Wilfried Haeberli: Glacial lakes, emerging risks and water issues

Wilfried Haeberli Geography Department University of Zurich

Glacial lakes, emerging risks and water issues

Trift glacier Swiss Alps Alean

New lakes: tourist attraction hydropower potential hazard source water resource conflict area possible synergies

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Trift glacier Swiss Alps Alean

Glaciers and lakes in Nepal Landsat

Miller glacier New Zealand Chinn

Tasman glacier New Zealand Chinn

Recognizing overdeepenings in glacier beds: potential future glacier lakes I.  Distinct break in slope II.  Reduction of glacier width (narrowing) III.  crevasse-free part is followed by a heavily crevassed part

Frey, H., Haeberli, W., Linsbauer, A., Huggel, C. and Paul, F. (2010): A multi level strategy for anticipating future glacier lake formation and associated hazard potentials. Natural Hazards and Earth System Science 10, 339-352.

Example: Trift glacier 1948 - 2006

Trift glacier Swiss Alps Frey

I. Distinct break in slope 2006

1948

© Gesellschaft für ökologische Forschung

II.

Reduction of glacier width (narrowing)

III. crevasse-free part is followed by a heavily crevassed part

Modelling of possible future lakes

Rhone glacier Swiss Alps Linsbauer, Alean

contour lines (50 m) glacier outlines flowlines surface slope base points interpolated glacier bed

Linsbauer, A., F. Paul, M. Hoelzle, H. Frey and W. Haeberli (2009): The Swiss Alps without glaciers - a GIS-based modelling approach for reconstruction of glacier beds. In: Geomorphometry 2009 Conference Proceedings, Purves, R., Gruber, S., Straumann, R., and Hengl, T. (eds.), University of Zurich, Zurich, 243-247, www.geomorphometry.org

Modelling of possible future lakes

Rhone glacier Swiss Alps Linsbauer, Alean

contour lines (50 m) glacier outlines flowlines surface slope base points interpolated glacier bed

Linsbauer, A., F. Paul, M. Hoelzle, H. Frey and W. Haeberli (2009): The Swiss Alps without glaciers - a GIS-based modelling approach for reconstruction of glacier beds. In: Geomorphometry 2009 Conference Proceedings, Purves, R., Gruber, S., Straumann, R., and Hengl, T. (eds.), University of Zurich, Zurich, 243-247, www.geomorphometry.org

Modelling of possible future lakes

Rhone glacier Swiss Alps Linsbauer, Alean

contour lines (50 m) glacier outlines flowlines surface slope base points interpolated glacier bed

Linsbauer, A., F. Paul, M. Hoelzle, H. Frey and W. Haeberli (2009): The Swiss Alps without glaciers - a GIS-based modelling approach for reconstruction of glacier beds. In: Geomorphometry 2009 Conference Proceedings, Purves, R., Gruber, S., Straumann, R., and Hengl, T. (eds.), University of Zurich, Zurich, 243-247, www.geomorphometry.org

Modelling of possible future lakes

Rhone glacier Swiss Alps Linsbauer, Alean

contour lines (50 m) glacier outlines flowlines surface slope base points interpolated glacier bed

Linsbauer, A., F. Paul, M. Hoelzle, H. Frey and W. Haeberli (2009): The Swiss Alps without glaciers - a GIS-based modelling approach for reconstruction of glacier beds. In: Geomorphometry 2009 Conference Proceedings, Purves, R., Gruber, S., Straumann, R., and Hengl, T. (eds.), University of Zurich, Zurich, 243-247, www.geomorphometry.org

Modelling of possible future lakes

Rhone glacier Swiss Alps Linsbauer, Alean

contour lines (50 m) glacier outlines flowlines surface slope base points interpolated glacier bed

Linsbauer, A., F. Paul, M. Hoelzle, H. Frey and W. Haeberli (2009): The Swiss Alps without glaciers - a GIS-based modelling approach for reconstruction of glacier beds. In: Geomorphometry 2009 Conference Proceedings, Purves, R., Gruber, S., Straumann, R., and Hengl, T. (eds.), University of Zurich, Zurich, 243-247, www.geomorphometry.org

Scenario of glacier retreat and lake formation Swiss Alps (Aletsch) Assumption: temperature increase 4째C by 2100, time steps 15 years Linsbauer

Glaciers and permafrost in the Alps ice volume km3 80

PermaNET

25

Ice volume in pe

rmafrost

time 2010

2050?

Aletsch region Swiss Alps

Schaub

Glaciers, new lakes, permafrost and steep, destabilizing mountain flanks in the Alps

Corbassière glacier Swiss Alps

Hydropower and flood protection

Terrier

Terrier Künzler

seasons

P cold Q

Q P warm

Alps/Cordilleras: precipitation, mass balance storage and runoff

seasons

P dry Q

Q

wet

Kaser/Osmaston

P

vanishing surface ice

permafrost degradation slope instability

disappearing support of steep glacier parts, ice avalanches from steep hanging glaciers

de-buttressing of lateral rock slopes Milhuacocha Cordillera Blanca Hegglin

ice avalanches and rock falls not on glacier tongue any more but directly into lake

oversteepened inside slope of lateral moraine

lake formation

Haeberli, W., Clague, J.J., Huggel, C. and Kääb, A. (2010): Hazards from lakes in high-mountain glacier and permafrost regions: Climate change effects and process interactions. Avances de la Geomorphología en España, 2008-2010, XI Reunión Nacional de Geomorphología, Solsona, 439-446.

Lessons learned from the Hualcรกn case

12.04.2010

Nevado Hualcรกn Cordillera Blanca Portocarrero

Pampa de Jonquil Cordillera Blanca

Río Chucchún Cordillera Blanca

río Chucchún

Conclusions Hualcán: • Succesfull hazard prevention: many lives saved • Efficient risk reduction but not to zero • Shift of hazard source to summit areas: polythermal (?) hanging glaciers and warm permafrost • Larger events (106 m3) and new lakes possible, hence further measures necessary • Observation of starting zone important (stabilisation/destabilisation?)

• Enhancement of freeboard (deeper tunnel, breach closure) • Retention at Pampa de Shonquil (multipurpose structure) • Passive measures in town (EWS, escape information)

Palcacocha, Peru HualcĂĄn-Carhuaz Cordillera Blanca Schneider

Modeling the process chain and installation of an early warning system ‌

Lake probably shallow Lake probably deep Lake formation uncertain Lake formation ongoing or imminent Lake formation in coming decades

Hualcรกn-Carhuaz Cordillera Blanca possible retention

New lakes: model chain for scenario development and hazard assessment spatial models of climate/glacier scenarios spatial model of ice thickness

digital terrain model without glaciers spatial model of new lakes

spatial models of potential rock, ice and rock/ice avalanches into lakes spatial models of potential floods and debris flows from new lakes

Create a knowledge basis for future generations what do we expect? what can we do? how should we proceed?

Gruben glacier Swiss Alps