Water Sensitive Urban Design: Construction Systems, Materials Choice and Use Criteria to Improve Surface Temperatures

Abstract

Water sensitive urban design stormwater and rainwater management construction systems (hereinafter, WSUDs) contribute to the resilience of areas to water when they are implemented in urban development and they enable recovery of the water cycle. However, these systems can increase surface temperatures in a context of rising planet temperatures. This article aims to establish criteria for choosing and using WSUDs that lower surface temperatures in a climate of hot and dry summers. It summarizes the main results of seven years (five years of measurements) of WSUD surface temperature records. The methodology is mainly based on manual and in situ measurements, at a detailed scale, under the green canopy, with a thermographic camera and other devices that measure complementary parameters at the same scale (light meter, anemometer, hygrometer). The conclusion is that there are two main groups of WSUDs and materials, depending on their thermal performance: those that contain and retain water and those with a faster infiltration speed, with surface temperatures above the environmental ones during hot summers. Parameters that clearly influence surface temperatures are the specific heat of the water, in the first group, and the shade of the building and the green area, the albedo, the thermal inertia and the granulometry in the second one.