Coimbatore corporation begins work to identify urban heat islands

Coimbatore: The city corporation has initiated mapping of urban heat islands in the city.

An urban heat island is an area significantly warmer than its surroundings with limited green cover, where surfaces like roads, buildings and parking lots absorb and retain heat.

Localities such as Gandhipuram and Ganapathy have been identified as urban heat island in the city, thanks to increased built-up areas and minimal vegetation.

Now that a preliminary ward-wise assessment of total area and green cover percentage has been completed, findings indicate that the central zone has the least green cover, whereas areas along the Noyyal river have dense vegetation. Based on these insights, the city corporation aims to enhance green cover across its limits.

This initiative is being carried out in collaboration with the International Council for Local Environmental Initiatives (ICLEI) - South Asia. A member of the technical team explained that green cover was assessed based on trees with a minimum height of two to three meters, as smaller trees do not provide significant shade or mitigate heat.

Addressing challenges in the mapping, the team member noted that determining the precise percentage of green cover was complex. The proportion of green space is often misinterpreted in relation to total land area. Accurate calculations require the exclusion of built-up areas, roads, waterbodies, open spaces, hospitals, residences and industries, the member said.

"For example, out of the corporation's total area of 257sqkm, approximately 80sqkm is covered with greenery. The immediate assumption is that the remaining 177sqkm lacks green cover, overlooking existing utilities. Additionally, some areas with large open spaces may experience less heat retention because of wind movement. These factors must be considered before deriving accurate data on the urban heat islands," the team member explained.

Commenting on the initiative, corporation commissioner M Sivaguru Prabhakaran stated that in the initial phase, all open space reservation (OSR) lands will be identified for afforestation. "Besides parks, available OSR lands will be utilized for tree plantations. If a parcel of OSR land is designated for purposes like a playground or community hall, trees will be planted along its perimeter. Out of the 2,000-odd parcels of OSR land, at least 250 will be developed for green cover. Geographic information system (GIS) mapping is in progress, and the goal is to plant one lakh trees this year. Additionally, an 11-acre site at Vellalore has been earmarked for afforestation."