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PLEASE NOTE: This dataset has been retired. It has been superseded by https://environment.data.gov.uk/dataset/04532375-a198-476e-985e-0579a0a11b47. Links to this data will be removed after April 2025. We encourage users to download this Flood Zones dataset if you would like to retain a comparison ability beyond this date.
The Flood Map for Planning (Rivers and Sea) includes several layers of information. This dataset covers Flood Zone 3. It is our best estimate of the areas of land at risk of flooding, when the presence of flood defences are ignored and covers land with a 1 in 100 (1%) or greater chance of flooding each year from Rivers; or with a 1 in 200 (0.5%) or greater chance of flooding each year from the Sea.
This dataset is designed to support flood risk assessments in line with Planning Practice Guidance; and raise awareness of the likelihood of flooding to encourage people living and working in areas prone to flooding to find out more and take appropriate action.
The information provided is largely based on modelled data and is therefore indicative rather than specific.
Locations may also be at risk from other sources of flooding, such as high groundwater levels, overland run off from heavy rain, or failure of infrastructure such as sewers and storm drains.
The information indicates the flood risk to areas of land and is not sufficiently detailed to show whether an individual property is at risk of flooding, therefore properties may not always face the same chance of flooding as the areas that surround them. This is because we do not hold details about properties and their floor levels.
Information on flood depth, speed or volume of flow is not included.
The Flood Map for Planning (Rivers and Sea) includes several layers of information. This dataset covers Flood Zone 3. It is our best estimate of the areas of land at risk of flooding, when the presence of flood defences are ignored and covers land with a 1 in 100 (1%) or greater chance of flooding each year from Rivers; or with a 1 in 200 (0.5%) or greater chance of flooding each year from the Sea.This dataset is designed to support flood risk assessments in line with Planning Practice Guidance; and raise awareness of the likelihood of flooding to encourage people living and working in areas prone to flooding to find out more and take appropriate action.The information provided is largely based on modelled data and is therefore indicative rather than specific.Locations may also be at risk from other sources of flooding, such as high groundwater levels, overland run off from heavy rain, or failure of infrastructure such as sewers and storm drains.The information indicates the flood risk to areas of land and is not sufficiently detailed to show whether an individual property is at risk of flooding, therefore properties may not always face the same chance of flooding as the areas that surround them. This is because we do not hold details about properties and their floor levels.Information on flood depth, speed or volume of flow is not included.NOTE: We have paused quarterly updates of this dataset. Please visit the “Pause to Updates of Flood Risk Maps” announcement on our support pages for further information. We will provide notifications on the Flood Map for Planning website to indicate where we have new flood risk information. Other data related to the Flood Map for Planning will continue to be updated, including data relating to flood history, flood defences, and water storage areas.Defra Network WMS server provided by the Environment Agency
Open Government Licence 3.0http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/
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The Flood Map for Planning Service includes several layers of information. This includes the Flood Zones data which shows the extent of land at present day risk of flooding from rivers and the sea, ignoring the benefits of defences, for the following scenarios:
• Flood Zone 1 – Land having a less than 0.1% (1 in 1000) annual probability of flooding. • Flood Zone 2 – Land having between 0.1% - 1% (1 in 100 to 1 in 1000) annual probability of flooding from rivers or between 0.1% - 0.5% (1 in 200 to 1 in 1000) annual probability of flooding from the sea, and accepted recorded flood outlines . • Flood Zone 3 – Areas shown to be at a 1% (1 in 100) or greater annual probability of flooding from rivers or 0.5% (1 in 200) or greater annual probability of flooding from the sea.
Flood Zone 1 is not shown in this dataset, but covers all areas not contained within Flood Zones 2 and 3. Local Planning Authorities (LPAs) use the Flood Zones to determine if they must consult the Environment Agency on planning applications. They are also used to determine if development is incompatible and whether development is subject to the exception test. The Flood Zones are one of several flood risk datasets used to determine the need for planning applications to be supported by a Flood Risk Assessment (FRA) and subject to the sequential test.
The Flood Zones are a composite dataset including national and local modelled data, and information from past floods.
