FEMA Flood Zone

This data was adopted by the City of Spokane via Ordinance C34612 amending SMC Title 17E.030 effective 07/06/2010. The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the 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 file is georeferenced to earth?s surface using the UTM projection and coordinate system. The specifications for the horizontal control of DFIRM data files are consistent with those required for mapping at a scale of 1:12,000.本数据集由斯波坎市通过第C34612号条例正式采纳，该条例修订了SMC第17E.030章，生效日期为2010年7月6日。数字洪水保险费率地图（Digital Flood Insurance Rate Map, DFIRM）数据库涵盖了用于构建洪水风险数据的相关信息及配套支撑数据集。其采用的主要风险分级包括：年发生概率1%的洪水事件、年发生概率0.2%的洪水事件，以及极低洪水风险区域。本DFIRM数据库源自洪水保险研究报告（Flood Insurance Studies, FISs）、此前发布的洪水保险费率地图（Flood Insurance Rate Maps, FIRMs）、为支持上述FISs与FIRMs所开展的洪水灾害分析，以及可获取的最新测绘数据。前述FISs与FIRMs均由美国联邦紧急事务管理局（Federal Emergency Management Agency, FEMA）发布。本数据集文件采用通用横轴墨卡托（UTM）投影及坐标系完成地理配准，以锚定地球表面空间位置。DFIRM数据文件的水平控制规范，与1:12,000比例尺测绘工作的要求保持一致。