Fifteen years of WRTDS for advancing water-quality science: A critical review of methodological developments and global applications

Environmental Science and Technology
By: , and 

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Abstract

Contamination by nutrients, major ions, and metals poses a major threat to global water sustainability. Understanding how these pollutants vary across time and space requires long-term monitoring and robust statistical approaches. Traditional methods, however, often struggle to account for streamflow variability, seasonality, and nonlinear responses. Introduced in 2010, the Weighted Regressions on Time, Discharge, and Season (WRTDS) method offers a flexible, data-driven framework that generates both observed and flow-normalized estimates of concentration and load. Over the past 15 years, WRTDS has become a state-of-the-art tool for water-quality science and management, with applications spanning a wide range of hydrologic, climatic, and policy contexts─including major watersheds across North America, Europe, Asia, Australia, and the Arctic. In this review of WRTDS, we document the method’s major advancements, examine its expanding geographic and thematic applications, and summarize its relevance to water-quality management programs and policies worldwide. We also discuss its performance relative to other regression and machine-learning approaches. Finally, we identify key priorities for future development to support the continued evolution of WRTDS as a trusted and practical tool for scientists and managers working to protect and sustain water resources.

Suggested Citation

Zhang, Q., Hirsch, R.M., DeCicco, L.A., and Murphy, J.C., 2026, Fifteen years of WRTDS for advancing water-quality science: A critical review of methodological developments and global applications: Environmental Science and Technology, v. 60, no. 15, p. 11170-11182, https://doi.org/10.1021/acs.est.5c12895.

Publication type Article
Publication Subtype Journal Article
Title Fifteen years of WRTDS for advancing water-quality science: A critical review of methodological developments and global applications
Series title Environmental Science and Technology
DOI 10.1021/acs.est.5c12895
Volume 60
Issue 15
Publication Date April 07, 2026
Year Published 2026
Language English
Publisher American Chemical Society
Contributing office(s) Central Midwest Water Science Center
Description 13 p.
First page 11170
Last page 11182
Additional publication details