The Flood Zones are designed to only give an indication of flood risk to an area of land and are not suitable for showing whether an individual property is at risk of flooding. This is because we cannot know all the details about each property.
http://reference.data.gov.uk/id/open-government-licencehttp://reference.data.gov.uk/id/open-government-licence
The Flood Map shows the areas across Wales that could be affected by flooding from rivers or the sea. It also shows flood defences and the areas that benefit from them. Flood Map is designed to raise awareness among the public local authorities and other organisations of the likelihood of flooding and to encourage people living and working in areas prone to flooding to find out more and take appropriate action. The Flood Map includes several layers of information, this layer is: Flood Zone 3, which is NRWs best estimate of the areas of land with a 100 to 1 (or greater) chance of flooding each year from rivers or with a 200 to 1 chance (or greater) of flooding each year from the sea.
An online viewable version of this dataset is available via the NRW website.
http://reference.data.gov.uk/id/open-government-licencehttp://reference.data.gov.uk/id/open-government-licence
Flood Map shows the areas across Wales that could be affected by flooding from rivers or the sea. It also shows flood defences and the areas that benefit from them. Flood Map is designed to raise awareness among the public local authorities and other organisations of the likelihood of flooding and to encourage people living and working in areas prone to flooding to find out more and take appropriate action. The Flood Map includes several layers of information, this layer is: Flood Zone 2, which is NRWs best estimate of the areas of land between Zone 3 and the extent of the flood from rivers or the sea with a 1000 to 1 chance of flooding in any year. It includes those areas defined in Flood Zone 3.
An online viewable version of this dataset is available via the NRW website.
Open Government Licence 3.0http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/
License information was derived automatically
The Flood Map for Planning (Rivers and Sea) includes several layers of information. This layer and documentation covers Flood Zone 2. It is the Environment Agency's best estimate of the areas of land at risk of flooding, when he presence of flood defences are ignored and covers land between Zone 3 and the extent of the flooding from rivers or the sea with a 1 in 1000 (0.1%) chance of flooding each year. This dataset also includes those areas defined in Flood Zone 3.This dataset is designed to support flood risk assessments in line with Planning Practice Guidance ; and raise awareness of the likelihood of flooding to encourage people living and working in areas prone to flooding to find out more and take appropriate action. This dataset is republished by the West of England Combined Authority for supplementing information within our Local Nature Recovery Strategy. If you are using it for statutory purposes, you should refer to the Environment Agency's canonical version, linked in the Attributions field below as this is likely to be more current.
This dataset has been discontinued. New Flood Zones will be available when the new Flood Map for Planning is published at the end of Summer 2021. Flood Map shows the areas across Wales that could be affected by flooding from rivers or the sea. It also shows flood defences and the areas that benefit from them. Flood Map is designed to raise awareness among the public local authorities and other organisations of the likelihood of flooding and to encourage people living and working in areas prone to flooding to find out more and take appropriate action. The Flood Map includes several layers of information, this layer is: Flood Zone 2, which is NRWs best estimate of the areas of land between Zone 3 and the extent of the flood from rivers or the sea with a 1000 to 1 chance of flooding in any year. It includes those areas defined in Flood Zone 3.
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showing boundaries of flood zone as defined by environment agency. medium and high risk areas combined.
