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.

This dataset comprises river centrelines, digitised from OS 1:50,000 mapping. It consists of four components: rivers; canals; surface pipes (man-made channels for transporting water such as aqueducts and leats); and miscellaneous channels (including estuary and lake centre-lines and some underground channels). This dataset is a representation of the river network in Great Britain as a set of line segments, i.e. it does not comprise a geometric network.

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)

Data shows the location of Priority Habitat Chalk rivers and Streams. Replaces the existing 1:50,000 scale data.Based on Environment Agency Detailed River Network (DRN) version 3. All fields from DRN have been retained. This subset of chalk rivers uses the old 1:50,000 Biodiversity Action Plan (BAP) chalk river data, BGS geology, WWF report "The State of England’s Chalk Streams" and stakeholder knowledge to produce an updated chalk river network for England.Full metadata can be viewed on data.gov.uk (to follow).

OS Open Rivers is a generalised open water network showing the flow and the locations of rivers, streams, lakes and canals across the whole of Great Britain. The new product is part of the OS Open suite and is designed to be used with other OpenData product sets. It’s mapping that can help you question, visualise and share results quickly and clearly. With OS Open Rivers you can: Understand the water network at a ‘high level’ with generalised geometry and network connectivity.View a network of main rivers, identifying the main river course along its full length.Pin information on the connected network for personal or business use. Take an informed overview of a situation along the network to manage it strategically. Compare and monitor stretches of water. Share information, such as flood alerts and flood risk areas.The currency of this data is 04/2025 The coverage of the map service is GB. The map projection is British National Grid.

This is a web map service of the UKCEH digital river network of Great Britain (1:50,000). It is a river centreline network, based originally on OS 1:50,000 mapping. There are four layers: rivers; canals; surface pipes (man-made channels such as aqueducts and leats) and miscellaneous channels (including estuary and lake centre-lines and some underground channels).

One of the two datasets that make up the Priority River Habitat Map. Consists of rivers and streams that exhibit a high degree of naturalness. The naturalness classification used to map priority river habitat is based on recent work to review the river SSSI series. It evaluates four main components of habitat integrity: hydrological, physical, physico-chemical (water quality) and biological. An additional classification of the naturalness of headwaters (defined as streams with a catchment area of <10km2 to coincide with WFD typology boundaries) uses land cover data as a surrogate for direct information on river habitat condition (information which is generally lacking on headwaters). Streams and rivers operating under natural processes, free from anthropogenic impact and with a characteristic and dynamic mosaic of small-scale habitats that supports characteristic species assemblages (including priority species), are the best and most sustainable expression of river ecosystems. Key elements are: a natural flow regime; natural nutrient and sediment delivery regimes; minimal physical modifications to the channel, banks and riparian zone; natural longitudinal and lateral hydrological and biological connectivity; an absence of non-native species; low intensity fishery activities. These conditions provide the best defence against climate change, maximising the ability of riverine ecosystems to adapt to changing conditions. They also provide the most valuable and effective transitional links with other priority habitats, including lakes, mires and coastal habitats. In English rivers and streams, high levels of naturalness are rare.Full metadata can be viewed on data.gov.uk.

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.

Land Cover Map 2021 (LCM2021) is a suite of geospatial land cover datasets (raster and polygon) describing the UK land surface in 2021. These were produced at the UK Centre for Ecology & Hydrology by classifying satellite images from 2021. Land cover maps describe the physical material on the surface of the country. For example grassland, woodland, rivers & lakes or man-made structures such as roads and buildingsThis is a 10 m Classified Pixel dataset, classified to create a single mosaic of national cover. Provenance and quality:UKCEH’s automated land cover classification algorithms generated the 10m classified pixels. Training data were automatically selected from stable land covers over the interval of 2017 to 2019. A Random Forest classifier used these to classify four composite images representing per season median surface reflectance. Seasonal images were integrated with context layers (e.g., height, aspect, slope, coastal proximity, urban proximity and so forth) to reduce confusion among classes with similar spectra.Land cover was validated by organising the pixel classification into a land parcel framework (the LCM2021 Classified Land Parcels product). The classified land parcels were compared to known land cover producing confusion matrix to determine overall and per class accuracy.View full metadata information and download the data at catalogue.ceh.ac.uk

This is a view service of the CEH 1:50k rivers dataset. This is a river centreline network, based originally on OS 1:50,000 mapping. There are four layer: rivers; canals; surface pipes (man-made channels such as aqueducts and leats) and miscellaneous channels (including estuary and lake centre-lines and some underground channels).

