The rate and magnitude of conductive and advective thermal processes that control the efficiency and sustainability of mine water geothermal and thermal energy storage are poorly quantified. We present results of multiphysical observations collected during a 25-day heat extraction experiment performed on an abstraction–reinjection mine water well doublet at the UK Geoenergy Observatory in Glasgow. The results showed how the thermal plume generated by injection of cool water developed from the injection borehole, mainly driven by advection at the level of mine workings. Heat conduction around the cased part of the injection borehole resulted in different cooling rates related to lithological variations, clearly shown in the distribute temperature sensing data. The electrical resistivity tomography monitoring provided a time-lapse image of the evolution of the cool plume, which extended laterally within the mine workings to pass a borehole located at 10 m away in less than 2 days, and later above the mine workings into the bedrock. It also showed how the effects of cooling remained for at least 18 days after the injection stopped, providing new insight into thermal storage behaviour of mine water systems. The results provide an unprecedented opportunity to visualize the effects of geothermal operation in mine water settings and are useful guidance for project developers and regulators.

Heat transfer rates are critical to underground heat storage recovery potential and sustainability of thermal abstraction for heating and cooling buildings. A 17-day heat injection - abstraction experiment into a flooded, disused mine working was conducted at the UK Geoenergy Observatory in Glasgow. Analysis of the thermal response of different lithologies intersected by an injection borehole during and after a heat injection experiment is used to quantify the heat exchange between rock mass and circulating mine water. The monitoring data from Distributed Temperature Sensing (DTS) has been analysed and numerical models using COMSOL Multiphysics were developed to characterise the rates and controls on thermal processes during heat injection and recovery. The results suggest the key control of the borehole construction on the temperature change in the first 10 hour of heat injection. In the long term, the thermal response mainly depends on the thermal conductivity of the lithologies. The radial heat transfer reaches a steady charging rate of 23 W/m2 and 16 W/m2 in the sandstone and clay intervals, respectively, and a maximum of 14 W/m2 and 10 W/m2 at the start of recovery. This is accompanied by upward heat diffusion/convection from the mine working. This study demonstrates the ability of DTS to identify lithological heterogeneities at a high resolution, and the importance of considering the overburden structure and lithology for thermal storage applications.

Flooded disused mines have significant potential to supply clean heating and cooling and for seasonal storage in areas that could continue benefiting from the mines after closure. A proved technology, a more widespread deployment of mine water geothermal development is hampered by technical, socio-economical, and regulatory challenges. Among the technical challenges, the long-term system behaviour is an uncertain but fundamental element, regarding both the groundwater flow and heat distribution in the subsurface aquifer and the optimal performance of the geothermal installation and its components. A further development of mine water geothermal requires information and data from pilot, commercial and research installations to improve the knowledge about these complex systems, understand the interaction with the surrounding environment and learn from the experiences towards a more optimal design and construction of the geothermal infrastructure. The UK Geoenergy Observatory (UKGEOS) in Glasgow was built between 2019 and 2023 as an at-scale research facility to study mine water geothermal. The observatory includes five boreholes drilled and screened into two levels of mine workings, four of them equipped with pumps and valves to allow for multiple configurations of abstraction and reinjection with operational pumping rates up to 12 l/s. The mine water boreholes are also equipped with hybrid fibre-optic cables for distributed temperature sensing (DTS) and electrical resistivity tomography (ERT) sensor arrays. The monitoring capabilities are complimented with an additional non-screened mine borehole, also equipped with DTS and ERT, and five environmental boreholes screened into the bedrock and the superficial aquifer to monitor the hydrogeological and thermal responses in the surrounding aquifers. The geothermal installation includes a sealed pipe between the abstraction/reinjection boreholes, three heat exchangers that can be used independently to test their performance, and a 200-kW heat pump/chiller. The system is equipped with sensors in the geothermal pipe circuit, the wellhead and downhole for high temporal resolution monitoring of hydraulic and thermal changes during the use of the Observatory and under natural conditions. In this work we present results from some of the first geothermal tests performed in the Observatory in 2023. These include abstraction-reinjection in both heating and cooling modes with multiple configurations and variable flow rates and reinjection temperatures taking advantage of the capabilities of the Observatory. The datasets have been processed and examined with the support of numerical modelling. The analysis of hydraulic and thermal data from the multiple sensors in the mine and monitoring boreholes, the DTS and ERT, and the geothermal installation before and after heat exchange and reinjection have provided further insights about short- and long-term responses of the system. The observations show the different temporal and spatial scales of the hydraulic and thermal responses to the use of the geothermal infrastructure that constitute valuable information for the design of new geothermal installations in disused mines. The Observatory is now operative and open to academic and research projects aiming to understand better mine water systems.

