During and subsequent to a rainfall event, stormwater runoff can transport heat from an urban area (which can be significantly warmer than its surrounding region) to a receiving water body, such as a stream, river, lake, or a wetland. Excess heat can affect an aquatic ecosystem in the following ways: direct lethal effect on sensitive plants or animals; indirect long-term effects on the aquatic ecosystem by affecting growth and/or reproduction; and indirect effects through changes in species distribution and diversity in the ecosystem.
Impervious pavement surfaces are a major source of heating for stormwater runoff from urban areas. These surfaces absorb more heat from solar radiation compared to natural surfaces and, when rainfall occurs, this heat can be transferred to the runoff and quickly transported to a receiving water body. Only a small subset of the research that has been published on the heating effects from stormwater effluent on water bodies has dealt specifically with the heat transfer between pavements and runoff water. Through these works, different ways to model the heat transfer between pavements and runoff water have been derived using physical and empirical approaches.
This paper provides a review of these approaches and a comparison of calculated pavement-runoff heat fluxes for a range of conditions. Also discussed in this paper is a path forward to improve the understanding of heat transfer between pavements and stormwater runoff, which would lead to more accurate modelling of this phenomenon.