Geography 103 Lab 1
Teaching Notes
N. Salant
LAB 1: TOPOGRAPHIC MAPS
Preparation
- Write name, email address (optional), lab section, lab time, and personal LAC hours on
board
- Set up overhead projector, check overhead pen
- Place maps on table
- Get protractors and rulers
- Get overheads out of binder, including images of globes and UTM grid
Introduction
- Pass out attendance sheet
- Ask students if they have questions from previous week regarding the introductory material
(especially significant figures and graphing criteria)
- Give brief outline of how lab will generally be conducted:
1. Review basic concepts of the week’s topic
2. Go through assignment together
3. Complete exercises in pairs or groups (and come check answers when finished)
Main points
- Topographic maps are valuable sources of information for geographers
- We will discuss important features of topographic maps
- Main lessons:
Latitude/longitude vs. UTM coordinates
Three different types of scale found on maps
Topography described by elevation (contour lines), slope aspect, and gradient
1) Topographic maps
= Detailed representation of both natural and man-made physical features
Ex) Rivers, vegetation, mountains
Ex) Roads, buildings
Reference information on margins:
(Point these out to students on map)
Map location
Scale
Contour intervals
Publication information
Cartographic symbols
(See back side of map)
Features of topographic maps:
A. Coordinate systems = How to represent locations on a map
2 types:
- Geographic Grid (a.ka. latitude and longitude)
- Universal Transverse Mercator (UTM)
1. Geographic Grid
(Put up overheads of globes)
Latitude lines = ‘Parallels’ = East-West parallel to Equator
MUST specify North or South of the Equator
(Indicate on figures)
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Geography 103 Lab 1
Teaching Notes
N. Salant
Longitude lines = ‘Meridians’ = North-South between North and South Poles
MUST specify East or West of the Equator
(Indicate on figures)
Conventions and units:
Latitude (N/S) stated before longitude (E/W)
Expressed as Degrees (), minutes (), seconds ()
1 Degree = 60 Minutes = 60 Seconds
Ex) Location of UBC Geography building
49º15’55’’N
123 º15’58’’W
2. Universal Transverse Mercator (UTM)
(Put up overhead of grid)
Rectangular grid placed over a map for SIXTY different zones covering world
Some overlap of zones
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Geography 103 Lab 1
Teaching Notes
N. Salant
Uses metric system to describe locations
Useful for quickly identifying points on the maps
and calculating distances between points
Each rectangle = ‘quadrilateral’ or ‘grid zone’ = 6º latitude by 8º longitude
6º
Example of ‘nested’
squares (not to scale)
8º
Within each quadrilateral/grid zone:
Nested squares 100,000 m x 100,000 m and
100 m x 100 m
Each quadrilateral/grid zone has designation
Each 100,000 m square has identification
e.g. ‘3N’ on overhead
e.g. ‘NF’
(Show grid zone designation and 100,000 m identification on map)
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Geography 103 Lab 1
Teaching Notes
N. Salant
100,000 m square
identification
Grid zone
designation
Each 100 m square has 6-digit identification number
‘Easting’ = first 3 digits = x-coordinate = left-right on map
‘Northing = last 3 digits = y-coordinate = up-down on map
Remember, ‘read Eastings first’
(Do example with class – Figure 1.5 in lab manual)
Easting:
Read number on the grid line immediately
left of the point = 97
Estimate tenths of a square from this line
eastward to the point = 5
Northing:
Read number on the grid line immediately
below the point = 98
Estimate tenths of a square from this line
northward to the point = 4
UTM 6-digit reference code: 975984
Full UTM reference code is 11U NF 975 984
B. Map scales
Scale = ratio between the representation on the map and the actual distance on the ground
(‘Map distance’ vs. ‘real distance’)
3 types:
- Linear, bar or graphic scale
- Verbal scale
- Representative Fraction
Linear, bar, or graphic scale
Pictoral representation of scale
(Show example on map)
Advantage is that it holds true even if map is stretched or distorted
Not used in this class
Verbal scale
Most familiar scale, expressed in words
(e.g. ‘One cm on the map equals one kilometre in real life’)
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Geography 103 Lab 1
Teaching Notes
N. Salant
Representative Fraction (RF) ***
Most common and most useful scale for interpreting maps
Only scale used in this class
Unitless fraction – doesn’t matter what units you use
For example, if the RF is 1:25,000
1 pen cap on the map = 25,000 pen caps in real life
1 inch on the map = 25,000 inches in real life
1 cm on the map = 25,000 cm in real life
1:25,000
or
1
25,000
no units are specified
(Show on map where RF is indicated - 1:50,000)
(Go through example)
How to calculate distance from the RF scale:
Measure the distance on the map and convert to the ‘real’ distance
Distance on map x 50,000 = Distance in real life
e.g. 10 cm on photo x 25,000 = 250,000 cm in real life
= 2,500 m in real life
C. Map orientation: Reading compass bearings on map
(Draw compass and show N, S, E, W – 0, 90, 180, 270º)
N = 0 or 360º
E = 90º
S = 180º
W = 270º
Degrees = ‘Azimuth’
(Ignore section on magnetic declination – we are always going to assume true north in this class)
How to measure compass bearing on a map:
1. Draw a straight line from the starting point (‘A’) to the end
point (‘B’)
2. Extend line to the border of the map
3. Align the edge of the protractor with the border of the map (so
that the protractor edge points straight up – straight North). DO
NOT align with UTM grid.
