TC Terrain Mapping Guidelines

8/10/2019 TC Terrain Mapping Guidelines

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TableofContents

1.0 INTRODUCTION .................................................................................................................................. 5

2. 0 SURFICIAL GEOLOGY MAPPING .................................................................................................... 6

2.1 Description of Surficial Geology Mapping ......................................................................................... 6

2.2 Example of Surficial Geology Mapping in Northern Canada ............................................................. 6

3.0 ENGINEERING TERRAIN ANALYSIS .............................................................................................. 7

3.1 General Description of Engineering Terrain Analysis and Mapping .................................................. 7

3.2 Preliminary Engineering Terrain Analysis and Mapping (Level 1D) ................................................. 7

3.3 Detailed Engineering Terrain Analysis and Mapping (Level 2D) ...................................................... 7

3.4 Example of Preliminary and Detailed Engineering Terrain Analysis (Level 1D and Level 2D) from

Northern Canada ....................................................................................................................................... 8

3.5 Example of Preliminary and Detailed Engineering Terrain Analysis (Level 1D and 2D) for Pipeline

Projects in Alberta and BC........................................................................................................................ 9

4.0 SELECTION ENGINEERING TERRAIN MAPPING SYSTEM FOR A PIPELINE PROJECT ...... 11

4.1 Existing Government Surficial Geology Mapping System ............................................................... 11

4.2 Consider the Terrain Issues Relevant to the Area of Study .............................................................. 11

4.3 Consider the Terrain Mapping Experience of the Government Reviewers of the Pipeline Project .. 11

5 0 ENGINEERING TERRAIN ANALYSIS AND ITS CONTRIBUTION TO DETERMINING KEY

ITEMS FOR PIPELINE PLANNING, CONSTRUCTION AND OPERATION ...................................... 12

5.1 Pipeline Right of Way Continuous Terrain Information for Engineering ........................................ 12

5.2 Pipeline Right of Way Ditch Properties ............................................................................................ 12

5.3 Level 1D and Level 2DTerrain Mapping Describes Land at Pipeline Infrastructure Sites .............. 12

5.4 Location of Geohazards .................................................................................................................... 13

5.5 Terrain Maps as Project Baseline ...................................................................................................... 13

6.0 IMPORTANT ELEMENTS TO BE CONSIDERED IN DETAILED ENGINEERING TERRAIN

ANALYSIS (LEVEL 2D) ........................................................................................................................... 14

6.1 Determine Air Photo, LIDAR and Mapping Scale ........................................................................... 14

6.2 Determine the Map Base ................................................................................................................... 14

6.3 Refine Level 1D Mapping During Detailed Engineering Terrain Analysis (Level 2D) Mapping .... 15

6 4 D ib L l 2D T i M i C ti 15


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7.5 Terrain Classes in Map Legend ........................................................................................................ 18

7.6 Textural Modifiers for Mapping ....................................................................................................... 19

7.7 Landform Terms ............................................................................................................................... 20

7.8 Geomorphological Process Terms .................................................................................................... 20

7.9 Map On-Site Terrain Symbols .......................................................................................................... 21

7.10 Mapping Composite Terrain Units and Stratigraphic Terrain Units ............................................... 21

7.11 Typical Terrain Unit Titles for Terrain Stability Maps ................................................................... 22

7.12 Map Presentation ............................................................................................................................ 23

8.0 TERRAIN DATABASE FOR PRELIMINARY (LEVEL 1D) AND DETAILED (LEVEL 2D)

TERRAIN MAPPING ................................................................................................................................ 24

8.1 Pipeline Project Mapping (Level 1D and 2D) Database ................................................................... 24

8.2 BC Government Mapping Database for Submitting Mapping to Government ................................ 24

9.0 QUALITY CHECKING AND MAPPER QUALIFICATIONS .......................................................... 25

9.1 Quality Checking of Desktop PreliminaryTerrain Mapping (Level 1D) and Detailed Terrain

Mapping (Level 2D) ............................................................................................................................... 25

9.2 Terrain Mapper Qualifications In Canada Outside of BC................................................................. 25

9.3 Terrain Mapper Qualifications in BC ............................................................................................... 25

10.0 REFERENCES ................................................................................................................................... 27

APPENDIX A: LEGEND - TERRAIN CLASSIFICATION ALBERTA PIPELINE CORRIDOR (GSC

Terrain Classification System) .................................................................................................................... 28

APPENDIX B: PHYSIOGRAPHIC SUBDIVISION - ROCKY MOUNTAINS LEGEND (BC Terrain

Classification System) ................................................................................................................................ 31


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2. 0 SURFICIAL GEOLOGY MAPPING

2.1 Description of Surficial Geology Mapping

Surficial geology mapping forms the background for preliminary engineering terrain analysis (Level 1D).

It consists of preparing maps, cross sections, reports and tables of data that depict the extent, geometry

and properties of surficial materials. It also provides interpretative information concerning the geological

history and origin of the surficial materials. In Canada, this type of mapping has been carried out since

1842 by the Geological Survey of Canada (GSC) and more recently by provincial and territorial

geological and soil surveys. Most of Canada has been glaciated, so most near surface deposits have been

laid down since the last glaciation that began about 36,000 years ago and ended 10,000 years ago. These

deposits include glacial deposits (moraine, glaciofluvial, glaciolacustrine, and glaciomarine) and

nonglacial deposits (organic, alluvial, colluvial, lacustrine, marine and volcanic).

Mapping surficial geology on stereoscopic air photos made it possible to quickly trace map unit contacts

and to locate features without physically inspecting all map units and features them on the ground.

Reliance on air photos for identifying and tracing maps units reinforced the role of surface landforms in

defining map units (Fulton, 1993).

2.2 Example of Surficial Geology Mapping in Northern Canada

Surficial geology mapping in the Mackenzie Valley, Northwest Territories is an example of surficial

geology mapping carried out by the GSC from the 1960s to the present. Maps have been produced at

1:250 000 and 1:125,000 scale with summary maps at smaller scales. The mapping is based on

government stereo air photos produced at various scales ranging from 1:30 000 to 1:50 000. The surficial

geology maps have been field checked to confirm air photo interpretation.

Map legends for Mackenzie Valley map-sheets vary slightly between areas depending on slight deviations

in mapping conventions. The maps units are based on the stereo interpretation of landforms and their

characteristics including geological origin, texture, thickness, topography, drainage pattern and ground

ice. The GSC surficial geology mapping system allows the user to group terrain units into major terrain

classes of landforms with similar geological origin and surficial materials. Comments on the relationship

of terrain to engineering issues are also included in matrix style legends that often appear with the

surficial geology maps.


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3.0 ENGINEERING TERRAIN ANALYSIS

3.1 General Description of Engineering Terrain Analysis and Mapping

Engineering terrain analysis and mapping is related closely to surficial geology mapping discussed

previously. Engineering terrain analysis maps the distribution of certain types of surficial materials and

rock in specific landforms. It also identifies the geological processes that affect the terrain units and

assesses and rates the ability of various landforms and their materials to support different types of

activities during engineering construction and development.

