Statutory Main Rivers Map is a spatial (polyline) dataset that defines statutory watercourses in England designated as Main Rivers by the Environment Agency.

Watercourses designated as ‘main river’ are generally the larger arterial watercourses. The Environment Agency has permissive powers, but not a duty, to carry out maintenance, improvement or construction work on designated main rivers.

All other open water courses in England are determined by statute as an ‘ordinary watercourse’. On these watercourses the Lead Local flood Authority or, if within an Internal Drainage District, the Internal Drainage Board have similar permissive powers to maintain and improve.

The Statutory Main River Map Variations dataset defines proposed changes to the Statutory Main River Map.

Statutory Main Rivers Map defines statutory watercourses in England designated as Main Rivers by Environment Agency.

Watercourses designated as ‘main river’ are generally the larger arterial watercourses. The Environment Agency has permissive powers, but not a duty, to carry out maintenance, improvement or construction work on designated main rivers.

All other open water courses in England are determined by statute as an ‘ordinary watercourse’. On these watercourses the Lead Local flood Authority or, if within an Internal Drainage District, the Internal Drainage Board have similar permissive powers to maintain and improve.

The Environment Agency notifies the public and interested parties of our intentions to make a change to the statutory main river map and decides which watercourses are designated as Main Rivers following a legal process to determine and publish changes.

The change, or variation, to the Statutory Main River Map is either a deletion (also known as a demainment) or an addition (also known as an enmainment).

There are two reasons for a change to the Statutory Main River Map - Designation and Factual.

Designation changes are required when we make a decision to lengthen or shorten the section of a river designated as a 'main river'. These changes will determine which risk management authority may carry out maintenance, improvement or construction work on the watercourse. These changes result also in differing legislation applying to the riparian owner and others with an interest.

Factual changes may be required to update the map to represent the real position of the watercourse. They do not involve any changes of authority or management. Typical examples of factual changes are when: a watercourse has changed course naturally, a watercourse has been diverted or a survey of a culvert shows a different alignment.

A change to the Statutory Main River Map goes through the following stages (identified as Status within the data):

• Draft
• Consultation
• Pending Determination
• Determination
• Appeals
• Pending Appeals
• Pending Implementation
• Implemented (Month and Year)

Web Map containing Statutory Main River Map, Statutory Main River Map Variations 2022 and Statutory Main River Variations pre 2021 feature layers.Created for use by Web Mapping Application: Main River Map

This dataset consists of an interactive map (and supporting guidance) containing background information that informs how we understand flood risk across the Severn River Basin District. The map shows the River Basin District, component river basins and the coastline together with layers showing land use and topography.

This dataset together with equivalent datasets for each River Basin District, supports the Preliminary Flood Risk Assessment for England report which has been written to meet the requirements of the Flood Risk Regulations (2009) - to complete an assessment of flood risk and produce supporting maps of river catchments. Attribution statement: © Environment Agency copyright and/or database right 2018. All rights reserved. © Crown copyright and database rights 2018 Ordnance Survey 100024198 © Bluesky International Ltd/Getmapping PLC. Some features of this map are based on digital spatial data from the Centre for Ecology & Hydrology, British Antarctic Survey and British Geological Survey. © NERC (Centre for Ecology & Hydrology; British Antarctic Survey; British Geological Survey).
Contains public sector information licensed under the Open Government Licence v3.0.

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.

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.Lineage:

First published to support the woodland creation grant under Countryside Stewardship (CS), launched in 2015. The layer methodology was then revised by Forest Research and the layer was updated in 2022 to cater for the new England Woodland Creation Offer (EWCO) scheme.

A detailed methodology describing the development of this layer can be requested from evidence@forestrycommission.gov.uk.

CFRAM Modelled River Centrelines. Published by Office of Public Works. Available under the license Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 (cc-by-nc-nd).Abstract: This data shows the centre-line of rivers that have been modelled to generate the CFRAM flood maps. It is an indicator of the channels that have been included in the river network model and from which the resultant fluvial flood extents have been derived.

Data has been produced for the 'Areas of Further Assessment' (AFAs), as required by the EU 'Floods' Directive [2007/60/EC] and designated under the Preliminary Flood Risk Assessment, and also for other reaches between the AFAs and down to the sea that are referred to as 'Medium Priority Watercourses' (MPWs). River reaches that have been modelled are indicated by the CFRAM Modelled River Centrelines dataset.

Flooding from other reaches of river may occur, but has not been mapped, and so areas that are not shown as being within a flood extent may therefore be at risk of flooding from unmodelled rivers (as well as from other sources).

The purpose of the Flood Maps is not to designate individual properties at risk of flooding. They are community-based maps.

Lineage: The modelled river centrelines data is a derivative of the Environmental Protection Agency River Network dataset, which is released as Open Data under the CC BY 4.0 licence.

