The Scottish Government

« Previous | Contents |

Listen

Footnotes

¹ Source: http://www.metoffice.com/climate/uk/2004/august/maps.html .
² Note that the traffic flow figures are highly variable on a seasonal basis. The figures quoted are the maximumfigures available from 2003 and 2004 records and are generally in either July or August. The minimum figures were 3,000 for the A83, 7,200 for the A9 and 2,300 for the A85 in either January or February.
³ Note that in debris flows lubricated by air, rock is usually the dominant solid material. Such debris flows are thus often referred to as rockslides or rockfalls (after Erismann and Abele, 2001). Air lubricated rock falls are considered by the existing Rock Slope Hazard System (McMillan and Matheson, 1997) and are considered further in Section 6.3.
⁴ Sources: The Independent, 8 September 2004 and BBC World, 9 September 2004.
⁵ Source: http://www.ukcip.org.ukand Personal Communication from D J Price (2005).
⁶ Ablation tills are those materials formed as a result of ice wasting, primarily melting, that are often unsorted but can show some signs of stratification with larger particles having settled to the base of the deposit. Many moraine deposits are formed by ablation processes.
⁷ Glaciofluvial are not strictly tills, but are formed by deposition from streams flowing from ice mass margins. Depending upon stream flow and the distance to the point of deposition the level of sorting can vary from poorly sorted to well sorted. Streams and their deposits often interact with ablation processes especially if supraglacial deposits contain sand and silt forming a mass movement or debris flow.
⁸ Lodgement tills are formed by a 'plastering-on' process at the base of an ice bed. They are normally compact and rich in fine particles usually exhibit preferred orientation of the larger particles which may indicate the direction of ice movement. Shear planes, joints and fissures are frequently found in lodgement tills.
⁹ Colluvium is material that has been transported down slope by the action of water and/or gravity and includes hillwash, scree (talus) and other materials.
¹⁰ A DTM differs from the basic topographical model in that it comprises three-dimensional data that can be manipulated and interrogated to determine, for example, slope angles or those areas of slope that lie within a range. The topographic data is essentially a digital map the underlying data of which cannot usually be accessed, let alone manipulated or interrogated.
¹¹ Synoptic sites are those sites which are used to build up regional and/or national pictures. They have been selected as delivering data typical of an area, and to which a long term commitment has thus been made.
¹² Further information from: http://www.metoffice.gov.uk/climate/uk/networks/index.html .
¹³ Further information from: http://www.ceh.ac.uk/data/lcm/LCMclassInfo.shtm .
¹⁴ Landslides may trap air resulting in 'fluidisation' and long run-out as an alternative medium to water, but this mechanism is not considered further here.
¹⁵ Note that the traffic flow figures are highly variable on a seasonal basis. The figures quoted are the maximum figures available from 2003 and 2004 records and are generally in either July or August. The minimum figures were 7,200 for the A9 and 400 for the A835 in either January or February.
¹⁶ This approach appears to allow for shorter stopping distances than those given in the Highway Code (source: www.highwaycode.gov.uk ) for the speed limit of such roads. It is assumed that this approach has been adopted to allow for a range of actual vehicle speeds. For example, taking speeds of 40mph to 60mph gives stopping distances of 36m to 73m. Allowing for some rounding the range of 40m to 60m seems reasonable for cars in dry conditions with good visibility; given that at most hazard sites speeds close to the speed limit are highly unlikely. However, for debris flows which are likely to be encountered in wet conditions with poor visibility some adjustment may be necessary for conditions and possibly also for vehicles with longer stopping distances.
¹⁷ The processes involved in the day-to-day management of slopes in Hong Kong can be studied through the following web link; http://hkss.ced.gov.hk/hkss/eng/whatsnew/index.htm .
¹⁸ Note that while this moves traffic past a potential hazard rapidly if a convoy is hit the losses would be greater than might otherwise be the case.
¹⁹ Source: http://hkss.ced.gov.hk/hkss/eng/index.htm .

« Previous | Contents |