4. Measure angle of line relative to North (remember N = 0º)
D. Topography
Components of surface topography obtainable from topographic maps:
a. Contour lines and intervals
b. Slope aspect
c. Gradient and slope angle
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Geography 103 Lab 1
Teaching Notes
N. Salant
a. Contours
Imaginary lines that joins points of equal elevation
Visual representation of topography (spacing of lines)
Accurate information about elevation and slope
and
(Show example – draw mountain and contours around mountain, projected to flat surface)
Contour interval = vertical distance between adjacent contours
Indicated at bottom of map
Same interval over entire map
Index contour
= every fifth contour line, in bold print with elevations identified
Benchmarks
= prominent landmark or peak that has been surveyed, exact elevation indicated
Interpolation
= estimating elevation for points located between contour lines
(above the lower elevation contour, below the higher elevation contour)
b. Slope aspect
= compass direction that a slope faces
(Draw compass, show 8 possibilities – N, S, E, W, NE, SE, SW, NW)
(Ask class to think about an example – e.g. Point Grey Cliffs, next to the anthropology museum face N)
To measure aspect:
Draw straight line perpendicular to contour lines of slope
Measure compass direction of line
Example of ~SE aspect
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Geography 103 Lab 1
Teaching Notes
N. Salant
c. Gradient
From contours:
Spacing ~ steepness
(Have them imagine walking up two different sets of stairs)
Wide spacing = gradual
Tight spacing = steep
(Walk through ‘Hints for successfully interpreting contour lines’ with class – have each student read one.
Emphasise underlined points)
1. The elevation value of any given contour line is some multiple of the contour interval.
2. Contour lines never touch or cross one another, except when the topography being portrayed is a vertical
wall.
3. Every contour forms a closed polygon, either within or beyond the limits of the map. In the latter case,
the ends of the contour will extend to the edge of the map.
4. Uniformly spaced contours indicate a uniform slope. Widely spaced contours indicate a gentle slope.
Contours that are close together indicate a steep slope. Spacing ~ steepness.
5. Contours form a “V” along a stream course, with the base of the “V” pointing upstream.
6. Contours also form a “V” along a ridge or ‘spur’, but the base of the “V” points down the ridge.
7. A contour that forms a closed polygon within the limits of the map represents a hill or rise. If closed
contours are hachured, they represent a depression. The hatches are directed into the depression.
(POINT OUT DIAGRAM IN MANUAL)
8. The elevation of a hilltop, unless noted by a bench mark, is estimated. It is somewhere between the
value of the highest contour below the peak and the value of the next contour above the peak (that does
not appear on the map).
9. The elevation of a depression contour is the same as that of the adjacent lower contour, unless otherwise
indicated.
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Geography 103 Lab 1
Teaching Notes
N. Salant
From slope angle:
Slope angle = change in elevation per unit of horizontal distance
(i.e. vertical change/horizontal change)
2 ways to express slope angle:
1. Percent (%) slope
= (rise/run) x 100
= (vertical distance/horizontal distance) x 100
Vertical distance = difference between top and bottom elevation
Horizontal distance = measured on map and converted to ‘real’ distance using RF
MUST be measured in the same units
2. Degree slope
= slope angle in degrees
= arctangent of the rise/run ratio
(Use calculator or table to get arctan or tan-1)
(Go through example in lab manual)
The Peak to Valley race starts at the Saddle on Little Whistler Peak (2115 masl) and ends at the
bottom of the Dave Murray Downhill run at Whistler Creekside (739 masl).
1. Calculate the rise = net vertical change in elevation from the highest point (2115 masl) to the
lowest point (739 masl)
Rise = 2115 – 739 = 1376 m
2. Calculate the run = the horizontal distance between the start and the finish, the two points of
interest. On the map, the distance is 10 cm. The map scale is 1:50,000.
Run = 10 x 50,000 = 500,000 cm = 5000 m
3. Calculate percent slope = rise / run x 100
1376 m / 5000 m x 100 = 27%
4. Calculate degree slope = arctangent of the rise / run ratio
1376 m / 5000 m = 0.27
arctangent of 0.27 = 15º (either from the table or by calculator)
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Geography 103 Lab 1
Exercises: Tips for students and answers for TAs
N. Salant
2) Lab exercises
PART I: FEATURES OF NORTH VANCOUVER TOPOGRAPHIC MAP
1. What is the full title of the map sheet you are using?
TIPS: Emphasise importance of map title; talk about ‘nested maps’ (G/6 is nested within G)
ANSWER: North Vancouver 92 G/6, 5th edition, 1:50,000
2. What colour are the roads? What do the colours indicate?
TIPS: Use legend
ANSWER: Roads = red, orange, and gray; Red = hard surface; orange = loose surface,
gravel; gray = winter road, vehicle track
3. What are the latitude and longitude coordinates (to the nearest minute) for Horseshoe Bay?
TIPS: Emphasise ‘to the nearest minute,’ for the centre of Horseshoe Bay, not the city
ANSWER: 4922’N 12316’W
4. What land feature do you find at location 884643 on your map sheet?
TIPS: Remember Easting is first 3 (= 88.4), Northing is last 3 (=64.3), ‘read Easting first’
ANSWER: City Hall
5. Find the Aquarium in Stanley Park. Provide the full UTM reference code for this location
(include the quadrilateral, 100,000 square m and 100 square m codes).
