Ordnance Survey (OS), the Environment Agency (EA) and the Scottish Environment Protection Agency (SEPA) have collaborated to bring together a nationally consistent view of Great Britain’s watercourses. For over two decades the EA has carefully mapped the flow of water in rivers across England and Wales to help protect communities from flooding and to improve habitats for wildlife through their Detailed River Network. This new collaboration combines the data from the Detailed River Network with SEPA’s data on Scotland’s watercourses to produce one comprehensive view of all watercourses across Great Britain.

This project led to the creation of OS MasterMap Water Network and, following its initial launch in 2015, became a full product in April 2019. This new dataset is a crucial element in understanding our natural environment. As the only detailed, heighted water network of Great Britain, OS MasterMap Water Network is continually updated and improved, showing the flow and precise course of rivers, streams, lakes and canals, at a national and local level.

OS MasterMap Water Network will support analysis used for planning and policy initiatives. This would include managing and reporting of water quality, water resources, fisheries status, mapping navigations, predictive modelling, risk assessment, regulation, incident response and a host of other river-related initiatives, from permitting applications to catchment delineation.

Since its initial launch in 2015, OS, EA and SEPA have continued to work together to improve the product. As a result, we have made 850,000 improvements to the data which focused on watercourse connectivity, flow direction, contiguous naming and identified primary flow path.

Joint working has identified and delivered improvements to successive versions of the dataset through testing. OS and EA are delighted to confirm that EA will start to migrate from their existing Detailed River Network to the OS MasterMap Water Network and will be progressively implementing this across all systems and projects where a network of watercourses is required.

Click here to read more and access the OS MasterMap