WHY IS IT SO IMPORTANT? - in1touch€¦ · Terrain Analysis, Why is it so Important? 16 WHAT IS TERRAIN ANALYSIS – MINIMUM POLYGON SIZE Scale influences minimum polygon size Scale

Terrain Analysis

WHY IS IT SO IMPORTANT?

Presentation to Alberta Institute of Agrology

Banff, Alberta

Dennis O’Leary, P.Ag

Dr. Anne Sommerville, Ph.D., P.Ag.

March 29, 2019

___AGENDA

1. Introductions

2. Who uses Terrain Data

3. What is Terrain Analysis

4. Components of Terrain Analysis

5. Coffee Break

6. Importance of Scale

7. Tools

8. What can go wrong without proper terrain data

9. Qualifications for Terrain Mapping

2

___Terrain Analysis, Why is it so Important?

3

W H O U S E S T E R R A I N D ATA

Who Uses Terrain Data


4


Who Uses Terrain Data?

❑ Engineers

❑ Soil scientists

❑ Geologists

❑ Ecologists

❑ Landscape architects

❑ Planners

❑ Archaeologists


5


What industries use Terrain Data

❑ Agriculture

❑ Mining

❑ Landfill/Disposal sites

❑ Recreation

❑ Ski operators

❑ Railways

❑ Transportation

❑ Pipelines

❑ Transmission

❑ Renewables

❑ Water/electric hydro

❑ Wind farms


6

What is Terrain Analysis


7

W H AT I S T E R R A I N A N A LY S I S

Terrain……no definition, see “Terrane”

Terrane……

A region of CRUST with well-defined margins, which differs

significantly in TECTONIC evolution from neighboring regions

Dictionary of Geology


8


Terrain……..no definition

Terrane………

A rock formation, a cluster of rock formations, or the general

areas of outcrops

Dictionary of Earth Science


9


Terrain……

The physical characteristics of the natural features of an area,

i.e. its LANDFORMS, vegetation and soils

Dictionary of Physical Geography


10


Terrain Analysis…….

The scientific interpretation of the landforms, vegetation and

soils of a given area in relation to the uses to which it may be

put.



11


Terrain-type map……

A map depicting all the different types of terrain in a region,

classified into categories with broadly similar attributes, e.g.,

slope gradient, AVAILABLE RELIEF, degree of dissection, and

depicted with distinctive shading, colouring and/or numerical

notation.



12


❑ Terrain is the interface between the geotechnical world

and the biophysical world!


13



14

W H AT I S T E R R A I N A N A LY S I S - P U R P O S E

❑ What is the purpose of the mapping?

❑ Regional

❑ Planning, allocation of land

❑ Local

❑ Oilsands development

❑ Site specific

❑ River crossing

❑ Facility


15

W H AT I S T E R R A I N A N A LY S I S - S C A L E

❑ Purpose influences scale

❑ Regional

❑ Broad scale > 1:50,000

❑ Local

❑ Medium scale 1:10,000 to 1:50,000

❑ Site Specific

❑ Large scale 1:500 to 1:2,000


16

W H AT I S T E R R A I N A N A LY S I S – M I N I M U M P O LY G O N S I Z E

❑ Scale influences minimum polygon size

Scale Average1

Polygon (ha)

Minimum2

Polygon (ha)

1:250,000 1,900 – 3,400 625

1:100,000 280 – 500 100

1:50,000 150 – 425 25

1:20,000 16 – 100 4

1:10,000 12 - 25 2

1:2,0003 3 – 103 0.4

1:5003 0.43 0.1

1. From Guidelines and Standards to Terrain Mapping in British Columbia (RIC 1996)

2. Minimum polygon size at any scale is 1 cm2

3. Data from Golder Associates Ltd.

Increased

level of

detail

Operational

scale data


17

Components of Terrain Analysis


18

C O M P O N E N T S O F T E R R A I N A N A LY S I S

❑ Involves the subdivision of the landscape for a particular

purpose at a given scale


19


Surficial geology of

AlbertaFenton et al. 2013

• 1:1,000,000 scale

• Compilation map


20


Quaternary

Geology,

Southern AlbertaShetsen 1987

• 1:500,000 scale

• Compilation map


21

Surficial geology map Terrain map



22



23



24


Drainage

Topography

Geoprocesses

SlopeSoil Parent Materials

Depth to Bedrock

Texture

No one variable

takes precedence

over another!

