© RIL, 2016

Glacial behaviour in theUpper Indus Basin and

implications for hydropower development

Prof. John M. Reynolds

Reynolds International Ltd, Mold, UK

© RIL, 2016

Outline

• Types of glaciers and their behaviour

• Types of hazard

• Conclusions

Glacial behaviour in the Upper Indus Basin and implications for hydropower development

© RIL, 2016

Rock glaciers

Cirque glaciers

Valley glaciers and tributaries

Surge-type glaciers and tributaries:- Repeat-surge (surge periods identifiable) Rapid glacier slide Single flow-unit surge Multiple and synchronous glacier surges

Evidence of both advancing and retreating glaciers

Implications for basin hydrology and river flow

Types of glaciers

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Ice and Rock glaciers

Confusion over glacierised areas and implications of rock glaciers for TL pylon foundations

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Types of glaciers and their behaviour

Bazhin Glacier

Advancing glacier

Moraine-dammed lake Collapsing ice tunnel with sub-glacial drainage

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Types of glaciers and their behaviours

Baltoro Glacier(Landsat image courtesy of F. Paul)

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Types of glaciers and their behaviours

Shimshall valley – series of surge-type glaciers

Attabad lake

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Proto-supra-glacial lake formation

Hispar Glacier

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Proto-supra-glacial lake formation

Hispar Glacier

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Types of glacial hazard

Glacier feature Hazard type Consequence

Rock glacier None Minimal

Cirque glacier Minimal Minimal

Advancing glacier Valley blocking Ice dam outburst flood

Advancing glacier Episodic flushing Localised flooding

Retreating glacier Episodic flushing Localised flooding

Moraine-dammed lake GLOF Localised flooding

Lateral pro-glacial lake Episodic flushing Localised flooding

Supra-glacial lake - transient Episodic flushing Localised flooding

Supra-glacial lake – perennial^ Very large lake volume ?Catastrophic flushing

Surge-type – glacier sliding Valley blocking Ice dam outburst flood

Surge type – isolated glacier Valley blocking Ice dam outburst flood

Surge type – synchronous Valley blocking Ice dam outburst flood^Proto-mega-supra-glacial lake

Note: Processes and related hazards vary with and over time

© RIL, 2016

Conclusions

There are four types of glacier within the Upper Indus Basin ranging from

rock and cirque glaciers to valley glaciers, some of which exhibit surge-

type activity.

While some glaciers are retreating and shrinking, it is notable that many

are stable or even advancing.

Surging and advancing glaciers can block river valleys and impound

significant volumes of water, with the potential to form major catastrophic

floods when the ice dam fails.

Several glaciers with very flat surfaces are starting to form proto-mega-

supra-glacial lakes that may grow to contain many billions of m³ of water.

The hazards associated with the various types of glacier can be indicated

by their relative consequences on downstream hydropower facilities and

simply represented by a ‘traffic lights’ system.

© RIL, 2016

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