3.2 Preliminary Engineering Terrain Analysis and Mapping (Level 1D)

Preliminary engineering terrain analysis and mapping (Level 1D) is developed from existing government

geological mapping, augmented by air photo interpretation where government mapping is not available.

Preparing the Level 1D map is used when analyzing the location of the pipeline corridor(s). This map also

highlights terrain issues along proposed pipeline corridor(s) before Level 2 D terrain mapping is carried

out on a chosen corridor. The Level 1D mapping provides preliminary information for construction cost

estimates before the more detailed Level 2D Engineering Terrain Analysis is completed.

Level 1D terrain analysis and mapping is carried out by transferring terrain unit boundaries from existingfederal or provincial government surficial geology maps to a map or maps with the pipeline corridor

superimposed. This information is entered into the project geomatics database. In areas where preliminary

surficialgeology mapping is missing government stereo photos are would be interpreted to fill in the

terrain mapping gaps. A list of typical terrain units along the pipeline route would be compiled by

kilometer post. Geological and engineering characteristics of terrain units along the right of way would be

collected in a matrix style legend by physiographic region. Terrain units would be grouped by geological

origin so that queries of major terrain groups can be carried out during preliminary engineering

assessment.

3.3 Detailed Engineering Terrain Analysis and Mapping (Level 2D)

The Level 2 D terrain analysis and mapping is carried out at a larger more detailed mapping scale (e.g.,

1:20 000 scale) when stereoscopic air photos have been flown along the selected pipeline corridor. The

Level 2D mapping both subdivides large polygons identified in the Level 1D mapping and incorporates

other project data (e.g., field observations from route reconnaissance and terrain mapping investigations,

boreholes logs or geophysics data) in the terrain unit descriptions. The first step in Level 2D engineering

terrain analysis is to map and describe the landforms and their characteristics on the air photos. Each

landform has a common geological origin, geomorphic expression, thickness and texture (grain size).

Landforms are then grouped on the basis of geological origin into major terrain groups.


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If the proposed pipeline project is located in more than one physiographic region, legends for each region

will be prepared because a terrain unit with a distinct geological origin can have different textural and

other properties in different physiographic regions. For example, the same map unit in the northern part ofthe Interior Plains of Canada may differ in material type and/or ground ice content from the same terrain

unit found in the southern Interior Plains.

A detailed engineering terrain mapping legend is usually shown in matrix style so that both geological

and geotechnical properties of terrain units can be viewed easily and queried in engineering analysis.

All information from the engineering terrain analysis (Level 2D) is entered into the project geomatics

database.

3.4 Example of Preliminary and Detailed Engineering Terrain Analysis (Level 1D and Level 2D)

from Northern Canada

Since the late 1970s engineering terrain analysis based on the GSC approach to landform and materials

mapping has been applied to northern pipelines proposed for the Mackenzie Valley (Polar Gas, 1975;

Beaufort Delta Oil pipeline, 1976; Foothills Pipelines, 1979 to 1982 both Yukon and B.C. Sections); Ikhil

Pipeline, 1996 and Mackenzie Gas Pipeline, 2003 to 2007).

The most recent engineering terrain mapping for the Mackenzie Gas Project followed the two stage

approach to engineering terrain analysis. The first stage of preliminary engineering terrain analysis (Level

1D) was carried out early in the pipeline project. It provided a generalized quick assessment of terrain

conditions along the pipeline corridor. It provided a conceptual assessment for the preliminary cost

estimate and determined areas where terrain conditions might require different routing. It was carried out

by transferring terrain unit boundaries from existing GSC surficial and bedrock geology maps to a base

map that followed the pipeline corridor. In areas where preliminary surficial geology mapping wasmissing, 1:50,000 and 1:60 000 scale government photos were interpreted to fill in the terrain mapping

gaps. A list of typical terrain units along the route was compiled by kilometer post and engineering

considerations related to the terrain units along the right of way were collected in a matrix style legend.

Legends were prepared for each of the physiographic regions. Terrain units were grouped by geological

origin so that queries of major terrain groups or other right of way considerations could be carried out

during engineering assessment.

The second level terrain analysis known as Level 2D terrain mapping was carried out on the Mackenzie

Gas Project right of way from 2004 to 2006 after the route was finalized. It was based on larger scale 1:20

000 stereo air photos that were flown for the pipeline project. In this more detailed mapping large

polygons identified in the 1D mapping were subdivided into more categories based on the mapping scale

and the incorporation of borehole data and field investigation information in terrain unit descriptions. For

example, the thickness of organic terrain units could be distinguished more easily using the more detailed


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Terrain units were grouped by geological origin so that queries of major terrain groups or other right of

way considerations such as geohazards could be carried out during engineering assessment. It should be

noted that the more detailed (level 2D) engineering terrain analysis should systematically record thicknessinformation for stratigraphic units. For example, a terrain unit indicated as a veneer is 3 m

thick.

3.5 Example of Preliminary and Detailed Engineering Terrain Analysis (Level 1D and 2D) for

Pipeline Projects in Alberta and BC

Terrain analysis has also been carried along pipeline corridors in Alberta and BC. The methodology was

the same as that used in the two stage Mackenzie Valley pipeline corridor mapping where both Level 1D

and 2D engineering terrain analysis was carried out. GSC, Alberta Geological Survey (AGS) or British

Columbia government surficial geology mapping was used for preliminary Level 1D work.

Level 2D mapping has been carried out at several locations in northern and central Alberta by consultants

to TransCanada. Project air photos at 1:20 000 scale and LIDAR were used for the detailed Level 2D

mapping. Boreholes and/or geophysics, when available, added information to describe terrain polygonsand stratigraphic conditions in the detailed terrain analysis. This Level 2D terrain analysis work in Alberta

usually has terrain unit titles similar to those used in northern Canada mapping because the GSC and AGS

regional surficial geology mapping systems used in the Level 1D mapping are fairly similar( for legend

see Appendix A).

It should be noted that the BC terrain classification and stability mapping system developed for the forest

industry in BC differs to some extent from GSC and AGS surficial geology mapping. This system was

developed originally to aid the forestry industry for mapping terrain and terrain stability in mountainous

areas. Terrain stability ratings based on slope class and material type were applied to individual polygons

and related to the development of cut blocks and roads in these polygons. The BC system has codified

and published explanations of every aspect of terrain mapping. This detail was required because the

terrain stability mapping system was written into legislation governing forest practices and has methods

and standards that can be included as legally binding contracts with terrain mappers (Ryder and Howes,

1984; Howes and Kenk, 1988 and 1997).

The BC mapping system emphasizes terrain stability ratings in mountainous terrain and does not have

certain details regarding terrain unit thickness and stratigraphy that applies to pipeline planning andconstruction. It does not always present a matrix style legend that can be applied to engineering queries.

Recently the BC system has been applied to terrain mapping for some Alberta pipeline projects.