Climate

Change

Seismicity


25

C O M P O N E N T S O F T E R R A I N A N A LY S I S -

M AT E R I A L S

❑ Soil Parent Materials

Soil Parent Materials

• Anthropogenic

• Colluvium

• Eolian

• Fluvial / Alluvium

• Glaciofluvial

• Glaciolacustrine

• Glaciomarine

• Ice

• Lacustrine

• Marine

• Moraine (till)

• Organic

• Pre-glacial gravels

• Rock/Bedrock

• Weathered Bedrock

Highly

dependent upon

geology and

glacial history


26

C O M P O N E N T S O F T E R R A I N A N A LY S I S - M AT E R I A L S

❑ Issue………

❑ Not all till materials are the same…..

❑ Not all glaciofluvial materials are the same…..

❑ Not all organics are the same…….

❑ Purpose of terrain analysis is to identify these landforms and

deposits as they will all have different physical and chemical

properties that influence a particular use (e.g., construction,

reclamation)

Till: Mainly till comprised of

clay, silt and sand as well

as a mixture of pebbles,

cobbles and boulders.

Locally may include blocks

of bedrock, stratified

sediment, or lenses of

glaciolacustrine and/or

glaciofluvial sediment

Fenton et al (2013)


27


Moraine

Hummocky ablation till

Morainal plain

Ridged moraine


28


Glaciofluvial

Kettled glaciofluvial deposits

Outwash plain

Esker


29


Colluvium

Scree slope Colluvial materials

Debris flow track

Boulder colluvium


30

C O M P O N E N T S O F T E R R A I N A N A LY S I S - T E X T U R E

❑ Pedological “Soil” textures

❑ % sand, silt and clay

Engineers

ABHOR

the term/concept of

LOAM

Not in their

vocabulary!


31


❑ “Terrain soil” textures


32


❑ Textural terms

Specific Clastic

Terms

Common Clastic

Terms

Organic

Terms

▪ Blocks

▪ Boulders

▪ Cobbles

▪ Pebbles

▪ Sand

▪ Silt

▪ Clay

• Mixed fragments

• Angular fragments

• Gravel

• Rubble

• Mud

• Shells

• Fibric

• Mesic

• Humic

From: Terrain Classification System for British Columbia (Howes and Kenk 1997)


33


❑ Engineers use the Unified Soil Classification System (USCS)

• Used to define terms

cobbles, gravels, sand and

“fines” (silt and clay)

• No “loams”

• Engineering properties

(e.g., plasticity) assigned

to each group (e.g., GM,

GC, CL, CH)


34

C O M P O N E N T S O F T E R R A I N A N A LY S I S – D E P T H T O B E D R O C K

❑ Overburden thickness / Depth to Bedrock

❑ Bedrock at surface

❑ Bedrock < 1 m below surface

❑ Bedrock 1 – 3 m below surface

❑ Bedrock > 3 m below surface

Veneer (< 1 m)

> 3 m thick


35

C O M P O N E N T S O F T E R R A I N A N A LY S I S - T O P O G R A P H Y

❑ Topography / Surface Expression

❑ “General configuration of a surface, including its relief; the natural

surface features of a region treated collectively as to form”

Dictionary of Earth Science

• Planar / level

• Inclined

- Gentle

- Moderate

- Moderately steep

- Steep

• Apron

• Cone

• Depression

• Fan

• Hummocky

• Rolling

• Ridged

• Terraced

• Undulating


36

C O M P O N E N T S O F T E R R A I N A N A LY S I S - S L O P E

❑ Slope

❑ Straight

❑ Concave

❑ Convex

❑ May be controlled either by:

❑ Bedrock (e.g., upper mountain slopes)

❑ Thick soil materials (e.g., eskers)

❑ May occur over short or long distances


37

C O M P O N E N T S O F T E R R A I N A N A LY S I S - S L O P E

❑ Percent slope classes

1. Coincide with USDA slope classes.

Canadian

System of Soil

Classification1

B.C. Terrain

Classification

System Reality?

0 – 0.5

0.5 – 2

2 – 5

6 – 9

10 – 15

16 – 30

30 -50

50 – 70

> 70

0 – 5

6 – 26

27 – 49

50 – 70

> 70

0 – 1

2 – 5

6 – 20

20 – 40

40 – 60

60 – 80

>80


38

C O M P O N E N T S O F T E R R A I N A N A LY S I S - D R A I N A G E

❑ Drainage

❑ Perhaps the most important feature of the landscape

❑ Often not considered or considered enough

❑ Influences land use decisions

- siting of facilities

❑ Affects pipeline integrity (SCC)

❑ Critical to ecological mapping

Follow

the water!


