Flood Hazard - Floodways Estees Project

The Federal Emergency Management Agency (FEMA) has developed the Advisory Flood Zones. They provide full geospatial representation of the coastal and riverine Advisory Base Flood Elevations (1% annual chance coastal flood hazard), including both storm surge and wave components. FEMA is providing an advisory floodway to provide a geospatial limit of the channel of rivers or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than the designated height. FEMA has developed the Coastal A Zone to approximate the extent of breaking waves less than 3 ft and equal to and greater than 1.5 ft in height for the 1-Percent-Annual-Chance flood events美国联邦紧急事务管理局（Federal Emergency Management Agency, FEMA）构建了咨询洪水区域（Advisory Flood Zones）数据集。该数据集完整呈现了海岸与河域的咨询基准洪水高程（Advisory Base Flood Elevations）的地理空间分布特征，对应1%年超越概率的海岸洪水灾害场景，涵盖风暴潮与波浪两个分量。FEMA同时配套发布了咨询洪水行洪通道（advisory floodway），用于划定河道或其他水道及其毗邻陆域的地理空间边界：此类区域需预留以宣泄基准洪水，且不会使水面高程较预设阈值出现累积性抬升。此外，FEMA还开发了海岸A区（Coastal A Zone），用于近似模拟1%年超越概率洪水事件中，高度介于1.5英尺至3英尺之间的碎波影响范围。