In BC the BC terrain classification and terrain stability mapping system has been used (with some

modification to terrain unit thickness data and legend structure and presentation) for engineering terrain


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and bioterrain maps) have complicated descriptions of percentages of types of material of different

geological origin in each polygon. This does not help the user in pipeline project planning determine the

primary character of each mapped polygon. Also terrain unit thickness descriptions in the B.C. terrainmapping system are not as systematic as they should be for buried pipelines. In pipeline work the

stratigraphy and thickness of terrain units is important to the characterization of the ditch. Therefore,

Level 2D maps should consider that terrain analysis and mapping for pipeline projects will need some

additional information not always evident in the B.C. mapping system.


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4.0 SELECTION ENGINEERING TERRAIN MAPPING SYSTEM FOR A PIPELINE

PROJECT

4.1 Existing Government Surficial Geology Mapping System

The terrain mapping system chosen for the Level 1D and Level 2D work should have similar terminology

to the existing federal or provincial government bedrock and surficial geology maps available for the area

in which the pipeline is located.

If ecosystem or bioterrain maps are the only available maps with geological descriptions they can also

contribute to preparing the Level 1D terrain maps and engineering takeoffs. However, these maps should

be assessed to make sure that the map units have information on landforms, soil material, and topography(B.C. Resources Inventory Committee, 1995).

4.2 Consider the Terrain Issues Relevant to the Area of Study

The terrain mapping system should assess the surficial and bedrock geology in the area that is crossed by

the pipeline. Any terrain mapping system chosen should consider mapping landforms and describing soil

and bedrock in the landforms including textures of soil materials, bedrock type, thickness of terrain units

and slope class information from DEM and/or LIDAR. Other terrain unit properties, geologic processes

and geohazards should also be shown.

In mountainous terrain slope class and terrain stability assessment should be included in the terrain

mapping system.

In permafrost terrain soil information should be assessed relative to frozen and unfrozen ground. Organic

thickness is critical and should be assessed carefully in northern areas with permafrost and non-

permafrost terrain.

4.3 Consider the Terrain Mapping Experience of the Government Reviewers of the Pipeline Project

If surficial geology maps are available along the pipeline corridor, government reviewers may be familiar

with the mapping system shown on these maps. Introduction of a new mapping system for the Level 1D

and 2D engineering terrain analysis that was developed in an area with different geology, soils and

topography may confuse reviewers who may not be familiar with a mapping system taken from another

area or mapping system.

Always consider the reason that the government geological mapping was produced (e.g., regional bedrockor surficial geology mapping or forestry or bioterrain work) and adapt what is relevant to Level 1 and 2 D

pipeline engineering terrain analysis and mapping.


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5 0 ENGINEERING TERRAIN ANALYSIS AND ITS CONTRIBUTION TO

DETERMINING KEY ITEMS FOR PIPELINE PLANNING, CONSTRUCTION AND

OPERATION5.1 Pipeline Right of Way Continuous Terrain Information for Engineering

Engineering Terrain Analysis (Level 1D and Level 2D) are used to provide a continuous record of terrain

units and their landform characteristics along a pipeline corridor The mapped terrain units and their

properties, presented in a matrix style legend, are queried using algorithms and these queries are used to

delineate issues related to pipeline planning, design and construction. This analysis also adds to

information needed to compile costs for construction and mitigation measures.

The properties of terrain units include information on the soil or bedrock type in each terrain unit, the

landform characteristics of the terrain unit including thickness of surficial soil material, topography of the

landform, slope classification, surface drainage information, active geological processes and geohazards

associated with each terrain unit. Comments about terrain units related to their natural state and their

reaction to disturbance during construction are also recorded in the matrix style legend and can also be

queried.

Engineering right of way issues including thaw settlement, erodability, roughness of the land surface,boulder content in terrain units, buoyancy and soil pipe interaction depend on the continuous take off of

pipeline terrain units and their characteristics. The terrain mapping may be used to locate boreholes along

the pipeline right of way. These boreholes may be necessary to confirm soil properties and stratigraphy.

5.2 Pipeline Right of Way Ditch Properties

Level 1D and Level 2D terrain unit information can also provide information that is important indescribing properties of the right of way ditch including:

the type and properties of overburden

overburden thickness (depth to bedrock)

bedrock type

Knowledge of these items taken from the Level 1D and Level 2D engineering terrain analysis and

mapping are used to determine ditchability and to calculate buoyancy, ditch settlement and/or frost heave.Bedding and padding requirements are also calculated from the right of way ditch properties.

5.3 Level 1D and Level 2DTerrain Mapping Describes Land at Pipeline Infrastructure Sites


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5.4 Location of Geohazards

The Level 1D and Level 2D engineering terrain analysis and mapping describes geohazards in varioustypes of terrain. The terrain mapping may show the geohazard as a terrain polygon or a map symbol. The

identified geohazards can affect pipeline routing, construction and operation (Rizkalla et al., 2008).

Geohazards may include:

landslides/mass movements (deep seated landslides, soil creek, thawed layer detachment slides,

rockfalls, snow or rock avalanches, debris flows)

tectonic events (recent faulting, earthquakes, liquefaction)

geochemical events (karst in gypsum or limestone, saline soil and groundwater, ML/ARD in

bedrock) hydrologic events (river channel migration, buoyancy or pipe uplift, rapid lake drainage, coastal

inundation and flooding)

volcanic events (ash falls, lahars, pyroclastic flows)

desert events (dune migration and flash flooding in wadis)

thermal events related to the freezing of unfrozen ground (frost heave of the pipe or ditch, frost

bulb development cross country and at river crossings, frost blisters and ice-wedge cracking)

thermal events related to thawing of permafrost (thaw settlement of pipe, ditch and right of way),

thawing of frost bulb on slopes, and thawing of massive ice (thermokarsting)

5.5 Terrain Maps as Project Baseline

Terrain maps provide baseline information that can be used on project alignment sheets or in a

geotechnical atlas that may accompany the project application. The terrain map can be upgraded and

revised during the life of the pipeline project as subsurface information is collected during various phases

of the project. Upgraded terrain map information can be used for later phase cost estimates and for

preparing for post construction operation of the pipeline.


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6.0 IMPORTANT ELEMENTS TO BE CONSIDERED IN DETAILED ENGINEERING

TERRAIN ANALYSIS (LEVEL 2D)

6.1 Determine Air Photo, LIDAR and Mapping Scale

The scale for air photo, LIDAR and mapping scale should be determined early in the project. The air

photo, LIDAR and terrain map scales should be chosen to meet regulatory requirements and to show

enough detail for the Level 2D terrain analysis. The scale choice should not be so detailed that terrain

mappers cannot meet the schedule required for office and field investigations. The air photos and terrain

mapping should be close to or at the same scale. Overlap on stereoscopic air photos should be at 60%,

similar to government of Canada stereo air photos.The map polygon size will be determined by the

mapping scale and also by the characteristics of terrain in different topographic settings. There will be

larger polygons in flat to rolling terrain than in mountainous terrain.

Level 2D mapping should cover the project footprint. The project footprint should be a minimum of 2 km

wide and centered on the pipeline This footprint should include the right of way and should be wide

enough to encompass geohazard areas (e.g. to top of ridges in mountainous terrain), wider areas at river

crossings to cover possible crossing relocations, and include potential off right of way locations (e.g.

camps or important access roads).