This map represents Flood Insurance Rate Map (FIRM) data important for floodplain management, mitigation, and insurance activities for the National Flood Insurance Program (NFIP). The National Flood Hazard Layer (NFHL) data present the flood risk information depicted on the FIRM in a digital format suitable for use in electronic mapping applications. The NFHL database is a subset of the information created for the Flood Insurance Studies (FIS) and serves as a means to archive a portion of the information collected during the FIS. The NFHL data incorporates Digital Flood Insurance Rate Map (DFIRM) databases published by Federal Emergency Management Agency (FEMA). The 100-year flood is referred to as the 1% annual exceedance probability flood, since it is a flood that has a 1% chance of being equaled or exceeded in any single year. 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 1% annual chance (base flood) is the flood that has a 1% chance of being equaled or exceeded in any year. The Special Flood Hazard area is the area subject to flooding by the 1% annual chance flood. Areas of Special Flood Hazard include Zones A, AE, AH, AO, AR, A99, D, V, VE, and X. These flood zones are explained below and reflects the severity or type of flooding in the area. A - Zone A is the flood insurance rate zone that corresponds to the 1-percent annual chance floodplains that are determined in the Flood Insurance Study by approximate methods of analysis. Because detailed hydraulic analyses are not performed for such areas, no Base Flood Elevations or depths are shown within this zone. Mandatory flood insurance purchase requirements apply. AE and A1-A30 - Zones AE and A1-A30 are the flood insurance rate zones that correspond to the 1-percent annual chance floodplains that are determined in the Flood Insurance Study by detailed methods of analysis. In most instances, Base Flood Elevations derived from the detailed hydraulic analyses are shown at selected intervals within this zone. Mandatory flood insurance purchase requirements apply. AH - Zone AH is the flood insurance rate zone that corresponds to the areas of 1-percent annual chance shallow flooding with a constant water-surface elevation (usually areas of ponding) where average depths are between 1 and 3 feet. The Base Flood Elevations derived from the detailed hydraulic analyses are shown at selected intervals within this zone. Mandatory flood insurance purchase requirements apply. AO - Zone AO is the flood insurance rate zone that corresponds to the areas of 1-percent shallow flooding (usually sheet flow on sloping terrain) where average depths are between 1 and 3 feet. Average flood depths derived from the detailed hydraulic analyses are shown within this zone. In addition, alluvial fan flood hazards are shown as Zone AO on the Flood Insurance Rate Map. Mandatory flood insurance purchase requirements apply. AR - Zone AR is the flood insurance rate zone used to depict areas protected from flood hazards by flood control structures, such as a levee, that are being restored. FEMA will consider using the Zone AR designation for a community if the flood protection system has been deemed restorable by a Federal agency in consultation with a local project sponsor; a minimum level of flood protection is still provided to the community by the system; and restoration of the flood protection system is scheduled to begin within a designated time period and in accordance with a progress plan negotiated between the community and FEMA. Mandatory purchase requirements for flood insurance will apply in Zone AR, but the rate will not exceed the rate for an unnumbered Zone A if the structure is built in compliance with Zone AR floodplain management regulations. A99 - Zone A99 is the flood insurance rate zone that corresponds to areas within the 1-percent annual chance floodplain that will be protected by a Federal flood protection system where construction has reached specified statutory milestones. No Base Flood Elevations or depths are shown within this zone. Mandatory flood insurance purchase requirements apply. D - Zone D designation is used for areas where there are possible but undetermined flood hazards. In areas designated as Zone D, no analysis of flood hazards has been conducted. Mandatory flood insurance purchase requirements do not apply, but coverage is available. The flood insurance rates for properties in Zone D are commensurate with the uncertainty of the flood risk. V - Zone V is the flood insurance rate zone that corresponds to areas within the 1-percent annual chance coastal floodplains that have additional hazards associated with storm waves. Because approximate hydraulic analyses are performed for such areas, no Base Flood Elevations are shown within this zone. Mandatory flood insurance purchase requirements apply. VE - Zone VE is the flood insurance rate zone that corresponds to areas within the 1-percent annual chance coastal floodplain that have additional hazards associated with storm waves. Base Flood Elevations derived from the detailed hydraulic analyses are shown at selected intervals within this zone. Mandatory flood insurance purchase requirements apply. X - Zone X is the flood insurance rate zones that correspond to areas outside the 1-percent annual chance floodplain – Areas protected from the 1-percent annual chance flood by levees. No Base Flood Elevations or depths are shown within this zone. Insurance purchase is not required in these zones. More information about the flood zones can be found here. The NFHL data are derived from Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps, flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data where available. The NFHL data is available at State level. The data is updated on monthly basis and FEMA is in the process of mapping all the flood zones and so some counties do not have complete data. For better visualization, it’s recommended to display the service with 50% transparency. The map service has a county layer that helps differentiate between the counties that have flood data available and those that do not. The flood data is scale dependent and is set to show from 1:3,000,000. This data is as of March 2011.
