to 2040 likely will not exceed ±10% with respect to the historical average, and ±15% from 2040 to 2070. In particular, Fe and Mn require special attention in the future.

KEYWORDS:

• major ions
• nutrients
• trace elements
• water quality

Editor A. Fiori Associate Editor K. Ryberg

Editor A. Fiori Associate Editor K. Ryberg

Acknowledgments

We acknowledge the contribution of Prof. Dr Jorge Oyarzún^† for his comments and suggestions on an early version of this document. The paper greatly benefited from the comments of two anonymous reviewers and Associate Editor Dr Karen Ryberg.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/02626667.2023.2212167

Additional information

Funding

This work was supported by ANID/FONDECYT/1210177 and ANID/FONDAP/15130015.