Superficial hydrogeological domains for the Gateshead area - Project Groundwater Northumbria

Whitbread, K.; Dewald, N.; Banks, V.; Murphy, B.; Reeves, T.. 2024 Superficial hydrogeological domains for the Gateshead area - Project Groundwater Northumbria. Nottingham, UK, British Geological Survey, 46pp. (Project Groundwater Northumbria series, CR/24/066N) (Unpublished)

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Abstract/Summary

This report has been produced by the British Geological Survey (BGS) on behalf of Project Groundwater Northumbria, the Flood and Coastal Resilience Innovation Programme (FCRIP) project led by Gateshead Council. It provides background and methodological information on the development of superficial hydrogeological domains for the Newcastle-Gateshead area and accompanies the delivery of datasets including a superficial hydrogeological domains map and a new superficial thickness model for the study area. The development of the domains was undertaken through analysis of 409 digitally coded boreholes including over 220 coded for this project. The boreholes were attributed for permeability according to previously used schemes and analysed to characterise the vertical succession of superficial deposits for classification as hydrogeological domains. Superficial hydrogeological domains have been mapped for the area based on a classification scheme defined through consultation with the clients and intended for a qualitive characterisation of areas of preferential vertical and lateral groundwater flow such as recharge and discharge from underlying bedrock aquifers. The domains have been characterised from a superficial thickness model using thickness thresholds as well as the attributed borehole distribution, the 1:50,000 scale geological map of the area and wider geological understanding of the region and associations of deposits. Five primary domains were identified in the area. Domain 1 reflects regions with less than 2 m of superficial deposits (including areas where no deposits have been mapped). Domain 2 reflects regions with only aquifer (permeable deposits) present, regardless of the thickness of deposits. Domain 3 covers areas with 2 – 10 m thickness of aquitard (low permeable deposits) within the succession, and domain 4 covers areas with 10 – 30 m of aquitard in the succession. The primary domains are further broken down into subdomains to highlight differences in the vertical sequence of aquifer and aquitard units. Note that domain 5 was included within the original classification scheme but all areas meeting the criteria (aquitard >30 m) fall within buried valleys and are therefore included in domain 6. Domain 6, defined as buried valleys, comprises elongate regions with more than 10 m of superficial deposits that form a contiguous network or buried-valley system. The architecture of sediments within the buried valleys was assessed using targeted cross-sections and inspection of borehole data. This process was used to define subdomains based on assemblages of deposit types within the buried valley system. Future work to improve understanding of the extent and lateral connectivity of buried sand bodies within domain 6 would enhance the mapping of the domains. Targeted coding of existing borehole records would help to locally improve the data coverage and take advantage of areas with denser borehole distributions (particularly in urban areas of Newcastle-Gateshead along the River Tyne). Furthermore, the capture of new borehole data down to rockhead (base of the superficial deposits), ideally with core suitable for high-resolution geological logging, is really needed for more accurate assessment of the range of material properties and geological interpretation of the deposits, and for direct quantification of the hydrogeological properties of the materials. The latter would also be improved by logging and analysis of exposed sections through key deposits in the field.

Item Type:	Publication - Report
Funders/Sponsors:	British Geological Survey, Gateshead Council
Additional Information. Not used in RCUK Gateway to Research.:	This item has been internally reviewed, but not externally peer-reviewed. Report made open in September 2024.
Date made live:	30 Sep 2024 15:44 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/538116

Item Type:

Publication - Report

Funders/Sponsors:

British Geological Survey, Gateshead Council

Additional Information. Not used in RCUK Gateway to Research.:

This item has been internally reviewed, but not externally peer-reviewed. Report made open in September 2024.

Date made live:

30 Sep 2024 15:44 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/538116