Geospatial Assessment of Land Use and Land Cover Change and its Impact on Urban Flood Vulnerability in the Twin Cities of Pakistan

Abstract

Worldwide land use and land cover (LULC) changes significantly disrupt the hydrological cycle, often exacerbating the risk and intensity of extreme hydrometeorological hazards such as urban flooding. Currently, urban flooding has emerged as a pressing environmental concern, posing a growing threat to environmental and urban sustainability in the rapidly urbanizing cities. In Pakistan, this phenomenon is particularly acute, where the intensity and vulnerability of urban floods have become increasingly severe due to abrupt changes in LULC and unplanned urbanization.This study investigates howland use land cover changes and haphazard urban expansion have intensified the flood vulnerability in the twin Cities of Pakistan—Islamabad and Rawalpindi from 2000 to 2023. This study employs a combination of remotely sensed satellite imagery from 2000-2023, field data, and secondary data sources. Landsat imagery with ≤ 10 cloud cover were acquired form USGS official site. For flood vulnerability analysis, data were collected from primary sources through field survey. Relevant secondary data were explored from Water and Sanitation Authority, PDMA, RESCUE 1122 and Punjab Development Statistics. For classification, four land use land cover classes: built-up, vegetation, bare land, and water were analyzed using the supervised classification method. Flood vulnerability was calculated using physical, environmental, social and economic vulnerability indices. The result of LULC indicates that significant increase in built-up area and reduction in permeable surface and barren areas has been reported in both Islamabad and Rawalpindi. Comparatively, the built-up of Rawalpindi is expending rapidly. The findings reveal that both Islamabad and Rawalpindi were highly susceptible and vulnerable to urban flooding, however, the degree of vulnerability varies considerably depending on administrative governance, land use policies, and socio-economic resilience. The results indicate that the cumulative FVI of Rawalpindi (0.47) is higher than Islamabad (0.24), indicating that Rawalpindi highly susceptible and vulnerable to urban flood as compared to Islamabad. Among the subzones of Rawalpindi, the Rawalpindi Metropolitan Corporation (RMC) demonstrates the highest vulnerability, particularly in terms of social (0.67) and physical (0.56) dimensions, primarily due to dense, unplanned settlements and insufficient compliance with urban development regulations. Conversely, Chaklala Cantonment displays the lowest vulnerability score (0.36), suggesting that more structured planning can effectively reduce flood risk. The findings of this study offer a practical roadmap and valuable insights for urban planners, disaster management authorities, and policymakers to effectively address the escalating challenges of urban flooding in Rawalpindi and other similarly vulnerable urban centers in developing countries.