TIPS: Emphasise full UTM reference code
ANSWER: 10U DK 905607
6. What is the RF scale on the North Vancouver map?
TIPS: Use margin
ANSWER: 1:50,000
7. Calculate the value of 2.5 centimetres on this map = ____ km on the actual ground
Hint: Always show your calculations – they may be worth partial marks on an exam even if your
answer is incorrect.
TIPS: Same as example we did as a class (using RF to calculate ‘real’ distance), SHOW WORK!!
ANSWER:
2.5 x 50 000
= 125 000 cm on Earth
 100 = 1250 m
 1000 = 1.25 km
8. A distance of 12 km on the earth would be represented by _____ mm on this map.
TIPS: Similar to previous, just do it in reverse note answer is in mm, keep units the same on both
sides, but RF itself is unitless, SHOW WORK!!
ANSWER:
12 km x 100 000
= 1 200 000 cm on Earth
 50 000
= 24cm on the map
x 10
= 240 mm on the map
PART II: WEST COAST ADVENTURES – SAILING
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Geography 103 Lab 1
Exercises: Tips for students and answers for TAs
N. Salant
1. If you want to sail from the lighthouse at the Jericho Beach Yacht Club to Second Beach at
Stanley Park, what is the map bearing, in degrees, relative to true north?
TIPS: Use ruler and protractor, follow steps from ‘Map orientation’ (draw line A to B, align
protractor, measure angle), report azimuth relative to North (i.e. the angle East or West of
north)
ANSWER: Compass bearing in degrees = azimuth = 48 E of N
2. If you sail in a relatively straight line, what distance in km will you travel?
TIPS: Use RF (never use bar scale)
ANSWER:
Distance on the map = 7.1 cm
Using the RF scale,
7.1 x 50 000
= 355 000 cm on the ground
= 3550 m on the ground
= 3.55 km on the ground
PART III: HIKING THE GROUSE GRIND
TIPS: Using contour map, determine elevations ands slopes of your hiking route
1. Find the elevation of:
a) Top of the gondola (“G”)
___1070__ m
b) Grouse Mountain summit
___1231__ m
c) Mount Fromme summit
___1185__ m
2. Calculate the elevation change:
a) Parking lot (“X”) to the top of the gondola (“G”)
__770__ m [1070 – 300 = 770]
b) Grouse Mountain summit to Mount Fromme summit ___46__ m [1231 – 1185 = 46]
3. Where is the steepest gradient along the hiking route? What is its slope aspect?
TIPS: In other words, which section of the hike is steepest (recall contour spacing ~ steepness)
ANSWER: The “Grouse Grind”, from the parking lot (X) to the top of the gondola (G). It
faces southwest.
4. Calculate the gradient or slope angle of the Grouse Grind.
TIPS: ‘Grouse Grind’ is section from X to G
a. Vertical distance
___770 __ m
b. Horizontal distance
Map distance
___6.5___ cm
Actual distance [6.5 x 20,000 = 130,000 cm]
___1.3___ km
c. Slope angle in percent [770 / 1300 x 100]
___59.2__ %
d. Slope angle in degrees [arctan (770/1300)]
___30.6__ 
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Geography 103 Lab 2
Teaching Notes
N. Salant
LAB 2: SURFICIAL MATERIALS
Preparation
- Set up sediment samples, photos of bedding, squirt bottle and sample for demonstrating
wet-texturing
- Set up overhead projector, check overhead pen
- Get overheads out of binder, including axis figure, texture triangle, flow chart
Introduction
- Pass out attendance sheet
- Ask students if they have questions from previous week
- Reminder regarding LAC hours: come with questions on any previous labs, also to make up
labs missed
Main points
- Identify materials based on physical properties and hand-texturing techniques
- Relationship between mode of transport and deposition and physical properties
- Learn skills to do stratigraphic analysis and interpret geologic history (for next week’s
field trip)
1) Terminology
Surficial materials (a.k.a. ‘soil’)
Unconsolidated, unlithified (i.e. not rock)
Accumulations of ‘clasts’
Clasts = individual rock particles
Surficial
material
Clast
Bedrock
Cover bedrock in most areas
Produced by weathering = the breakdown of rock
Weathering processes
Mechanical = physical breakdown (via wind, water, ice, etc.)