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The Flood Map for Planning includes several layers of information, which includes data created to support the use of Flood Zones in the planning process. This dataset shows the extent of land at risk of flooding to a defined annual exceedance probability (AEP) or chance of flooding each year. This dataset represents the following scenario: ● Defended: 3.3% AEP (1 in 30) Rivers/Sea Defended products take into account the presence of flood defences and assume that they operate in the way they were intended (or designed) to function. This does not include any asset failure (or removal) scenarios. This dataset is designed to only give an indication of flood risk to an area of land and are not suitable for showing whether an individual property is at risk of flooding. This is because we cannot know all the details about each property. Information on flood depth, speed or volume of flow is not included. Attribution statement: © Environment Agency copyright and/or database right 2025. All rights reserved.
https://durhamnc.maps.arcgis.com/sharing/rest/content/items/9030dd38e1604f868db7c50fbded83b8/datahttps://durhamnc.maps.arcgis.com/sharing/rest/content/items/9030dd38e1604f868db7c50fbded83b8/data
Flood zone mapping for development review purposes. Combination of 10/19/2018 effective and 3/31/2015 preliminary data). When remaining panels along southeast boundaries with Wake County and norheast boundary near Butner become effective, will revert to one set of data for flood insurance and development review purposes). Repository for all FEMA floodplain data and map revisions are found at: https://fris.nc.gov/fris/Index.aspx?FIPS=063=NC=General%20PublicCreditsFEMA, City of Durham, Durham CountyUse limitationsInformation depicted hereon is for reference purposes only and is compiled from the best available sources. The City of Durham/Durham County assumes no responsibility for errors arising from use or misuse of this map.
Federal Emergency Management Agency Floodplain for Deschutes County, Oregon. Updated by FEMA nationwide in 2007, 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 1973 Flood Disaster Protection Act). 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 insurance coverage offered through the NFIP. Q3 Flood Data files convey certain key features from the existing hard copy FIRM. Edge-matching errors, overlaps and deficiencies in coverage, and similar problems are not corrected during digitizing or post-processing. The Q3 Flood Data files are intended to provide users with automated flood risk data that may be used to locate SFHAs. More detailed information may be obtained from the paper FIRM.
The Flood Map for Planning includes several layers of information, which includes data created to support the use of Flood Zones in the planning process. This dataset shows the extent of land at risk of flooding to a defined annual exceedance probability (AEP) or chance of flooding each year, taking into account the possible effects of climate change as detailed below.
This dataset represents the following scenario:
● Defended: 3.3% AEP (1 in 30) Rivers/Sea
The defended products take into account the presence of flood defences and assume that they operate in the way they were intended (or designed) to function. This does not include any asset failure (or removal) scenarios.
Climate change scenarios have been produced to indicate the possible impacts of climate change on future risk. The climate change allowances are based on the latest UK Climate Projections (UKCP18) from the Met Office, using the Representative Concentration Pathway (RCP) 8.5. The specific climate change scenarios shown are as follows:
● the ‘Central’ allowance for the 2080s epoch (2070-2125) for risk of flooding from rivers
● the ‘Upper End’ allowance for risk of flooding from the sea, accounting for cumulative sea level rise to 2125
For climate change scenarios, it is assumed that existing flood defences continue to function in the same way as present day. No allowance is made for any future changes to flood defence design or operation.
These datasets are designed to only give an indication of flood risk to an area of land and are not suitable for showing whether an individual property is at risk of flooding. This is because we cannot know all the details about each property.
Information on flood depth, speed or volume of flow is not included. Attribution statement: © Environment Agency copyright and/or database right 2025. All rights reserved.
