Search

The London Clay Formation is particularly susceptible to shrink–swell behaviour that has resulted in a long history of foundation damage owing to ground movement across the outcrop. Damage has cost up to £500 million in a single year. Underlying most of the Greater London area, the London Clay Formation is of major engineering importance as it is on and within this formation that the majority of the city's infrastructure, buildings and underground services are constructed. The Volume Change Potential (VCP) of a soil is the relative change in volume to be expected with changes in soil moisture content, and the subsequent shrinkage or swelling can cause major damage to structures above or below ground. Detailed statistical and spatial analyses of data across the London Clay outcrop have revealed a significant geographical trend in the VCP of this deposit, confirming an overall increase from west to east, but also showing subtle trends with depth. This paper describes how this analysis was carried out and shows how such assessments can yield valuable information about shrink–swell behaviour not only of the London Clay but also of similar shrink–swell-prone argillaceous formations elsewhere.

The British Geological Survey’s 3D geological framework modelling of the entire Glasgow conurbation and surrounding River Clyde catchment, has been undertaken as part of the Clyde-Urban Super-Project (CUSP) and in partnership with Glasgow City Council and other local and regulatory authorities. The 3D modelling covers an area of complex glacial superficial deposits, overlain by heterogeneous anthropogenic deposits that reflect Glasgow’s industrial heritage, over coal-bearing Palaeozoic bedrock succession deformed by multiple faulting episodes. As such, the geology poses significant interpretive challenges for planners, regulators and engineers. The depth dimension of conventional geological maps is very hard for non-geologists to appreciate. As a result, decision makers rarely take full account of geoscience issues in planning and development; nor do they fully exploit potential subsurface assets. With the advances of 3D hardware and software, it is now possible to combine disparate geoscience data types for a wide range applications and scenarios and to display these data effectively, and in ways that non-geologists can easily understand and use to inform their decisions. Using several 3D modelling packages, but primarily GSI3D and GOCAD® workflows in tandem, we have created 3D models designed to ‘nest’ within each other. Lower resolution regional models (c.1:50,000-scale equivalent) therefore provide the context for higher resolution (1:10,000-scale equivalent), and ultimately site-specific, models. The geological framework models have been attributed with a wide range of parameters such as permeability, aquifer productivity and various engineering properties. They have also been exported to flow modelling packages to model time-series processes such as recharge and flow of groundwater and will be used to model migration of contaminant plumes and carbon dioxide. Man-made objects, such as tunnels and mine workings have been embedded as 3D objects and placed into th

A proliferation of 3D geological models has been created by the British Geological Survey (BGS) over the last 15 years, following significant developments in software, hardware and modelling methodology. Modelling of the subsurface by the BGS has been widespread, ranging in depth from 1m to 15000m, and covering areas in the orders of 0.1 km2 to 100 km2. These models have been produced to increase our understanding of the subsurface environment and to help us communicate issues pertaining to it, such as geological hazards, water protection and resource management. For these reasons, particular focus has been drawn to the major urban areas of the UK such as the Lower Mersey Corridor (Liverpool to Manchester), the Clyde basin (Glasgow and surrounding region) and Thames basin (London and surrounding region). This has led to the development of a number of overlapping models in these regions and, since these models have been created for specific purposes and at varying scales, there has been little consideration given to ensuring that the individual geological surfaces within them are consistent from one model to another. Methodology has now been developed through the Thames Basin Cross- Cutting Project to amalgamate multiple versions of individual geological surfaces taken from existing 3D models, some of them overlapping, into a series of unified surfaces that represent the preferred geological interpretation at any given set of coordinates. The methodology alleviates some of the issues that have arisen with the existing models, such as different scales of overlapping surfaces (expressed as cell or mesh size), and the use of different subsets of the available records (boreholes/seismic reflection profiles/geological maps), commonly with different interpretations. This methodology has been tested on four key horizons within the Thames basin catchment area which are the stratigraphic tops and bases of the Lambeth Group and Chalk Group. The unified surfaces will provide a

Engineering and hydrogeological site investigations in urban areas require an understanding of subsurface lithological variation and related properties, between and within stratigraphic units. In the Glasgow conurbation, Scotland, large-scale and long-term projects aimed at regenerating post-industrial (brownfield) sites are underway; these need to anticipate ground conditions and potential groundwater and contaminant migration pathways. To help planners at early stages in these activities the British Geological Survey (BGS) has undertaken a programme of attributed three-dimensional geological modelling, as part of the Clyde-Urban Super-Project (CUSP) and in partnership with Glasgow City Council and others. The modelling is based on a densely-spaced and extensive digital borehole dataset (>50,000 coded boreholes). This work compares the results of two different types of modelling workflow undertaken in central Glasgow – an area underlain by complex and heterogeneous glacial and post-glacial (including anthropogenic) deposits. The first workflow adheres to a determined lithostratigraphy and requires significant ‘geologically-reasoned’ input from the model operator, while the second adopts a stochastic approach using only lithological codes from the borehole dataset. While there is general agreement in terms of the overall sediment architecture produced by both models, notable differences in output exist between the two. These are assessed and the relative merits of each modelling workflow discussed. Outputs from both methodologies are also compared in terms of their potential for fusion with other (e.g. groundwater) modelling platforms. This combined approach will facilitate better understanding between geologists, groundwater modellers, engineers, planners, and regulators.

