Glacier Risks. Possibilities and Limits of Prevention and Mitigation. Jörg Hanisch Hannover, Germany John M. Reynolds Mold, UK

Size: px

Start display at page:

Download "Glacier Risks. Possibilities and Limits of Prevention and Mitigation. Jörg Hanisch Hannover, Germany John M. Reynolds Mold, UK"

Abner Banks
5 years ago
Views:

1 Glacier Risks Possibilities and Limits of Prevention and Mitigation Jörg Hanisch Hannover, Germany John M. Reynolds Mold, UK

2 Glacier Hazards

3 Ice Falls, Surges, and Avalanches Glacier Hazards

4 Glacier Hazards Ice Falls, Surges, and Avalanches Glacier Lake Outburst Floods (GLOFs)

5 Glacier Hazards Ice Falls, Surges, and Avalanches Glacier Lake Outburst Floods (GLOFs) Sturzstroms of Ice and Debris

6 Glacier Hazards Ice Falls, Surges, and Avalanches Glacier Lake Outburst Floods (GLOFs) Sturzstroms of Ice and Debris Local, Limited Reach

7 Glacier Hazards Ice Falls, Surges, and Avalanches Glacier Lake Outburst Floods (GLOFs) Sturzstroms of Ice and Debris Local, Limited Reach Extended Reach, Medium Velocity

8 Glacier Hazards Ice Falls, Surges, and Avalanches Glacier Lake Outburst Floods (GLOFs) Sturzstroms of Ice and Debris Local, Limited Reach Extended Reach, Medium Velocity Extended Reach, Extreme Velocity

9 Ice Falls and Avalanches

10 Mattmark Ice Avalanche 1965 (Switzerland, courtesy: W. Häberli)

11 Glacier Lake Outburst Floods (GLOFs)

12 GLOF in Brit. Columbia (from Evans & Clague 1994)

13 Dig Tsho Outburst, Nepal 1985 (WECS)

14 Dig Tsho GLOF 1985: 8000 m 3 /s WECS (WECS) 1988

15 Sturzstroms

16 Huascarán Sturzstrom 1970, Peruvian Andes (Welsch & Kinzl 1979) Y

17 The Karmadon Sturzstrom- Disaster in Kaukasus 2002 Photo: Alexander Polkvoy

18 Alexander Polkvoy

20 Kolka Glacier June 2003

21 Alexander Polkvoy

22 End of Karmadon Sturzstrom Karmadon Google Earth

23 Conclusion: Glacier Risks are to 90 % Debris-Flow Risks

24 Risks consist of two components:

25 Risks consist of two components: - Hazard (probability of a major natural event to happen)

26 Risks consist of two components: - Hazard (probability of a major natural event to happen) - Vulnerability (potential casualties and/or major values at risk)

27 In Engineering Geology: Risk = Hazard x Vulnerability

28 V u l n e r a b i l i t y H a z a r d R i s k = H a z a r d x V u l n e r a b i l i t y

29 What can be done against these horrific threats?

30 Mitigation Improved monitoring systems

31 Mitigation Improved monitoring systems Improved early warning and warning systems

32 Mitigation Improved monitoring systems Improved early warning and warning systems Improved mapping methods of hazards and risks

33 Mitigation Displacement of roads and bridges

34 Mitigation Displacement of roads and bridges Debris-flow deflection walls

35 Mitigation Displacement of roads and bridges Debris-flow deflection walls Widened channels through villages

36 Mitigation Displacement of roads and bridges Debris-flow deflection walls Widened channels through villages Preparedness of population

37 from: Braun & Fiener 1995 Example of GLOF risk mapping along a Himalayan valley

38 Glacier Hazard Prevention Strategies

39 Prevent Initiation of GLOFs Glacier Hazard Prevention Strategies

40 Glacier Hazard Prevention Strategies Prevent Initiation of GLOFs Prevent GLOFs and Sturzstroms from reaching areas of high vulnerability

41 Prevention of Initiation of GLOFs

42 Prevention of Initiation of GLOFs Lowering of lake level by siphoning tunneling trenching

43 Siphoning of glacier lakes Pump Valve Principle of hydraulic syphon Suction head Water level from Grabs & Hanisch (1993) Water outlet Water intake Terminal morraine Bedrock

44 (1993) Limitations of hydaulic siphons: Suction head Volume of drained water

45 (1993) Tsho Rolpa, 4500 m, Nepal J.M.R. Test Siphons at Tsho Rolpa, Nepal

46 Hydraulic siphons in Peru Lake level lowering by drainage tunnel, Peru Courtesy: John M. Reynolds

47 Trenching: Tsho Rolpa, 4500 m, Nepal Channel completed 2000 Water level reduced by 3.5 m Costs ~ US$ 3 million J.M.R.

48 Court.: J. Reynolds Gate at Tsho Rolpa (Nepal)

49 Disaster of Quebrada los Cedrs, Peru 1949

50 Failed mitigation works in Peru 1949 Lliboutry et al Lake level lowered by 15 m by trenching Collapse of glacier snout which before had been under buoyancy

51 Lliboutry et al Displacement wave rushing through trench Breaching of morraine by regressive erosion GLOF killing several hundred people

52 Special method to control the spillway Emergency Agency Almaty, Kazakhstan

56 Drastic protection measures

57 GLOF Front in Kazakhstan Court.: Kazselezaschita, Almaty

58 GLOF Front in Kazakhstan

60 Medeo Debris-Flow Protection Dam, upstream Almaty, Kazakhstan

61 Medeo Debris-Flow Protection Dam Emergency Agency Almaty

62 Emergency Agency Almaty Medeo Debris- Flow Protection Dam under Construction 1972

63 Medeo Debris- Flow Protection Dam under Construction 1972

64 Debris-flow retaining dam in Kazakhstan Emergency Agency Almaty Sarkand

65 Talgar Emergency Agency Almaty

66 Flexible debris-flow retaining dam in Kazakhstan

67 Switzerland, Geobrugg

68 Switzerland, Geobrugg Kazakhstan, Emergency Agency

either - try to prevent the outburst - prevent the

69 Conclusions Most of the glacier hazards cannot be totally prevented GLOF-prevention strategies can either - try to prevent the outburst - prevent the consequent debris flow from reaching areas of high vulnerability

70 Conclusions Any mitigation measure needs careful assessment of risk (vulnerability of travel path)

71 Thank you very much!

Glacial Lake Outburst Flood Mitigation Measures, Monitoring and Early Warning Systems

Chapter 12 Glacial Lake Outburst Flood Mitigation Measures, Monitoring and Early Warning Systems There are several possible methods for mitigating the impact of Glacial Lake Outburst Flood (GLOF) surges,