Flood Hazard Assessment ILWIS Case study Drs Nanette

Flood Hazard Assessment: ILWIS Case study. Drs. Nanette C. Kingma INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION

Generalized physiographic map. From: Geological map of Bangladesh, 1990.

Flood map Bangladesh.

Extreme flooding: 1988.

1987 : Dry Season. SPOT band 1 1987 dry-season SPOT band 2 1987 dry-season SPOT band 3 1987 dry-season

Moderate Flood 1987 SPOT band 1 1987 flood SPOT band 2 1987 flood SPOT band 3 1987 flood

Severe flood 1988 SPOT band 1 1988 flood SPOT band 2 1988 flood SPOT band 3 1988 flood

Overview DRY 87 MFL 87 FL 88

Why band ratio’s § Clouds § Shadows

Band Ratio DRY 1987. Brdry 87: Band ratio: band 3/band 1 dry-87.

Band Ratio Moderate Flood 1987 Brmfl 87: Band ratio: band 3/band 1 mfl-87.

Band Ratio Severe Flood 1988 Brfl 88: Band ratio: band 3/band 1 flood-88.

Slicing of Brdry 87 into land water. Dry 87 wl: Slicing into water and land of band ratio 3/1 dry 87.

Slicing of Brmfl 87 into land water. Slicing into water and land of band- ratio 3/1 mfl-87.

Slicing of Brfl 88 into land water. Fl 88 wl: Slicing into water and land of band- ratio 3/1 flood 88.

Cross operation result: dry 87 wl and mfl 87 wl. Cross dry 87 wl and mfl 87 wl output map Dryfl.

Crossing of: Dry. Fl with fl 88 wl. Final result map Crossing of: dry 87 wl, mfl 87 wl, and fl 88 wl.

Bangladesh: Confluence Ganges - Meghna. Cross table: maps drywl-mfl 87 wl Cross table: final map drymflcr - fl 88 wl.

Bangladesh: Confluence Ganges - Meghna. Final result map crossing of: dry 87 wl, mfl 87 wl, and fl 88 wl; with legend.

Map Layout.