PLEASE NOTE: This dataset has now been retired and is superseded by a new dataset called: Reduction in Risk of Flooding from Rivers and Sea due to Defences. The Areas Benefiting from Defences dataset was assessed as no longer sufficiently meeting the needs of our customers and partners and was last updated on 02/11/2022. The Flood Map for Planning (Rivers and Sea) includes several layers of information one of which is areas benefiting from defences. This dataset shows those areas that benefit from the presence of defences in a 1 in 100 (1%) chance of flooding each year from rivers; or 1 in 200 (0.5 %) chance of flooding each year from the sea. If the defences were not there, these areas would flood in a 1 in 100 (1%)/ 1 in 200 (0.5 %) or larger flooding incident. Note that we do not show all areas that benefit from all flood defences. Some defences are designed to protect against a smaller flood with a higher chance of occurring in any year, for example a flood defence which protects against a 1 in 30 chance of flooding in any year. Such a defence may be overtopped in a flood with a 1 in 100 (1%)/ 1 in 200 (0.5%) chance of occurring in any year, but the defence may still reduce the affected area or delay (rather than prevent) a flood, giving people more time to act and therefore reduce the consequences of flooding. We do not always map areas that benefit from defences that offer a lower standard of protection. Other defences are designed to withstand a larger flood with a smaller chance of occurring in any year. In this case, we show only the area that would have been affected in a flood with a 1 in 100 (1%)/ 1 in 200 (0.5%) chance of occurring in any year, even though further areas would benefit in the event of more severe flooding for example in a 1 in 1000 (0.1%) flood. The rivers and sea criteria 1 in 100 (1%)/ 1 in 200 (0.5%) chance of occurring in any year aligns with Flood Zone 3 as described in the Planning Practice Guidance. In mapping areas benefiting from defences, we assume that flood defences and other operating structures act perfectly and give the same level of protection as when our assessment of the area was made. Please download our related dataset Risk of Flooding from Rivers and Sea to understand the flood risk that remains in locations where the location of flood defences and their condition have been included in the modelling. Attribution Statement: © Environment Agency copyright and/or database right 2018. All rights reserved.Some features of this map are based on digital spatial data from the Centre for Ecology & Hydrology, © NERC (CEH) © Crown copyright and database rights 2018 Ordnance Survey 100024198

The objective of the priority habitat map in England is to:• help organisations protect the most natural remaining examples of rivers from further impacts on natural processes, and • highlight any aspects of habitat integrity (hydrological, chemical, physical, biological) that could most usefully be improved. The priority river habitat map that has been produced is an English interpretation of the UK definition of priority river habitat, focusing on naturalness as the principal criterion in recognition of the vital importance of natural processes in delivering sustainable riverine habitats and supporting characteristic biodiversity.Full metadata can be viewed on data.gov.uk.

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 2 and should not be used without 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 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.

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.

This dataset is published as Open DataWhat OS Open Rivers provides you withSolve challengesModel simple what-if scenarios. OS Open Rivers lets you answer questions like ‘which rivers would be affected by a toxic discharge from this site?’Water quality dataFor sharing water quality data, this is ideal. OS Open Rivers lets you tag information with the river IDs used by environment agencies so everybody can use it.Comprehensive map dataOS Open Rivers GIS data contains over 144,000 km of water bodies and watercourses map data. These include freshwater rivers, tidal estuaries and canals.

Riparian Shade data from the Environment Agency. Shows relative shading of rivers and streams by vegetation and topography. Areas with least shade are ideal areas for tree planting to provide a benefit to freshwater ecology.Tile Map Service showing national coverage down to sub-catchment scale (ca. 1:18,000)For larger scales, add in the Riparian Shade Detail layer to your map and swap the visible range over at Neighbourhood scale.

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.