Chemical = breakdown by changes to chemical composition of minerals
Other processes acting on surficial materials
Erosion = Wearing away of land or soil by wind, rain, running water or moving ice
Mass movement = Downslope movement of large land mass as single unit (e.g. landslide)
Deposition = Removal from transport and accumulation of soil or sediment particles
Strata = layers of surficial materials
Stratigraphy = the study of the sequence of strata to determine the geologic and geomorphic
history of a site
Characteristics and position of material ~ history of erosion, transport, and deposition
2 principles use in stratigraphy:
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Geography 103 Lab 2
Teaching Notes
N. Salant
Principle of Original Horizontality
– Most sedimentary strata were more or less horizontal at the time of deposition
Principle of Superposition
– Except for tectonically disturbed strata, the youngest rocks in a vertical sequence of
sedimentary strata occur at the top of the succession
Youngest
Each layer has
different
properties that
reflect its
geologic history
Stratigraphic
sequence
Oldest
2) Physical properties of surficial materials
A. Size
Wentworth Classification System
British system, commonly used, one of several
Size Class
Range in diameter (mm)
Boulders
> 256
Cobbles
64 – 256
Pebbles
2 – 64
Sand
0.0625 – 2
Silt
0.004 – 0.0625
Clay
< 0.004
(Refer to table in lab manual – note there is no ‘gravel’ class = pebbles and cobbles)
Methods for determining size:
Coarse clasts (pebbles, cobbles, boulders):
Measure three dimensions (length, width, height) with calliper or ruler
Size is shortest dimension
(Show overhead)
Fine clasts:
Wet or dry-sieving through sieves with specified mesh size
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Geography 103 Lab 2
Teaching Notes
N. Salant
B. Texture
Combination and relative amount of different clast sizes
Example) ‘Silty-sand’ = sand-dominated mix of silt and sand
Texture class
Relative abundance of sand, silt, and clay (fine clasts)
Indicated on texture triangle
12 different classes
(Put up overhead of triangle)
(Do example with class)
Example) 40 % sand, 30% silt, 30% clay = ‘clay loam’
Loam = class that has a mixture of all 3 sizes (some classes only have 2)
Two methods for determining texture:
1. Measure % of each class in laboratory and apply to triangle
2. Hand texturing
Note: For samples with coarse clasts mixed with fine clasts:
Texture = texture class of ‘matrix’ + size of coarse clasts
Matrix = fine clasts in sample
Example) ‘Silty-sand with pebbles’
(Show students hand-texturing ‘flow-chart’ and generally how it works
– tell them you’ll do this with them in small groups after lecture)
C. Sorting
Range of size classes within material
Well-sorted (all material is 1 class) to unsorted (more than 4 classes) – see table
Related to transport process –
CLASS
DESCRIPTION
TRANSPORT PROCESS
well sorted
1 size class
Water or wind
moderately sorted
2 size classes
Water or wind
poorly sorted
3 size classes
Chaotic environment (e.g. fluctuating streams)
unsorted
‘Diamicton’; 4+ size classes
Glacier, mudflow, landslide
D. Bedding (a.k.a. stratification)
Layering of sediments within a surficial material - indicates deposition by water
Bedding planes
E. Shape or rounding
Applies to coarse clasts (pebbles, cobbles, boulders)
Related to type and distance of transport, and resistance of transport material
3 categories:
- Angular (i.e. sharp edges)
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Geography 103 Lab 2
Teaching Notes
N. Salant
- Subangular (i.e. some sharp, some smooth edges)
- Round (i.e. smooth edges)
Rounder = farther transport
Rounder = water or ice transport
Flat on one side = ice or wind transport
F. Organic materials
Appear brown or black, from samples near surface, undecomposed or decomposed
Examples: leaves, sticks, wood, roots (undecomposed), humus (decomposed)
3) Transport and deposition
Physical properties ~ mode of transport and depositional environment
Velocity of water (or wind) determines size of material in transport:
Higher velocities (e.g. rivers)  coarse material transported and deposited
Slow velocities (e.g. lakes)  fine material transported and deposited
Glacial ice  mix of particle sizes
(Use table from manual to show relationship – really emphasize this, very important)
SORTING AND TEXTURE
TRANSPORT AND DEPOSITION ENVIRONMENT
a)
well sorted - fine texture
still or standing water (lake or ocean) or wind
b)
well sorted - coarse texture
flowing water
c)
moderately to poorly sorted
turbulent flowing water
d)
degree of sorting varies/ or alternates
between bedding planes
flowing water with pauses in deposition
e)
unsorted - not compact
mudflows, landslides, glacial till
f)
unsorted - very compact
glacial till that has been overridden ridden by glacial ice
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Geography 103 Lab 2
Exercises: Tips and Answers
N. Salant
LAB 2: ASSIGNMENT
PART I: VISUAL ASSESSMENT OF SURFICIAL MATERIALS
Observe Photographs 1 – 5. For each photograph,
 estimate the size and size class of the largest clast
 determine the degree of sorting (“sorting class”)
 indicate whether or not the material is bedded or stratified (“bedding”)
TIPS:
Show students where photographs are; emphasize they are estimating the size of the largest class
Remind them to refer back to table in manual that defines the sorting class
Tell them that sorting refers to the material within each bed, not across beds
Photograph
1
2
3
4
5
Clast size (cm)
Size class
Sorting Class
(within each bed)
Bedding
5.5 cm
pebble
(large)
poorly sorted to unsorted
yes
> 30 cm
boulders
unsorted
no
< 0.2 cm or
< 2mm
sand/silt/clay
well sorted
yes
4 cm
pebbles
poorly sorted to unsorted
no
< 0.2 cm or
< 2mm
silt/clay
well sorted
yes
TIPS:
Photograph 1: glaciofluvial deposits in a post-glacial riverbed that has multiple episodes of turbulent fast
moving water (beds with unsorted clasts) and periods of slow/still water (beds with fine, well-sorted clasts).
The largest clasts are pebbles (c. 5.5 cm along their short dimension). There are clear horizontal beds
visible in the photograph. For the photograph as a whole, the clasts are not sorted (poorly sorted to
unsorted). Within some beds, particularly those with fine clasts (probably silt and clay) the clasts are well
sorted.
Photograph 2: clasts rounded by flowing water; glaciofluvial deposits in old riverbed
The largest clasts are boulders > 256mm across. There are no beds visible in the photograph. The clasts
range from boulders to fines (sand, silt, clay) = poorly sorted to unsorted.