The UK Geoenergy Observatory in Glasgow is a unique at-scale research facility to study mine water geothermal and thermal energy storage. In this work we present results from two heat injection experiments performed at two mine levels characterised by different mine workings. The experiments resulted in different thermal breakthrough times, even under similar test conditions. We compare the results and discuss the influence of the mine geometry and working types on the groundwater flow and heat transport processes with support from numerical modelling. This quantification is important to assess the long-term sustainability and potential of flooded mines for geothermal exploitation.

Mine-water geothermal resources have potential to provide low-carbon heating and cooling in many areas; however, this potential has not been fully realised due to technical, economic and policy challenges. The UK Geoenergy Observatory (UKGEOS) in Glasgow was developed to provide an at-scale research facility designed to help de-risk mine-water geothermal usage. The limited knowledge of the hydrogeological systems altered by former mining activities is a key determinant of the long-term sustainability of water and heat abstraction/reinjection. This work presents a hydrogeological conceptual model developed using groundwater monitoring data obtained during the construction of the Observatory between 2020 and 2022, results from initial pumping tests performed in 2020, and results of hydrochemistry analysis from 25 sampling rounds collected between 2019 and 2022. The analysis of the data provides evidence of the dominant role of mine workings in controlling groundwater flow, with high intra-mine connectivity; increased fracturing in sandstones above mine workings; and limited inter-mine connectivity. Groundwater recharge is meteoric, mean residence times are >50 years, and there is a general upwards circulation from the deeper mine levels to the superficial deposits and the River Clyde. Faults play a significant role in limiting the extent of the highly transmissive mine workings, but there remains uncertainty surrounding the role of the faults in connecting different mine workings and their hydraulic behaviour in nonmined units. The conceptual model, that will be refined as new data become available, will be used to help guide monitoring and sampling programs and plan research activities in the Observatory.

The transition to renewable energies requires adaptation of existing technologies and the development of new techniques. Geothermal energy could play an important part in the development of “green” energy industries for climate change mitigation and diversification of energy sources. Distributed fibre optic sensing (DFOS) solutions provide flexible, multi-parameter measurements for the exploration and exploitation of the full range of geothermal resources, from shallow borehole, ground source heat to hydrothermal geothermal projects and Enhanced Geothermal Systems (EGS). The UK Geoenergy Observatories are new national facilities for research and innovation in shallow geothermal energy recovery and storage with field test sites in Cheshire and Glasgow, UK. The Glasgow Observatory facilitates collaborative research to improve understanding of subsurface processes, environmental and induced change related to mine thermal energy storage (MTES). It provides scientific and engineering infrastructure for investigating the shallow, low-enthalpy geothermal energy and thermal storage resources available in abandoned and flooded coal mine workings which underly up to 25% of UK settlements. Borehole monitoring capability includes composite fibre-optic cables for distributed temperature and acoustic sensing (DTS & DAS) behind casing, for passive monitoring or for performing heat pulse tests in active mode, as well as ERT sensors for measuring geoelectrical properties in the wells and surrounding rock mass. The Cheshire Observatory enables testing, monitoring and quantification of subsurface heat transfer processes, ground behaviour, thermogeology and hydrogeology, providing insights into sustainable operational management and maintenance requirements. The Cheshire Observatory comprises 20 instrumented boreholes drilled to 100m below ground level in the Chester Formation of the Sherwood Sandstone Group aquifer, with associated surface control, monitoring and data management systems. The installed fibre optic monitoring capability includes passive and active DTS, DAS and an advanced heat pulse controller serving multiple boreholes. Here we present an overview of the fibre optic sensing capability deployed at the Glasgow and Cheshire Observatories. Further information on the Glasgow and Cheshire Observatories is available online at: www.ukgeos.ac.uk. To discuss access or ideas for field experiments please contact BGS at: ukgeosenquiries@bgs.ac.uk