Engineering terrain analysis and mapping at a scale of 1:20 000 has been used for many long distance

pipeline projects in Canada. This mapping scale provides enough detail to map terrain for continuous

engineering take off work and can be completed in a reasonable time period for project use.

If the mapping is being done in BC., Level D terrain stability mapping should be part of the terrain

mapping output on the 1:20 000 scale air photos. In Level D terrain stability mapping, the Terrain Survey

Intensity Level (TSIL) requires that 1 to 20% of the polygons would be ground checked by vehicle and

flying with limited ground observations. Other detailed mapping at an even larger scale (e.g. 1:7 500)

may be carried out at a later date in unstable areas where necessary (Ryder, 2002).

The continuous terrain map of the pipeline corridor is the baseline information for engineering queries on

the right of way and for terrain descriptions off right of way.

6.2 Determine the Map Base

Terrain mapping should be compiled on an air photo map base prepared from the project air photos or ontopographic maps at a scale of 1:20 000 (e.g., B.C. Government topographic TRIM maps). It should be

noted that project air photos and topographic map bases do not always match, particularly where air

photos are more recent than the maps. If this is the case, it is probably better to use the air photos to make

the base map. It should be noted that pipeline alignment sheets and geotechnical atlas sheets are mostly

developed from project air photos. If air photos are used, a geomatic determination of slopes using


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6.3 Refine Level 1D Mapping During Detailed Engineering Terrain Analysis (Level 2D) Mapping

It is important to use the Level 1D terrain mapping in early stages of project work and to upgrade themapping during Level 2Ds mapping activities. The Level 2D mapping will show more detail because of

the larger scale of the project air photos. Larger polygons from the Level 1D mapping will be subdivided

and more terrain features will be mapped on the larger scale air photos. If the Level 1D mapping was

done for other purposes than surficial geology mapping (e.g. bioterrain mapping or ecosystem mapping)

terrain and landform information will be refined in the Level 2D mapping.

6.4 Describe Level 2D Terrain Mapping Conventions

Terrain units should be compiled into genetic terrain groups. These groups are then organized from the

geologically youngest to oldest in the terrain legend that is prepared for each physiographic region.. The

genetic categories should be relevant to the geology of the area being mapped. For example, the major

terrain groups in glaciated and non-glaciated terrain in Canada are from youngest to oldest: Organic,

Colluvial, Lacustrine, Marine, Eolian, Fluvial (Alluvial), Glaciolacustrine, Glaciofluvial, Moraine, and

Bedrock. The terrain units (including information on their properties) in each of the genetic categories

may vary between physiographic regions. For this reason, a matrix style legend should be prepared foreach physiographic region so that specific categories of information can be compiled and queried.

The individual terrain units fall within the major terrain groups. Each terrain unit is listed in the legend by

terrain group. Thickness, textural information, topography, soil drainage, slope class and any mass

wasting features identified in the polygon are important for each terrain unit described in the matrix style

legend. In some cases it may be necessary to map more than one landform in a polygon. However, this

should not be done in every map polygon because it is important to know the primary landform and its

properties for pipeline engineering analysis. If two or more titles are used in a polygon percentagebreakdowns should be shown in the polygon title. Landforms and landform morphology terms should be

explained in the map legend. Each terrain polygon should have a unique number for use in preparing the

final map product.

The textural modifiers may vary in different mapping systems. Their letter symbols usually precede the

capital landform symbol. The order of textural modifiers used should be in agreement with the mapping

system being used and the order of the letter symbols should be described in the legend. The order of the

textural symbols differs between the B.C. and GSC and AGS mapping systems. The legend should define

the order of importance of the textural properties.

Geomorphological process terms following a dash (-) after the terrain unit symbol. These process terms

and any drainage terms used in the map polygons should be described in the map legend. Terrain features

that are shown with symbols on the map should also be identified in the legend. Any slope class

breakdowns and ranges of slopes in percent and degrees should also be listed in the map legend If a


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7.0 B.C. TERRAIN CLASSIFICATION AND MAPPING AND TERRAIN STABILITY

MAPPING APPLIED TO DETAILED ENGINEERING TERRAIN ANALYSIS (LEVEL

2D) FOR PROPOSED BC PIPELINESThis section of the report describes how to apply the BC Terrain Classification and Mapping and Terrain

Stability Mapping Systems to proposed pipeline corridors in BC. The details of these mapping systems

are described in BC government publications listed in References (Forest Practices Code of BC, 1995 and

1999; Howes and Kenk, 1988 and 1997; Resource Inventory Committee 1996a and 1996b; Ryder and

Howes, 1984 and Ryder and Associates, 2002). The BC terrain classification and mapping system and

terrain stability mapping system were developed for the forestry industry and differ in some respects

from the terrain mapping systems used in other parts of northern and western Canada. Certain types of

information relevant to pipelines need to be added when applying this type of mapping to pipelines.

7.1 Determine Map Boundary Lines.

In B.C. terrain mapping and terrain stability mapping, three types of boundary lines are used (page 30 of

Ryder 2002 publication). These line types were used to represent well-defined (solid line), approximate

(dashed line) and assumed (dotted line) boundaries. In order to carry out digital mapping and map

takeoffs and database enquiries for pipeline engineering quantities solid lines should be used for all

boundaries in pipeline terrain mapping using the BC terrain mapping system.

7.2 Designate the Terrain Unit

Terrain maps subdivide the land surface viewed on stereo air photos into a series of polygons or terrain

map units. The map unit is the main descriptive subdivision of the map. It attempts to subdivide themapped area into the purest units consistent with the mapping scale. Each terrain map unit is identified

primarily on the basis of its geological origin, landform and texture. The geologic origin is represented by

the upper case letter in the middle of the terrain unit symbol. The texture of the material in the terrain unit

is represented by the lower case letters before the upper case letter and the surface expression is

represented by the letters that follow the upper case geological origin symbol. For example, sg FGt is a

sand and gravel (sg) glaciofluvial terrace (FGt) according to the terminology of the B.C. terrain mapping

system. Geological processes (active and past) that affect terrain units are also recorded during the

mapping process. For example the sgFGt mentioned above may have been affected by a geologicalprocess. A symbol sgFGt-H indicates a glaciofluvial terrace that is kettled (-H) was affected by a past

geological process that is currently inactive. Geological features that are too small to map as polygons are

noted as symbols during the mapping process. Other geological characteristics (topography, slope class,

drainage, and permafrost) are also described during the mapping process and can be shown in the terrain

unit title and/or in the matrix style terrain legend


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properties (e.g. a boulder moraine plain from one type of glaciation btMp(1) versus moraine plain with a

gravel sized coarse fraction gMp(2) from a second type of glaciation. Even though till (t) also recorded as

a combination of textures (dscz) is assumed and not recorded in the title of M terrain units in B.C. terrainstability mapping, pipeline work always needs to distinguish (t) or (dscz) as a texture preceding the M in

the terrain unit title. This texture is useful in engineering queries for ditchability and in planning for

subsurface field assessments.. The matrix legend that describes the M terrain unit may also show that

different types of till are found in different physiographic regions.