39

C O M P O N E N T S O F T E R R A I N A N A LY S I S - D R A I N A G E

❑ Drainage classes

❑ Rapid

❑ Well

❑ Moderate

❑ Imperfect

❑ Poor

❑ Very poor

Associated with

Mineral wetlands

Associated with

Organic soils

Associated with

upland soils

• Determined by specific

criteria (e.g., presence /

absence of mottling,

gleying, etc.)

• Some use a “Very Rapid”

drainage class

• Does bedrock have

drainage?

• Does not necessarily

equate to permeability!


40

C O M P O N E N T S O F T E R R A I N A N A LY S I S - G E O P R O C E S S E S

❑ Geoprocesses

❑ Naturally occurring or man-made phenomena that have the

potential to alter the landscape

❑ Include:

❑ Landsliding

❑ Gullying

❑ Groundwater seepage

❑ Permafrost

❑ Karst

❑ Flooding

Cougar Creek debris torrent, Canmore 2013


41


❑ Geomorphological Processes

Did you see all those Geoprocesses when

driving from Calgary to Banff?

• Debris flows

• Debris torrents

• Landslides

• Rock slide

• Avulsion

• Gullying

• Rock fall

• Avalanching

• Areas subject to flooding

• Stream bank erosion

• Seepage


42


❑ Geomorphological Processes

❑ Mass movement processes

❑ Erosional processes

❑ Fluvial processes

❑ Hydrologic processes

❑ Periglacial processes

Assumed to be

active processes


43


❑ Rapid and Slow Mass Movements (landslides!)

Rapid Mass Movements Slow Mass Movements

• Debris flow

• Debris torrent

• Debris fall

• Rock fall

• Avalanche

• Lateral spread

• Tension cracks

• Soil creep

• Rock creep

• Thaw slide

Rapid and Slow Mass

Movements

• Earthflow

• Slump

• Slump/earthflow

• Debris slide

• Rock slide

Thaw slide from

permafrost degradation Tension cracks


44


❑ Erosional Processes

❑ Gully erosion

❑ Karst

❑ Piping

❑ Deflation

❑ Washing

Gullying in southern

Alberta


45


❑ Fluvial processes

❑ Braided channel

❑ Irregular sinuous channel

❑ Anastomosing channel

❑ Meandering channel

Anastomosing channel

Meandering

channel

Braided stream channel

Sinuous channel, Bow River


46


❑ Hydrologic processes

❑ Inundation / flooding

❑ Groundwater seepage

❑ Springs

Flooding in Nebraska March 2019

Seepage in winter period

Spring / seep


47


❑ Periglacial processes

❑ Cryoturbation

❑ Nivation

❑ Solifluction

❑ Permafrost processes

❑ Thermokarst

❑ Palsas, peat plateaus

❑ Thaw flow slides

❑ Ice wedge polygons

❑ Patterned ground

Solifluction

Cryoturbated soil

Ice wedge polygons

Palsa

Thermokarst


48

C O M P O N E N T S O F T E R R A I N M A P P I N G

❑ Need to consider other factors in combination, including:

❑ Climate

❑ Climate change

❑ Seismic events

Liquified leda clays, Lemieux

Landslide June 20, 1993

Materials

+

Slope angle

+

Precipitation / snow melt

+

Land Use

+

Time

___

Terrain Analysis, Why is it so Important?

Coffee Break

49


50

I M P O R TA N C E O F S C A L E

❑ Do you consider the concept of scale when you start a

project?

❑ Scale is a common word…….hence may not give it the attention

it deserves…..

❑ Government regulations vs. what is needed by industry!


51


❑ Macro versus Micro Scale

❑ Small versus Large Scale

❑ 1:500,000 vs. 1:2,000 vs. 1:500

❑ Glaciolacustrine = clays, stone free

❑ Moraine = whatever texture + stones

❑ Glaciofluvial = sands and gravels

❑ Colluvium = steep slopes, coarse angular fragments

❑ Organics = depressional landscape

❑ Fluvial = sands and gravels

Theory

vs.

Reality


52


❑ What is the size of an oilsands operation?

❑ What is the size of an upgrader?

❑ What is the size of a well site?

❑ What is the length of a pipe segment?

❑ What is the width of a gravel road?

❑ What is the width of a paved two lane highway?