Photograph 3: glaciolacustrine deposits = sediments deposited in a glacial lake (standing water)
Horizontal beds are very thin but distinct. The clasts are well sorted. The grainy looking sections of the
photo = sand particles; these beds have eroded and are indented. Note the vertical “drips” of clay that
has become saturated and dripped down the face of the profile.
Photograph 4: clasts range from sand to pebbles; shape = subangular and rounded
This is the base bed from photograph 2 = basal till overlain by a series of glaciofluvial deposits. The clasts
include sand and pebbles (fine silts and clays are not evident) that are unsorted. There are no beds visible.
Photography 5: glaciolacustrine deposits = sediments deposited in a glacial lake (standing water)
Horizontal beds are very thin but distinct. The clasts are well sorted and include only silt and clay. Note,
like photo 3, clay has become saturated and dripped down the face of the profile.
1
Geography 103 Lab 2
Exercises: Tips and Answers
N. Salant
PART II. TEXTURE DETERMINATION
A. USE OF TEXTURAL TRIANGLES
TIP: Refer students back to texture triangle and example done together
1. Determine the texture class of samples A, B, and C plotting them on the U.S.D.A. textural
triangle.
Sample
Ex.
A
B
C
% Sand
50
20
50
85
% Silt
20
30
10
10
% Clay
30
50
40
5
Texture Class
sandy clay loam
clay
sandy clay
loamy sand
2. If I have a loam that is 40% sand and 40% silt, what is the proportion of
clay?_____20%________
3. For a loam that is 50% sand, what is the possible range of silt content in percent?
________28-45%_________
B. HAND TEXTURING
TIPS: Get half the class to start on photographs and texture triangle, gather other half and show
them hand texturing with dry and wet sample (Sample D).
Talk about difference in feel between dry sand, silt, and clay (sand and silt feel ‘gritty’, sand falls
apart easy, silt feels soft, clay forms hard angular fragments).
Show them how to add small amount of water to sample, and walk through the hand-texturing
flow chart with them…sample should feel gritty, contains all 3 size classes
B. HAND TEXTURING
For Sample D (provided by the teaching assistant), answer the following questions:
1. Example a dry portion of Sample D. Does it contain sand? silt? clay? Explain the
observations of the sample that support your answers.
Grains of sand are visible; feels and “tastes” gritty
2. Use Figure 2.3 to determine the texture class of Sample D.



moist sample remains in a ball when squeezed
cannot form a ribbon of uniform thickness and width
loamy sand
2
Geography 103 Lab 2
Exercises: Tips and Answers
N. Salant
PART III. ANALYSIS OF SURFICIAL MATERIALS
TIPS: Show students samples
Tell them to not waste material when doing hand texturing
Tell them to refer back to tables to determine classes and possible depositional environments.
Sample
Clast size
class(es)
Notes
Estimated
texture class
Sorting
Class
Clast
Shape
1
sand
no ribbon
sand
(medium)
well
sorted
NA
2
ribbon  3cm
feels gritty
sandy clay
loam
well
sorted
NA
a = still or standing
water
3
sand
silt
clay
clay
ribbon > 5cm
feels very smooth
clay
well
sorted
NA
a = still or standing
water
4
sand
falls apart when
squeezed
sand
moderately
sorted
NA
a = still or standing
water
5
ribbon  2.5cm
feels very gritty
sandy loam
and
pebbles
sand
(fine)
poorly
sorted to
unsorted
well
sorted
pebbles =
angular
subangular
NA
f = compacted
glacial till
6
silt
sand
pebbles
sand
7
sand
no ribbon
sand
(coarse)
well
sorted
NA
b = flowing water
8
no clasts
NA
organic
material
unsorted
NA
terrestrial
plant matter
9
sand
pebbles
falls apart when
squeezed
sand and
pebbles
pebbles =
subangular
c = turbulent flowing
water
10
pebbles
clast size
2-64 mm
pebbles
(small)
poorly
sorted to
unsorted
well
sorted
round
subangular
b = flowing water
11
pebbles
clast size
2-64 mm
pebbles
(large)
well
sorted
round
b = flowing water
12
cobbles
clast size
64-256 mm
cobbles
well
sorted
round
b = flowing water
13
pebbles
clast size
2-64 mm
well
sorted
round
subangular
b = flowing water
14
sand
pebbles
falls apart when
squeezed
pebbles
(small and
large)
sand and
pebbles
silt
sand
pebbles
ribbon < 1.5cm
feels very gritty
sandy loam
and pebbles
pebbles =
angular
subangular
pebbles =
angular
subangular
e = glacial till
15
poorly
sorted to
unsorted
poorly
sorted to
unsorted
no ribbon
3
Possible
depositional
environments
a = still or standing
water
a = still or standing
water
e = landslide
Geography 103 Lab 3
Teaching Notes
N. Salant
LAB 3: INTRODUCTION TO STREAMFLOW REGIMES
Preparation
- Set up overhead projector, check overhead pen
- Get overheads out of binder, including images of hydrographs, example of cross-section
Introduction
- Pass out attendance sheet
- Ask students if they have questions from previous week
Main points
- Three concepts introduced in lab:
o Discharge rating curve
o Flood hydrograph
o Stream flow regime
- Learn to examine relations between streamflow regime, temperature, and precipitation
1) Estimating discharge from flow data (a.k.a. ‘Rating curves’)
Rating curve = relationship between discharge (Q) and stage level (h)
Three steps to estimating Q:
450
400
1. Gauge and record water height (‘gage
height’, h) over time (e.g. hourly)
350
Discharge (Q) (m3/s)
(Draw example)
300
2. Directly measure discharge (Q) of
channel at periodic intervals (e.g.