7.3 Prepare the Map Legend

A map legend classifies and describes terrain units that have been shown on the map. The objective of the

legend is to provide information on the characteristics of the terrain units in an organized way. A matrix

style legend should be used to show this information and to simplify database queries on terrain unit

engineering properties. The compliment of terrain units in the matrix terrain legend may differ between

physiographic regions and subdivisions along the pipeline corridor (Holland, 1976). For example, till in

the Rocky Mountains may differ texturally from till in the Coast Mountains. Separate legends should be

made for each physiographic division. Elements that should be included in each physiographic division

matrix style legend are as follows:

1. Primary Legend Elements

The map unit symbol including genetic, geomorphologic textural information (e.g. gFf)

The landform represented by the terrain unit including a written description (e.g. Fluvial Fan)

Landform characteristics [morphology, topography, texture, rock type (if known), permafrostand ice content, drainage, groundwater (if known), thickness of terrain unit (relative to

pipeline thickness categories), average slope class (Howes and Kenk, 1997, p.27), active

geological processes, permafrost and ice content information (if present) comments on terrain

units relative to construction, and terrain stability rating]

Note: The texture of soil material in the terrain unit (order of texture terms has most

important texture next to terrain unit title (e.g., btMp)

2. Separate Legend Information Including Tables and Symbols

Table showing genetic categories and Terrain Class Letter

Table describing textural terms for surficial materials


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List of symbols showing features that are too small to map as polygons (e.g. gullies,

escarpments and geohazard features)

Symbols showing the locations for field investigations (e.g. surface observation sites,borehole locations and geophysics lines)

Description and example of qualifying legend descriptors

Table explaining stability classes for terrain units (Forest Practices Code, 1995)

An example of a typical BC terrain legend is given in Appendix B

7.5 Terrain Classes in Map Legend

Individual terrain units are grouped into terrain classes (youngest to oldest) based on their genetic origin.

Grouping terrain units into terrain classes helps in compiling summary properties for engineering

database queries. The summary terrain class labels (letters) in the B.C. Terrain Classification are shown in

Table 1. If colors are used in map presentation, it is proposed that they should follow the standard colors

used in federal mapping. Water should be shown in a different blue than marine and glaciomarine.Geomatics database work and computer mapping have difficulties in registering superscript titles (e.g.FG,

LG) so column two in Table 1 shows an alternate scripting that can be used in database and mapping

work.

TABLE 1:GENETIC CATEGORYTERRAIN CLASS B.C.TERRAIN MAPPING SYSTEMTerrain Class Label

(Letter)

Terrain Class (Label)

Letter for Database &Geomatics Work

Class Name Color on Map****

A Anthropogenic -

O Organic Grey

I Ice -White

F Fluvial Yellow

C Colluvial Brown

E Eolian Yellow Grey

L, Lacustrine Light Purple

W Marine Light BlueLG LG Glaciolacustrine Purple

WG WG Glaciomarine Blue

FG FG Glaciofluvial Orange

M Moraine(Till) Green


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7.6 Textural Modifiers for Mapping

Textural modifiers are symbolized on terrain maps as small letters before the letter signifying the geneticclass. These are attached to terrain unit titles and confirmed by field investigations (field mapping and

boreholes). If no field work is carried out in the polygon, the texture is only an estimate from the

knowledge base of the mapper. However, these textures are important to estimate during the desktop

mapping exercise because field confirmation often occurs sometime after the preliminary terrain mapping

is completed and the 1D terrain take offs are carried out. The textural titles can be changed as a result of

field investigations.. Common textural modifiers shown as small letters before the letter signifying the

genetic class are shown in Table 2.

There are conventions for indicating textural terms when more than one texture is shown in a terrain unit

designator (p. 7 & 8, Howes and Kenk, 1997). Usually not more than three textural terms should be used

and they are listed in reverse order of importance so that the terrain unit designator may be easily

verbalized. For example b,gFt indicates that the common texture is gravel (g) but the gravel has some

boulders (b). Bedrock terms, like terrain textures, are shown before the genetic term in the terrain unit

title. For example, a limestone polygon (ls) could be mapped as lsRs where limestone on steep slopes is

involved. The order of rock types is similar to the order of soil textures with the most common rock type

next to the R symbol.

TABLE 2:TEXTURAL MODIFIERS (FROM B.C.TERRAIN MAPPING SYSTEM;HOWES AND KENK,1997)

Letter Texture Brief Description

a * Blocks Angular Particles > 256 mm in size

b * Boulders Rounded Particles > 256 mm in size

k Cobbles Rounded particles between 64 and 256 mm in size

p Pebbles Rounded particles between 2 and 64 mm in sizes * Sand Particles between .0625 and 2 mm in size

z* Silt Particles between 2m and .0625mm in size

c* Clay Particles < 2m in size

d Mixed Fragments A mixture of rounded and angular fragments greater than 2 mm in size

x Angular Fragments A mixture of angular fragments greater than 2 mm ins size; (i.e. mixture of blocksand rubble)

g * Gravel A mixture of two or more size ranges of rounded particles greater than 2 mm in

size (e.g. a mixture of boulders, cobbles and pebbles); may have interstitial sandr * Rubble Angular particles between 2 and 256 mm; may include interstitial sand. Usually

no fine material

m Mud A mixture of silt and clay; may also contain a minor fraction of fine sand

y Shells A sediment consisting dominantly of shells and/or shell fragments

e Fibric - Organic Least decomposedorganics- Well preserved fibre (40%or more) identifiedas


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7.7 Landform Terms

Landform morphology (also known as surface expression) terms are indicated after the genetic terrain

class letters in the terrain unit designator. The Terrain Classification System for British Columbia p. 26

gives a list of the key to landform terms that are summarized in Table 3 below (Howes and Kenk, 1997).

TABLE 3: LANDFORM MORPHOLOGY TERMS IN B.C.TERRAIN CLASSIFICATION SYSTEMLandform Morphology or SurfaceExpression Name

Letter Symbol in Terrain Unit Designator

moderate slope (apron) a

blanket b

cone(s) cdepression(s) d

fan(s) f

hummock(s) h

gentle slope j

Moderately steep slope k

rolling m

plain p

ridge(s) r

steep slope sterrace(s) t

undulating u

veneer v

mantle of variable thickness w (Dont use for Pipeline Terrain Work)

thin veneer X (Dont use for Pipeline Terrain Work)

The B.C. Terrain Classification System publication (Howes and Kenk, 1997, p. 27) describes the method

of selecting surface expression terms. It should be noted that the thickness determination of a blanket anda veneer should be modified to assist pipeline engineering take-offs. Engineering terrain analysis for

pipelines is cognizant of the pipeline location within the ditch. With this requirement considered, the

veneer would include veneer and thin veneer and would be 3

m thick.

