Floodplains (FEMA, DFIRM 2026)

The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop risk data. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual- chance flood event, and areas of minimal flood risk. The DFIRM Database is derived from Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). The FIRM is the basis for floodplain management, mitigation, and insurance activities for the National Flood Insurance Program (NFIP). Insurance applications include enforcement of the mandatory purchase requirement of the Flood Disaster Protection Act, which "... requires the purchase of flood insurance by property owners who are being assisted by Federal programs or by Federally supervised, regulated or insured agencies or institutions in the acquisition or improvement of land facilities located or to be located in identified areas having special flood hazards, " Section 2 (b) (4) of the Flood Disaster Protection Act of 1973. In addition to the identification of Special Flood Hazard Areas (SFHAs), the risk zones shown on the FIRMs are the basis for the establishment of premium rates for flood coverage offered through the NFIP. The DFIRM Database presents the flood risk information depicted on the FIRM in a digital format suitable for use in electronic mapping applications. The DFIRM database is a subset of the Digital FIS database that serves to archive the information collected during the FIS. For more information, contact: GIS Manager Research & Strategic Projects (RSP), Montgomery County Planning Department, MNCPPC T: 301-650-5620数字洪水保险费率图（Digital Flood Insurance Rate Map, DFIRM）数据库用于呈现用于生成洪水风险数据的洪水风险信息及配套支撑数据。该数据集采用的核心风险分级包括年超越概率1%的洪水事件、年超越概率0.2%的洪水事件，以及最低洪水风险区域。DFIRM数据库的来源包括洪水保险研究（Flood Insurance Studies, FISs）、此前发布的洪水保险费率图（Flood Insurance Rate Maps, FIRMs）、为支撑FISs与FIRMs开展的洪水灾害分析成果，以及可获取的新型测绘数据。上述FISs与FIRMs均由美国联邦紧急事务管理局（Federal Emergency Management Agency, FEMA）发布。洪水保险费率图是美国国家洪水保险计划（National Flood Insurance Program, NFIP）开展洪泛区管理、灾害减灾以及保险业务的核心依据，其保险相关应用场景包括落实1973年《洪水灾害保护法》规定的强制投保要求，该法案第2条第(b)款第(4)项明确要求："由联邦项目提供援助，或由联邦监管、管控或承保的机构协助收购或改造位于已识别特殊洪水风险区域的土地设施时，相关物业所有者必须购买洪水保险"。除了识别特殊洪水危险区域（Special Flood Hazard Areas, SFHAs）外，FIRM上标注的风险分区同时也是制定NFIP项下洪水保险保费费率的基础依据。DFIRM数据库将FIRM所载的洪水风险信息转换为适配电子测绘应用的数字化格式，该数据库是数字FIS数据库的子集，用于归档FIS研究过程中收集的全部相关信息。如需获取更多相关信息，请联系：蒙哥马利县规划局研究与战略项目（Research & Strategic Projects, RSP）地理信息系统主管，蒙哥马利县规划委员会（Montgomery County Planning Department, MNCPPC），联系电话：301-650-5620。