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    OS MasterMap Water Network - Public Sector Geospatial Agreement (PSGA)


    The Environment Agency and Ordnance Survey have worked together to deliver a digital representation of watercourses to supersede the detailed river network (DRN).

    How is this dataset different to the Detailed River Network?

    The OS MasterMap Water Network Layer (OS WN) offers a more detailed product, showing the flow, connectivity, gradient and precise course of every river, stream, lake and canal in Great Britain. Watercourses that are underground or below structures are included where Ordnance Survey capture processes or accepted sources can infer a connection.

    Will this be used as the EA’s standard river network?

    The Environment Agency will use this data as its standard river network, but it will take time to integrate it across all its existing systems.

    Who is this dataset available to?

    This dataset is published by the OS and is only available under strict licensing conditions. It was brought under the Public Sector Geospatial Agreement in 2020 and is available for our contractors and partners to download from the Defra Data Services Platform (DSP).

    You will need to register on the DSP as one of our contractors or partners first.

    How frequently will this dataset be updated?

    This dataset will be updated quarterly in line with the schedule of updates by the OS. To receive an email notification each time the dataset is updated simply follow the datasets section on the forum. 

    How can I notify the OS that something looks wrong?

    You can notify the OS of any issues with the data via the link below, selecting ‘Business’ and ‘Report a mapping error’


    Where can I find out more information?

    More information about this dataset, including its technical specifications is provided by the OS here:

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