Mine water geothermal has great potential to provide low carbon heating, cooling and energy storage. Some successful examples have shown that a flooded mine is a reliable, low carbon heat source and could contribute to a new green energy future for many European post-mining regions. To date, however, this potential has been hindered by scientific and technical challenges that have resulted in delay, cost overrun, or even abandonment of some mine water geothermal projects. Key sources of uncertainty that present challenges for developers, operators and regulators are groundwater flow behaviour and temperature distribution in abandoned mines under abstraction/reinjection cycles, the long-term sustainability of the geothermal system, and its interactions and impacts in the surrounding environment. The UK Geoenergy Observatory (UKGEOS) in Glasgow, Scotland, is an at-scale research facility with exceptional levels of hydrogeological and thermal characterisation and downhole instrumentation designed to monitor and quantify subsurface change and provide data to address challenges and risks associated with mine water geothermal systems design and operation. The Observatory includes four mine water boreholes connected in an open loop configuration with pumps for abstraction/reinjection, a heat pump-chiller and three different heat exchangers to enable testing of multiple modes of heat pump operation (heating and cooling) and component performance. A further two boreholes intercepting mine workings are equipped with downhole electrical resistivity tomography (ERT) and hybrid fibre-optic cables for distributed temperature sensing (Passive and Active DTS). Together with five environmental monitoring boreholes, a seismic monitoring borehole and ten hydrogeological downhole data loggers for continuous pressure, temperature, and electrical conductivity monitoring, the dedicated Observatory, which is not connected to any customers, is well equipped to examine the interaction and impacts of geothermal energy systems.In this work we present a comprehensive set of initial hydrogeological and thermal observations collected during the construction and commissioning stages of the Observatory, including long term baseline monitoring, results of initial well pumping and heat abstraction/reinjection tests. These observations include evidence for the general groundwater flow circulation in the system, groundwater level response to recharge events, different transmissivities in different mined zones, and limited connectivity between mine workings at different depths, the surrounding aquifers and the River Clyde. We have integrated hydrogeological, thermal, and other information to develop an initial conceptual hydrogeological model of the system. Using the conceptual model and field data we have developed flow and heat numerical models to evaluate alternative scenarios of heating and cooling. Modelling results indicate variable flow paths and response times for thermal breakthrough for different geothermal operational configurations. Academic and commercial researchers are encouraged to get in touch to discuss using the Observatory’s unique capability for future mine water geothermal energy investigations, including investigating the behaviour, sustainability and impacts of groundwater flow and temperature under geothermal abstraction/reinjection cycles.

<p>Deep (> 500 m below ground) geothermal energy is generated by heat sources within the Earth, including unusually high  lithospheric basal heat flow and/or intrusive bodies rich in radioactive isotopes, that heat the surrounding rocks and aquifers. This warm water can then be used for electricity production or to provide heat for buildings. These relatively high geothermal gradients can be found at depth in sedimentary basins where aquifers are surrounded by rocks with low thermal conductivity. Investigating the suitability of a basin for deep geothermal energy exploration requires, therefore, a thorough geological investigation of its spatially variable structure, stratigraphy and evolution. Low temperature thermochronology, namely apatite fission track and (U-Th-Sm)/He methods, are able to reconstruct the thermal structure of the shallow crust through time and, when data are available from boreholes, to quantify the evolution of the geothermal gradient, providing insights on the most promising areas where aquifers could be unusually warm.</p> <p> </p> <p>We have applied low temperature thermochronology to the study of the Midland Valley (MV) Basin, an extensive sedimentary basin onshore Scotland, hosting many potential energy consumers in the cities of Glasgow and Edinburgh. The Midland Valley mainly consists of alternating succession of sandstone and siltstone with mudstone, limestone and coal, predominantly of Carboniferous and Devonian age. The MV also experienced folding and faulting throughout its geological history; therefore, the succession is spatially highly variable, difficult to reconstruct by simply using the sparse borehole-derived stratigraphic constraints. Apatite fission track data from across the eastern sector of the basin and the UK Geoenergy Observatories borehole in Glasgow indicate a 1) rapid burial in the Carboniferous-Permian; 2) Permian-Mesozoic cooling and a 3) a relatively rapid early Cenozoic cooling, an event that is asynchronous across the basin. Using a combination of forward and inverse modelling techniques, we constrain the palaeo-geothermal gradients and highlight areas where the thermal structure of the shallow crust could still be relatively hot for aquifer geothermal energy.</p>

