User Guide : BGS Superficial Deposit Thickness Model (SDTM)

The Superficial Deposit Thickness Model (SDTM) is a dataset designed to demonstrate the regional variation in thickness of superficial deposits that lie on top of bedrock, across Great Britain. These deposits are unconsolidated sediments and may include river channel and floodplain deposits, beach sands, talus gravels and glacial drift and large areas of peat. Superficial deposits are of importance for geologists, civil engineers, hydrogeologists and environmental scientists as they are often unconsolidated and, together with other processes, form pathways for groundwater to travel along. Their thickness over much of the country relates to the glacial history of the UK over the Quaternary period.
The dataset combines borehole data records and mapped superficial and artificial geology (at 1: 50 000 scale). The different components of the SDTM provide the user with rasterised surfaces of potential superficial sediment thickness distribution across Great Britain as well as information on the distribution of the input data sources.
The SDTM has been created as part of ongoing scientific research into the 3-D distribution of these superficial deposits across Great Britain.
The intended scale of use of this dataset is 1:100,000 with a vertical modelled precision of +/-5m elevation. The dataset is intended for use at national, regional and local scales but not site scales where specific ground investigation works should be undertaken to determine superficial thickness and / or rockhead elevation.
The information provided in this User Guide is intended to provide a quick start guide to using and understanding this BGS data product.
Users should not use the SDTM datasets without first reading this User Guide in full, in particular section 5 on data limitations.