In recent years, the urban areas of Elgin, Nairn and Forres have been threatened by severe river flooding events leading to the expenditure of millons of pounds on the design and installation of new flood prevention measures. The most severe catastrophic flood in modern British history occurred on August 3rd 1829, along the course of the River Findhorn, which reaches the coast near Forres. Reconstructions suggest that more than 100mm of rain fell in 24 hours and peak flows exceeded 1,400 cubic metres per second in parts of the catchment. BGS studies around Forres, commissioned by Moray Council, indicate that groundwater has a significant impact on flooding particularly in the lower reaches of this ‘flashy’catchment. Targeted work has now been completed, that included detailed Quaternary mapping and geotechnical testing to supplement ground water measurements from boreholes and trial pits, to establish the permeability of the shallow geology of the catchment around Forres. A GSI3D model has been constructed of the shallow geology that has 43 separate layers. This will be demonstrated during the workshop. The model has also been reattributed with permeability values and this is now being linked to a ZOOM ground water model to produce the most detailed evaluation of shallow groundwater movements in any part of Scotland.
The Glasgow conurbation is Scotland’s most densely populated area (approximately 1.2 million people). The city is built upon a complex succession of Quaternary sediments, which were deposited during multiple ice sheet cycles, periods of higher relative sea level, and more recently, through modern anthropogenic processes (arising from Glasgow’s industrial heritage).
In the Glasgow area, several large-scale and long-term projects aimed at regenerating post-industrial (brownfield) sites are underway. These projects need to anticipate ground conditions and potential groundwater and contaminant migration pathways within the underlying Quaternary sediments. To help planners at early stages in such activities the British Geological Survey (BGS) has undertaken a programme of attributed three-dimensional geological modelling of the Quaternary deposits, using the geomodelling software GSI3D and GOCAD, 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).
The geological models allow planners to have a three-dimensional preview of the properties of the subsurface, allowing critical decisions to be made before any expensive site investigation takes place, and potentially saving time and money. The models can also be used to aid recognition of major resources (such as water, thermal and sand and gravel) in a buried valley system under Glasgow (and elsewhere in central Scotland), and inform groundwater modelling studies.
We present an interpretation of two-dimensional sub-bottom profiling data from Loch Lomond, Scotland, UK. Sediments deposited during and following the last glacier advance have been investigated for decades around the shores of Loch Lomond. For the first time, this study presents an interpretation of the subsurface providing a window into the late Quaternary and Holocene history of Loch Lomond and its surrounding. The seismic stratigraphy records the infill of the loch during the final stages of the Loch Lomond Stadial (LLS, 12.9–11.7 ka BP), through the Holocene and into the present day. Results reveal the presence of distinct seismic facies (SF) identifying four principal seismic horizons; SF-I, SF-II, SF-III, and SF-IV. The SF-I horizon represents the glaciated surface, interpreted as subglacial till (locally forming drumlins), glacial moraines or bedrock. Ice retreat was accompanied by glaciolacustrine sedimentation in a proglacial lake setting, depositing up to 44 m of laminated sediments and ice marginal fans (SF-IIa, b). A period of landscape instability followed with extensive deposition of mass transport deposits (SF-III). These deposits, characterised by chaotic seismic facies with an erosional basal surface, are up to 43 m thick and may represent up to 50 % of the sediment fill. SF-IV comprises finely laminated sediments deposited during the Holocene and highlights slower sedimentation rates in comparison to earlier phases of sedimentation. This study reveals new insights into the deglaciation of Loch Lomond, including previously unrecognised extensive mass transport deposits buried in the subsurface, associated with a period of paraglacial adjustment.
New data is presented regarding the character and timing of glaciation in Orkney and Shetland and adjoining continental shelf, and a chronology of deglaciation is reconstructed for this critical area of the North Atlantic sector of the British and Fennoscandian Ice Sheets (BIS & FIS). Specifically seabed morphology is interpreted using the Olex echosounder dataset to determine ice stream tracks and glacial limits. Onshore landscape morphology is interpreted using the NEXTMap high resolution DEM and tested using ground survey, and a landsystems approach is applied in the reconstruction of styles of glaciation across the Northern Isles of Scotland. Crucially using Olex, terminal positions of the confluent BIS-FIS offshore at maximum glacial extent and during retreat are determined, and evidence of ice sheet separation is shown. The seabed and landscape evidence for ice streaming, in both erosive and depositional terrains is highlighted. There is evidence for several phases of ice sheet dynamics during Late Devensian deglaciation: confluent streaming ice from FIS/BIS; separation of the ice sheets and the establishment of a remnant ice cap over Shetland; and finally a readvance phase where ice flowing from the Moray Firth overwhelmed much of Orkney. New cosmogenic surface exposure age data is presented giving the first dated constraints on the timing of ice sheet separation, which combined with evidence from the UK continental shelf and North Sea Basin begin to give a chronology for the decline of the ice sheet systems on the western European margin. Finally, it is argued that the timing of these phase changes in the dynamics of the FIS and BIS are coincident with major changes in wider Earth systems, in particular eustatic sea level rise in response to global warming during the waning phase of the Lateglacial.
The Philippines is exposed to numerous typhoons every year, each of which poses a potential threat to livelihoods, shelter, and in some cases life. Flooding caused by such events leads to extensive damage to land and buildings, and the impact on rural communities can be severe. The global community is calling for action to address and achieve disaster risk reduction for communities and people exposed to such events. Achieving this requires an understanding of the nature of the risks that flooding and typhoons pose to these communities and their homes. This paper presents the findings from a field based case study assessment of three rural settlements in the Philippines, where typhoons and associated flooding in recent years has caused significant damage to houses and livelihoods, leading to the reconstruction of homes that more often than not reproduce similar structural vulnerabilities as were there before these hazards occurred. This work presents a methodology for risk assessment of such structures profiling the flood and wind hazards and measuring physical vulnerability and the experience of communities affected. The aim of the work is to demonstrate a method for identifying risks in these communities, and seeks to address the challenge faced by practitioners of assisting communities in rebuilding their homes in more resilient ways. The work set out here contributes to the discussion about how best to enable practitioners and communities to achieve the sought for risk reduction and especially highlights the role that geoscience and engineering can have in achieving this ambition.
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.
The INSPIRE Directive (2007/2/EC of the European Parliament and of the Council and in force from the 15th May 2007) establishes an infrastructure for spatial information in the European Community. By facilitating the availability and access of spatial (geographic) information, best use can be made of the data for the benefit of a wide variety of users in different sectors and disciplines. Planning and development in Scotland bring together such a broad mix of users of spatial data. Therefore, the INSPIRE Directive has a key role to play in promoting improvements to spatial data infrastructures on which the efficiency and effectiveness of the planning process and successful and sustainable development depend. As a result, the Scottish economy will benefit, especially within the construction sector (which accounted for 6.6% of GDP in 2004, with a £12 billion turnover (www.scotland.gov.uk/Publications/2006/12/19143801/0)), as will society as a whole.
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