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Seasonal total coliform dynamics in a drinking water reservoir
Journal article   Peer reviewed

Seasonal total coliform dynamics in a drinking water reservoir

Carlos Eduardo Veras, John Tobiason, Amanda Carneiro Marques, Yuehlin Lee and Emily Kumpel
Water research (Oxford), v 284, 123850
15 Sep 2025
PMID: 40446766

Abstract

Drinking water Reservoir Seasonality Surface water Total coliform Water Quality
•Studied seasonal total coliform concentrations in a protected, oligotrophic reservoir•Analyzed 10 years water quality and meterological data from Quabbin Reservoir, MA (USA)•Proxies of algae, organic matter, dry conditions, and temperature most associated with total coliform•Reservoir has pristine water quality with low variability and low fecal bacteria indicator•High total coliform concentrations likely originate from an autochthonous process. Maintaining high-quality drinking water supply reservoirs is important for protecting public health. Despite extensive watershed protection efforts, reservoirs can still experience seasonal, elevated total coliform bacteria concentrations, indicator bacteria commonly used for regulations. This study aimed to understand associations between concentrations of total coliform and an array of water quality, soil, and meteorological parameters over 10 years to identify potential causes and correlations of elevated total coliform bacteria concentrations in a protected watershed and clear, oligotrophic waters. Leveraging long-term data, we performed extensive data analysis and a data-driven model to investigate these relationships in the Quabbin Reservoir (Massachusetts, USA). Data analysis and data-driven modeling results indicated that proxies of algae, organic matter, and dry conditions, as well as water temperature and dissolved oxygen, were most associated with increased total coliforms in the reservoir. Although indicator bacteria such as total coliform are frequently used for routine monitoring, our findings highlight that it was unlikely that their proliferation is indicating a likely elevated risk in the reservoir. The studied reservoir has pristine water quality with low variability and low fecal bacteria indicator levels with no sign of external contamination; therefore, the high concentrations of total coliform bacteria in the summer is likely an autochthonous process. Additionally, applying machine learning methods to leverage long-term routine data collected by monitoring agencies highlights opportunities to better understand how to maintain high-quality surface water in drinking water supply reservoirs through a rapidly changing climate.

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UN Sustainable Development Goals (SDGs)

This publication has contributed to the advancement of the following goals:

#6 Clean Water and Sanitation
#11 Sustainable Cities and Communities
#3 Good Health and Well-Being
#14 Life Below Water

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Collaboration types
Domestic collaboration
Web of Science research areas
Engineering, Environmental
Environmental Sciences
Water Resources
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