monthly) and develop a Q-h relation
(data points on graph)
250
200
150
100
3. Use relation to estimate Q for every h
measurement
50
0
0
5
10
15
20
25
Gage height (h) (m)
Why? Because measuring Q is timeconsuming and difficult, but measuring
gage height is relatively easy
How to measure discharge at given location:
(Put up image of cross section – explain discharge measured for entire cross-section at one time is only one
point on the Q-h graph – developing relation takes long time to develop)
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Geography 103 Lab 3
Teaching Notes
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(Draw cross section and each ‘slice,’ indicate where width, depth, and velocity are measured)
(Explain that average velocity is measured in 2 ways – ‘2-point method’ at 20% and 80% of flow depth,
then averaged, or just once at 40% of flow depth – but that the values given in this lab are already
averaged)
For each slice (slice ‘i):
vi = average velocity of slice (measured at centre)
di = depth of slice (measured at centre)
Wi = width of slice
Partial discharge = discharge of slice = velocity x depth x width = vi diWi = qi
i n
Total discharge (Q) = sum of all ‘slices’
Q   qi
i1
2) Hydrograph Analysis
Hydrograph = plot of channel discharge over time (i.e. how flow levels change over time)

(Show overheads of sample hydrographs – point out 3 different time scales (annual, storm,
diurnal))
Annual = entire year, can change with season
Storm or event = varies, 1-2 days
Snowmelt = characteristic daily fluctuation
(e.g. spring snowmelt and summer storms)
(i.e. peaks at warmest time of day)
Hydrograph components:
(point out on figure)
Rising limb = increase in discharge resulting from runoff of rainfall or snowmelt
Peak flow = maximum discharge of hydrograph
Recessional limb = decrease in discharge as flood passes
Base flow = ‘normal’ flow discharge of stream, not due to runoff
Peak flow hydrograph = from date of initial increase to date of return to baseflow
Factors affecting shape of hydrograph:
Upstream area
Topography
Glacier cover
Vegetation
Soil moisture capacity
Annual snow pack
Groundwater conditions
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Geography 103 Lab 3
Teaching Notes
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Example) Snow- or glacier-melt vs. rain-dominated annual hydrograph
Glacier-dominated:
Highest flows in June, July, August – because of snow-melt in spring and glacier-melt in
summer
Rain-dominated:
Highest flows in November and December – because of large winter storms
3) Catchment water balance
Basic idea: Input = output + storage
(Get students to think about what are water inputs/outputs)
In water terms:
Precipitation = evapotranspiration + runoff + storage
Precipitation = rain or snow
Evapotranspiration = loss of water due to evaporation and transpiration from plants (i.e. plant
‘breathing’) – highest when temperatures are high (i.e. summer or late afternoon)
Runoff = flow over land surface
storage = change in storage in the basin
Surface water = temporary storage in lakes and streams
Groundwater = temporary storage in the subsurface (under the ground)
Snowpack = snow on the ground surface
Glacier ice = ice on the ground surface
If precipitation ≠ runoff, either ET or S will account for the difference
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Geography 103 Lab 3
Exercises: Tips and Answers
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LAB 3 – ASSIGNMENT:
Part I. Calculating a Discharge From Field Data
1.
Complete the partial discharge calculations (qi) for BX Creek, based on the cross-section and velocity
measurements provided in Table 1. Now, sum the values to estimate the total discharge (Q):
TIPS: Remind students of formulae for partial and total discharge – just W x d x v (all values given) and
then sum all partial Qs to get total
TABLE 1: Cross sectional data for B.X. Creek
(May 23, 1991: Stage = 1.420 m)
Distance (m) Width (m) Depth (m)
Velocity (m/s)
0
0.00
0
0
0.2
0.35
0.12
0.40
0.5
0.40
0.18
0.71
1
0.50
0.27
0.81
1.5
0.50
0.37
0.88
2
0.50
0.44
0.95
2.5
0.50
0.53
1.15
3
0.50
0.57
1.21
3.5
0.40
0.40
0.90
3.8
0.35
0.15
0.52
4
0.00
0
0
Total Discharge
partial Q
0.00
0.02
0.05
0.11
0.16
0.21
0.30
0.34
0.14
0.03
0.00
1.37
Part II. Estimating and Analysing Daily Discharge Data.
1.
Using the data in Table 2, plot the discharge on the Y axis against date on the X axis, using appropriate
vertical and horizontal scales for discharge and time (you may used the graph paper labelled GRAPH
1, provided). BY HAND, sketch on a reasonable baseflow curve on your diagram.
TIPS: Point out table and graph paper on next page to use
Remind them of graphing essentials (see introductory material in lab manual)
Time goes on the X axis, discharge on the Y
Use pencil
Choose scale for axes before plotting values
Point out data is from BX Creek (fill in title of graph)
Baseflow curve will connect the lowest flows of the graph from before to after the event
ANSWER: See sample below
2. When does the highest discharge (called the “peak” flow) occur, and how high is the peak?
ANSWER: Peak discharge occurs on May 31st, peak discharge is 9.59 m3/s
3.