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License information was derived automatically
The Flood Map for Planning includes several layers of information, which includes data created to support the use of Flood Zones in the planning process. This dataset shows the extent of land at risk of flooding to a defined annual exceedance probability (AEP) or chance of flooding each year, taking into account the possible effects of climate change as detailed below. This dataset represents the following scenario: ● Defended: 3.3% AEP (1 in 30) Rivers/Sea The defended products take into account the presence of flood defences and assume that they operate in the way they were intended (or designed) to function. This does not include any asset failure (or removal) scenarios. Climate change scenarios have been produced to indicate the possible impacts of climate change on future risk. The climate change allowances are based on the latest UK Climate Projections (UKCP18) from the Met Office, using the Representative Concentration Pathway (RCP) 8.5. The specific climate change scenarios shown are as follows: ● the ‘Central’ allowance for the 2080s epoch (2070-2125) for risk of flooding from rivers ● the ‘Upper End’ allowance for risk of flooding from the sea, accounting for cumulative sea level rise to 2125 For climate change scenarios, it is assumed that existing flood defences continue to function in the same way as present day. No allowance is made for any future changes to flood defence design or operation. These datasets are designed to only give an indication of flood risk to an area of land and are not suitable for showing whether an individual property is at risk of flooding. This is because we cannot know all the details about each property. Information on flood depth, speed or volume of flow is not included. Attribution statement: © Environment Agency copyright and/or database right 2025. All rights reserved.
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The Historic Flood Map is a GIS layer showing the maximum extent of individual Recorded Flood Outlines from river, the sea and groundwater springs that meet a set criteria. It shows areas of land that have previously been subject to flooding in England. This excludes flooding from surface water, except in areas where it is impossible to determine whether the source is fluvial or surface water but the dominant source is fluvial.
The majority of records began in 1946 when predecessor bodies to the Environment Agency started collecting detailed information about flooding incidents, although we hold limited details about flooding incidents prior to this date.
If an area is not covered by the Historic Flood Map it does not mean that the area has never flooded, only that we do not currently have records of flooding in this area that meet the criteria for inclusion. It is also possible that the pattern of flooding in this area has changed and that this area would now flood or not flood under different circumstances. Outlines that don’t meet this criteria are stored in the Recorded Flood Outlines dataset.
The Historic Flood Map takes into account the presence of defences, structures, and other infrastructure where they existed at the time of flooding. It will include flood extents that may have been affected by overtopping, breaches or blockages.
Flooding is shown to the land and does not necessarily indicate that properties were flooded internally.
[Metadata] Tropical storms, hurricanes, and tsunamis create waves that flood low-lying coastal areas. The National Flood Insurance Program (NFIP) produces flood insurance rate maps (FIRMs) that depict flood risk zones referred to as Special Flood Hazard Areas (SFHA) based modeling 1%-annual-chance flood event also referred to as a 100-year flood. The purpose of the FIRM is twofold: (1) to provide the basis for application of regulatory standards and (2) to provide the basis for insurance rating.SFHAs identify areas at risk from infrequent but severe storm-induced wave events and riverine flood events that are based upon historical record. By law (44 Code of Federal Regulations [CFR] 60.3), FEMA can only map flood risk that will be utilized for land use regulation or insurance rating based on historical data, therefore, future conditions with sea level rise and other impacts of climate change are not considered in FIRMs. It is important to note that FEMA can produce Flood Insurance Rate Maps that include future condition floodplains, but these would be considered “awareness” zones and not to be used for regulatory of insurance rating purposes.The State of Hawai‘i 2018 Hazard Mitigation Plan incorporated the results of modeling and an assessment of vulnerability to coastal flooding from storm-induced wave events with sea level rise (Tetra Tech Inc., 2018). The 1% annual-chance-coastal flood zone with sea level rise (1%CFZ) was modeled to estimate coastal flood extents and wave heights for wave-generating events with sea level rise. Modeling was conducted by Sobis Inc. under State of Hawaiʻi Department of Land and Natural Resources Contract No: 64064. The 1%CFZ with 3.2 feet of sea level rise was utilized to assess vulnerability to coastal event-based flooding in mid