This cached tiled map service, hosted at MassGIS' ArcGIS Online site, represents FEMA National Flood Hazard Layer (NFHL) data currently available for Massachusetts. At scales 1:80,000 and closer, flood zone abbreviation labels appear (from the FLD_ZONE field). The National Flood Hazard Layer (NFHL) dataset represents the current effective flood risk data for those parts of the country where maps have been modernized by the Federal Emergency Management Agency (FEMA). It is a compilation of effective Flood Insurance Rate Map (FIRM) databases and any Letters of Map Revision (LOMR) that have been issued against those databases since their publication date. The NFHL is updated as new data reaches its designated effective date and becomes valid for regulatory use under the National Flood Insurance Program (NFIP). See full metadata from MassGIS.

All data included in this layer are considered "final" by FEMA. Any preliminary data that appear on maps displayed at community meetings, etc., are not included here.

This map service includes data published by FEMA as of July 2, 2023.

To display a legend for this layer, add https://massgis.maps.arcgis.com/home/item.html?id=8455678914e64b03b565b97d07577279 to your map along with this service

This layer is sourced from maps.coast.noaa.gov.

This map service presents spatial information developed as part of the National Oceanic and Atmospheric Administration (NOAA) Office for Coastal Management’s Coastal Flood Exposure Mapper. The purpose of the online mapping tool is to provide coastal managers, planners, and stakeholders a preliminary look at exposures to coastal flooding hazards. The Mapper is a screening-level tool that uses nationally consistent data sets and analyses. Data and maps provided can be used at several scales to help communities initiate resilience planning efforts. Currently the extent of the Coastal Flood Exposure Mapper covers U.S. coastal areas along the Gulf of Mexico and Atlantic Ocean. NOAA provides the information “as-is” and shall incur no responsibility or liability as to the completeness or accuracy of this information. NOAA assumes no responsibility arising from the use of this information. For additional information, please contact the NOAA Office for Coastal Management (coastal.info@noaa.gov).

© NOAA Office for Coastal Management

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). Spatial data is georeferenced to the earth surface using the Transverse Mercator projected coordinate system and the North American Datum of 1983. The specifications for the horizontal control of DFIRM data files are consistent with those required for mapping at a scale of 1:6000.

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 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). Spatial data is georeferenced to the earth surface using the Wisconsin Transverse Mercator projected coordinate system and the North American Datum of 1983. The specifications for the horizontal control of DFIRM data files are consistent with those required for mapping at a scale of 1:6000.

The National Flood Hazard Layer (NFHL) dataset represents the current effective flood risk data for those parts of the country where maps have been modernized by the Federal Emergency Management Agency (FEMA).Also see the Map Service and Tile service.

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). In addition to the preceding, required text, the Abstract should also describe the projection and coordinate system as well as a general statement about horizontal accuracy.

The FIRM Database is the digital, geospatial version of the flood hazard information (location and attributes for boundaries of flood insurance risk zones) shown on the published paper Flood Insurance Rate Maps (FIRMs). The FIRM 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 FIRM Database is derived from Flood Insurance Studies (FISs), previously published 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 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 FIRM Database presents the flood risk information depicted on the FIRM in a digital format suitable for use in electronic mapping applications. The FIRM Database serves to archive the information collected during the Flood Risk Project.Informing Worcester is the City of Worcester's open data portal where interested parties can obtain public information at no cost.

Authority: Executive Order No. 149: FEMA and Flood Plain Use. Jurisdiction: Floodplains in the Commonwealth of Massachusetts. Applicability: Construction by state agencies must avoid floodplains. State-administered grant and loan programs must avoid supporting construction in flood plains, to the extent possible. Regulatory Designates the Massachusetts Department of Conservation and Recreation (DCR, formerly the Department of Environmental Management) as the state coordinating agency to implement the National Flood Insurance Program. Requires all state agencies, to the extent possible, to avoid construction, provision of loans or grants, conveying, or permitting projects in floodplains. Provides for Massachusetts participation in the National Flood Insurance Program. Review Process: Contact the Federal Emergency Management Agency (FEMA) to determine if a proposed project is in a floodplain. Projects proposed in floodplains are reviewed in conjunction with Massachusetts Environmental Policy Act (15), Massachusetts Wetlands Protection Act (17), and Massachusetts Office of Coastal Zone Management (22) reviews. Technical assistance is also available from the DCR Flood Hazard Management Program. Forms: No additional forms for floodplain review. Fees No additional fees for floodplain review. Website: FEMA at http://store.msc.fema.gov/webapp/wcs/stores/servlet/FemaWelcomeView?storeId=10001&catalogId=10001&langId=-1 DCR Flood Hazard Management Program at http://www.mass.gov/dcr/stewardship/mitigate/.