Priority habitats form part of the UK’s commitment to the International Convention on Biodiversity. Each country who signed up to to the Convention is required to define a range of habitats (and individual species) where action is a priority to protect and restore biodiversity, and then to take the necessary action. The UK’s list of priority habitats includes both river and lake habitats. Existing nationally generated maps of river/stream and lake restoration priorities are now being refined with stakeholders to become a mechanism for highlighting local priorities for different sorts of restoration of natural habitat function – hydrological, physical, chemical and biological. Any site that falls under the UK river and lake priority habitat definitions (which essentially means any river, stream or lake), and therefore warrants specific consideration, can be highlighted as a priority for restoration action, if the action restores natural function. Restoration of natural habitat function of rivers and streams can involve many different practical measures – 21 measures are explicitly itemised within the river and stream restoration priorities layer. These arePhysical RestorationEstablish riparian zone of natural vegetationEstablish at least patchy cover of native riparian treesAllow natural delivery and retention of woody materialRestore natural mire-stream transition zoneRestore natural lateral movement of the channelRemove in-channel structuresRestore natural channel bed levelsRemove flood embankmentsRe-establish alluvial woodlandRestore natural floodplain wetland mosaicHydrological RestorationRestore natural springflows to headwater streamsRestore natural flow regimeRemove land drainageChemical RestorationTarget critical pollution source areas of the catchmentEstablish naturally functioning habitat mosaics on critical areasEstablish effective soil/nutrient conservation regimes on critical areasBiological RestorationStrategic area-based control of non-native speciesReduce intensity of/halt fish stockingHalt fishery-driven removal of non-target native fish speciesReduce/halt in-channel and marginal weed cuttingEliminate heavy grazing of riparian vegetationThis dataset is in the early stages of development and will grow as more partners and stakeholders add their local knowledge. See the Priority Habitat data portal for more information on priority river (including streams) and lake habitats in England, how you can get involved in their protection and restoration, and in particular how you can provide information on the sites you visit to help prioritise conservation action. Other parts of the UK have their own approaches to conserving priority habitats as part of their separate biodiversity strategies.You can also view this data via the Data Display app on the Priority Habitat Data Portal which allows you to easily visualise the different measures being recommended at each site.

The Flood Map for Planning (Rivers and Sea) includes several layers of information. This dataset covers Water Storage Areas. It shows those areas that act as a balancing reservoir, storage basin or balancing pond. Their purpose is to attenuate an incoming flood peak to a flow level that can be accepted by the downstream channel. It may also delay the timing of a flood peak so that its volume is discharged over a longer time interval. We have assumed that water storage areas act perfectly and give the same level of protection as when our assessment of the area was carried out. Water storage areas do not completely remove the chance of flooding and can be overtopped or fail in extreme weather conditions. This dataset is designed to raise awareness 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. Attribution statement: © Environment Agency copyright and/or database right 2025. All rights reserved. Some features of this map are based on digital spatial data from the Centre for Ecology & Hydrology, © NERC (CEH) © Crown Copyright and Database Rights 2025 OS AC0000807064.

This September, we all came together for rivers to take part in our first Big River Watch Weekend, launched to help build a picture of river health across the country. It's good for you, and good for our rivers. This mapping layer allows you to view the results submitted by our citizen science volunteers. Whether you’re a swimmer or a paddler, an angler or a rambler, a wildlife spotter or a sit-and-watch-er, Big River Watch is a chance to be part of the movement improving our freshwater spaces. In just three easy steps, you can contribute to a national data set that will help us build a picture of river health across the UK and Ireland. Since September 2023 Big River Watch has been held twice a year, in the spring and autumn. With your help, we are building a picture of rivers in the UK and Ireland over time from the perspective of citizen scientists.How can you contribute?Step 1: Sign upSign up and download the survey app to your phone before visiting your chosen river.Step 2: Take partPick a riverside location and spend just 15 minutes observing and answering the questions on the survey. You can complete the survey at your favourite local spot, or choose to get to know somewhere new.Step 3: UploadUpload your survey. It's that simple to get involved!Find out more Visit theriverstrust.org/take-action/the-big-river-watch

The Main River Consultation Area defines the easement associated with the Statutory Main River Map enabling Local Planning Authorities to check when statutory consultation with the Environment Agency is required in line with Town and Country Planning Act 2015.

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

This new GIS layer is showing the 20 metre easements either side of Main Rivers using the Statutory Main River Map Variations including the river itself. A precautionary approach has been taken around structures like culverts, for example when there was a different line shown on our Asset Information Management System compared to the Main River line.