7.8 Geomorphological Process Terms

Geomorphological process terms follow the landform or surface expression term in the terrain unit

designator. For example zLGt-V is a silty glaciolacustrine terrace that is gullied by active

geomorphological processes. The B.C. Terrain Classification System has a description and list of the

geomorphological process terms in Chapter 4 Table 4 below is compiled from that publication (Howes


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TABLE 4:GEOMORPHOLOGICAL PROCESS TERMS FOR B.C.TERRAIN CLASSIFICATIONSYSTEM

Group Process Name Map Symbol Assumed Status of Process

Erosional Processes DeflationKarstPipingGullyingWashing

DKPVW

ActiveActiveActiveActiveActive

Fluvial Processes Braiding ChannelIrregular Channel (sinuous)

Anastomosing ChannelMeandering Channel

BIJM

ActiveActiveActiveActive

Mass MovementProcesses

Snow AvalanchesSlow Mass MovementsRapid Mass Movements

AFR

ActiveActiveActive

Periglacial Processes CryoturbationNivationSolifluctionPeriglacial Processes (General)Permafrost Processes

CNSZX

ActiveActiveActiveActiveActive

Deglacial Processes Channelled

Kettled

C

H

Inactive

InactiveHydrologic Processes Inundated

Surface SeepageUL

ActiveActive

Geomorphological SubClass Terms are listed in Chapter 7 of the B.C. Terrain Classification System

Publication (Howes and Kenk, pages 66 to 73, 1997) and will not be repeated here. These subclasses

relate to Mass Movement Processes, Fluvial Processes, Permafrost Processes and Bedrock Subclasses.

These terms should be used in polygon titles where relevant. Tables describing the terms used should

show as part of the terrain map legend. It appears that the most used subclass terms in the terrain stability

mapping process will come from Table 6.1 Subclasses for Mass Movement. Bedrock Subclasses should

conform whenever possible to the rock types in either column 2 or 3 of Tables 6.4 to 6.6 (Howes and

Kenk, p. 71 to 72, 1997). Major bedrock types can be determined from the existing GSC and B.C.

government bedrock maps. The rock types in column 3 are the most detailed and used if possible. Mixing

of the rock types from columns 2 and 3 should be avoided.

7.9 Map On-Site Terrain Symbols

Terrain symbols are graphic representations used to describe landforms, features or processes. These

symbols represent features that are too small to map as polygons, indicate a location in a landform for a

feature or process, or indicate a landform or feature that cant be shown by a terrain unit designator. A list


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polygon. Composite terrain units have been shown in various ways by delimiters (Howes and Kenk, page

63, 1997) or deciles (Howes and Kenk, page 64 and 90, 1997).

For clarity in engineering take offs, deciles should be used to describe composite units (e.g., 6tMv4Cv or6tMv4Cv in database script). It should be noted that it is difficult to make engineering queries if too many

composite polygons are outlined during the mapping process. Distinct single unit polygons are preferred

whenever possible.

Stratigraphic terrain units are shown when one type of material overlies another type of material. This

type of unit is particularly important for pipeline work. Materials are shown in stratigraphic order

separated by a line. For example,

(also shown as sLv/gFGp or sLv\gFGpfor mapping and database

work) represents less than 1 m of lacustrine sand overlying gravelly glaciofluvial plain deposits that aregreater than 3 metres thick.

Before accepting a mapping convention for a composite or stratigraphic terrain unit, the terrain mapping

database must be set up and structured to accommodate composite and stratigraphic terrain units so that

deconstructing the various symbol elements into component parts for each terrain unit will permit

engineering queries to be conducted. If the title is more complicated it will need to have other title

elements also deconstructed in the original terrain mapping database (e.g. geomorphological process

terms and composite terrain unit titles). An example of the original terrain database structure should be

supplied early in the mapping process along with the preliminary map examples to see if it can be used

for engineering queries.

7.11 Typical Terrain Unit Titles for Terrain Stability Maps

The terrain unit title shown on a terrain stability map should have the following information:

polygon number

terrain unit title including grain size preceding the terrain unit

major slope class in the polygon in % and degrees (Classes 1 to 5)(according to Howes and Kenk,

p.27, 1997. These classes are as follows:

Class % Degrees

1 0 5 0 3

2 6 -26 4 15

3 27 49 16 26

4 50 70 27 35


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units, slope classes and stability consideration in the five stability classes for each of the

physiographic subdivisions.

For example, the title on a polygon for a terrain stability map might be as follows:

Example Symbol: 105 ..Polygon Number

tMb (Slope Class 2; tMb is Terrain Symbol)

2 lsR lsR

w Drainage

II Stability Class (Stable)

7.12 Map Presentation

Terrain stability mapping will be shown on a series of 1:20 000 scale base maps along the pipeline

corridor with a relevant physiographic subdivision detailed legend attached to maps in each physiographic

subdivision. Only one terrain stability map, not a series of maps, will be prepared for any specific area

along the pipeline corridor.

Detailed legends will be prepared for each of the major physiographic subdivisions as described in

Sections 7.3 to 7.8 of this report. The legend describing the terrain units and terrain classes will be matrix

style (Section 2.3 and Appendix B). The rest of the legend will consist of attached tables describing

terrain classes, textural terms, landform morphology terms, geomorphological process terms, mass

movement processes, qualifying descriptors, and a table describing slope stability interpretations. A list of

symbols will be part of the legend as will be a description of the slope classes in percent and degrees (see

Section 7.11 of this report).


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8.0 TERRAIN DATABASE FOR PRELIMINARY (LEVEL 1D) AND DETAILED

(LEVEL 2D) TERRAIN MAPPING

8.1 Pipeline Project Mapping (Level 1D and 2D) Database

The terrain mapping database structure should be set up to capture mapping information in column format

and use algorithms to construct terrain mapping codes for use on maps. It must be able to construct and

deconstruct symbology and will need to be shared with geomatics specialists assigned to specific pipeline

projects. . It is essential that all elements of the terrain mapping are stored in queriable fields and formats

for the purposes of generating associated engineering takeoffs.

8.2 BC Government Mapping Database for Submitting Mapping to Government

The Terrestrial Ecosystem Information Digital Data Submission Standard Draft for Field Testing,

Database and GIS sets our procedures and rules for submitting Terrestrial standards(RISC, 2012) sets

out procedures and rules for submitting Terrestrial Ecosystem Information (TEI) data to the B.C. Ministry

of Environments Terrestrial Ecosystem Information System (TEIS) and other database systems. The

ministry has developed Contractor Package (Version 10, Dec 19, 2012) containing information for

contractors to meet the goals of acquiring and administering terrain related data in an organized fashionthroughout the province to meet the objectives of the Resources Information Standards Committee

(RISC). This draft document consolidates all of the submission standards for terrestrial ecosystem

mapping (TEM), bioterrain mapping and terrain stability mapping (TSM) into a single framework for

digital data submission. The new standard reflects the change from the B.C. Ministry of Environmentrequired data submission in .E00 format to .gdb format.

The database schema associated with this standard (TEI_Long_Tbl Feature Class Data Description) is

found in Appendix A of the standard. The database stores individual attributes in a normalized manner

that facilitates data queries and construction of map symbols. Additional descriptions of attribute fields,metadata, allowable codes and domain tables in the geodatabase are included in the other appendices. The

database structure can be modified with additional fields and with additional allowable codes in given

fields as required for each specific project. Any terrain mapping contractor should review the database

schema to ensure consistency with these specifications when submitting mapping to the government.