This report describes methods for checking and remediating problems within GSI3D models post calculation for non-faulted models. These checks are particularly concerned with how the geometry of units have calculated and if they are a true resemblance of what has been drawn in cross-section. These issues include:  Missing Envelopes or cross-section correlations  Lack of correlation nodes on cross-section lines  Wrongly attributed correlation lines in cross-section

The subsurface is used intensively to support economic stability and growth. Human interaction with the shallow subsurface ranges from exploitation of resources, accommodation of utilities, harnessing of energy (ground source heat pumps) and storage of waste. Current practice of managing these shallow subsurface zones is far from ideal. Many subsurface interventions are preceded by feasibility studies, predictive models or investigative measures to mitigate risks or predict the impacts of the work. However, the complex interactions between the anthropogenic structures and natural processes mean that a holistic impact assessment is often not achievable. By integrating these subsurface infrastructures within three dimensional framework models, a comprehensive assessment of the potential hazards in these shallow subsurface environments may be made. Some Geological Survey Organizations (GSOs) are currently developing subsurface management systems that will aid decision making in the shallow subsurface [1]. The British Geological Survey (BGS) is developing an open Environmental Modeling Platform [2] to provide the data standards and applications to link models, numerical simulations and ultimately socio-economic models so as to generate predictive responses to questions concerning sustainable us of the subsurface.

Meeting the challenges of sustainable development and regeneration to support city growth requires the provision of attributed 3D geological and geotechnical data, information and process understanding in the urban subsurface. This provides a 3D framework for the characterisation of the spatial variability of the properties and processes within the shallow subsurface to aid sustainable land use planning and regeneration. The subsurface has to provide the resources and ecosystem services to sustain and create economic growth and meet societal needs, now and in the future while minimising the environmental impact of development. The 3D variability of the ground results from anthropogenic (man-made) processes as well as geological. Human exploitation of the subsurface and rapid land use change in response to population growth and urbanisation, result in temporal and spatial modification of the ground. The integration of 3D geological and anthropogenic deposits models is therefore essential for the characterisation of urban "zone of human interaction" and its response to anthropogenic environmental change. Model integration to aid land use planning has been applied in the formerly heavily industrialised cities of NW England and Northern Ireland to provide a basis for linear transport assessment, urban planning and the assessment of aquifer vulnerability.

Geological Survey Organisations (GSOs) were originally founded to produce an inventory of the earth’s resources to inform governments and support construction and primary industries. Therefore, their initial emphasis was on finding construction material, metalliferous minerals and hydrocarbons. Throughout the 20th century the focus shifted towards aggregates, water and more recently to environmental concerns such as waste, reuse of post-industrial contaminated land, climate change and biodiversity. Although the external drivers for their existence have changed, the fundamental purpose has not, and this is unlikely to change in the future. Price (1992) summarises the mission of a GSO to “maintain the national geoscience knowledgebase” in order to “ensure the availability of the geoscience information and expertise to promote the wise use of the nation’s natural resources and the safety, health and well being of its people” However as many countries move towards knowledge and service driven economies faced with global environmental challenges ,GSOs of the 21st century will have to continue to evolve, adapt and in particular change the ways they operate. This is especially true against a background of rapidly advancing geospatial technology. The GSO’s agenda must be to confirm themselves as the natural custodians of the subsurface, not focussed on one particular industry or science area, but assisting governments, industry and the general public to manage the subsurface in an integrated, holistic and sustainable manner. They must then engage with other organisation to link the understanding of the subsurface with the wider environment, to understand the interaction of the subsurface with the atmosphere, biosphere and hydrosphere (see Figure 1) Last but not least they have a duty to make their knowledge and information accessible and understandable to the people on behalf of whom the governments act and to whom they are accountable. Taking the British Geological Survey