to - late century.The 1%CFZ with sea level rise would greatly expand the impacts from a 100-year flood event meaning that more coastal land area will be exposed to damaging waves. For example, over 120 critical infrastructure facilities in the City and County of Honolulu, including water, waste, and wastewater systems and communication and energy facilities would be impacted in the 1%CFZ with 3.2 feet of sea level rise (Tetra Tech Inc., 2018). This is double the number of facilities in the SFHA which includes the impacts of riverine flooding.A simplified version of the Wave Height Analysis for Flood Insurance Studies (WHAFIS) extension (FEMA, 2019b) included in Hazus-MH, was used to create the 1% annual chance coastal floodplain. Hazus is a nationally applicable standardized methodology that contains models for estimating potential losses from earthquakes, floods, tsunamis, and hurricanes (FEMA, 2019a). The current 1%-annual-chance stillwater elevations were collected using the most current flood insurance studies (FIS) for each island conducted by FEMA (FEMA, 2004, 2010, 2014, 2015). The FIS calculates the 1%-annual-chance stillwater elevation, wave setup, and wave run-up (called maximum wave crest) at regularly-spaced transects around the islands based on historical data. Modeling for the 1%CFZ used the NOAA 3-meter digital elevation model (DEM) which incorporates LiDAR data sets collected between 2003 and 2007 from NOAA, FEMA, the State of Hawaiʻi Emergency Management Agency, and the USACE (NOAA National Centers for Environmental Information, 2017).Before Hazus was run for future conditions, it was run for the current conditions and compared to the FEMA regulatory floodplain to determine model accuracy. This also helped determine the stillwater elevation for the large gaps between some transects in the FIS. Hazus was run at 0.5-foot stillwater level intervals and the results were compared to the existing Flood Insurance Rate Map (FIRM). The interval of 0.5-feet was chosen as a small enough step to result in a near approximation of the FIRM while not being too impractically narrow to require the testing of dozens of input elevations. The elevation which matched up best was used as the current base flood elevation.Key steps in modeling the projected 1%CFZ with sea level rise include: (1) generating a contiguous (no gaps along the shoreline) and present-day 1%-annual-chance stillwater elevation based on the most recent FIS, (2) elevating the present-day 1%-annual-chance stillwater elevation by adding projected sea level rise heights, and (3) modeling the projected 1%-annual-chance coastal flood with sea level rise in HAZUS using the 1%-annual-chance wave setup and run-up from the FIS. The 1%CFZ extent and depth was generated using the HAZUS 3.2 coastal flood risk assessment model, 3-meter DEM, the FIS for each island, and the IPCC AR5 upper sea level projection for RCP 8.5 scenario for 0.6 feet, 1.0 feet, 2.0 feet, and 3.2 feet of sea level rise above MHHW (IPCC, 2014). The HAZUS output includes the estimated spatial extent of coastal flooding as well as an estimated flood depth map grid for the four sea level rise projections.Using the current floodplain generated with Hazus, the projected 1%-annual-chance stillwater elevation was generated using the four sea level rise projections. This stillwater elevation with sea level rise was used as a basis for modeling. The projected 1%-annual coastal flood with sea level rise was modeled in Hazus using the current 1%-annual-chance wave setup and run-up from the FIS and the projected 1%-annual-chance stillwater elevation with sea level rise. Statewide GIS Program staff extracted individual island layers for ease of downloading. A statewide layer is also available as a REST service, and is available for download from the Statewide GIS geoportal at https://geoportal.hawaii.gov/, or at the Program's legacy download site at https://planning.hawaii.gov/gis/download-gis-data-expanded/#009. For additional information, please refer to summary metadata at https://files.hawaii.gov/dbedt/op/gis/data/coastal_flood_zones_summary.pdf or contact Hawaii Statewide GIS Program, Office of Planning and Sustainable Development, State of Hawaii; PO Box 2359, Honolulu, Hi. 96804; (808) 587-2846; email: gis@hawaii.gov.
The purpose of this collection is to provide researchers and near real-time users, a daily view of river and standing water flooding over the Americas. On the GOES-R series satellites flood detection is based on 10-minute full disk scans first, and then a composition process is done on all the previous 10-minute flood maps to update the results each hour. The product within this collection is a cloud free composite based on 24 hourly map composites. The data are gridded on an equal latitude-longitude area grid. Variables within this dataset include Water Detection, Quality Flags, and Quality Information.
Spatial data supporting appropriately located and designed woodland creation to help reduce flood risk by slowing flood flows and increasing the retention and infiltration of water on the land.
The layer shows where there is ‘Opportunity for Floodplain’ woodland creation and ‘Opportunity for Wider Catchment’ woodland creation.
