ARIA Flood Water Depth Estimate derived from OPERA DSWx Product Suite on May 6, 2024 for the May 2024 Brasil Floods

Date of Images: 5/6/2024 Date of Next Image: Unknown Summary: The floodwater depth raster produced for the 06th May 2024 for long-term floods in southern Brazil was generated using the Flood Water Depth Estimation Tool (Cohen et al, 2018, 2019; Peter et al, 2020). The Floodwater Depth Estimation Tool (FwDET) is a solution for producing timely floodwater depth data during flood activations that require emergency response and post-flood assessment. FwDET is based solely on a flood extent layer and a digital elevation model (DEM). The DEM used here was the NASA SRTM data. The flood extent layer was derived from the OPERA Dynamic Surface Water eXtent (DSWx) from the Harmonized Landsat Sentinel-2 (HLS) product. The DEM used was the NASA Shuttle Radar Topography Mission (SRTM) data. The computation involves identifying elevations at the boundaries of the flood extent layer and using those elevations to assign floodwater surface elevation to each cell within the flooded domain by identifying its nearest boundary cell. The modeled flood surface elevation is then subtracted from the original DEM to retrieve depth. The results posted here are preliminary and unvalidated results, primarily intended to aid the field response and people who wanted to have a rough first look at the flood inundation depth. The flood depth map may contain errors due to inaccurate elevations in the NASA SRTM DEM or the water surface estimation. Data Sources: OPERA Dynamic Surface Water eXtent from Harmonized Landsat Sentinel-2 (DSWx-HLS) - based flood inundation extent raster generated by the ARIA/OPERA group at NASA JPL. NASA SRTM (Shuttle Radar Topography Mission) Digital Elevation 30 m (openly available on Google Earth Engine) Suggested Use: The darkest shades of blue indicate where the product is estimating the largest floodwater depth, while lighter shades indicate shallower flooding Satellite/Sensor: Harmonized Landsat Sentinel-2 (HLS) MultiSpectral Instrument (MSI) on European Space Agency's (ESA) Copernicus Sentinel-2A/2B satellites NASA SRTM (Shuttle Radar Topography Mission) Digital Elevation 30 m (openly available on Google Earth Engine) Resolution: 30 meters Credits: Dinuke Munasinghe - NASA JPL Water and Ecosystems Team, NASA JPL ARIA/OPERA Team Product POCs: Dinuke Munasinghe ([e-mail]) FwDET Algorithm Documentation: Cohen, S., Brakenridge, G.R., Kettner, A., Bates, B., Nelson, J., McDonald, R., Huang, Y, Munasinghe, D., and J. Zhang (2018). Estimating Floodwater Depths from Flood Inundation Maps and Topography. Journal of the American Water Resources Association, 54(4), 847-858. DOI: https://doi.org/10.1111/1752-1688.12609 Cohen, S., Raney, A., Munasinghe D., Loftis, D., Molthan, A., Bell, J., Rogers, L., Galantowicz, J., Brakenridge, G.R., Kettner, A., Huang, Y., and Y. Tsang (2019). The Floodwater Depth Estimation Tool (FwDET v2.0) for Improved Remote Sensing Analysis of Coastal Flooding. Natural Hazards and Earth System Sciences, 19(9), 2053-2065. DOI: https://doi.org/10.5194/nhess-19-2053-2019 Farr, T.G., Rosen, P.A., Caro, E., Crippen, R., Duren, R., Hensley, S., Kobrick, M., Paller, M., Rodriguez, E., Roth, L., Seal, D., Shaffer, S., Shimada, J., Umland, J., Werner, M., Oskin, M., Burbank, D., and Alsdorf, D.E., 2007, The shuttle radar topography mission: Reviews of Geophysics, v. 45, no. 2, RG2004, at https://doi.org/10.1029/2005RG000183. Peter, B., Cohen, S., Lucey, R., Munasinghe, D., Raney, A., and G. Brakenridge (2020). "Google Earth Engine Implementation of the Floodwater Depth Estimation Tool (FwDET-GEE) for Rapid and Large Scale Flood Analysis". IEEE Geoscience and Remote Sensing Letters. DOI: https://doi.org/10.1109/lgrs.2020.3031190 OPERA. 2023. OPERA Dynamic Surface Water Extent from Harmonized Landsat Sentinel-2 CalVal Database (Version 1). Ver. 1.0. PO.DAAC, CA, USA. Dataset accessed [2024-05-09] at https://doi.org/10.5067/OPDSW-PCVV1 Esri REST Endpoint: See URL section on right side of page WMS Endpoint: https://maps.disasters.nasa.gov/ags03/services/brasil_flood_202405/fwdet_flood_depth/MapServer/WMSServer Data Download: https://aria-share.jpl.nasa.gov/202405-RioGrandeSul_Brazil-floods/FloodDepth/