Flood Zones and Hydrologic Data

Overview This feature service provides comprehensive flood hazard and hydrologic data for DeKalb County, including detailed flood zone delineations, hydraulic structures analysis, and local flood study boundaries. It supports flood risk assessment, management, and planning by local governments and related agencies. Feature Layers Basins: Represents watershed basins with attributes such as basin identifiers, sizes, and structural counts. Useful for hydrologic analysis and water resource planning. Overtopped Structure Points and Lines: These layers identify hydraulic structures like bridges and levees that are overtopped during various storm events, presenting water surface elevations, flow, velocity, width, and depth for multiple storm annual chance frequencies. They help evaluate infrastructure vulnerability during floods. Cross Sections and Profiles: Includes effective cross-section and profile baseline data with multiple water surface elevations for different storm frequencies. This information is critical for hydraulic modeling and floodplain mapping. Local Flood Studies (100 Acres Plus): Defines flood hazard boundaries from local studies smaller than FEMA studies, focusing on drainage areas of 100 acres or more. This higher standard dataset enhances flood risk awareness and mitigation efforts in DeKalb County. State Waters: Contains river and stream flowlines and cartographic features, aiding in understanding water flow patterns and hydrologic connections. Building Footprints: Reflects the shape and orientation of ground floors of structures, supporting public safety, planning, and floodplain management by local authorities. Flood Zones and Floodways: Layers depicting various FEMA flood zones (Zone A, AE, AO, AE Floodway, Shaded Zone X) and special flood hazard areas, along with Base Flood Elevation adjustments and future conditions scenarios, supporting regulatory and planning activities. Geographic Coverage All layers in the service cover DeKalb County, Georgia, providing detailed information for local floodplain management and resilience planning. Use Cases Flood risk assessment and mapping for local government floodplain management. Infrastructure vulnerability analysis during flood events. Support for community awareness and flood resilience planning. Hydrologic and hydraulic modeling supporting regulatory compliance and urban planning.概览 本要素服务可为佐治亚州迪卡尔布县(DeKalb County)提供全面的洪水灾害与水文数据，涵盖精细的洪水区划定、水工构筑物分析以及本地洪水研究边界等内容，可支撑地方政府及相关机构开展洪水风险评估、管理与规划工作。 要素图层 流域图层：表示流域盆地，附带流域标识符、面积、构筑物数量等属性字段，可用于水文分析与水资源规划。 漫溢构筑物点与线图层：该类图层可识别各类暴雨事件中发生漫溢的桥梁、堤坝等水工构筑物，并提供多种暴雨年超越概率下的水面高程、流量、流速、宽度及水深数据，有助于评估洪水期间基础设施的脆弱性。 断面与剖面图层：包含有效断面与剖面基线数据，涵盖不同暴雨频率下的多组水面高程信息，该数据对于水工建模与洪水淹没区制图至关重要。 本地洪水研究（≥100英亩）图层：基于规模小于美国联邦紧急事务管理局(FEMA)相关研究的本地洪水研究成果，划定洪水灾害边界，重点覆盖面积≥100英亩的汇水区。该高标准数据集可提升迪卡尔布县(DeKalb County)的洪水风险认知与减灾工作成效。 州级水系图层：包含河流与溪流的流线及制图要素，有助于理解水流模式与水文连通性。 建筑足迹图层：展示构筑物首层的形状与朝向，可辅助地方主管部门开展公共安全、规划及洪水淹没区管理工作。 洪水区与行洪通道图层：该图层展示美国联邦紧急事务管理局(FEMA)划定的各类洪水区（Zone A、AE、AO、AE Floodway、Shaded Zone X）及特殊洪水灾害区域，同时包含基准洪水高程(Base Flood Elevation)调整与未来情景数据，可支撑监管与规划活动。 地理覆盖范围 本服务中的所有图层均覆盖佐治亚州迪卡尔布县(DeKalb County)，可为本地洪水淹没区管理与韧性规划提供详细数据支撑。 应用场景 1. 面向地方政府洪水淹没区管理的洪水风险评估与制图； 2. 洪水事件期间的基础设施脆弱性分析； 3. 支撑社区洪水风险认知提升与韧性规划； 4. 为满足监管合规与城市规划需求的水文与水工建模提供支持。