LAND-COVER CHANGE AND FLOOD SUSCEPTIBILITY IN MALAKAND DIVISION, PAKISTAN, DURING THE 2010 AND 2022 FLOOD YEARS

Abstract

Flood mapping in northern Pakistan must distinguish water observed during an event from terrain susceptible to rapid runoff or inundation. This study compared land cover, spectral indicators and mapped flood susceptibility in Malakand Division during the flood years of 2010 and 2022. Landsat-derived vegetation, water and surface-temperature maps were examined alongside precipitation, slope, drainage density, soil and five-class susceptibility maps. Reported class inventories were reconciled before interpreting differences between years. Built-up land increased from 206 to 422 km², a gain of 216 km² or 104.9% relative to its initial mapped area. Mapped water increased by 88 km², while vegetation, cropland and ice or glacier cover declined by 560, 195 and 148 km², respectively. The five classes accounted for 9,835 km² in 2010 and 9,236 km² in 2022. This difference of 599 km² limits attribution of individual losses to conversion and precludes treating the two tabulations as a closed transition inventory. The upper endpoint of the normalised difference water index was 0.70 in both years, despite the larger mapped water area in 2022. The two observations therefore illustrate how an index maximum and the extent of a classified surface can convey different information. Susceptibility maps showed recurring contrasts between the northern and southern sectors, but neither supplied a measured event footprint or water depth. The comparison identifies where independent flood observations would add the most information and establishes which changes can be quantified from the available maps. A common spatial mask, dated flood-stage observations and independent reference samples are required to estimate inundated area or assess transfer between events.