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)

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 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).The dataset was produced within a long-term project of the Institute of Hydrology (now CEH) between the mid-1970s and the late 1990s. The project digitised, (either manually or using 'laser scanners') the "blue line" layer of the Ordnance Survey's 1:50,000 2nd series (Landranger) maps. The dataset consists of all the single blue lines from the source maps, plus centre-lines from double sided rivers, lakes and estuaries. All gaps in the source material have been closed, using local knowledge where necessary, to give a river network that is continuous from source to mouth

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.

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.

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).

"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. "

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.

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

There are 49 rivers in England and 31 rivers in Wales that regularly support salmon, although some of the stocks are very small and support minimal catches. Of these, 64 rivers were designated ‘principal salmon rivers’ on the basis of the prospect of annual rod catches of at least 50 fish around the time (~1996) of the development of Salmon Action Plans (SAPs*).These data are recreated from SALMON STOCKS AND FISHERIES IN ENGLAND AND WALES, 2021 figure 1 using OS Open Rivers. Attributes include if a river has a SAP and if it is designated as a Special Area of Conservation (SAC) in which salmon must be maintained or restored to favourable conservation status (SALMON STOCKS AND FISHERIES IN ENGLAND AND WALES, 2021 Table 1).These data are intended for visualisation only and should not be used for statutory purposes or connectivity modelling.*Salmon Action Plans in Wales are now referred to as ‘Know Your Rivers’ reports.

One of the two datasets that make up the Priority River Habitat Map. Under the UK BAP definition all headwaters potentially form part of the priority habitat definition. The headwater resource can be a significant proportion of the river habitat network, accounting for the large majority of total river length. The headwater areas selected as most natural by land cover comprise a relatively large proportion of the upland headwater resource but a very small proportion of the lowland resource. The headwater analysis is the least certain component of the naturalness analysis – for example, highly natural headwater streams running through very small catchment areas, often wooded, would not be detectable by the analysis that has been undertaken. Equally, land cover is a crude measure of naturalness and various types of impact on river habitat are not well correlated with it (e.g. abstraction pressure, point source pollution). These issues can only be addressed through local interpretation of the final priority habitat map. Attribution statement: © Natural England copyright. Contains Ordnance Survey data © Crown copyright and database right [year].

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 10/2024 The coverage of the map service is GB. The map projection is British National Grid.

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.

PLEASE NOTE: This record has been retired. It has been superseded by: https://environment.data.gov.uk/dataset/f81508d3-cf5a-44ed-ae7e-452be665af84 This dataset is a product of a national assessment of flood risk for England produced using local expertise. It is produced using the Risk of Flooding from Rivers and Sea data which shows the chance of flooding from rivers and/or the sea, based on cells of 50m. Each cell is allocated one of four flood risk categories, taking into account flood defences and their condition. This dataset uses OS address data and Royal Mail postcode data to show how many properties are in each of four flood risk categories in each postcode, based simply on the category allocated to the cell that each property is in. 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 Check Your Long-Term Flood Risk website to indicate where we have new flood risk information. Attribution statement: © Environment Agency Copyright and/or Database Rights 2023. 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 2023 OS AC0000807064. This product is produced in part from PAF® and Multiple Residence Data, the copyright in which is owned by Royal Mail Group Limited and/or Royal Mail Group plc. All rights reserved. Licence number AC0000807064.

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 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.

PLEASE NOTE: This dataset has now been retired. It was last updated on 02/11/2022 and has been replaced by the Spatial Flood Defences (inc. standardised attributes) dataset. This is a more comprehensive dataset of assets, comes with attribution and is updated daily. See: https://environment.data.gov.uk/dataset/8e5be50f-d465-11e4-ba9a-f0def148f590

The Flood Map for Planning (Rivers and Sea) shows the areas across England that could be affected by flooding from rivers or the sea. It also shows flood defences and the areas that benefit from them.

The 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 dataset is: Spatial Flood Defences (without standardised attributes), which shows those defences constructed which have a standard of protection equal to or better than 1 in 100 (1%) for rivers and 1 in 200 (0.5%) from the sea. (Some additional defences are also shown). 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 River Obstacles dataset is an inventory of weirs, waterfalls, sluices, dams, culverts, fords and flap gates, compiled initially from digital Ordnance Survey maps and the Environment Agency's Detailed River Network AfA036 (DRN) and improved and extended using information submitted by users via the River Obstacles App.
The information collected using the River Obstacles App is quality checked and verified before being added to the dataset.

The Flood Map for Planning (Rivers and Sea) includes several layers of information. This dataset covers Flood 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 flood storage areas act perfectly and give the same level of protection as when our assessment of the area was carried out. Flood 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.

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.