GREEN PARKING - MITIGATING SURFACE URBAN HEAT ISLAND EFFECT OF OPEN PARKING LOTS: A SIMULATION STUDY IN THALAWATHUGODA, SRI LANKA

Parking lots have been identified as an islet of the Surface Urban Heat Island (SUHI) effect, as a substantial proportion of such spaces contain impervious materials. In the current situation, conventional parking lots serve as empty, lifeless zones, which unconsciously accumulate heat within the city. However, there is a potential for green integration into parking lots to minimize the SUHI effect in the Tropics. Since this area is designated for specialized purposes, much thought should be given to the best method of arranging the vegetation. This study investigates the best vegetation arrangements for integrating trees and grass in two parking lots in the sub-urban area of Thalawathugoda, Sri Lanka. Three vegetation arrangements (Perimeter Landscaping, 2. Perimeter Landscaping and Interior Landscaping by tree planters, 3. Perimeter Landscaping and interior Landscaping by diamond planters.) were modeled in addition to the baseline scenario for each case study. For this study, the SUHI is measured by the two parameters, the Surface Temperature and Sensible Heat Flux using micro climatological fluid dynamic (CFD) modeling capabilities in ENVI-met software, and the mitigation rate was calculated for each option. The analysis indicated that all three proposed options decrease SUHI in comparison to the baseline, where option 3 was found to be the best for both locations. Providing one tree per 66 sqm, as per the layout in option 3 could result in a reduction of 3.44 0C in surface temperature and 109 Wm-2 in Sensible heat flux for case study one. For case study two, providing one tree per 160 sqm and 0.18 sqm of grass per one sqm of space, as per the layout in option 3 would reduce the surface temperature by 5.26 0C and Sensible heat flux by 191 Wm-2. For both studies, the trees were spherical, deciduous, 5m in height, and crown diameter. Therefore, a high potential for SUHI reduction from vegetation was identified in this study, which merits policy initiatives for greening parking lots in the tropics.