Thermal energy from groundwater in abandoned, flooded, coal mines has the potential to make a significant contribution to decarbonization of heat and net-zero carbon emissions. In Glasgow, UK, a subsurface observatory has been constructed for mine water heat and heat storage research. We synthesize geological and mine water resource findings from a 4 year period of borehole planning, drilling, logging and testing. The heterogeneous bedrock is typical of the Scottish Coal Measures Group, whereas superficial deposits are more sand- and gravel-dominated than predicted. Mine water boreholes encountered workings in the Glasgow Upper, Glasgow Ell and Glasgow Main coal seams, proving water-filled voids, mine waste, fractured rock mass and intact coal pillars, with high yields on initial hydrogeological testing. Although the depth and extent of mine workings delineated on mine abandonment plans proved accurate, metre-scale variability was expected and proved in the boreholes. A mine water reservoir classification established from the observatory boreholes highlights the resource potential in areas of total extraction, stowage, and stoop and room workings. Because their spatial extent is more extensive across the UK than shafts or roadways, increasing the mine water energy evidence base and reducing exploration risk in these types of legacy workings is important. Supplementary material: Borehole reports and other datasets are available at https://ukgeos.ac.uk/data-downloads (mixture of over 20 DOI datasets and reports or data packs published openly on https://nora.nerc.ac.uk ; all material is deposited in the National Geoscience Data Centre).

Mine water geothermal energy could provide sustainable heating, cooling and storage to assist in the decarbonisation of heat and achieving Net Zero carbon emissions. However, mined environments are highly complex and we currently lack the understanding to confidently enable a widespread, cost-effective deployment of the technology. Extensive and repeated use of the mined subsurface as a thermal source/store and the optimisation of operational infrastructure encompasses a range of scientific and technical challenges that require broad partnerships to address. We present emerging results of a pioneering multidisciplinary collaboration formed around an at-scale mine water geothermal research infrastructure in Glasgow, United Kingdom. Focused on a mined, urban environment, a range of approaches have been applied to both characterise the environmental change before geothermal activities to generate “time zero” datasets, and to develop novel monitoring tools for cost-effective and environmentally-sound geothermal operations. Time zero soil chemistry, ground gas, surface water and groundwater characterisation, together with ground motion and seismic monitoring, document ongoing seasonal and temporal variability that can be considered typical of a post-industrial, urban environment underlain by abandoned, flooded coal mine workings. In addition, over 550 water, rock and gas samples collected during borehole drilling and testing underwent diverse geochemical, isotopic and microbiological analysis. Initial results indicate a connected subsurface with modern groundwater, and resolve distinctive chemical, organic carbon and stable isotope signatures from different horizons that offer promise as a basis for monitoring methods. Biogeochemical interactions of sulphur, carbon and iron, plus indications of microbially-mediated mineral oxidation/reduction reactions require further investigation for long term operation. Integration of the wide array of time zero observations and understanding of coupled subsurface processes has significant potential to inform development of efficient and resilient geothermal infrastructure and to inform the design of fit-for-purpose monitoring approaches in the quest towards meeting Net Zero targets.

Recent research suggests that the effects of climate change are already tangible, making the requirement for net zero more pressing than ever. New emissions targets have been announced in April 2021 by various governments, including by the United Kingdom, United States, and China, prior to the Conference of the Parties (COP26) in Glasgow. Part of the solution for net zero will be geo-energy technologies in the subsurface, these include: mine water geothermal, aquifer thermal energy storage (ATES), enhanced geothermal systems and other thermal storage options, compressed air energy storage (CAES), and carbon dioxide capture and storage (CCS) including bioenergy CCS (BECCS). Subsurface net zero technologies have been studied by geologists at laboratory scale and with models, but also require testing at greater-than laboratory scale and in representative conditions not reproducible in laboratories and models. Test, pilot and demonstration facilities aid rock characterisation process understanding and up-scaling, and thereby provide a bridge between laboratory testing and computer modelling and full-scale operation. Examples of test sites that have progressed technology development include the Otway International Test Centre (Australia, CCS) and the Äspö Hard Rock Laboratory (Sweden, geological radioactive waste disposal). These sites have provided scale up for key research questions allowing science issues of relevance to regulation, licencing and permitting to be examined at scale in controlled environments. Successful operations at such sites allow research to be seen at first hand to inform the public, regulators, supply chain companies and investors that such technologies can work safely and economically. A Geological Society conference on the “Role of subsurface research labs in delivering net zero” in February 2021 considered the value of test sites and gaps in their capability. Gaps were identified in two areas: 1) test facilities to aid the design of low cost, high resolution, unobtrusive seismic and other monitoring for a seismically noisy urban environment with a sensitive human population, for example for ATES in urban areas; and 2) a dedicated through-fault zone test site to understand fault transmissivity and reactivation. Conference participants also recommended investment and development in test sites, shared facilities and risk, joint strategies, data interoperability and international collaboration.