How would you describe the general shape of the peak flow hydrograph? Be sure to consider the
length and steepness of the rising and falling limb?
TIPS: Description should include how long (how many days) the rising and falling limbs are, how high the
peak is, and thus how steep (i.e. short time to a high peak = steep limb)
ANSWER: Base flow of this hydrograph is ~ 1 m3/s and there are a couple small events between the
16th and 29th of May. The peak discharge of the large event occurs on May 31st. The rising limb of this
event is very steep, increasing from ~1.85 m3/s on May 29th to 9.59 m3/s on May 31st. The recessional
limb is much longer and more gradual, decreasing to base flow (~1 m3/s) by June 15th (15 days total).
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Geography 103 Lab 3
Exercises: Tips and Answers
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12.00
10.00
Q (m3/s)
8.00
6.00
4.00
2.00
0.00
10-May 15-May 20-May 25-May 30-May
4-Jun
9-Jun
14-Jun
19-Jun
Day
GRAPH 1:
TABLE 2: Daily flows for BX Creek from May 15 to June 15, 1996
MAY
Q (m3/s)
JUNE
Q (m3/s)
15
0.96
1
5.50
16
1.19
2
4.75
17
1.32
3
4.30
18
2.26
4
3.85
19
2.26
5
3.30
20
1.90
6
2.82
21
1.77
7
2.55
22
2.35
8
2.20
23
2.25
9
1.95
24
2.10
10
1.75
25
2.08
11
1.47
26
2.06
12
1.31
27
1.96
13
1.18
28
1.86
14
1.12
29
1.84
15
1.05
30
3.25
31
9.59
4.
Considering the date of peak flow occurrence and the shape of the hydrograph, what sort of hydrologic
processes do you think produced the peak flow?
TIPS: Remind them of the differences between rain and snowmelt dominated regimes
ANSWER: Peak in May-June indicates a melting of snowpack
Part III. Monthly Runoff Regimes.
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Geography 103 Lab 3
Exercises: Tips and Answers
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1.
Plot the annual regime on GRAPH 2 as a bar graph, where the x-axis is the month of the year (January
to December) and the y-axis is the monthly runoff in mm/month. The data is provided in Table 3.
TIPS: Again remind them of graphing essentials (see introductory material in lab manual)
Point out this is a bar graph, not a line graph like Graph 1
Remind them that discharge (Q, column title) and runoff are the same thing
ANSWER: See sample below
2. Now plot the precipitation data (reported in mm/month) for BX Creek on the graph.
TIPS: Point out that the units of runoff and precipitation are the same, both are bar graphs
ANSWER: See sample below
80
Runoff
Monthly runoff or precipitation (mm)
70
Precipitation
60
50
40
30
20
10
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
GRAPH 2: BX Creek Monthly Flows and Precipitation
3.
Describe the relationship between precipitation and runoff with respect to their timing and magnitude.
Try to explain the similarities and/or differences in terms of the factors controlling changes in storage
and evapotranspiration.
- Runoff (Q) shows a distinct peak in May, whereas precipitation is high both during late spring/early
summer (May-June) and in the winter (November-January). In contrast, runoff is very low during
the winter months, despite high precipitation. Discharge is also low during the late summer months.
- According to the water balance equation, if precipitation and runoff do not equal this must be
explained by either a change in evapotranspiration (ET) or a change in storage (S).
- Precipitation is greater than runoff during all months of the year except May, which must be
explained by an increase in either ET or storage. Low discharge during the winter, despite high
precipitation, can be explained by an increase in storage due to the formation of glacial ice or
snowpack. Low discharge during the summer can be explained by an increase in evaoptranspiration
due to the hot temperatures (up to 19 o C in July) and the increased plant cover.
- Runoff is greater than precipitation during May only, which can be explained by either a decrease
in ET or storage. Most likely, this peak is due to a decrease in storage due to the melting of
snowpack.
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Geography 103 Lab 4
Teaching Notes
N. Salant
LAB 4: RIVERS AND FLUVIAL LANDFORMS
Preparation
- Get stereoscope and aerial photos from GIC
- Get pieces of string, aerial photos and topographic maps
- Set up overhead projector, check overhead pen
- Get overheads out of binder, including flow chart and images of rivers
Introduction
- Pass out attendance sheet
- Ask students if they have questions from previous week
Main points
- Use aerial photos and topographic maps to:
o Differentiate between stream types and measure stream characteristics
o Identify landforms
1) Channel types
Bedrock channels
Steep, flow in natural valleys
Don’t generally build landforms
Alluvial channels
Flow on thick layer of sediment (called ‘alluvium’)
Channel changes form
Develops floodplains, terraces, bluffs
(Show overhead of mountains with river running along floodplain – point out features)
(Put up overhead of flowchart)
3 types of alluvial channels
(theoretically):
- Straight
- Meandering
- Braided
Classification not distinct – continuum
Defined by # of channels and sinuosity
(‘wiggliness’)
Straight =
(a.k.a. irregular, non-meandering)
Single channel (single-thread)
Low sinuosity (P < 1.5)
Meandering =
Single channel
High sinuosity (P > 1.5)
Narrow and deep
(Put up image of rivers in planform)
Braided =
Multiple channels
Low sinuosity (P < 1.5)
Wider, shallower, and straighter
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Geography 103 Lab 4
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(Put up image of floodplains/terraces)
2) Fluvial landforms
Floodplains
Form when river has amounts of sediment
River floods and deposits outside normal river banks
Terraces
Form when river has low amounts of sediment
River floods and incises (cuts into) floodplain
(Put up image of meander)
Point bar
Sediment deposited on inside
of channel bend
Undercut (eroding) bank and pool
Erosion occurs outside of channel
bend
Meandering river landforms:
(Put up second image of meander)
Oxbox lake
Overtime, sinuosity increases
Meander becomes cut off from main channel
Cut-off meander becomes lake
Meander scrolls
As river migrates across floodplain
Sediment deposited in ridges across point bar
Braided river landforms:
Mid-channel bars
Gravel and sand deposited within channel
May be submerged at high flow
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Geography 103 Lab 4
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3) Quantifying Channel Morphology: Sinuosity and stream gradient
Sinousity (P)
= Channel length/Valley length = lc/lv
(Show class how to measure lengths using string on the map
– channel follows river, valley straight line start to end point)
Stream gradient
= Rise =. Vertical distance in m .
