Impact of Growth and Development of Built-Up Area on Land Surface Temperature and Vegetation Cover

Abstract

Urbanization has become one of the most influential processes shaping the environmental and spatial structure of modern cities. Rapid expansion of built-up areas often occurs at the cost of natural vegetation, leading to rising surface temperatures and the intensification of Urban Heat Island (UHI) effects. The present study examines the relationship between urban growth, vegetation change, and thermal variation in Prayagraj during the period 2000–2020 using geospatial techniques and satellite-based indices. The study employs the Normalized Difference Built-up Index (NDBI) to analyse urban expansion, the Normalized Difference Vegetation Index (NDVI) to assess vegetation cover, and Land Surface Temperature (LST) to evaluate thermal conditions across eight administrative zones of the city. Multi-temporal Landsat satellite imagery and GIS-based spatial analysis were utilized to investigate temporal and spatial transformations in the urban landscape.

The findings reveal a substantial increase in built-up areas from 66.69 sq. km in 2000 to 197.81 sq. km in 2020, indicating rapid urban expansion across the city. In contrast, vegetation cover declined sharply from 199.69 sq. km to 56.72 sq. km during the same period, reflecting continuous pressure on green spaces due to urban development. Simultaneously, mean Land Surface Temperature increased significantly in all zones, demonstrating the thermal impacts of expanding impervious surfaces and declining vegetation. The study establishes a strong positive relationship between NDBI and LST, while NDVI exhibits a significant negative relationship with LST, indicating the crucial role of vegetation in regulating urban temperature. Peripheral zones, particularly Zones 5, 6, 7, and 8, recorded the highest rates of urban expansion, vegetation loss, and thermal stress, highlighting their emergence as major urban growth corridors.

The study underscores the environmental consequences of uncontrolled urbanization and emphasizes the urgent need for sustainable urban planning, ecological conservation, and green infrastructure development to reduce thermal stress and promote environmental sustainability in rapidly growing Indian cities.