Scottish Road Network Landslides Study - University of Glasgow

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42 INFORMATION SOURCES Limitations: It is acknowledged that some misclassification of the land use will have been made at the time of survey but this is thought to be relatively minor in nature. Also, the dataset was based on 1990 information and it is possible that the land use has changed since that time Table 3.1 – The correspondence between the 25 'target' cover-types and the 17 'key' cover types of the Land Cover Map of Great Britain. Those classes denoted thus are considered to be of particular relevance to this study. Land Cover Category (17 Class System) Target Classes (17 Class System) Aa 1b Sea/Estuary 1c Sea/Estuary B 2 Inland Water 2 Inland Water C 3 Beach/Mudflat/Cliffs 3 Beach and Coastal Bare D 4 Saltmarsh 4 Saltmarsh E 5 Rough Pasture/Dune Grass/ 5 Grass Heath Grass Moor 9 Moorland Grass F 6 Pasture/Meadow/Amenity Grass 6 Mown/Grazed Turf 7 Meadow/Verge/Semi-natural G 7 Marsh/Rough Grass 19 Ruderal Weed 23 Felled Forest 8 Rough/Marsh Grass H 8 Grass Shrub Heath 25 Open Shrub Heath 10 Open Shrub Moor I 9 Shrub Heath 13 Dense Shrub Heath 11 Dense Shrub Moor J 10 Bracken 12 Bracken K 11 Deciduous/Mixed Wood 14 Shrub/Orchard 15 Deciduous Woodland L 12 Coniferous/Evergreen Woodland 16 Coniferous Woodland M 13 Bog (Herbaceous) 24 Lowland Bog 17 Upland Bog N 14 Tilled (Arable Crops) 18 Tilled Land O 15 Suburban/Rural Development 20 Suburban/Rural Development P 16 Urban Development 21 Continuous Urban Q 17 Inland Bare Ground 22 Inland Bare Ground 0 Unclassified 3.3.6 Digital Elevation Models Digital elevation models (DEMs) are models of the Earth’s surface that can be used within a GIS environment to identify and quantify many aspects of topography such as slope angle and slope height, which can be incorporated into an assessment of potential slope instability. There are several sources of DEMs in the UK, as follows: CEH Enhanced OS Landform PANORAMA Dataset 10m contours. OS Landform Profile Contours 5m contours. NEXTMap Britain Digital Surface Model.
NEXTMap Britain Digital Terrain Model. 43 INFORMATION SOURCES The Ordnance Survey’s Landform Profile Contours and Intermap Technologies Inc’s NEXTMap are the main sources of DEMs for national and regional scale studies. Lidar data are more accurate but expensive to fly and have only been acquired for a relatively small number of areas, largely for flood prediction studies. Currently the NEXTMap Britain dataset is the most accurate national digital elevation dataset of Great Britain. It is a homogenous dataset that was captured with one sensor over two years. The other current national elevation datasets available for GB offer a much coarser resolution and lower vertical accuracy and were captured with multiple techniques over the course of forty years, thus affecting the level of detail, currency and consistency of the data. Therefore, the NEXTMap Britain dataset can provide a previously unattainable level of detail about the surface of the earth in Great Britain. Although both OS and Intermap are due to launch updated, more accurate versions of their DEMs in the near future it is likely that NEXTMap will continue to contain the more accurate data. NEXTMap Britain is a modern and accurate digital elevation and image data set covering England, Wales and Scotland. It utilises Intermap’s STAR-3i® IFSAR (Interferometric Synthetic Aperture Radar) which can quickly collect large areas of high resolution image data irrespective of the conditions. The product includes both elevation data and orthorectified radar imagery (ORRI). The Digital Elevation Models (DEM) comprise two further data formats, Digital Surface Model (DSM) and Digital Terrain Model (DTM), whereas ORRI provides an enhanced image with a ground resolution of up to 1.25 metres (Table 3.2). Table 3.2 – Data contained within Intermap NEXTMap. Product Description Resolution Accuracy DSM Digital Surface Model. Includes vegetation and cultural features as well as terrain surface. 5m post spacing 1.0m vertical DTM Digital Terrain Model. Has been filtered to remove 5m post spacing smaller cultural features and areas of vegetation. Hydrologically enhanced. 1.0m vertical ORRI Orthorectified Radar Image. Greyscale radar image. 1.25m pixels 2.0m horizontal DEM comparisons: Staff in the BGS Remote Sensing laboratory compared the results of the available datasets for a section of the Trent Valley to determine their suitability for a range of geological projects. Their findings were as follows: CEH enhanced OS landform panorama: The Centre for Ecology and Hydrology DTM is based on Ordnance Survey (OS) Landform PANARAMA dataset with 50m cell spacing. The CEH have enhanced the base OS product by enhancing the hydrological features. Full coverage of Great Britain is available to BGS’s Science Budget projects but commercial projects have to enter complex negotiations with OS over derived data licensing. It is understood that OS have stopped supporting the base product and intend to withdraw it. OS Landform Profile contours: Ordnance Survey (OS) Landform PROFILE contours, UK coverage. Useful for studying large areas but lacks detail in low-relief areas. Supplied as DXF format contours and spot heights and gridded in-house. The effective cell spacing is 10m.
