Retracing the Lost Natural Wetland of Barkat Colony, Lahore, Using Remote Sensing Techniques

Abstract

Wetlands are crucial ecosystems that regulate floods, store carbon, and support a wide range of biodiversity. Their loss negatively impacts the surrounding areas; in flood-prone regions, this increases vulnerability to floods and endangers lives. The conversion of natural wetlands to agricultural lands is common in Punjab; this process often involves intentionally draining wetlands to utilize them as agricultural lands. In Lahore, natural wetlands are often overlooked, and they vanish undocumented due to encroachment, leading to gaps in our existing knowledge about Lahore's natural wetlands. The study verifies and retraces a lost natural wetland in the current Barkat colony to address this gap. Multi-temporal Landsat imagery (1990–2024) was analyzed with Modified Normalized Difference Water Index (MNDWI) and Normalized Difference Water Index (NDWI) to delineate wetland extent, while historical Google Earth imagery and digital elevation models (DEMs) were employed to understand site-specific changes and flood vulnerability. Results reveal that in 2001, there existed at least 150 acres of a natural wetland, identified as an oxbow lake in the area now known as Barkat Colony. This wetland’s existence was never officially documented. The site is highly vulnerable to floods and is 10 meters lower in elevation than the surrounding areas, leading to stagnant floodwaters that persisted for an entire year in 2013. Such findings highlight the use of remote sensing techniques in reconstructing the history of undocumented wetlands, filling critical local data gaps, and providing insights for flood risk mitigation, ecological conservation, and urban planning in Lahore. This paper provides a framework that can be employed to delineate and document other wetlands in Lahore.

Keywords: Natural Wetlands, Remote Sensing Indices, Land use change, lost wetlands, Flood vulnerability.