In order to construct terrain polygon labels to display on maps, the B.C. Ministry of Environment uses a

script to create a concatenated label derived from the TEI_Long_Tbl (parsed 280 fields). The long table

schema has all the data parsed out so a user can create a concatenated terrain label.On site symbols arealso included in the B.C. Ministry of Environments Operation Geodatabase. Any terrain mapping project

should provide feature coded feature classes for on-site symbols.


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9.0 QUALITY CHECKING AND MAPPER QUALIFICATIONS

9.1 Quality Checking of Desktop PreliminaryTerrain Mapping (Level 1D) and Detailed Terrain

Mapping (Level 2D)

Preliminary (Level 1D) mapping and detailed (Level 2D) will need to have quality assurance checking by

the user (engineering in the case of pipeline terrain mapping) to make sure that the mapping meets the

users needs. Each mapper, if more than one is doing the work, should undertake a small section of

mapping (e.g. 25 km) so that mapping styles can be coordinated.

Further checking should be done using LIDAR, where available, as it sometimes refines polygon

boundaries.

Preliminary legends should be prepared before field investigations. Both terrain mapping and legends can

be upgraded after field investigations are completed.

Field notes should be kept in an organized way so that they can be used to finalize the Level 2D terrain

maps.

9.2 Terrain Mapper Qualifications In Canada Outside of BC

Terrain mapping outside of BC is not regulated to the same extent as it is in BC. However, terrain

mappers in Canada are generally geologists with knowledge of geological mapping and the principles of

air photo interpretation and engineering terrain analysis. Occasionally terrain mapping is undertaken by

foresters, soil scientists or engineers but these individuals need to have some of the same background as

geologists in both desktop and field studies. It is preferable that mappers are registered as a professional

geoscientist, professional engineer, or professional agrologist in the area where they are working. All

mappers should understand the government geological mapping that is used for Level 1D mapping alongthe pipeline corridor that they are mapping.

9.3 Terrain Mapper Qualifications in BC

BC requires that a registered professional heads up terrain mapping and terrain stability mapping (Forest

Practices Code, 1995).. This individual should have substantial experience in terrain mapping and

landslide hazard interpretation. Junior mappers can do this work under close, professional supervision..

Professionals that currently carry our terrain or terrain stability mapping include:

Professional geoscientists (P.Geo) are primarily geologists and geomorphologists who have

terrain and terrain stability mapping experience and are registered with the Association of

Professional Engineers and Geoscientists of BC (APEGBC)


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Resumes of all mappers should be attached to terrain mapping proposals submitted for terrain and terrain

stability mapping of pipeline corridors.


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10.0 REFERENCES

Forest Practices Code of British Columbia. 1995. Mapping and Assessing Terrain Stability Guidebook.

B.C. Ministry of Forests and B.C. Environment.

Forest Practices Code of British Columbia. 1999. Mapping and Assessing Terrain Stability Guidebook.

B.C. Ministry of Forests and B.C. Environment

Ecosystems Working Group of the Terrestrial Ecosystems Task Force Resources Inventory Group. 1995.

Standards for Terrestrial Ecosystems Mapping in B.C. The Province of British Columbia, Resources

Inventory Committee, 190p.

Fulton, R.J. 1993. Surficial Geology Mapping at the Geological Survey of Canada: Its Evolution to meet

Canadas Changing Needs. Canadian Journal of Earth Sciences, Volume 30, Number 2.

Holland, S.S. 1964 (Revised 1976). Landforms of British Columbia: A Physiographic Outline. British

Columbia Department of Mines and Petroleum Resources, Bulletin No. 48.

Howes, D.E. and Kenk, E. editors. 1988. Terrain Classification System for British Columbia Revised Ed.

Ministry of Environment Recreational Fisheries Branch and Ministry of Crown Lands, Surveys and

Resource Mapping Branch, MOE Manual 10.

Howes, D.E. and Kenk, E. 1997. Terrain Classification System for British Columbia (Version 2) FisheriesBranch, Ministry of Environment and Surveys and Resource Mapping Branch, Ministry of Crown Lands,

province of British Columbia, MOE Manual 10 (Version 2).

Resource Inventory Committee. 1996a. Interim (1996) Terrain Database Manual: Standards for Digital

Terrain Data Capture in British Columbia.

Resource Inventory Committee. 1996b. Specifications and Guidelines for Terrain Mapping in British

Columbia, Surficial Geology Task Force, British Columbia.

RISC. 2012. Terrestrial Ecosystem Information Digital Data Submission Standard Draft for Field

Testing, Database and GIS Data Standards. Prepared by Ministry of Environment Knowledge

Management Branch for the Terrestrial Ecosystem Resources Information Standards Committee, March

20, 2012, Version 2.1.

Rizkalla, M. (editor). 2008. Pipeline Geo-Environmental Design and Geohazard Management. Pipeline

engineering Monograph Series, ASME, Three Park Avenue, New York, 353p.

Ryder J.M. and Howes, D.E. 1984. Terrain Information, a Users Guide to Terrain Maps in BritishColumbia in DEGIFS Publication.

Ryder, J.M. and Associates. 2002. A Users Guide to Terrain Stability Mapping in British Columbia,

British Columbia Surveys and Resource Mapping Branch, Victoria.


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30

SLOPE INFORMATION

SLOPE CLASS PERCENT DEGREES

1 0 - 0.5 0

2 0.5 - 2 0.3 - 1

3 2 - 5 1 - 34 6 - 9 3.5 - 5

5 10 - 15 6 - 8.5

6 16 - 30 9 - 177 31 - 45 17 - 24

8 46 - 70 25 - 359 71 - 99 36 - 4510 100 45

POLYGON INTERPRETATION

Fen Organic Veneer overlying Moraine Plain = fOv/tMp


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31

APPENDIX B: PHYSIOGRAPHIC SUBDIVISION - ROCKY MOUNTAINS LEGEND (BC Terrain Classification System)

MapSymbol TerrainUnit Texture Thickness Topo-graphy Soil Drainage Permafrost SlopeClass(es)

(After

Howes &

Kenk, 1997)

Mass WastingFeatures Comments StabilityRating (After

Forest

Practice Code)

Ov Organic

Veneer

Peat and Fen 3m Level Poorly Drained Possible inorganics

1 None PoorTrafficability

I = Stable

Cv ColluvalVeneer

Matrix is SiltySand or sandysilt; Also hasrock fragments(rubble)

< 1m Gently toSteeplysloping

Well Drainedover rock;Moderately wellto imperfectlydrained overfine grainedmaterial

None 2 to 5 Gullies andDebris TorrentGullies

II toV= Stableto Unstable

Cb Colluvial

Blanket

Sand or sandy

silt; Also hasrock fragments(rubble)