The Midland Valley Basin of Scotland (MVS) is a major NE-SW trending, fault-bounded sedimentary basin in central Scotland, UK, comprised predominantly of Carboniferous and Devonian sedimentary rocks. Changing palaeo-environments of the MVS produced alternating successions of sandstone, siltstone, mudstone, limestone and coal. The MVS also experienced folding, fault inversion and development of a widespread unconformity during the latest Carboniferous culmination of the Variscan Orogeny and minor tectonic events thereafter. The MVS’ geological resources played a major role in driving Scotland’s economic, industrial, and cultural development in the 19th - 20th. The region was heavily exploited for coal and hydrocarbon energy resources and material for construction, manufacturing, and agriculture. The MVS basin remains as relevant in the 21st century having been identified as a viable source of low-carbon geo-energy resources (e.g., geothermal energy) and potential for subsurface energy storage (Heinemann et al., 2019). While the geology of the MVS has been well-studied, thermal and burial history reconstructions have typically relied on techniques focused on the maturation of organic matter (e.g., vitrinite reflectance, VR), which lack quantitative information on timing. Moreover, tracing sediment provenance can be challenging but crucial for understanding the tectonic evolution of the surrounding source region. Here, we present the results of a geochronological and thermochronological investigation of the MVS basin designed to better understand sediment pathways to the basin from surrounding upland regions and the post-depositional thermal history of the MVS. Our data includes zircon and apatite U-Pb data and apatite fission-track (AFT) data from across the basin and AFT data from a UK Geoenergy Observatories borehole in Glasgow. With our U-Pb data, we identify distant source areas in Greenland, more local source areas in the Scottish Highlands, and recycling of older sedimentary rocks and reworked material in the basin that change through the tectono-magmatic evolution of the basin. Our AFT data and associated thermal history modelling identify three main thermal events: i) Carboniferous-Permian heating; ii) Permian-Mesozoic cooling, and iii) relatively rapid Cenozoic cooling (McKenna, 2021; Hattie, 2021). These are attributed to post-Carboniferous burial followed by post-Permian exhumation. However, ambiguity in some of our models suggests some heating in the Mesozoic may have occurred and, due to the limitations on the temperature sensitivity of the AFT technique, the timing and rate of Cenozoic cooling is poorly resolved. Through our modelling we explore the influence changing palaeo-geothermal gradients has on our thermal history and whether the lower temperature thermochronometer apatite (U-Th)/He can better resolve the most-recent cooling event. Heinemann, N., Alcalde, J., Johnson, G., Roberts, J. J., McCay, A. T., & Booth, M. G. (2019). Low-carbon GeoEnergy resource options in the Midland Valley of Scotland, UK. Scottish Journal of Geology, 55(2), 93-106. McKenna, Eamon (2021) The Provenance and thermal histories of the Carboniferous Midland Valley of Scotland, PhD thesis, University of Glasgow. Hattie, Andrew (2021) Constraining the post-burial history of the central Midland Valley of Scotland using apatite fission track analysis: implications for geothermal energy. MSc(R) thesis, University of Glasgow.

In their analysis of temperature data, Watson and Westaway (2020) make substantial use of initial open information provided by the UK Geoenergy Observatory: Glasgow Geothermal Energy Research Field Site. They also offer criticisms on site location, heat resource size, design and costs; however, these criticisms appear to be based on a misunder-standing of the purpose of the Glasgow Observatory. In order to mitigate misapprehensions for future Observatory users, we write in reply. The Glasgow Observatory has been developed as a multidisciplinary research facility; it is not a demonstrator of maximum mine water heat resource, which is by implication what Watson and Westaway (2020) would deem a success.

Mine water geothermal heat production and storage can provide a decarbonised source of energy for space heating and cooling, however the large resource potential has yet to be exploited widely. Besides economic, regulatory and licensing barriers, geoscientific uncertainties such as detailed understanding of thermal and hydrogeological subsurface processes, resource sustainability and potential environmental impacts remain. The UK Geoenergy Observatory in Glasgow is a research infrastructure for investigating shallow, low-temperature coal mine water heat energy resources available in abandoned and flooded mine workings at depths of around 50-90 m. It is an at-scale ‘underground laboratory’ of 12 boreholes, surface monitoring equipment and open data. The Glasgow Observatory is accepting requests for researchers and innovators to undertake their own experiments, test sensors and methods to increase the scientific evidence base and reduce uncertainty for this shallow geothermal technology.