This report describes the results of a study carried out by the British Geological Survey (BGS) on behalf of the Environment Agency NW to investigate the underlying geology beneath Knowsley Industrial Park, Merseyside, NW England. The overarching aim of the project was to establish a 3D geoscience framework beneath the Knowsley Industrial Park to enable the Environment Agency (the Agency) to assess the vulnerability of the underlying Sherwood Sandstone aquifer. The vulnerability of the aquifer to pollution from current and historic contamination of land, potentially leaking foul sewers and contaminated surface water drains could then be assessed by reference to the underlying geology. In addition to the 3D geological model, United Utilities pipeline data for foul and surface water drainage was provided by the Agency. This pipeline information was analysed and integrated with the geological data to provide an assessment of the potential linkage between the pipes and the underling bedrock or superficial geology in which they are sited. Over 300 additional paper borehole records were provided by the Agency from previous environmental site investigations carried out in the industrial park and incorporated into the BGS databases. In total, 1279 coded boreholes were used in the study. Of these, 733 were used to construct 58 geological cross-sections. The 3D geological model revealed a sequence of superficial deposits across the site comprising glacial, post-glacial and artificial deposits overlying the Sherwood Sandstone Group, that in places are deeply weathered to form loose sand. In the south-east and north-west of the site, rocks belonging to the Sherwood Sandstone Group crop out at surface. The vulnerability of the Sherwood Sandstone aquifer beneath the site, to pollution from contaminated water, depends in part on the distribution and thickness of weakly permeable superficial deposits such as clay or silt. The geological model has revealed that till is the only clay

In recent years national geoscience organizations have increasingly utilized 3D model data as an output to the stakeholder community. Advances in both software and hardware have led to an increasing use of 3D depictions of geoscience data alongside the standard 2D data formats such as maps and GIS data. By characterizing geoscience data in 3D, knowledge transfer between geoscientists and stakeholders is improved as the mindset and thought processes are communicated more effectively in a 3D model than in a 2D flat file format. 3D models allow the user to understand the conceptual basis of the 2D data and aids the decision making process at local, regional and national scales. Some of these issues include foundation and engineering conditions, ground water vulnerability, aquifer recharge and flow, and resource extraction and storage. The British Geological Survey has established a mechanism and infrastructure through the Digital Geoscience Spatial Model Programme (DGSM) to produce these types of 3D geoscience outputs. This cyber-infrastructure not only allows good data and information management, it enables geoscientists to capture their know-how and implicit and tacit knowledge for their 3D interpretations. A user of this data will then have access to value-added information for the 3D dataset including the knowledge, approach, inferences, uncertainty, wider context and best practice acquired during the 3D interpretation. To complement this cyber-infrastructure, an immersive 3D Visualization Facility was constructed at the British Geological Survey offices in Keyworth, Nottingham and Edinburgh. These custom built facilities allow stereo projection of geoscience data, immersing the users and stakeholders in a wealth of 3D geological data. Successful uses of these facilities include collaborative 3D modeling, demonstrations to public stakeholders and Virtual Field Mapping Reconnaissance.

Knowsley Industrial Park, NW England and its buried sewerage network presents a potential source of pollution to the underlying Triassic Sherwood Sandstone aquifer. Weakly permeable superficial deposits beneath the site may provide a barrier to potential pollution of groundwater in the aquifer. The aim of the study was to develop and apply a 3D model of the superficial deposits beneath the park to a qualitative assessment of the vulnerability of the underlying aquifer to potential pollution. The study also aimed to devise a method for the integration of the 3D geological model of the shallow sub-surface with the buried utility network. The 3D model revealed 8 superficial units. Glacial till, comprising clay and silt, was the only weakly permeable deposit identified. Other deposits were interpreted as permeable. The underground utility network was integrated in 3D with the geological model. Those utilities overlying less than 2.5 m of till were interpreted to represent the most vulnerable parts of the underlying aquifer. The greatest relative vulnerability to the aquifer occurred in the south and south-west of the project area. The study identified a novel method for the integration of a 3D geological model and a buried sewerage network. The identification of these utilities prioritised the areas of highest relative vulnerability of the Sherwood Sandstone aquifer to potential pollution from utility leakage. This approach enabled the development of a hazard identification and prioritisation scheme for future improvements to the buried sewerage network serving Knowsley Industrial Park.

This report summarises the 3-D superficial geology beneath Manchester and Salford (including Trafford Park) and should be used in conjunction with the digital 3-D geological model supplied within the Subsurface Viewer (© Insight Geologische Softwaresysteme GmbH). The area is underlain by a complex sequence of superficial deposits comprising glacial, post-glacial and anthropogenic (man-made) material. For example, the area beneath Trafford Park is characterised by over 40 m of superficial material infilling an incised valley cut into the underlying bedrock. 3-D geological modelling in the shallow sub-surface provides a powerful tool for understanding and predicting potentially difficult engineering ground conditions and in Trafford Park, a powerful tool for assessing aquifer vulnerability and recharge to the underlying Sherwood Sandstone. The geological model shows the top, base and thickness for each natural and artificial deposit within the area. Each unit is coloured according to its lithological composition, lithostratigraphy, inferred permeability and engineering classification. 2-D synthetic cross-sections and 1-D synthetic predictive borehole logs can be generated from the model in any area. For example, a cross-section can be drawn along the route of an existing or proposed road or around a proposed development area. Synthetic borehole logs can be generated to predict potential ground conditions at a point location. The 3-D geological model of superficial deposits in the area is not intended as a replacement for any invasive site investigation. It provides an additional tool for the development of conceptual ground models for a range of users. The model provides a powerful means of assessing the nature of the ground, but with additional 3-D information, not previously available from any existing 2-D geological map. It provides essential applied geoscience information relevant to any requirement for information on ground conditions in the shallow sub-surface.

