The baseline comprises several steps:
- HER Review of Archaeological Investigations which has produced more significant information on the key research themes previously explored in 2015.
- Rapid literature review of more recent academic publications which provide new synthesis or re-interpretation (the big questions and key stories) relating to the previous research themes.
- Analysis of the potential future impacts on archaeological heritage in the region through climate change.
- Consultation with key specialists to assess if there are other research themes which could be considered as part of the process.
CVARF Region Climate Change Impact Modelling
The projected impact upon historic environment sites from projected environmental change is dramatic throughout the Clyde. This information has been gathered from national overviews modelling future flood levels created by SEPA and coastal erosion by Dynamic Coast. This not only shows devastation to the historic record, but also the communities which thrive up and down the Clyde. However, environmental change has happened throughout time with changes in coastline evident. Understanding how people of the past reacted to environmental change is key to understanding and empowering a broader audience to how we can also respond to our rapidly changing climate.
Predictive modelling of future impacts
The underpinning data source of both Dynamic Coast and SEPA Future Flood modelling are UK Climate Projections (UKCP18) created by Met Office. This data was created by statistical methods to create a probabilistic model for climate change at high resolution, the newest data available was previously at a 12km scale for the UK but has been downscaled to an even higher resolution of 2.2km. This allows for projections of highly localised events.
As both Dynamic Coast and SEPA projections are built from UKCP they are underpinned by widely accepted national data, but it is unclear if they have been updated to the highest resolution. SEPA is nationally responsible for flood risk and as such has provided data specific to Scotland utilising the UKCP18 high emissions scenario of Median High Water Surge (MHWS) for the year 2080 95th percentile confidence limit. The data from UKPC was mapped against Ordnance Survey mapping and LiDAR (where available) to create a polygon of the area covered by probable flooding of the coast and rivers. The accuracy of the LiDAR when the information was first published was 1m with 1 point taken per square meter (ppsm) and subsequent phases of LiDAR surveys enables higher accuracy to 50cm, however there is still incomplete coverage of Scotland as a whole. In 2019 SEPA commissioned their own LiDAR survey with enhanced accuracy to 16ppsm or accurate to 25cm, while vastly improving the accuracy of their modelling, this only covered the Outer Hebrides.
From the SEPA coastal and river flood changes Dynamic Coast predicted areas of coastal erosion. The data was narrowed to the coastline to highlight areas of static coastline which will be eroded by high water surges. An additional approach to vegetation edge’ was adopted as the coastline as this is the most recognisable land boundary from aerial, satellite and drone. Dynamic Coast itself used Dumbarton as a case study to create a resilience and adaption plan.
Impact on Historic Environment
The models outlined above formed the areas of high risk to the historic environment to gather the sites which sit within these zones, GIS was used to highlight the sites which intersect with the both future floods and eroding coasts.
Environmental Change in the past
There are similar modelling exercises for the past environment such as BRITICE by the University of Sheffield which evaluated land formation from geological survey as well as satellite, aerial and LiDAR survey to create a generalised map for the UK of the last British-Irish Ice Sheet.
A survey of the Firth of Clyde was undertaken along the North Ayrshire Coast which mapped past coastlines and coastal historic environment sites (Bicket et al 2017). Although this was not located within the CVARF study area it does provide information of the Estuarine Clyde further afield.