Assessing Sea Water Intrusion and Its Impacts on Crop Land and Forest Cover Using Geo Spatial Techniques in District Thatta, Sujawal and Badin (Sindh)

Abstract

Seawater intrusion is one of the destructive environmental issues of Pakistan affecting the Sindh coastal districts in particularly Thatta, Sujawal and Badin. In this study, geographic information techniques are applied to analyze the impact of seawater intrusion on crop land and forest area (Mangroves). This study employs multispectral imagery and geospatial analysis using ArcMap software to investigate land cover and land use changes over the past two decades, with a focus on identifying areas susceptible to seawater intrusion. Parameters used for geospatial analysis were Land Use Land Cover (LULC), Normalized Difference vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Normalized Difference Salinity Index (NDSI). These parameters demonstrate the change from past two decades in vegetation cover, crop land, and seawater intrusion. Statistical analyses reveal profound correlations between seawater intrusion and land degradation, highlighting the significant impact of saline water intrusion on terrestrial ecosystems. The analysis of spatial trends in the Sindh coastal area from 2000 to 2024 reveals significant environmental shifts. Seawater intrusion exhibited a 3.5% increase, agricultural land (cropland) decreased by 11.8%, forest cover declined by 5.5%, built-up areas increased by 6.4%, and barren land expanded by 9.3%. The reduction in agricultural land directly diminishes crop yield and agricultural output, intensifying food security challenges for local communities. The degradation of forest ecosystems, particularly mangrove habitats, poses a critical threat to biodiversity and significantly impairs the carbon sequestration potential of these vital carbon sinks.