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Engineering Geomorphology

ENGE 486

ENGINEERING GEOMORPHOLOGY ENGE 486

Tim Davies

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Term 3: Tim Davies, applied geomorphology (6)

Term 4: David Bell/Marlene Villeneuve, ground failure

(6)

Course outline on Learn

1-day field visit 11 or 12 August

Assessment: 2 assignments @ 30%, final exam @

40%

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Engineering Geomorphology is

UNDERSTANDING THE HISTORYAND

PREDICTING THE FUTURE OF ALANDSCAPE BY EXAMINING ITS FORM

AND UNDERSTANDING HOW IT

FORMEDSo that structures and facilities can be

SITED/DESIGNED TO BEAT ACCEPTABLE

RISK OF DAMAGE FROM LANDSCAPEPROCESSES

(analysis & synthesis)

(application)

We focus mostly on analysis & synthesis

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Site Investigation

Underground

Engineering

Geology

Above ground

Engineering

Geomorphology

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How does the landscape behave?

IT CHANGES SHAPEBY MASS TRANSFER

ErosionSedimentation or aggradation (floods)

Uplift

Volcanic eruption

Landslide

Debris flow

Glaciation

Earthquake

..

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Why is the landscape the shape it is at present?

Present shape = past shape + CHANGES

The shape of the landscape is alwayschanging and always wi l l.

So siting and design of permanent facilities, infrastructure,

lifelines, dwellings etc. must take this into account.

However it usually doesnt which is why we get this sort of

thing happening:

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Examples of geomorphic processes. Debris flows:

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Examples of geomorphic processes. Rock Avalanches:

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Socompa depositSimulation

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Site investigation/analysis:

2. Identify landforms at the site and the processes that

generated them (river deposition, debris flow, glacier,

landslide, ..)

3. If a number of processes or events are evident,establish their chronological orders (& if possible ages)

4. Establish their relative (& if possible absolute)

magnitudes

6. Are there processes likely or possible for which

there is nogeomorphic evidence?

7. Establish the recorded history of the site

5. Infer the likely triggers for the identified events

1. Establish the geomorphic context of the site in the

larger landscape

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1966

2002

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Boscastle, UK, 2001

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Boscastle, UK, 2002

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Some or all of the following may be useful information

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Some or all of the following may be useful information

sources:

Aerial Photos (including stereo, multispectral, earliest,)

Contour maps/DEMs/surveying/GPS

Geological maps/investigation

Soil & substrate maps/survey

Vegetation maps/survey

Satellite images (e.g. Google Earth)

Dating techniques: soil age, tephras, carbon, cosmogenic,

luminescence, rock weathering-rind, lichenometry,

dendrochronology,

Oblique photos, old photos, sketches, old paintings,

old maps, old books, old newspapers, old people,

I f th l t b h i f th it t f th

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Infer the long-term behaviour of the site as part of the

larger-scale landscape (e.g. uplift, base-level change,

climate change, river migration, fan progradation etc.)

Infer the types, frequencies and magnitudes of event thatpunctuate the long-term behaviour

Over the specified planning period, develop a realistic

eventconsequence sequence, with probabilities

Infer the consequences that result from these events (e.g.

earthquakes cause landslides that dam rivers and causeflooding)

Develop also a worst-caseeventconsequence sequence

Investigate the possibilities for modifying the events and

their consequences, and invest igate the geomo rphic

consequences of the mod i f icat ions

Infer the largest conceivable magnitudes for all events