The impact of lakes on urban thermal comfort: A case study of lake Van

Throughout history, humans have determined their settlement areas by taking climatic conditions into account; in particular, coastal regions surrounding large bodies of water have ranked among the primary preferences due to their temperate climate conditions, suitability for agriculture and animal husbandry, and economic potential. However, the rapid urbanization and construction processes that have accelerated over the past century have caused these areas to lose their natural functions, leading to various adverse effects such as the formation of urban heat islands and micro-scale climate changes. In this study, the regulatory effects of Lake Van—a large body of water—on both regional and micro-scale climatic conditions and urban thermal comfort, specifically in the context of Van province, were analyzed. On a regional scale, temporal and spatial analysis maps were created based on the Physiological Equivalent Temperature (PET) values obtained through the analysis of long-term climatic data from districts located along the lake's coast and in inland areas. On a micro-scale, meteorological data were collected throughout the year 2024 at a height of 1.5 meters from five locations at varying distances from Lake Van and with different urban textures; for two of these locations, a total of 36 climate-adaptive design scenarios were implemented for both summer and winter seasons using the ENVI-met microclimate model. According to the scenario results, in the first location, climate-adaptive design Scenario 7—where vegetation cover was reduced by 50%—was found to decrease PET by 0.7 °C and increase wind speed by 0.4 m/s during midday in summer, while in winter, it increased air temperature by 0.7 °C and PET by 1.7 °C at 10:00 and 12:00, producing positive results. Therefore, this scenario has been evaluated as a potential climate-adaptive application scenario. In the second location, Scenario 5, which included the addition of a water surface, reduced air temperature by 1.1 °C in the summer, while in winter it increased temperature throughout the day by between 2.2 °C and 8.3 °C. It also increased PET values by 1 °C to 1.5 °C and decreased wind speed by 7.2%. Moreover, climate-adaptive design Scenario 7, which involved 75% vegetation coverage, successfully reduced PET values by between 0.9 °C and 1.2 °C during midday in summer. Both of these scenarios have been considered among the priority climate-adaptive design scenarios. This study demonstrates that Lake Van plays a significant role as a climate regulator at both regional and micro scales with regard to urban climate and thermal comfort. It was determined that especially in coastal areas, the lake improves microclimatic conditions by creating cooling effects in summer and warming effects in winter. PET analyses and ENVI-met simulations have shown that vegetation density and the presence of a water surface are key determinants of thermal comfort. These findings iv highlight the importance of strategically using water and vegetation elements in the design of sustainable and climate-sensitive urban open spaces