Post-Flood Damage Assessment of Sindh 2022 Using Geospatial Technology

Abstract

The devastating effects of floods include a number of consequences, such as the demise of buildings, disruption of vital amenities, degradation of agricultural lands, and damage of transportation networks. The necessity for accurate evaluation and mapping of flood damages is becoming more critical as the frequency and intensity of floods continue to increase due to factors including climate change and urbanization. The main objective of this study is flood extent mapping and damage assessment on cropland and infrastructure by 2022 flood in most affected Sindh province, particularly tailored to the specific challenges and characteristics of this region by integrating Remote Sensing & GIS techniques with robust datasets. Sentinel-2 data along with spectral indices (MNDWI, NDVI, and NDBI) used in precise estimation of land use land cover (LULC) change and flood impacts. An accuracy assessment revealed an impressive overall accuracy of 85-90% for classification approach. Approximately 1.1 million hectares of crop land were directly affected by the flood & 2.8 million hectares in the preceding crop affected by flood and torrential rainfall collectively. The analysis found production losses of 37% (1 million tons), 66% (2.2 million bales), and 10% (0.7 million tons) for rice, cotton, and sugarcane. Considering the summer 2022 commodity prices, the crops rice, cotton, and sugarcane observed loss of USD 363 million, USD 304 million, USD 18 million respectively. This multidisciplinary approach significantly contributes to comprehensive flood mapping and damage assessment strategies, offering insights that hold relevance not only for Sindh Province but also for flood-prone areas globally.