Fluvial and coastal flood map data is developed using hydrodynamic modelling, based on calculated design river flows and extreme sea levels, surveyed channel cross-sections, in-bank / bank-side / coastal structures, Digital Terrain Models, and other relevant datasets (e.g. land use, data on past floods for model calibration, etc.).

The process may vary for particular areas or maps. Technical Hydrology and Hydraulics Reports set out full technical details on the derivation of the flood maps.

For fluvial flood levels, calibration and verification of the models make use of the best available data, including hydrometric records, photographs, videos, press articles and anecdotal information. Subject to the availability of suitable calibration data, models are verified in so far as possible to target vertical water level accuracies of approximately +/-0.2m for areas within the AFAs, and approximately +/-0.4m along the MPWs.

v101 (March 2025) The section of map near Oranmore Galway updated following a map review process see https://www.floodinfo.ie/map-review/ for further information, Map Review Code: MR019.

Purpose: The data has been developed to comply with the requirements of the European Communities (Assessment and Management of Flood Risks) Regulations 2010 to 2015 (the “Regulations”) (implementing Directive 2007/60/EC) for the purposes of establishing a framework for the assessment and management of flood risks, aiming at the reduction of adverse consequences for human health, the environment, cultural heritage and economic activity associated with floods....

This dataset consists of an interactive map (and supporting guidance) containing background information that informs how we understand flood risk across the Humber River Basin District. The map shows the River Basin District, component river basins and the coastline together with layers showing land use and topography.

This dataset together with equivalent datasets for each River Basin District, supports the Preliminary Flood Risk Assessment for England report which has been written to meet the requirements of the Flood Risk Regulations (2009) - to complete an assessment of flood risk and produce supporting maps of river catchments.

WWNP Floodplain Woodland Planting Potential is our best estimate of locations where tree planting on the floodplain may be possible, and effective to attenuate flooding. The dataset is designed to support signposting of areas of floodplain not already wooded. The dataset is based upon fluvial Flood Zone 2 of the Flood Map for Planning. A set of open access constraints data was used to erase areas which contained existing woodland, watercourses, peat, roads, rail and urban locations.The information provided is largely based on modelled data and open constraints data, and is therefore indicative rather than specific. Locations identified may have more recent building or land use than available data indicates. It is important to note that land ownership and change to flood risk have not been considered, and it may be necessary to model the impacts of significant planting.The Environment Agency’s Flood Map for Planning (2016) - Flood Zone 2 (0.1% AEP) was used to delineate areas close to the watercourse in the floodplain which may be suitable for tree planting. The ‘Woodland Constraints’ data was then applied, masking existing woodland, watercourses, peat, roads, rail and urban areas.

Large-scale, accurate and fully attributed digital river centreline covering England and Wales. The dataset has full-feature network geometry cross-referenced with OS MasterMap following Digital National Framework principles. The dataset has full-feature network geometry cross-referenced with OS MasterMap following Digital National Framework. It is made of the three following layers: - Links: lines representing the river network. It is a river centreline dataset, based on OS MasterMap for surface features and Environment Agency culvert surveys for underground features (where available). There are many attributes associated with this dataset to enable it to be used for many different business purposes. It is topologically correct to allow it's use in network tracing tasks. - Offline Drainage: lines representing the sections of river and drains that do not obviously connect to the main online drainage network represented by the DRN. Sections with uncertain flow direction and connectivity are presented here, although in reality some may connect to the main DRN, and be added to it as more information becomes available. - Nodes: points representing the junctions between discrete stretches of the online DRN. It is used to assist in connectivity and flow direction, as every DRN stretch is attributed with the 'from' and 'to' nodes. Nodes are also included where line features cross, but do not intersect, such as an aqueduct passing over a river. Nodes have types to determine whether they are at for example junction or at a change in river type.

WWNP Floodplain Reconnection Potential is our best estimate of locations where it may be possible to establish reconnection between a watercourse and its natural floodplain, especially during high flows. The dataset is designed to support signposting of areas where there is currently poor connectivity such that flood waters are constrained to the channel and flood waves may therefore propagate downstream rapidly. The dataset is based upon the Risk of Flooding from Rivers and Sea probability maps, and identifies areas of low and very low probability that are close to a watercourse, but which do not contain residential property or key services.The areas may contain non-residential property so it is important to consider this and recent buildings or defences when considering floodplain reconnection. Locations identified may have more recent building or land use than available data indicates. It is important to note that land ownership and change to flood risk have not been considered, and it may be necessary to model the impacts of significant reconnection.Areas of low or very low probability of fluvial flooding were identified from the Risk of Flooding from Rivers and Sea dataset. The Detailed River Network (2013) was used to derive the proximity of the watercourses to the floodplain, but not displayed due to data licensing restrictions. The National Receptor Dataset (2014) property points were used to screen out areas with residential property and key services. This dataset is not open data, so is also not displayed in the mapping work

Watercourses which have been designated as ‘main’ are generally the larger arterial watercourses. The Environment Agency has permissive powers, but not a duty, to carry out maintenance, improvement or construction work on designated main rivers.

