For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov/.

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment-visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.Suggested citation: Verdin, James; Verdin, Kristine; Mathis, Melissa; Magadzire, Tamuka; Kabuchanga, Eric; Woodbury, Mark; and Gadain, Hussein, 2016, A software tool for rapid flood inundation mapping: U.S. Geological Survey Open-File Report 2016-1038, 26 p., http://dx.doi.org/10.3133/ofr20161038. AbstractThe GIS Flood Tool (GFT) was developed by the U.S. Geological Survey with support from the U.S. Agency for International Development's Office of U.S. Foreign Disaster Assistance to provide a means for production of reconnaissance-level flood inundation mapping for datasparse and resource-limited areas of the world. The GFT has also attracted interest as a tool for rapid assessment flood inundation mapping for the Flood Inundation Mapping Program of the U.S. Geological Survey. The GFT can fill an important gap for communities that lack flood inundation mapping by providing a first-estimate of inundation zones, pending availability of resources to complete an engineering study. The tool can also help identify priority areas for application of scarce flood inundation mapping resources. The technical basis of the GFT is an application of the Manning equation for steady flow in an open channel, operating on specially processed digital elevation data. The GFT is implemented as a software extension in ArcGIS. Output maps from the GFT were validated at 11 sites with inundation maps produced previously by the Flood Inundation Mapping Program using standard one-dimensional hydraulic modeling techniques. In 80 percent of the cases, the GFT inundation patterns matched 75 percent or more of the one-dimensional hydraulic model inundation patterns. Lower rates of pattern agreement were seen at sites with low relief and subtle surface water divides. Although the GFT is simple to use, it should be applied with the oversight or review of a qualified hydraulic engineer who understands the simplifying assumptions of the approach.

For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprodTo order this and other USGS information products, visit http://store.usgs.gov Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. AbstractThis study produced a comprehensive estimate of the magnitude of hydropower potential available in the streams that drain watersheds entirely within the State of São Paulo, Brazil. Because a large part of the contributing area is outside of São Paulo, the main stem of the Paraná River was excluded from the assessment. Potential head drops were calculated from the Digital Terrain Elevation Data,which has a 1-arc-second resolution (approximately 30-meter resolution at the equator). For the conditioning and validation of synthetic stream channels derived from the Digital Elevation Model datasets, hydrography data (in digital format) supplied by the São Paulo State Department of Energy and the Agência Nacional de Águas were used. Within the study area there were 1,424 rain gages and 123 streamgages with longterm data records. To estimate average yearly streamflow, a hydrologic regionalization system that divides the State into 21 homogeneous basins was used. Stream segments, upstream areas, and mean annual rainfall were estimated using geographic information systems techniques. The accuracy of the flows estimated with the regionalization models was validated. Overall, simulated streamflows were significantly correlated with the observed flows but with a consistent underestimation bias. When the annual mean flows from the regionalization models were adjusted upward by 10 percent, average streamflow estimation bias was reduced from -13 percent to -4 percent. The sum of all the validated stream reach mean annual hydropower potentials in the 21 basins is 7,000 megawatts (MW). Hydropower potential is mainly concentrated near the Serra do Mar mountain range and along the Tietê River. The power potential along the Tietê River is mainly at sites with medium and high potentials, sites where hydropower has already been harnessed. In addition to the annual mean hydropower estimates, potential hydropower estimates with flow rates with exceedance probabilities of 40 percent, 60 percent, and 90 percent were made.