Assessment of vegetation cover and urban expansion using spectral indices (NDVI, NDWI) in the district of Kalar, Sulaymaniyah Governorate

Abstract

This study aimed to analyze the changes in vegetation cover and urban density in the study area during the period (1990–2024) using the (NDVI) and (NDBI) indices. The results of the (NDVI) index showed that the "No Vegetation" category increased from (43.52 km²) to (291.72 km²) with a change rate of (570%), while the "Low-Density Vegetation" category recorded an increase from (244.81 km²) to (558.74 km²) (128.2%). In contrast, the "Medium-Density Vegetation" category rose from (706.17 km²) to (796.2 km²) (12.7%), whereas the "Dense Vegetation" category decreased from (712.99 km²) to (60.33 km²) (-91.5%), indicating a degradation of dense cover and its transformation into lower density categories or barren lands.

As for the (NDBI) index for urban density, it showed a significant decrease in the area of the " Underutilized" category from (321.17 km²) to (41.11 km²) (-87.2%), and the "Low Urban Density" category from (651.28 km²) to (199.11 km²) (-69.4%). Conversely, the "High Urban Density" category increased from (197.71 km²) to (1033.31 km²) (422.5%), while the "Medium Urban Density" category recorded a slight decrease from (537.07 km²) to (433.96 km²) (-19.2%).

The results indicate a direct impact of urban expansion on the degradation of vegetation cover, with an increase in low-density areas at the expense of dense cover. The study recommends developing land management strategies, preserving dense vegetation cover, and limiting unplanned urban sprawl to ensure ecosystem sustainability and improve environmental quality.