Data layers in this child item include high-water mark and storm-sensor data collected by the U.S. Geological Survey (USGS) New England Water Science Center following the January 4, 2018, and March 2-4, 2018, winter-storm events in New England. High-water marks and continuous water-level sensor data range from Portland, Maine, to Provincetown, Massachusetts, and reference the North American Vertical Datum of 1988 (NAVD88). For more information about these storm events and the data collection, please see Bent, G.C., and Taylor, N.J., 2020, Total water level data from the January and March 2018 nor’easters for coastal areas of New England: U.S. Geological Survey Scientific Investigations Report 2020–5048, 47 p., accessed June 3, 2021, at https://doi.org/10.3133/sir20205048 Flood-inundation map layers and interim products used to create them also are included in this child item. The USGS polygon of the stillwater-inundation map reflects a statistical storm with a 1-percent annual exceedance probability from Portland, Maine, to Provincetown, Massachusetts, based on coastal tide-gage data. The January and March 2018 inundation maps are polygon shapefiles of estimated flood extent derived from the high-water mark and storm-sensor data following the storm events. The flood extents and water-surface elevations were derived from simplified estimations of high-water mark and storm-sensor data and delineated using 2-meter-resolution lidar digital-elevation models. Interim data layers that were used to create the flood-inundation polygons include a coastal flood-profile line and coastal watershed boundaries. The compressed zip files contain ESRI shapefiles that include xml metadata files. Detailed processing steps are documented in the metadata for each layer. See the Scientific Investigation Report associated with this data release for more information.

Effective (2017) and Preliminary (2023) FEMA Flood Zones for Arlington, MA and the changes between the data

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).

NFHL with Q3 data only where no NFHL data exist. Neither dataset is available in Franklin county. See the MassGIS metadata pages for more information abut FEMA Q3 and NFHL data.

This EnviroAtlas dataset describes the total counts and percentage of population, land area, and impervious surface in the 1% Annual Chance Flood Hazard area or 0.2% Annual Chance Flood Hazard area of each block group. The flood hazard area is defined by the National Flood Hazard Layer (NFHL) produced by the Federal Emergency Management Agency (FEMA, www.fema.gov). This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