1 to 3m Gently to

SteeplySloping

Well Drained

over rock;Moderately wellto imperfectlydrained overfine grainedmaterial

None 2 to 4 Gullies and

Debris TorrentGullies

II to IV Stable

to Unstable

CfColluvialFan

Rock rubble(angularfragments);Some finegrained matrix

>3mGently toSteeplysloping

Well Drained None 3 to 4Active ColluvialFan

IV PotentiallyUnstable toUnstable

Ca ColluvialApron

Rock rubble(angularfragments);Some fine

grained matrix

>3m Gently toSteeplySloping

Well Drained None 3 to 4 ActiveCoalescingColluvial FansformColluvial

Apron

IV PotentiallyUnstable toUnstable


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32

Map

Symbol

Terrain

Unit

Texture Thickness Topo-

graphy

Soil Drainage Permafrost Slope

Class(es)

(After

Howes &

Kenk, 1997)

Mass Wasting

Features

Comments Stability

Rating (After

Forest

Practice Code)

Ds Debris Slide Highly variable(depends onsourcematerial);Ranges fromfine to coarserock rubble

>3m Gently toSteeplySloping

Well toImperfectlyDrained

None 3 to 4 Old Debris Slide IV Unstable

Ls Landslide Angular rockrubble

>3m Moder-ately toSteeply

Sloping

Well Drained None 4 Old Landslide IV Unstable

Dt DebrisTorrent

Gully

Variable; bothcoarse and fine

debris

Variable;Mostly>3

m

Moder-ately to

SteeplySloping

Well Drained None 3 to 5 Active DebrisTorrent Gully

Debristorrent Gully

ends in Fan

IV Unstable

Lv LacustrineVeneer

Silt, Sand &Clay

3m Level toGentlySloping

Moderately Wellto PoorlyDrained

PossibleUnderOrganicCover atHigherElevations

1 to 2 None I Stable

Fv FluvialVeneer

Gravel (roundedto sub-rounded);Some sand

&fines; PossibleMoraine atDepth


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33

Map

Symbol

Terrain

Unit


graphy


Class(es)

(After

Howes &

Kenk, 1997)

Mass Wasting

Features

Comments Stability

Rating (After

Forest

Practice Code)

Fb FluvialBlanket

Gravel (roundedto sub-rounded); Some

sand &fines;PossibleMoraine atDepth

1 to 3m

Level toGentlySloping

Well Drained None 1 to 2 None

Could be asource ofgood qualitygranularmaterial

I Stable

Fp Fluvial Plain Gravel(Rounded toSub-rounded;

Sand & Fines;Some bouldersand cobbles

>3m Level Well to PoorlyDrained

None 1 None May be wet I Stable

Ft FluvialTerrace

Gravel(Rounded toSub-rounded;

Sand & Fines;Some bouldersand cobbles

>3m Level toGentlySloping

Well Drained None 1 None May besource ofgood quality

granularmaterial

I Stable

Ff Fluvial Fan Gravel

(Rounded toSub-rounded;

Sand & Fines;Someboulders

andcobbles

>3m Level to

GentlySloping

Well Drained

but somesaturated zones

None 1 to 2 None; but maybe

activelydepositingmaterial

Crossed by

activedrainages;Seasonallywet

I Stable

FGv Glacio-

fluvialVeneer

Gravel(Rounded toSub-rounded),Sand & Fines;

possible

moraine atdepth


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34

Map

Symbol

Terrain

Unit


graphy


Class(es)

(After

Howes &

Kenk, 1997)

Mass Wasting

Features

Comments Stability

Rating (After

Forest

Practice Code)

FGt Glacio-

fluvialTerrace

Gravel(Rounded toSub-rounded),Sand & Fines


Well Drained None 1 to 2 None Could be asource ofgood qualitygranularmaterial

I Stable

FGp Glacio-

fluvial Plain

Gravel

(Rounded toSub-rounded),Sand & Fines

>3m Level to

GentlySloping

Well to

Moderately WellDrained

None 1 to 2 None Could be a

source ofgood qualitygranularmaterial

I Stable

FGu UndulatingGlaciofluvial

Gravel(Rounded toSub-rounded).

Sand & Fines

>3m Gentlyrolling toundu-

lating

Well toModerately WellDrained

None 1 to 2 None Could be asource ofgood quality

granularmaterial

I Stable

FGh Hummocky

GlaciofluvialGravel(Rounded toSub-rounded).Sand & Fines

>3m Humm-ocky

Well toModerately WellDrained

None 1 to 4 None Could be asource ofgood qualitygranularmaterial

I Stable

FGf Glaciofluvial

Fan

Gravel

(Rounded toSub-rounded).Sand & fines;Some boulders& cobbles

>3m Gently

Sloping

Well Drained None 1 to 2 None Could be a

source ofgood qualitygranularmaterial

I Stable

LGp Glacio-

lacustrinePlain

Silt, Clay &sand



PossibleUnderOrganicCover atHigherElevation

1 to 2 None I Stable

L Gt Glacio-lacustrineTerrace

Silt, Clay &sand



PossibleUnderOrganicCover atHigherElevation

1 to 2 None Sideslopeson terracecould beunstable

I to III Stable toPotentially

unstable onterracesideslopes


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35

Map

Symbol

Terrain

Unit


graphy


Class(es)

(After

Howes &

Kenk, 1997)

Mass Wasting

Features

Comments Stability

Rating (After

Forest

Practice Code)

Mv MoraineVeneer

Till matrix isprimarily silt,sand & clay;

Coarsefragments at>2mm;Subangular to

sub-roundedand comprise

30% of till

2mm;

Subangular tosub-roundedand comprise

30% of till

1 to 3m Reflectsunderlyingunit

Moderately Wellto Well Drained

None 1 to 4 May have masswasting featureson steeper slopes

I to IV Stableto PotentiallyUnstable

Mp MorainePlain

Till matrix isprimarily silt,sand & clay;Coarsefragments at

>2mm;Subangular tosub-roundedand comprise

30% of till

>3m GentlySloping

Moderately Wellto Well Drained

None 1 to 3 None I Stable

Mm RollingMoraine(Drumlins)

Till matrix isprimarily silt,sand & clay;Coarse

fragments at>2mm;Subangular to

sub-roundedand comprise30% of till

>3m Rolling tolinear

Well drained onupper slopes ofridges; Some

poorly drainedareas betweenridges

None 1 to 4 None I to II Stable


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MAP UNIT EXAMPLE

302 = Polygon Number

tMb (Slope Class 2; tMb Terrain Symbol)2 IsR IsR till over limestone

w Soil Drainage11 Slope Stability Class (Stable)

SLOPE CLASS(After Howes & Kenk, 1997)

Class % Degrees1 0-5% 0-32 6-26% 4 -15

3 27-49% 16 - 264 50-70% 27 -355 >70% >35

OTHER DESCRIPTIVE LEGEND TABLES BC TERRAIN MAPPING GUIDELINES

TERRAIN CLASSESTEXTURAL TERMS

LANDFORM TERMSGEOMORPHOLOGICAL PROCESS TERMS (ACTIVE AND INACTIVE)

MASS WASTING TERMSROCK TERMS

CRITERIA FOR SLOPE STABILITY INTERPRETATION

TC Terrain Mapping Guidelines

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