Appropriately located and designed proposals can help reduce flood risk by slowing flood flows and increasing the retention and infiltration of water on the land by creating; woodland in the wider catchment – creating woodland here can help to, reduce fertiliser and pesticide usage, protect sensitive soils from disturbance and erosion, increase infiltration and reduce water runoff and intercept sediment and chemical pollutants in run-off, reducing the delivery of pollutants to watercourses.
Floodplain woodland – creating woodland here can act as a permeable partial barrier to a river when in flood, helping to slow flood flows.
Riparian woodland – creating woodland along watercourses can create a buffer between rivers and the adjacent land, reducing water temperature by providing shade and slowing flood flow water delivery to watercourses.
Cross-slope woodland – creating smaller areas (typically shelterbelts) of woodland (all types) across hill slopes can reduce rapid runoff from higher land. Trees also encourage infiltration and increase the soil’s water storage capacity.
Data input sources: - Spatial prioritisation of catchments suitable for Natural Flood Management (Environment Agency) - Flood Map for Planning (Rivers and Sea) - Flood Zone 3 (Environment Agency) - Soil-derived spatial prioritisation of woodland creation for NFM in the wider catchment (Forest Research)
Attributes: ‘LANDSCAPE’ – the targeting category: Opportunity for Floodplain Woodland / Opportunity for Wider Catchment Woodland. ‘AreaHa’ – Area of the feature in hectares.
Link to landing page referenced by identifier. Service Protocol: Link to landing page referenced by identifier. Link Function: information-- dc:identifier.
[Metadata] Tropical storms, hurricanes, and tsunamis create waves that flood low-lying coastal areas. The National Flood Insurance Program (NFIP) produces flood insurance rate maps (FIRMs) that depict flood risk zones referred to as Special Flood Hazard Areas (SFHA) based modeling 1%-annual-chance flood event also referred to as a 100-year flood. The purpose of the FIRM is twofold: (1) to provide the basis for application of regulatory standards and (2) to provide the basis for insurance rating.
SFHAs identify areas at risk from infrequent but severe storm-induced wave events and riverine flood events that are based upon historical record. By law (44 Code of Federal Regulations [CFR] 60.3), FEMA can only map flood risk that will be utilized for land use regulation or insurance rating based on historical data, therefore, future conditions with sea level rise and other impacts of climate change are not considered in FIRMs. It is important to note that FEMA can produce Flood Insurance Rate Maps that include future condition floodplains, but these would be considered “awareness” zones and not to be used for regulatory of insurance rating purposes.
The State of Hawai‘i 2018 Hazard Mitigation Plan incorporated the results of modeling and an assessment of vulnerability to coastal flooding from storm-induced wave events with sea level rise (Tetra Tech Inc., 2018). The 1% annual-chance-coastal flood zone with sea level rise (1%CFZ) was modeled to estimate coastal flood extents and wave heights for wave-generating events with sea level rise. Modeling was conducted by Sobis Inc. under State of Hawaiʻi Department of Land and Natural Resources Contract No: 64064. The 1%CFZ with 3.2 feet of sea level rise was utilized to assess vulnerability to coastal event-based flooding in mid to - late century.
The 1%CFZ with sea level rise would greatly expand the impacts from a 100-year flood event meaning that more coastal land area will be exposed to damaging waves. For example, over 120 critical infrastructure facilities in the City and County of Honolulu, including water, waste, and wastewater systems and communication and energy facilities would be impacted in the 1%CFZ with 3.2 feet of sea level rise (Tetra Tech Inc., 2018). This is double the number of facilities in the SFHA which includes the impacts of riverine flooding.
A simplified version of the Wave Height Analysis for Flood Insurance Studies (WHAFIS) extension (FEMA, 2019b) included in Hazus-MH, was used to create the 1% annual chance coastal floodplain. Hazus is a nationally applicable standardized methodology that contains models for estimating potential losses from earthquakes, floods, tsunamis, and hurricanes (FEMA, 2019a).
The current 1%-annual-chance stillwater elevations were collected using the most current flood insurance studies (FIS) for each island conducted by FEMA (FEMA, 2004, 2010, 2014, 2015). The FIS calculates the 1%-annual-chance stillwater elevation, wave setup, and wave run-up (called maximum wave crest) at regularly-spaced transects around the islands based on historical data. Modeling for the 1%CFZ used the NOAA 3-meter digital elevation model (DEM) which incorporates LiDAR data sets collected between 2003 and 2007 from NOAA, FEMA, the State of Hawaiʻi Emergency Management Agency, and the USACE (NOAA National Centers for Environmental Information, 2017).