Page 1 and 2: Scottish Road Network Landslides St
Page 3 and 4: Electronic copies of this report ma
Page 5 and 6: MINISTERIAL FOREWORD The landslide
Page 7 and 8: 3 WORKING GROUP Dr Roger Moore: Rog
Page 9 and 10: 5 EXECUTIVE OVERVIEW Outlining poss
Page 11 and 12: 7 EXECUTIVE OVERVIEW The initial st
Page 13 and 14: 1 INTRODUCTION TO LANDSLIDE HAZARDS
Page 15 and 16: 11 INTRODUCTION Section 6 describes
Page 17 and 18: 13 BACKGROUND However, Varnes (1978
Page 19 and 20: 15 BACKGROUND squares that showed s
Page 21 and 22: 17 BACKGROUND events that do not im
Page 23 and 24: 19 BACKGROUND The A9 was blocked by
Page 25 and 26: 21 BACKGROUND important to note tha
Page 27 and 28: 23 BACKGROUND earthworks stability
Page 29 and 30: 3 DEBRIS FLOW INFORMATION SOURCES b
Page 31 and 32: 27 INFORMATION SOURCES whereas stre
Page 33 and 34: 29 INFORMATION SOURCES Detailed haz
Page 35 and 36: 7. Meteorological: a) Antecedent ra
Page 37 and 38: 33 INFORMATION SOURCES 1:50,000 sca
Page 39 and 40: 35 INFORMATION SOURCES socio-econom
Page 41 and 42: 37 INFORMATION SOURCES Figure 3.6 -
Page 43 and 44: 39 INFORMATION SOURCES team using a
Page 45: 41 INFORMATION SOURCES events would
Page 49 and 50: 4 DEBRIS FLOW TYPES AND MECHANISMS
Page 51 and 52: 47 TYPES AND MECHANISMS damage. Exa
Page 53 and 54: 49 TYPES AND MECHANISMS Figure 4.4
Page 57 and 58: 53 TYPES AND MECHANISMS The shear r
Page 59 and 60: Preparatory Factors 55 TYPES AND ME
Page 61 and 62: 57 TYPES AND MECHANISMS Road cuts m
Page 63 and 64: 59 TYPES AND MECHANISMS such featur
Page 65 and 66: 61 TYPES AND MECHANISMS ruptures to
Page 67 and 68: 4 6 10 -6 10 m/s -6 10 m/s -6 m/s L
Page 69 and 70: 65 TYPES AND MECHANISMS detachment
Page 73 and 74: 69 CONTRIBUTORY FACTORS There is ho
Page 75 and 76: 5.1.2 Geological, Geotechnical and
Page 77 and 78: 73 CONTRIBUTORY FACTORS Other hydro
Page 79 and 80: 75 CONTRIBUTORY FACTORS to the fail
Page 81 and 82: 77 CONTRIBUTORY FACTORS 5.3 FACTORS
Page 83 and 84: 79 CONTRIBUTORY FACTORS upon the lo
Page 85 and 86: 6 PROPOSED METHODOLOGY FOR DEBRIS F
Page 87 and 88: 83 PROPOSED METHODOLOGY ground is u
Page 89 and 90: 85 PROPOSED METHODOLOGY presence of
Page 91 and 92: 87 PROPOSED METHODOLOGY The exposur
Page 93 and 94: 89 PROPOSED METHODOLOGY Once a haza
Page 95 and 96: A84 South of Strathyre (8km) HIGH H
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HIGH HAZARD AREAS AND EARLY OPPORTU
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8 DEBRIS FLOW MANAGEMENT AND MITIGA
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8.2.3 United Kingdom MANAGEMENT AND
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MANAGEMENT AND MITIGATION OPTIONS D
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MANAGEMENT AND MITIGATION OPTIONS a
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MANAGEMENT AND MITIGATION OPTIONS N
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MANAGEMENT AND MITIGATION OPTIONS r
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MANAGEMENT AND MITIGATION OPTIONS F
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9 SUMMARY AND RECOMMENDATIONS FOR D
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SUMMARY AND RECOMMENDATIONS The ini
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SUMMARY AND RECOMMENDATIONS extensi
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115 REFERENCES Chan, R. K. S. 2000.
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117 REFERENCES Moore, R., Lee, E. M
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APPENDIX - PROJECT WORKSHOP AGENDA
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Scottish Road Network Landslides Study - University of Glasgow

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