Comment: We wish to comment on factual inaccuracies around the purpose of the UK Geoenergy Observatory in Glasgow (GGERFS) in the recent Energies paper by Watson et al [...]

Mine water geothermal heat production and storage can provide a decarbonised source of energy for space heating and cooling, however the large resource potential has yet to be exploited widely. Besides economic, regulatory and licensing barriers, the geoscientific uncertainties remain significant. A lack of detailed understanding of thermal and hydrogeological subsurface conditions and processes, resource sustainability, and the potential impacts on the subsurface-to-surface environmental impacts have so far hampered a more widespread development of this resource.The British Geological Survey (BGS) is in the final stages of constructing the Glasgow Geothermal Energy Research Field Site on behalf of the Natural Environment Research Council with UK Government funding. As one of the two new UK Geoenergy Observatories, the Glasgow site will facilitate collaborative research to improve our understanding of subsurface processes and change. It will provide scientific infrastructure for investigating the shallow, low-temperature coal mine water geothermal energy resources available in abandoned and flooded mine workings at depths of around 50-90 m below the eastern parts of the city.The Glasgow site was chosen due to its commonalities with other parts of the UK and beyond in terms of its coal mining history, geology and legacy of industrial land use. Mine water geothermal resources in these settings could provide sufficient heat for community-scale district heating networks.The research infrastructure comprises arrays of mine water and environmental baseline boreholes for characterisation and monitoring, and the boreholes are instrumented with permanent geophysical sensors. Here we report on interim results from drilling the environmental baseline and mine water boreholes, and opportunities for research and innovation.Continuous monitoring and regular sampling data will be provided for the science community to examine a dynamic subsurface geo-, hydro- and bio-sphere. The facility will also provide opportunities for researchers to undertake their own experiments, with the aim of producing high-quality scientific evidence to reduce uncertainty on mine heat energy systems and understand their environmental impacts, for schemes across the UK and beyond.

We have reached a key milestone in history where the majority of the world’s population now lives in urban areas. The urban subsurface is increasingly being seen as a resource to place infrastructure and habitation, as well as a source of drinking water and green energy. The natural and artificially modified deposits and rocks under cities provide both opportunities and constraints which mediate/regulate our interactions with the subsurface. With such competing demands it is critical that cities maximise the economic, social and environmental benefits of their subsurface resources while also safeguarding them for the future. Urban 3D geological modelling is an important tool for managing and de-risking the urban subsurface. Geological models allow a range of characteristics of subsurface environments to be predicted and simulated, aiding the mitigation of geohazards, management of groundwater resources, and development of infrastructure. However, for effective applications at the urban-scale, high-resolution 3D characterisation of geological systems and integration of non-geological data (such as buried assets, land uses, and nature of building foundations) and knowledge are required. Furthermore, urban 3D modelling also requires predicting deposits that are not often shown on traditional Geological Survey maps such as human-made ground and sub-formational heterogeneity. Using case studies, we explore the advances, benefits, and challenges of shallow subsurface, urban-scale 3D modelling in the UK context. We highlight applications for predicting and characterising natural and human-made ground to identify potential ground hazards and to protect archaeological deposits, and the use of 3D modelling to support a new underground observatory for understanding resource sustainability and the subsurface environmental impacts of mine water geothermal heating. We will also show how models can be used to understand how different hazards can interact with each other in the subsurface.

ABSTRACT The Glasgow area has a combination of highly variable superficial deposits and a legacy of heavy industry, quarrying and mining. These factors create complex foundation and hydrological conditions, influencing the movement of contaminants through the subsurface and giving rise locally to unstable ground conditions. Digital geological three-dimensional models developed by the British Geological Survey are helping to resolve the complex geology underlying Glasgow, providing a key tool for planning and environmental management. The models, covering an area of 3200km 2 to a depth of 1.2km, include glacial and post-glacial deposits and the underlying, faulted Carboniferous igneous and sedimentary rocks. Control data, including 95,000 boreholes, digital mine plans and published geological maps, were used in model development. Digital outputs from the models include maps of depth to key horizons, such as rockhead or depth to mine workings. The models have formed the basis for the development of site-scale high-resolution geological models and provide input data for a wide range of other applications from groundwater modelling to stochastic lithological modelling.