A 3-D geological model of the area between Doncaster and Retford was created in order to characterise the thickness and distribution of superficial deposits to allow hydrogeological domains to be derived above the Sherwood Sandstone aquifer. The overarching aim of the study was to use a domains approach, derived from the output of the 3-D model to assess potential recharge to the Sherwood Sandstone aquifer. The results of the study are intended to help the Environment Agency meet its regulatory requirements under the Water Framework Directive and Catchment Abstraction Management Strategy (CAMS) and form part of its overall East Midlands – Yorkshire Sherwood Sandstone Groundwater Study. The 3-D model revealed a complex sequence of pre-glacial, glacial and post-glacial sediments deposited on a rockhead surface that extends in paces to –26mOD as a result of deep incision into the bedrock. These channels are orientated north-west, south-east or east-west. The sequence of superficial deposits is generally less than 10m thick, increasing to 25m in places to the east and southeast of the project area. The area from Hatfield Moors in the north-east to Misson in the south-east is characterised by a sequence of peat, variably underlain by Blown Sand, Glaciolacustrine silt and clay and “Older River Gravel”. The Glaciolacustrine silt and clay is most thickly developed beneath Hatfield Moors, but is laterally discontinuous. Elsewhere, to the west of the study area, the superficial deposits comprise sand, gravel and till of limited extent and are generally less than 10m thick, except in some fluvial valleys. Seven hydrogeological domains were identified from the 3-D model and other published data sources. The domains were defined in terms of the potential for recharge to occur either directly into the Sherwood Sandstone or through the sequence of superficial deposits. Each of the units making up the superficial deposits in the area was classified according to its inferred hydroge

This report was commissioned by Canatxx Gas Storage Limited, who requested BGS produce an assessment of the geology of the Preesall area and a 3D model of the (Triassic) Preesall Halite. The work was required ahead of a Public Inquiry into the proposed development of an underground gas storage facility in an area to the east of the River Wyre and west of a former ICI brinefield. The main brief was to assess the geology, review borehole data held by BGS and additional borehole and seismic reflection data made available to BGS by Canatxx, and thereby provide the best-fit model from the current database. This has been completed. This report therefore considers the data both held by BGS and supplied to BGS by Canatxx and/or Mott MacDonald, for the purposes of this study. The British Geological Survey (BGS) already possess a considerable borehole database. BGS was also supplied with the Canatxx database of the tabulated top and base salt of those ICI brinefield wells and shaft data that were not already available to, or held by, BGS. The result is that 745 boreholes over the western Fylde area that were pertinent to the study were coded and entered in to the model. Several seismic reflection lines were also made available and have been reprocessed as part of this study. At a late stage, BGS gained access to velocity (sonic log) information from the Arm Hill and The Heads boreholes. These boreholes were drilled in early 2004 and permit calibration of the seismic reflection data, and identification of the Preesall Halite interval within the seismic data. The findings and conclusions reached here will contribute to the other proofs of evidence to be submitted on behalf of Canatxx Gas Storage Limited for the Public Inquiry. It should be noted that this report forms a wholly independent assessment of the location, extent, and general characteristics of the Preesall Saltfield. The report has not considered points of issue such as rock salt (halite) quality and its suitability

In May 2012, BGS scientists Andrew McKenzie, John Bloomfield, Stephanie Bricker, Andy Butcher and Ricky Terrington all took part in the filming for the BBC regional 'Inside Out : Drought' programme which included a GeoVisionary fly through of the 1:625k hydrogeological map with meteorologist Nick Miller to describe how the different aquifers are being affected by the drought and field visits to see just how low borehole levels really are and why, despite heavy rain and flood alerts, much of the country was still experiencing drought conditions.

In May 2012, BGS scientists Andrew McKenzie, John Bloomfield, Stephanie Bricker, Andy Butcher and Ricky Terrington all took part in the filming for the BBC regional 'Inside Out : Drought' programme which included a GeoVisionary fly through of the 1:625k hydrogeological map with meteorologist Nick Miller to describe how the different aquifers are being affected by the drought and field visits to see just how low borehole levels really are and why, despite heavy rain and flood alerts, much of the country was still experiencing drought conditions.