DFO Flood Event 4459

NE Bangladesh, April 8, 2017

Flood Maps

Layers, top to bottom: Light Blue is reference water extent mapped via NASA 90 m (spatial resolution) SWBD. Red is flood water mapped from ESA Sentinel 1 SAR and NASA MODIS data. Dark Blue is all previous satellite-mapped flooding.

Geotif version

GoogleEarth KMZ (from NASA NRT Global Flood Mapping)

Explanation

Event Reporting:

The Flood Observatory maintains a Global Active Archive of large flood events, 1985 to present. It is available to the public in both spreadsheet and GIS formats (both formats together provide the complete Archive). New events are entered into this archive each week. As of the end of 2016, there were 4432 events; each has a unique archive number.

Event Mapping:

In some cases, severe or damaging floods become the focus of Observatory inundation mapping. As part of collaborations with other organizations, and the Global Flood Partnership, the Observatory's maps and other data are made available to the public. With attribution, they can be used freely, including for commercial purposes, under the terms of the Creative Commons Attribution 3.0 Unported License. Geotif versions and GIS files are also provided for these maps through the links below. This event is selected for Observatory production of map and GIS data products.This web page and associated image and map (GIS) files are the permanent Flood Observatory record of this event.

This Event:

This Flood List link provides a summary. According to Flood List (March 31, 2017): "A long period of heavy rain from 29 March to 07 April caused flooding in Sylhet region in the north east of Bangladesh. The country’s Department of Disaster Management reported that 102,875 people have been affected. Farms and public transport have also suffered damage. In the city of Sylhet, 185 mm of rain fell in 24 hours between 29 and 30 March. Over 120 mm fell the following day and the rain has continued to fall. The Surma and Kushiyara rivers both exceeded danger levels at numerous points. The Department of Disaster Management also reported that 125,885 hectares of crops, chiefly rice, were damaged. Local media say that many farmers have been forced to harvest remaining crops early rather than lose them to flooding ".

Suggested citation for this Creative Commons-licensed publication:

Brakenridge, G.R., date accessed, "DFO Flood Event #", Dartmouth Flood Observatory, University of Colorado, Boulder, Colorado, USA, http address.

Image Data Sources:

NASA Landsat 8 and ESA Sentinel SAR data if used in this map were obtained from the the U.S. Geological Survey Hazards Data Distribution System. and the Sentinels Science Data hub, respectively. Landsat 8 is jointly managed by NASA and the United States Geological Survey. Flood modeling results if used are from the NASA/University of Maryland Global Flood Monitoring System (GFMS), Drs. Robert Adler and Huan Wu, University of Maryland/ESSIC.

GIS Data Sources:

GIS files supporting this Flood Event Map are located here.

Click here for access to the automated daily MODIS-derived .shp file GIS record (record commences in 2011). Choose appropriate 10 deg x 10 deg map sheet directory and appropriate dates; longitude and latitudes refer to upper left map sheet corner.

The Global Surface Water Explorer provides part of the (dark blue) annual surface water extent layer. It is based on Landsat data at a spatial resolution of 30 m (Jean-Francois Pekel, Andrew Cottam, Noel Gorelick, Alan S. Belward, High-resolution mapping of global surface water and its long-term changes. Nature 540, 418-422, 2016). On the map, it is shown together with the NASA Shuttle Water Boundary Data (SWBD) surface water extent (90 m resolution) processed from the 11-day February, 2000, SRTM mission and corrected using Landsat data. Large flood events are not normally depicted in either data set. Thus, red areas on our maps show flood extent beyond these more typical water extents

When used, NASA NRT Global Flood Mapping maximum water extent for the years 2013-2015, at 250 m spatial resolution, provide part of the (dark blue) maximum flood mapped. DFO creates these annual water extent layers from data provided by that project, by accumulating into one annual file all of the daily .shp files for each year. DFO has also produced flood extent files through mapping of individual floods (~ yr 2000 to present); these are also included where available in this maximum flood extent layer.

Related Data:

Global Flood Monitoring System (GFMS) displays, if provided, are from the University of Maryland. Reference: Wu, H., R. F. Adler, Y. Tian, G. J. Huffman, H. Li, and J. Wang (2014), Real-time global flood estimation using satellite-based precipitation and a coupled land surface and routing model, Water Resour. Res., 50, doi:10.1002/2013WR014710. Global Flood Awareness System (GloFAS) displays, if provided, are from the European Commission Joint Research Centre and the European Centre for Medium-Range Weather Forecasts. Reference: Alfieri, L., Burek, P., Dutra, E., Krzeminski, B., Muraro, D., Thielen, J., and Pappenberger, F.: GloFAS – global ensemble streamflow forecasting and flood early warning, Hydrol. Earth Syst. Sci., 17, 1161-1175, doi:10.5194/hess-17-1161-2013, 2013.

Funding, Data and Institutional Support have been provided by:

NASA's Earth Sciences Program, the Latin American Development Bank, the World Bank, the European Commission (Global Disaster Alert and Coordination System, GDACS), the Google Earth Engine research awards program, the Committee on Earth Observation Satellites (CEOS) Disasters Working Group-Flood Pilot, the Japanese Space Agency, and the European Space Agency. GPM and AMSR-2 satellite microwave data for River Watch is processed first within GDACS. The Dartmouth Flood Observatory was founded in 1993 at Dartmouth College, Hanover, NH USA and moved to the University of Colorado, INSTAAR, CSDMS in 2010. The institutional support of both universities is gratefully acknowledged.

(counting since April 10, 2017)