Unveiling the Power of Ordnance Survey's New Tidelines Data: A Comprehensive Guide to Coastal Erosion and Flood Risk Management
The Rising Tide of Coastal Challenges: A Call for Action
As Britain's coastlines face mounting pressure from heavier rainfall, rising sea levels, and dynamic shorelines, the need for innovative solutions to manage coastal erosion and flood risk has never been more urgent. The Ordnance Survey's (OS) new continuous tidelines dataset emerges as a timely tool to address these challenges, offering a comprehensive view of where land meets sea and how this boundary is evolving.
A New Dataset for a Changing Coastline
Earlier this year, the Environment Agency's National Flood Risk Assessment (NaFRA) shed light on the vulnerability of homes and businesses in England to flooding, with an expected increase in exposure over the coming decades. Alongside this, updated national coastal erosion risk mapping indicates that thousands of properties could be affected by coastal change within a single generation. To combat these challenges, OS has introduced a new tidelines dataset, providing a consistent and up-to-date view of the coastline.
The OS National Geographic Database (OS NGD) Tidal Boundary line features have been transformed into continuous lines, forming two new feature types: Tidal Boundary Continuous High and Tidal Boundary Continuous Low. This dataset can be used as overlay layers in the Tiles API, offering a clean and intuitive visual experience. It complements the NGD base layer and provides added value for contextual mapping and macro analysis.
A Comprehensive Solution for Environmental Monitoring and Regulation
The new tidelines dataset supports a wide range of environmental monitoring and regulation activities, including:
- Coastal erosion modelling: Understanding the impacts on people, property, and infrastructure, enabling better risk management and strategic planning.
- Coastal flooding modelling: Enhancing preparedness and response to flooding events.
- Updating boundary features: Aligning with coastal change to enable accurate and effective environmental monitoring and regulation, and better management of natural resources.
- Climate change assessments: Identifying and evaluating the impact of climate change, enabling informed decision-making and effective adaptation strategies.
- Understanding the foreshore: Identifying areas that provide natural flooding defences, essential for implementing flood risk management.
A Valuable Asset for Environmental Policy and Regulation
William Russell, senior coastal process scientist at the Wales Coastal Monitoring Centre, welcomes the new dataset, emphasizing its value in removing uncertainty from strategic monitoring programs and providing clearer insights into intertidal extents. This dataset is particularly valuable for those in environmental policy and regulation, supporting evidence-based decisions relating to water discharge, whether from a regulatory or flooding perspective.
A Comprehensive Analysis of Coastal Counties
Following the release of the continuous tidelines dataset, OS has ranked all ceremonial counties in GB by their percentage change in size between high and low tide. Merseyside emerges as the top county, with a nearly 17% difference in high and low tidelines. Orkney follows with the second-highest difference of 7%. Interestingly, counties considered to be landlocked, like Nottinghamshire and South Yorkshire, have rivers that are tidal for a long way upstream, causing significant changes in the size of the counties.
Location-Based Insights with Tidelines Data
The new location data can be overlaid with other information to enable essential location-based insights. Combining the tidelines data with UPRNs in ceremonial counties reveals that Greater London has the highest number of commercial and residential properties within 15 meters of high tides, followed by Cornwall and Devon.
Accessing the Data
The new location data has been released as part of the Public Sector Geospatial Agreement (PSGA), a contract between the Government Digital Service and OS for the provision of geospatial data and services to the emergency services and wider public sector organizations. To access all of OS's location data, visit the OS Data Hub, which provides access to the data through APIs and downloads.