53


Scotford Refinery

Approximately 1 mi2

or 640 ac


54


Hydraulic fracturing well pad in Marcellus Shale Basin

Typical well pad

varies from 1.5 to

3.5 ac

Gravel roads vary

from 6 – 10 m in

width


55


Average pipe segment is

12.2 m or 40 ft in length


56


❑ Pipe segments versus scale


57


~ 3.5 km or 287

pipe segments

Mapping at 1:2,000 to 1:5,000 depicted

at 1:10,000 scale

Landslide

Area

(19.7 ha)

122 m

crossing

145 m susceptible to

SCC issues

1.35 km of organic

materials; potential

buoyancy issues


58


Mapping at 1:500 scale

for integrity management

purposes

Colluvial slope is 83 m in

length with evidence of

groundwater seepage

and slumping

6.8 pipe segments

subject to threat


59

TOOLS


60

T E R R A I N A N A LY S I S

Terrain Analysis

Scoping

Model

Background Data

Mapping

Field Investigations

The 5 steps in a proper

terrain analysis program


61

T E R R A I N A N A LY S I S - 1 S T S T E P - S C O P I N G

❑ Scoping

❑ What is the purpose of the project

❑ How does it tie into other disciplines

❑ Given the purpose of the project, what scale of analysis is

required

❑ What is the schedule, including critical dates

❑ What are the deliverables


62

Terrain Analysis

Scoping

Model

Background Data

Mapping


T E R R A I N A N A LY S I S - 2 N D S T E P – M O D E L




63

T O O L S – 2 N D S T E P, D E V E L O P “ M O D E L ”

• Develop a model in your head

• Where am I working?

• What is your knowledge of the glacial history of the area?

• Is there a glacial history to your area?


64


Terrain Analysis

Scoping

Model

Background Data

Mapping





65

T O O L S – 3 R D S T E P - B A C K G R O U N D D ATA

❑ Background data

❑ Bedrock geology maps

❑ Surficial geology maps

❑ Soil survey maps

❑ Water well records

❑ Drift thickness maps

❑ Borehole records

Available from:

• Federal government agencies

• Provincial government agencies

• State government agencies

• University collections


66

T O O L S – 3 R D S T E P - B A C K G R O U N D D ATA

❑ Important consideration

❑ What is the scale of the background data

❑ Generally at

❑ 1:1,000,000

❑ 1:500,000

❑ 1:250,000

❑ 1:126,620

❑ 1:100,000

❑ 1:63,360

❑ 1:50,000

Small scale mapping intended for:

• Regional and subregional planning

• Mineral exploration

Government regulations generally

require mapping at 1:20,000 to

1:5,000 depending upon the nature

of the study

SO HOW DO WE GET

1:5,000 SCALE MAPPING

AND BETTER?


67


Terrain Analysis

Scoping

Model

Background DataMapping





68

T O O L S – 4 T H S T E P - M A P P I N G

❑ Mapping

❑ Generally completed using hardcopy aerial photographs and a

stereoscope (hopefully by an experienced terrain scientist)

Issues:

• Limited by scale of aerial photographs

• Most aerial photograph scales range from 1:15,000

to 1:60,000 with scales of 1:20,000 1:30,000 and

1:40,000 being most common

• 1:20,000 scale photos = 1:20,000 scale mapping

• Limited by stereoscope


69

T O O L S – 3 R D S T E P - M A P P I N G

❑ How do we overcome these limitations?

❑ New technologies

❑ Softcopy mapping

❑ LiDAR

❑ Drones

❑ Artificial Intelligence / Machine Learning (AI/ML)


70


❑ How do we overcome these limitations?

❑ Use of “softcopy” mapping tools

❑ Systems have been in use since 1996 (MicroStation-based)

❑ Combination of ArcGIS + Viewing software

❑ PurVIEW, Summit DAT/EM

Softcopy Mapping Station

• Get digital imagery from government

agencies

• Merge with DEM data (Provincial DEM

or LiDAR)

• Creates digital imagery that can be

seen in 3D on computer monitor


71


❑ What is softcopy?

❑ Suite of tools that allows mappers to view stereo digital stereo

imagery in 3D on a computer monitor with the aid of 3D glasses

❑ Advantages:

❑ Can zoom down from initial capture scales of 1:30,000 to scales as

large as 1:2,000 to 1:1,000 and larger

❑ Being able to zoom down into the imagery allows for better

identification, delineation and classification of key terrain features that

are not visible when viewing imagery at initial capture scales

❑ All work is completed in a digital environment


72


❑ Can use either:

❑ Aerial photographs

❑ Black & White

❑ Colour

❑ Black & White IR

❑ Colour IR

❑ Satellite imagery

❑ IKONOS

❑ Quick Bird

❑ GeoEye


73


• Area in southwest

Pennsylvania

• Mapping at 1:30,000

from 1:30,000 scale

aerial photographs

• Only 4 terrain

polygons, 3 valley

bottoms and the

larger upland ridged

terrain typical of the

Appalachian

Mountains


74


Mapping at 1:5,000

(from same 1:30,000

scale imagery)

