roads, impact critical infrastructure like water and sewer lines and can be deadly. It is difficult to identify where debris flows and mudflows are likely to happen using existing mapping methods. Professionals need a more effective way to map debris and mudflow risk areas.
The Base Flood Elevation (BFE) is how high floodwater is likely to rise during a 1%-annual-chance flood event. It is one way to measure and indicate flood risk. However, the study that established the BFE is only a snapshot in time. There are many factors that can cause floodwaters to rise above the BFE. These factors include debris-blocked bridge and culvert openings; blocked city storm sewer drains; higher-intensity rain events; storm tracks causing coinciding peak flows of flooding sources; high backwater conditions; and heavy rains on frozen ground with considerable snow depths. There is also always the potential for an event more severe than the 1%-annual-chance event. To communicate and reduce flood risk in areas beyond FEMA’s regulatory flood zones, communities need more information (especially spatial information) about flooding that exceeds the 1%-annual-chance event.
Many potential applicants do not understand how to develop competitive nature-based hazard mitigation project proposals for FEMA Hazard Mitigation Assistance (HMA) programs.). Without clear understanding a community may miss out on the opportunity to help reduce its potential for flood disasters.