Swinbourne et al. (2025) Trade-off between water-saving and cooling objectives: restricting irrigation increases the number of hot days

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Environmental Research Letters
• Year: 2025
• Date: 2025-11-13
• Authors: Cassady Swinbourne, Steven Kenway, Katherine R. O’Brien, Pui Kwan Cheung
• DOI: 10.1088/1748-9326/ae1f2b

Research Groups

Information not available from the abstract.

Short Summary

This paper investigates the trade-off between urban cooling and water conservation by simulating various irrigation scenarios in Melbourne, Australia, finding that increased irrigation significantly reduces heat stress, with quantifiable benefits for reducing heat stress days and mean air temperature.

Objective

• To consider the heat implications of restricting irrigation and to further understanding of how water-saving and cooling objectives compete in urban environments.

Study Configuration

• Spatial Scale: A Melbourne street (study site).
• Temporal Scale: 10 years.

Methodology and Data

• Models used: Ecohydrological model, Urban Tethys-Chloris (UT&C).
• Data sources: Model validated for Melbourne, Australia (implying local observational data for validation).

Main Results

• Heat stress is predicted to decrease with increasing irrigation amount.
• Every 1.5 mm of additional irrigation per week (up to 28 mm wk⁻¹) is predicted to reduce the number of heat stress days (where maximum Universal Thermal Climate Index (UTCI) > 32 °C) at the study site by one per year.
• Irrigation is most effective at cooling when air temperatures are the hottest.
• The number of days with a mean air temperature over 28 °C is predicted to increase by 15% if irrigation is restricted and by 20% if irrigation is stopped entirely.
• Approximately 7 mm d⁻¹ of irrigation is required to decrease the mean air temperature by 1 °C for oceanic climates.

Contributions

• Quantifies the trade-off between water-saving strategies and urban cooling objectives.
• Provides a direct relationship between irrigation amount and the reduction in heat stress days (UTCI > 32 °C).
• Highlights the critical importance of maintaining irrigation during hot periods to prevent heat-related mortality.
• Emphasizes the role of innovative urban planning and design, including onsite alternative water sources, to enable cooling through irrigation without exacerbating water stress.

Funding

Information not available from the abstract.

Citation

@article{Swinbourne2025Tradeoff,
  author = {Swinbourne, Cassady and Kenway, Steven and O’Brien, Katherine R. and Cheung, Pui Kwan},
  title = {Trade-off between water-saving and cooling objectives: restricting irrigation increases the number of hot days},
  journal = {Environmental Research Letters},
  year = {2025},
  doi = {10.1088/1748-9326/ae1f2b},
  url = {https://doi.org/10.1088/1748-9326/ae1f2b}
}