According to NOAA, "Floods are the most common and widespread of all weather-related natural disasters" and as our earth continues to warm due to climate change, precipitation events are becoming more frequent and more intense, dropping record-setting amounts of water from the sky. Whenever the volume of water on land overcomes the capacity of natural and built drainage systems to carry it away, inland flooding can result. Floods can happen in minutes or over long periods of time, but in either case the effects can be devastating and life-threatening. Building community resilience to inland flooding involves several steps including assessing vulnerability and risk of the community members. © 2024 Adobe Stock. All rights reserved.Riparian areas are lands adjacent to rivers, streams, lakes and other water bodies, and they provide a great deal of value to both wildlife as well as dissipate the energy of storm-generated waves and provide considerable resistance to streambank erosion. The natural sinuosity and complexity of river and stream channels helps to dissipate energy of raging flows during intense precipitation events. Identifying impervious surfaces and other concrete and "built" structures in the riparian zone and removing them allows for natural vegetation to take its place, thus increasing the resilience to flooding at a local level. This layer displays census tracts that are ranked according to which would benefit most from improving evacuation routes. The ranking is based upon a composite index built with the following attributes:Percent of Properties with Flooding Today in the Return Period 100 Scenario (%) - Data source no longer availablePercent Riparian Area (%)Percent of Area to Restore (%) - Expressed as a percentage of the tract with landcover classified as “built-up”.These attribute links take you to the original data sources. Preprocessing was needed to prepare many of these inputs for inclusion in our index. The links are provided for reference only.This layer is one of six in a series developed to support local climate resilience planning. Intended as planning tools for policy makers, climate resilience planners, and community members, these layers highlight areas of the community that are most likely to benefit from the resilience intervention it supports. Each layer focuses on one specific flood resilience intervention that is intended to help mitigate against the climate hazard.Restoring built-up areas to natural habitat has many benefits including mitigating flood damage. For more information, the Commonwealth of Massachusetts has an excellent document that describes the functions of riparian areas for storm damage prevention. Additionally, here is a resource from the EPA.Layers in the inland flooding series include,Where Would Better Flood Awareness Improve Inland Flood Resilience?Where Would Better Evacuation Routes Improve Flood Resilience?Where Would Open Space Preservation Improve Flood Resilience?Where Would Reducing Impervious Surfaces Improve Flood Resilience?Where Would Restoring Built-up Areas Improve Flood Resilience?Where Would Future Flood Prone Areas Benefit From Slowing Development?Did you know you can build your own climate resilience index or use ours and customize it? The Customize a climate resilience index Tutorial provides more information on the index and also walks you through steps for taking our index and customizing it to your needs so you can create intervention maps better suited to your location and sourced from your own higher resolution data. For more information about how Esri enriched the census tracts with exposure, demographic, and environmental data to create composite indices called intervention indices, please read this technical reference.This feature layer was created from the Climate Resilience Planning Census Tracts hosted feature layer view and is one of 18 similar intervention layers, all of which can be found in ArcGIS Living Atlas of the World.

Floodplains in Newton, Massachusetts. The floodplains support Newton's Floodplain Ordinance of 2010. The ordinance defines floodways as the 100 year floodplain as defined in FEMA's Flood Insurance Rate (FIRM) Maps. These correspond to Zone AE on those maps. In addition, the oridinance lists most streams, not studied on the FIRM's by name and established as 30 foot corridor or buffer around each one.

The Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model is a numerical model used by National Weather Service (NWS) to compute storm surge. Storm surge is defined as the abnormal rise of water generated by a storm, over and above the predicted astronomical tides. Flooding from storm surge depends on many factors, such as the track, intensity, size, and forward speed of the hurricane and the characteristics of the coastline where it comes ashore or passes nearby. For planning purposes, the NHC uses a representative sample of hypothetical storms to estimate the near worst-case scenario of flooding for each hurricane category.

SLOSH employs curvilinear polar, elliptical, and hyperbolic telescoping mesh grids to simulate the storm surge hazard. The spatial coverage for each SLOSH grid ranges from an area the size of a few counties to a few states. The resolution of individual grid cells within each basin ranges from tens to hundreds of meters to a kilometer or more. Sub-grid scale water features and topographic obstructions such as channels, rivers, and cuts and levees, barriers, and roads, respectively, are parameterized to improve the modeled water levels.

NHC provides two near worst case scenario planning products based on hypothetical storm tracks: Maximum Envelopes of Water (MEOWs) and Maximum of Maximums (MOMs). MEOWs are created by computing the maximum storm surge resulting from up to 100,000 hypothetical storms simulated through each SLOSH grid of varying forward speed, radius of maximum wind, intensity (Categories 1-5), landfall location, initial water level, and storm direction. A MEOW product is created for each combination of category, forward speed, storm direction, and initial water level. SLOSH products do not include Category 5 storms north of the NC/VA border. For each storm combination, parallel storms make landfall in 5 to 10 mile increments along the coast within the SLOSH grid, and the maximum storm surge footprint from each simulation is composited, retaining the maximum height of storm surge in a given basin grid cell. No single hurricane will produce the regional flooding depicted in the MEOWs. SLOSH model MOMs are an ensemble product of maximum storm surge heights. MOMs are created for each SLOSH basin by compositing all the MEOWs, separated by category and initial water level, and selecting maximum storm surge value for each grid cell regardless of the forward speed, storm trajectory, or landfall location. The MOMs represent the worst case scenario for a given category of storm and initial water level under ideal storm conditions. A high tide initial water level was used for the storm surge hazard maps.

