Satellite-Detected Flood Extent in Bangladesh Divisions, May 2022

Satellite-detected surface water and flood impact data for Sylhet, Mymensingh, Dhaka, and Chattogram Divisions in Bangladesh. The analysis covers an area of about 12,000 km2, with approximately 4,500 km2 of land appearing flooded, including 3,400 km2 of cropland and 1,000 km2 of herbaceous wetland. This preliminary map was produced by the United Nations Satellite Centre (UNOSAT) from a Sentinel-1 image acquired on 28 May 2022.

Use Cases

• Estimate population exposure to flooding based on WorldPop data and detected water extents.
• Assess agricultural damage by analyzing flood waters over cropland areas.
• Model floodwater extent in wetland ecosystems using satellite radar imagery.
• Validate and improve automated flood detection machine learning methods with ground feedback.

Strengths

• Analysis quantifies flood extent over approximately 12,000 km2 with specific area estimates for flooded land (4,500 km2), cropland (3,400 km2), and wetland (1,000 km2).
• Includes population exposure estimates for specific districts, such as Sunamganj (~935,000 people) and Kishoreganj (~779,000 people).
• Data source is clearly identified as a Sentinel-1 satellite image from 28 May 2022 at 18:04 local time.

Limitations

• The analysis is preliminary and has not been validated in the field, as noted by the author.
• Flood detection from radar images may underestimate standing water in built-up and densely vegetated areas.
• Column-level documentation is absent; field semantics must be inferred after download.

Provenance

Source

United Nations Satellite Centre (UNOSAT)

Collection Method

Automated analysis with a machine learning method applied to Sentinel-1 radar imagery.

Time Range

28 May 2022

Freshness

Last updated 2026-04-29 10:13:41.345710; freshness should be verified.

Geography

Sylhet, Mymensingh, Dhaka, and Chattogram Divisions, Bangladesh