Impact of heat islands vs. city greening: Real-time monitoring and modeling of drinking water temperature in the city of Montreal in Canada

Faezeh Absalan; Fatemeh Hatam; Mirjam Blokker; Marie-Claude Besner; Michèle Prévost; Françoise Bichai

doi:10.1016/j.watres.2024.121490

Impact of heat islands vs. city greening: Real-time monitoring and modeling of drinking water temperature in the city of Montreal in Canada

Water Res. 2024 Mar 28:256:121490. doi: 10.1016/j.watres.2024.121490. Online ahead of print.

Authors

Faezeh Absalan¹, Fatemeh Hatam², Mirjam Blokker³, Marie-Claude Besner⁴, Michèle Prévost², Françoise Bichai²

Affiliations

¹ NSERC Industrial Chair in Drinking Water, Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, CP 6079, Succ. Centre-ville, Montreal, QC H3C 3A7, Canada. Electronic address: Faezeh.absalan@polymtl.ca.
² NSERC Industrial Chair in Drinking Water, Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, CP 6079, Succ. Centre-ville, Montreal, QC H3C 3A7, Canada.
³ KWR Water Research Institute, Delft University of Technology, Groningenhaven 7, 3433 PE Nieuwegein, the Netherlands.
⁴ Water Services, City of Montréal, Montréal, QC H3C 0G4, Canada.

PMID: 38614028
DOI: 10.1016/j.watres.2024.121490

Abstract

Urbanization increases the land surface temperature through surface mineralization, adversely affecting vegetation and enhancing the urban heat island (UHI) effect. Global climate change has intensified this warming effect with more frequent and intense heatwaves during hot seasons. While these transformations influence soil temperature, their consequences on drinking water temperature within the drinking water distribution system (DWDS) remains poorly understood. Literature proposes to increase pipe burial depths to mitigate drinking water heating during summer. In this study, we monitored drinking water temperatures in a DWDS in Montreal, Canada with deeply buried pipes (average 1.8 m) during the summer of 2022, focusing on two contrasting zones in terms of UHI and green coverage. Monitoring revealed a 8°C heating effect compared to the water treatment plant, attributed to low green coverage and anthropogenic heat. Conversely, the greener zone exhibited cooler drinking water temperatures, reaching a maximum cooling effect of 8°C as compared to the temperature at the exit of the water treatment plant. Utilizing a soil and water temperature model, we predicted drinking water temperatures within the DWDS with acceptable accuracy. Soil temperature modeling results aligned well with measured water temperatures, highlighting DWDS water temperature approaching its surrounding soil temperature fairly quickly. Despite heatwaves, no immediate correlation emerged between air temperature records and measured water temperatures, emphasizing soil temperature as a superior indicator. An increase in water age displayed no correlation with an increase in measured water temperature, underscoring the dominant influence of UHI and green coverage on water temperature. These findings highlight the cooling advantages of green spaces during summer, providing valuable insights for sustainable urban planning.

Keywords: Global warming; Urban greening; Urban heat island; Urban planning; Water distribution network; Water temperature modeling.