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Mid-Course Adjustment: Flood MapsIf you want to know how to get to where you are going, you'll probably consult a paper map or online mapping service. In the world of flood mitigation, preparedness, and response, those who want to locate risks within the floodplain consult FEMA's Flood Insurance Rate Maps (FIRMs).Today, millions of people in the United States and its territories depend on the accuracy of the FIRMs for information about where and how to build safely, rate policies for flood insurance coverage, manage development, site mitigation projects, and rebuild after floods occur. FEMA is committed to providing consumers with up-to-date, accessible, and accurate flood hazard mapping information. Modernizing FEMA's Maps Flood Map Modernization is a multiyear Presidential initiative supported by Congress that is directed at improving and updating the Nation's flood hazard identification maps. The updated maps will reflect new data as well as improved technologies for identifying flood hazards. With any long-term initiative, it is a good practice periodically to evaluate the original goals, seek feedback from stakeholders, and make adjustments as appropriate to ensure that the initiative is being implemented in the best manner possible. When the Map Modernization initiative approached the halfway point in its funding, FEMA performed a mid-program evaluation that considered input from Congress, the U.S. Government Accountability Office (GAO), the Department of Homeland Security's Inspector General, and other stakeholders. As a result of this evaluation, FEMA is now implementing changes to its Map Modernization Program that will result in better-targeted and more accurate flood data, as well as the production of digital flood maps for a significant portion of the United States. A Targeted Shift From the beginning of this initiative in 2003, Map Modernization has focused on creating a digital flood layer for all communities at risk of flooding. However, recommendations from stakeholders during the initiative's first years have indicated a preference for FEMA to focus on developing flood maps that meet new higher standards for mapping and for a shift in resource allocation to those communities that have the most significant flood risk, even though it would result in a delay in map production for communities with a lower risk of flooding. FEMA believes the "adjusted" course it is now implementing for Map Modernization is responsive to user and Congressional input and, based on improved data collected as part of the initiative, reflects a sound direction for the future. The Map Modernization Program's modified objectives are now: (1) producing new digital products; (2) providing new, updated, or validated engineering analyses; and (3) integrating the 2005 Floodplain Boundary Standard into the digital maps.
This table shows that, with the adjusted course, more engineering analysis will take place and there will be a higher level of compliance with the Floodplain Boundary Standard than would have been possible under the course originally intended. On the other hand, there will be a decrease in the total land area being mapped and the percentage of the U.S. population receiving a digital map product. The Floodplain Boundary Standard In response to input from Congress and the GAO as well as recent experience gained in converting paper maps to digital format, FEMA implemented an additional mapping standard midway through the initiative that is related to the conversion of digital flood boundaries. This new standard is called the Floodplain Boundary Standard, and it requires matching the available flood boundary from the paper map to the best available topographic information, and then merging both into the digital format. This process results in a digital map whose floodplain boundary line corrects any discrepancies in the paper map's boundary that may have existed either because topographic information was insufficiently detailed when the paper map was created or as a result of the conversion process. Map Modernization Progress Report The major advances FEMA has made in the process for modernizing FIRMs for the United States are listed below. Standardized Guidelines FEMA's release of Guidelines and Specifications for Flood Hazard Mapping Partners was a major achievement in coordinating and fostering accuracy and consistency in flood mapping. This document and its appendixes define the technical requirements and product specifications for flood hazard maps and related NFIP products, and also reflect changes to processes and products that have come about with Map Modernization, such as data capture standards and guidelines. The MHIP Another critical implementation aid developed by FEMA is the Multi-Year Flood Hazard Identification Plan (MHIP), which details FEMA's plan for prioritizing and delivering modernized flood maps nationwide. A standardized procedure for annually refining the MHIP is based on input from States and other stakeholders. Floodplain Boundary Standard Section 7 of FEMA's FY04-FY08 MHIP established a Floodplain Boundary Standard that must be met for a map to be considered "modernized." Guidance on implementation of the standard was issued to mapping partners in September 2005. This single step goes a long way toward alleviating the concerns of map users that boundaries improperly drawn on the paper maps would simply be transferred to the digital maps. With the Floodplain Boundary Standard in place, this potential inaccuracy is avoided. Mapping Information Platform In 2004, FEMA launched the Mapping Information Platform (MIP), a Web-based infrastructure that provides the ability to manage, extract, share, and produce mapping information. FEMA's mapping partners post and share data developed for flood study projects on the MIP. The site is enhanced continually to provide upgraded engineering and mapping tools to FEMA's mapping partners. Risk-Based Mapping Priorities FEMA uses a process called sequencing to compare flood risks between communities and then prioritize mapping for the higher risk area. Based on a series of factors (such as population and growth, housing units, flood insurance policies and claims, and repetitive flood losses), every county in the U.S. has been assigned a "risk factor" that is used by FEMA when determining allocation of study funds and priorities. In general, counties with the highest risk factor are high-priority targets for new maps. Sequenced priorities are communicated to the FEMA Regions and to the State, where further adjustments in priority may be based on local conditions. Census Block Groups Beginning with Fiscal Year 2006 funding (October 1, 2005), sequencing has been based on prioritized census block groups rather than on prioritized counties. Block groups are the smallest geographic unit for which the U.S. Census Bureau tabulates sample data. This adjustment allows for additional focus on those areas that comprise 90 percent of the Nation's flood risk, and account for 92 percent of the Nation's population. Although 10 percent of the flood risks in the country have received a lower priority as a result of the Map Modernization Program's mid-course adjustment, it remains FEMA's goal to map 100 percent of the United States. Stream Mile Measurements The improved detail and accuracy available with digital mapping techniques is enabling FEMA to shift from using map panels to using stream miles (including shoreline for the open ocean, lakes, and ponds) as a measure of progress. There are roughly 3 million stream and coastal miles of floodplains in the United States. Approximately 1 million of these lie within Federal lands such as national parks and military bases. Of the remaining 2 million stream and coastal miles that are or could be at risk of flooding due to development, about 1 million have been the subject of some type of flood hazard analysis. Initially, counting map panels was a convenient way to inventory flood maps because each covered a given area and the number remained fairly constant for a region. With the development of Geographic Information Systems (GIS) technology, the scale of a flood map now can readily be tailored to whatever its use. Therefore, the size of the "panels" and the number of panels needed to cover the country are no longer constant. On the other hand, the number of stream and coastal miles in the U.S. is fixed and thus provides a standard against which progress can be measured. Using stream miles rather than rectangular panels also allows depiction of a specific potential hazard so that differing vulnerabilities to flooding can be targeted individually. Further, use of stream miles permits more precise identification of areas that need additional attention, such as new flood data or a review of whether the mapping standards are being met along that reach of stream. As a result of the mid-course adjustment, 40 percent of the U.S. population will have maps that encompass stream miles based on new, updated, or validated engineering analysis. Map modernization will not eliminate the use of panels. They continue to be an effective tool for allowing insurance agents and building officials to make key insurance and mitigation decisions that are tied to a specific panel location, and aid in tracking past decisions. Looking Ahead From the inception of the Map Modernization initiative and continuing through to the present, there always has been an identified need for a post-Map Modernization phase that will account both for map maintenance and for other unmet needs. Specifically, areas that must be addressed during that phase include:
FEMA's mid-course adjustment in implementing the Map Modernization initiative will yield cost-effective benefits in terms of timely realization of digital flood map coverage for those areas in which it is most needed. Over the long term, these modernized flood maps will more accurately portray flood hazards so that risks to life and property can be assessed and appropriate action taken. |
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Last updated on March 1, 2007
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