Satellite Detected Water Extent and Evolution Over Eastern part of Bangladesh

This map illustrates satellite-detected water extent and evolution in Dhaka and Rajshahi divisions of the Central Bangladesh as imaged by the SENTINEL-1 satellite on 30 June 2016 and 24 July 2016. The analysis shows an expansion of waters of ~75% between the two dates. Heavy rains at the onset of the Monsoon season have caused flooding. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR-UNOSAT.

This map illustrates satellite-detected surface water extent in the northeastern parts of Bangladesh (Sylhet distric) & India (Assam, Tipura and Mizoram states) using a Sentinel-1 satellite image acquired on the 15 June 2018. The analysis shows an increase of surface waters in Sylhet district (Bangladesh) and Assam state (India). This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR-UNOSAT.

This map illustrates satellite-detected surface water extent in the central and southern parts of Bangladesh using a Sentinel-1 satellite image acquired on the 22 August 2017. In the analysed area; 608,747 ha of lands are likely affected. These lands are mainly cropland irrigated and rainfed areas and estimated to 475,000 ha. The population exposure analysis using WorldPop data shows that ~6,400,000 people are potentially affected by floods in the analysed zone: ~2,300,000 are located in Chittagong Division and ~2,170,000 in Dhaka Division. Please note that for visualization purposesanalyzed area is wider than the extent of this map. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR-UNOSAT.

**UNOSAT code: FL20200713BGD** This map illustrates satellite-detected surface waters over Chittagong, Dhaka, Mymensingh and Sylhet Divisions of Bangladesh as observed from a Sentinel-1 image acquired on 20 July 2020 due to the current monsoon rains. Within the analyzed area of about 14,250 km2, a total of about 7,120 km2 of lands appear to be flooded. Based on WorldPop population data and the detected surface waters, about 6,700,000 people area potentially exposed or living close to flooded areas. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR - UNOSAT. Important Note: Flood analysis from radar images may underestimate the presence of standing waters in built-up areas and densely vegetated areas due to backscattering properties of the radar signal.

**UNOSAT code: FL20200713BGD** This map illustrates satellite-detected surface waters in the central parts of Bangladesh as observed from a Sentinel-1 image acquired on 19 July 2020 and 13 July 2020. Within the analyzed area of about 40,000 km2, a total of about 8,700 km2 of lands appear to be flooded. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR - UNOSAT. Important Note: Flood analysis from Sentinel-1 imagery acquired on 19 July 2020 and 13 July 2020 may underestimate the presence of standing waters in built-up areas and densely vegetated areas due to backscattering properties of the radar signal.

Preliminary Satellite Detected Waters Evolution in Central Bangladesh Report (28 July 2016)