Before Hazus was run for future conditions, it was run for the current conditions and compared to the FEMA regulatory floodplain to determine model accuracy. This also helped determine the stillwater elevation for the large gaps between some transects in the FIS. Hazus was run at 0.5-foot stillwater level intervals and the results were compared to the existing Flood Insurance Rate Map (FIRM). The interval of 0.5-feet was chosen as a small enough step to result in a near approximation of the FIRM while not being too impractically narrow to require the testing of dozens of input elevations. The elevation which matched up best was used as the current base flood elevation.
Key steps in modeling the projected 1%CFZ with sea level rise include: (1) generating a contiguous (no gaps along the shoreline) and present-day 1%-annual-chance stillwater elevation based on the most recent FIS, (2) elevating the present-day 1%-annual-chance stillwater elevation by adding projected sea level rise heights, and (3) modeling the projected 1%-annual-chance coastal flood with sea level rise in HAZUS using the 1%-annual-chance wave setup and run-up from the FIS. The 1%CFZ extent and depth was generated using the HAZUS 3.2 coastal flood risk assessment model, 3-meter DEM, the FIS for each island, and the IPCC AR5 upper sea level projection for RCP 8.5 scenario for 0.6 feet, 1.0 feet, 2.0 feet, and 3.2 feet of sea level rise above MHHW (IPCC, 2014). The HAZUS output includes the estimated spatial extent of coastal flooding as well as an estimated flood depth map grid for the four sea level rise projections.
Using the current floodplain generated with Hazus, the projected 1%-annual-chance stillwater elevation was generated using the four sea level rise projections. This stillwater elevation with sea level rise was used as a basis for modeling. The projected 1%-annual coastal flood with sea level rise was modeled in Hazus using the current 1%-annual-chance wave setup and run-up from the FIS and the projected 1%-annual-chance stillwater elevation with sea level rise.
Statewide GIS Program staff extracted individual island layers for ease of downloading. A statewide layer is also available as a REST service, and is available for download from the Statewide GIS geoportal at https://geoportal.hawaii.gov/, or at the Program's legacy download site at https://planning.hawaii.gov/gis/download-gis-data-expanded/#009. For additional information, please refer to summary metadata at https://files.hawaii.gov/dbedt/op/gis/data/coastal_flood_zones_summary.pdf or contact Hawaii Statewide GIS Program, Office of Planning and Sustainable Development, State of Hawaii; PO Box 2359, Honolulu, Hi. 96804; (808) 587-2846; email: gis@hawaii.gov.
Open Government Licence 3.0http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/
License information was derived automatically
PLEASE NOTE: This dataset has been retired. It has been superseded by https://environment.data.gov.uk/dataset/04532375-a198-476e-985e-0579a0a11b47. Links to this data will be removed after April 2025. We encourage users to download this Flood Zones dataset if you would like to retain a comparison ability beyond this date.
The Flood Map for Planning (Rivers and Sea) includes several layers of information. This dataset covers Flood Zone 3. It is our best estimate of the areas of land at risk of flooding, when the presence of flood defences are ignored and covers land with a 1 in 100 (1%) or greater chance of flooding each year from Rivers; or with a 1 in 200 (0.5%) or greater chance of flooding each year from the Sea.
This dataset is designed to support flood risk assessments in line with Planning Practice Guidance; and raise awareness of the likelihood of flooding to encourage people living and working in areas prone to flooding to find out more and take appropriate action.
The information provided is largely based on modelled data and is therefore indicative rather than specific.
Locations may also be at risk from other sources of flooding, such as high groundwater levels, overland run off from heavy rain, or failure of infrastructure such as sewers and storm drains.
The information indicates the flood risk to areas of land and is not sufficiently detailed to show whether an individual property is at risk of flooding, therefore properties may not always face the same chance of flooding as the areas that surround them. This is because we do not hold details about properties and their floor levels.
Information on flood depth, speed or volume of flow is not included.