38 terrain units identified


75


Mapping at 1:2,000 scale

(from original 1:30,000

scale photos

Landslides

Possible route to

avoid landslides


76


❑ Aerial photographs / satellite imagery

Advantages Disadvantages

• Available for anywhere in the

world

• Black & White, colour, IR

• Inferences from vegetation data

• Flow of water in system,

drainage

• Inexpensive

• Historical

• Not all airphotos or satellite

imagery is the same

- scale / resolution dependent

- 1:15,000, 1:30,000, 1:60,000

• No automated processes to

classify imagery


77


❑ LiDAR

❑ Light Detection and Ranging

❑ Remote sensing method that uses light in the form of a pulsed

laser to measure ranges to the earth surface

❑ Elevation data that provides 3D hillshade models


78



79


❑ LiDAR

Advantages Disadvantages

• Excellent 3D representation of the

earths surface

• Slope and aspect

• Phenomenal data on “form”

• Great for deep-seated rotational

landslides, debris flows, etc.

• Not all LiDAR is equal; resolution

dependent

• No information on soil moisture /

soil drainage

• Limited vegetation

• Costly

• Not always available


80


❑ Drones

❑ More detailed data captured

❑ Generally for ¼ sections or pipeline segments

❑ Inspections

❑ Survey

❑ Monitoring


81

T O O L S – 3 R D S T E P M A P P I N G

❑ Artificial Intelligence / Machine Learning (AI/ML)

❑ Predictive mapping


82


Terrain Analysis

Scoping

Model

Background Data

Mapping





83

T O O L S – 4 T H S T E P - F I E L D I N V E S T I G AT I O N S

❑ Field investigations

❑ Dual purpose

❑ Verify the mapping

❑ Collect detailed data on physical and chemical characteristics of soil

material

❑ Texture,

❑ Coarse fragment content,

❑ pH,

❑ Depth to bedrock,

❑ Depth to water table Stratified glaciofluvial deposits

Morainal materials


84

T E R R A I N M A P P I N G – B E N E F I T S T O O T H E R D I S C I P L I N E S

Terrain Mapping

Soils Mapping

Vegetation Mapping

Wildlife Habitat Mapping

Land Use Decision Making


85

T E R R A I N A N A LY S I S – W H AT H A P P E N S W H E N T H I N G S G O W R O N G

❑ What can happen with inadequate terrain analysis?

February 2017

Edmonton, Oct 26, 1999


86

T E R R A I N A N A LY S I S – W H AT H A P P E N S W H E N T H I N G S G O W R O N G

Land disturbance associated with the progressive expansion of a

major pipeline and power corridor, along with extensive timber

harvesting, triggered the reactivation of an ancient, 100 million

cubic meter deep-seated landslide in northern Alberta. The

landslide threatened six major transmission pipelines and caused a

loss of containment in one of the pipelines. The level of landslide

activity and associated pipeline damage was surprising given the

relatively subtle disturbances in relation to the massive scale of the

slide.

Given the very shallow 4.5 degree slope inclination and the lack

of any surface expression of distress over most of the slope

area, this case history underscores the importance of

considering regionally specific geological conditions within

pipeline geohazard evaluations.


87

Q U A L I F I C AT I O N S F O R T E R R A I N M A P P E R S

❑ Passion for earth sciences…..

❑ Earth science background……

❑ Physical geography

❑ Quaternary geology

❑ Soils

❑ Geotechnical engineering

❑ Attention to detail……

❑ Must be inquisitive……open minded….

https://www.google.ca/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=2ahUKEwiP2afktaXhAhVJiVQKHR7YDScQjRx6BAgBEAU&url=https://www.soils4teachers.org/career-tools/career-profiles/9346178&psig=AOvVaw2eWcIwsLqDoJKHW4mNSaEA&ust=1553882471701991


88

Q U A L I F I C AT I O N S F O R T E R R A I N M A P P E R S

❑ Must be able to look at aerial imagery in stereo for long

hours, day after day, weeks after weeks…….

❑ P.Ag., P.Geo., or P.Eng.

❑ Implies that they must be properly trained and have been

mentored properly and pass requirements for individual

organizations, including both technical and ethical standards


89

Thank You!

Questions?

Documents

WHY IS IT SO IMPORTANT? - in1touch€¦ · Terrain Analysis, Why is it so Important? 16 WHAT IS TERRAIN ANALYSIS – MINIMUM POLYGON SIZE Scale influences minimum polygon size Scale