This dataset consists of an interactive map (and supporting guidance) containing background information that informs how we understand flood risk across the South West River Basin District. The map shows the River Basin District, component river basins and the coastline together with layers showing land use and topography.

This dataset together with equivalent datasets for each River Basin District, supports the Preliminary Flood Risk Assessment for England report which has been written to meet the requirements of the Flood Risk Regulations (2009) - to complete an assessment of flood risk and produce supporting maps of river catchments.

This dataset consists of an interactive map (and supporting guidance) containing background information that informs how we understand flood risk across the Solway Tweed River Basin District. The map shows the River Basin District, component river basins and the coastline together with layers showing land use and topography.

This dataset together with equivalent datasets for each River Basin District, supports the Preliminary Flood Risk Assessment for England report which has been written to meet the requirements of the Flood Risk Regulations (2009) - to complete an assessment of flood risk and produce supporting maps of river catchments.

See inset in Fig 2 for location of River Basic Districts.

This dataset consists of an interactive map (and supporting guidance) containing background information that informs how we understand flood risk across the Thames River Basin District. The map shows the River Basin District, component river basins and the coastline together with layers showing land use and topography.

This dataset together with equivalent datasets for each River Basin District, supports the Preliminary Flood Risk Assessment for England report which has been written to meet the requirements of the Flood Risk Regulations (2009) - to complete an assessment of flood risk and produce supporting maps of river catchments. Attribution statement: Open Government Licence

© Environment Agency copyright and/or database right 2018. All rights reserved. © Crown copyright and database rights 2018 Ordnance Survey 100024198 © Bluesky International Ltd/Getmapping PLC. Some features of this map are based on digital spatial data from the Centre for Ecology & Hydrology, British Antarctic Survey and British Geological Survey. © NERC (Centre for Ecology & Hydrology; British Antarctic Survey; British Geological Survey).
Contains public sector information licensed under the Open Government Licence v3.0.

Environment Agency flood monitoring gauges obtained via the EA real time flood-monitoring API (March 2017). It contains attributes such as station ID and parameters recorded, as well as a link to the EA river levels web page for each.This dataset has been attributed with CaBA partnership details. This was done using the 'Identity' tool in ArcMap. Take note that the original dataset has therefore been divided according to these boundary lines.

1. Basic data at river water quality monitoring points set by the Environmental Department; including station name, river basin, station coordinates, and more. 2. Station location map layer, packaged as a SHP layer in a zip file, including DBF, SHP, SHX, and other geographic data, for GIS mapping.

This dataset consists of an interactive map (and supporting guidance) containing background information that informs how we understand flood risk across the Northumbria River Basin District. The map shows the River Basin District, component river basins and the coastline together with layers showing land use and topography.

This dataset together with equivalent datasets for each River Basin District, supports the Preliminary Flood Risk Assessment for England report which has been written to meet the requirements of the Flood Risk Regulations (2009) - to complete an assessment of flood risk and produce supporting maps of river catchments. Attribution statement: © Environment Agency copyright and/or database right 2018. All rights reserved. © Crown copyright and database rights 2018 Ordnance Survey 100024198 © Bluesky International Ltd/Getmapping PLC. Some features of this map are based on digital spatial data from the Centre for Ecology & Hydrology, British Antarctic Survey and British Geological Survey. © NERC (Centre for Ecology & Hydrology; British Antarctic Survey; British Geological Survey).
Contains public sector information licensed under the Open Government Licence v3.0.

This EnviroAtlas dataset is a point feature class showing the locations of stream confluences, with attributes showing indices of ecological integrity in the upstream catchments and watersheds of stream confluences and the results of a cluster analysis of these indices. Stream confluences are important components of fluvial networks. Hydraulic forces meeting at stream confluences often produce changes in streambed morphology and sediment distribution, and these changes often increase habitat heterogeneity relative to upstream and downstream locations. Increases in habitat heterogeneity at stream confluences have led some to identify them as biological hotspots. Despite their potential ecological importance, there are relatively few empirical studies documenting ecological patterns across the upstream-confluence-downstream gradient. To facilitate more studies of the ecological value and role of stream confluences in fluvial networks, we have produced a database of stream confluences and their associated watershed attributes for the conterminous United States. The database includes 1,085,629 stream confluences and 383 attributes for each confluence that are organized into 15 database tables for both tributary and mainstem upstream catchments ("local" watersheds) and watersheds. Themes represented by the database tables include hydrology (e.g., stream order), land cover and land cover change, geology (e.g., calcium content of underlying lithosphere), physical condition (e.g., precipitation), measures of ecological integrity, and stressors (e.g., impaired streams). We use measures of ecological integrity (Thornbrugh et al. 2018) from the StreamCat database (Hill et al. 2016) to classify stream confluences using disjoint clustering and validate the cluster results using decision tree analysis. 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).