The flood level or inundation depth will then be 8m at the river, and zero at the 8-m HAND contour. For example, a 8-m stage flood indicates that when the water increases by eight meters in the river channel, the water will inundate until the 8-m HAND contour. For each of these hypothetical floods the HAND contour represents the area that would be flooded if the stage in the river rises to that level. To illustrate this, the figure below represents uniform hypothetical floods from 1m to 8m stage height in a region of the Philippines. Flood Event Viewer: Data collected during short-term flood events like hurricanes and multi-state storms. Flood Inundation Mapper: Shows where river flooding might occur over a range of water levels. The depth of the flood is the arithmetic inverse of the HAND height. USGS flood map products include: USGS Flood Information: Maps and resources for current and historical floods. The HAND contour map can simultaneously show the extent of inundation and the inundation depth. This gives information about the potential people and assets at risk. The different HAND contours represent hypothetical flood extents for different water levels, and give an impression of the floodplain at risk. These maps, which represent the potential extent of inundation, follow a simple static HAND approach as described in Nobre et al. The end user can then decide which ‘scenario’ or inundation map is most relevant for the current flood. Maps of fluvial flooding are created based on Height Above Nearest Drainage (HAND) contours as a first estimate flood map. This method should be applied on a subnational to regioanl scale and is maily usefull if detailed locaiton information of tweets is lacking. With multiple cities along the same river we could give an estimate of the inundation map which corresponds best with the available flood information from Twitter. These maps give information about the potential people and assets at risk. a ‘noise’ threshold of number of flood related social media messages at a certain area is exceeded, possible inundation maps are created for that location. Discover what Risk MAP can mean for your community. View existing Risk MAP projects in a list or interactive map. Explore products provide a more user-friendly analysis of flood risks. To get the expected flood height above ground, you would need to subtract your ground elevation from the base flood elevation.When an event is detected in the global twitter feed by FloodTags, i.e. Risk Mapping, Assessment and Planning (Risk MAP) The Risk MAP program promotes planning and development practices to help reduce that risk. The Base Flood Elevations are denoted in the datum NAVD 88, which represents the number of feet above mean sea level in that datum. On a map, it may read: AE13, which means the structure is in the AE flood zone with a BFE of 13. While the flood zones identify the extent of flood risk, the Base Flood Elevation identifies the expect height that flood waters are expected to reach in a high risk area. These zones range from high- to moderate-risk areas: VE, AE, AO, A, and X. Within the floodplains shown on the Flood Insurance Rate Maps (FIRMs) for New York City, there are five zones. These maps identify areas that are at risk to flooding. Areas with a high flooding risk are identified as being in the 100-year floodplain, and areas with a moderate flooding risk are identified as the 500-year floodplain. It is important to understand how to interpret the flood maps to better understand your risk.
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