This product uses the expertise of the NHC Storm Surge Unit to merge the operational SLOSH grids to build a seamless map of storm surge hazard scenarios using the MOM product. Each individual SLOSH grid for the Category 1-5 MOMs are merged into a single, seamless grid. The seamless grid is then resampled, interpolated, and processed with a Digital Elevation Model (DEM, i.e. topography) to compute the storm surge hazard above ground for each hurricane category. It should be noted that the SLOSH MOM storm surge hazard data used to create these maps are constrained by the extent of the SLOSH grids users should be aware that risk due to storm surge flooding could extend beyond the areas depicted in these maps. The resulting dataset is then reclassified into the bins described in the entity overview. The areas marked with a value of "99" represent certain levee areas, such as the Hurricane and Storm Damage Risk Reduction System in Louisiana. These areas are highly complex and this product should not be used to assess the storm surge hazard within these areas. Users are urged to consult local officials for flood risk inside these levee areas. Not all levee areas are included in this analysis - in particular, local features such as construction walls, levees, berms, pumping systems, or other mitigation systems found at the local level may not be included in this analysis.

Storm Surge Hazard Maps: https://www.nhc.noaa.gov/surge/nationalsurge/SLOSH Model: https://www.nhc.noaa.gov/surge/slosh.phpPotential Storm Surge Flooding Map: https://www.nhc.noaa.gov/surge/inundation/

Complete metadata are available in the GIS data layers available from https://www.nhc.noaa.gov/nationalsurge/

These SLOSH data were downloaded by the Massachusetts Office of Coastal Zone Management on 2024-02-21 and clipped to the Massachusetts offshore boundary. MassGIS received a tile package from MassCZM and published it as a hosted tile layer in ArcGIS Online.

This Coastal Barrier Resources System (CBRS) data set, produced by the U.S. Fish and Wildlife Service (Service), contains areas designated as undeveloped coastal barriers in accordance with the Coastal Barrier Resources Act (CBRA), 16 U.S.C. 3501 et seq., as amended. The boundaries used to create the polygons herein were compiled between 12/6/2013 and 12/16/2016 from the official John H. Chafee Coastal Barrier Resources System CBRS maps. The boundaries of the CBRS Units in Connecticut, Massachusetts, Rhode Island, and the Long Island portion of New York, were digitized from the official paper maps according to the guidelines in a notice published in the Federal Register on August 29, 2013 (see the â Georeferencing and Boundary Interpretationâ and â Boundary Transcriptionâ sections of 78 FR 53467; available at https://www.federalregister.gov/d/2013-21167). In all other cases where the official map was created through digital methods, the digital boundary was used. These digital polygons are only representations of the CBRS boundaries shown on the official CBRS maps and are not to be considered authoritative. The Service is not responsible for any misuse or misinterpretation of this digital data set, including use of the data to determine eligibility for federal financial assistance such as federal flood insurance. CBRS maps are either enacted by Congress or adopted administratively by the Secretary of the Interior (Secretary), and are maintained by the Service. As maps are revised, this data set will be updated with the new boundaries. Copies of the official CBRS maps are available for viewing at Serviceâ s Headquarters office and are also available to view or download at https://www.fws.gov/ecological-services/habitat-conservation/cbra/Maps/index.html. CBRS boundaries viewed using the CBRS Mapper or the shapefile are subject to misrepresentations beyond the Serviceâ s control, including misalignments of the boundaries with third party base layers and misprojections of spatial data. The official CBRS map is the controlling document and should be consulted for all official determinations. Official determinations are recommended for all properties that are in close proximity (within 20 feet) of a CBRS boundary. For an official determination of whether or not an area or specific property is located within the CBRS, please follow the procedures found at https://www.fws.gov/ecological-services/habitat-conservation/cbra/Determinations.html. For any questions regarding the CBRS, please contact your local Service field office or email CBRA@fws.gov. Contact information for Service field offices can be found at http://www.fws.gov/offices.