Run
Horizontal distance in km
(typically m/km or %)
Vertical distance = change in elevation between point upstream and a point downstream (use
contours)
Horizontal distance = length of the channel (including channel bends) between up- and
downstream points (use distance on map and convert to real distance using RF)
Steps to calculate stream gradient:
1. Find contours up and downstream; measure vertical distance
2. Measure horizontal distance of river (including meanders) on map
3. Convert to km using RF
4. Calculate gradient as rise/run
(Go through example calculation with class)
Example)
1. Locate benchmarks or contour lines up and downstream – calculate change in elevation = 100 ft
Convert ft to meters (100 ft = 30.48 m)
2. Measure horizontal distance of river using string = 10cm
3. Convert to ‘real’ km using RF
10 cm x 50,000 = 500,000 cm = 5 km in real life
4. Calculate rise/run = 30.48m/5 km = 6.10 m/km or 30.48m/500m = 0.61 %
4) Air photos
Identified by (in margins)
Reference code
e.g BC78081
BC = taken by BC Ministry of the Environment
78 = taken in 1978
081 = Film roll number (related to the flight line)
Photo number
e.g. 76 or 77
Dials on side of photo
(Note it is only visible on original, be sure to show)
1. Altimeter = elevation of aircraft (flying height)
2. Bubble = indicates whether the plane was level
Focal length
e.g. C152.91 = 152.61 mm
Camera number
e.g. Nr124223
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Geography 103 Lab 4
Teaching Notes
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3. Time the photo was taken
4. Date the photo was taken
Scale of photos:
S = H/f
Elevation of plane/focal length
Pay attention to units! Make sure H and f are the same
Elevation is usually in feet or meters
RF = 1/S
Interpreting aerial photos
– i.e. identifying landforms:
rivers
glaciers
ridges
valleys
e.g. if focal length (f) = 6 inches = 0.5 ft
e.g. H = 25,000 ft
S = 25,000ft/0.5ft = 50,000
e.g. 1:50,000
– and look for evidence of changes to landscape:
e.g where river used to run
(Introduce stereoscope – creates 3D image of photos, allows for more in-depth and detailed analysis – tell
class it will be set up and available to look at during lab)
(Tell class to read through section on air photo interpretation – however today’s assignment focuses on
river forms)
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Geography 103 Lab 4
Exercises: Tips and Answers
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TELL CLASS: DO NO DRAW ON MAPS OR PHOTOS (even if someone has already drawn on them)
PART 1: AIR PHOTOS AND TOPOGRAPHIC MAPS
TIPS: Main purpose is to learn how to get information from maps and photos
First step is to align photo and map (i.e. find location on map of which photo was taken)
Easiest way to do this is to look for the large meander in the NW corner of map, line up N edge
1. Select air photos number 76 and 77. Compare the photos with the Walker Creek map to identify the
north edge of the photos. You may need to look at the original air photos to answer questions 1c and 1d.
TIPS: Questions are about information in margin of photo
Because dials aren’t visible on copies, use original photo to answer 1c and 1d
a. In what year was photo number 76 taken?
___1978______
b. What is the roll number?
___081_______
c. What was the altitude of the plane when the photo was taken?
__24 000 feet__
d. Was the plane level when the photo was taken?
____Yes______
e. Is this reference information on the N, S, W or E edge of the photograph?
____South____
2. On the air photos, try looking for areas of different terrain, different vegetation types, and different river
types. Note human features: can you tell the difference between forest harvesting areas and alpine areas?
Can you tell roads from streams? (No need to write any answer here.)
TIPS: Tell students to take time to try and recognize things on map; refer to list of symbols on back of map
(e.g. vegetation, roads, rivers)
3. Name the river in the photographs.
TIP: Map has information you need – just link photos and map
ANSWER: McGregor River
4. In which direction does the river flow? Briefly explain your answer.
TIP: Remember, do rivers flow up or downhill? Then use information on map (hint: contour lines)
ANSWER: East to west across the map from high elevation (>2900 feet above sea level) to low
elevation (~2500 feet), determined from contour lines.
5. Locate the island in the river, half of which can be seen the southeast corner of photo number 76. Locate
it on the topography map. Give the 6-digit UTM coordinates for the centre of the island.
TIP: Remember first lab, lesson on UTM – 3 digits for Easting, 3 digits for Northing
ANSWER: 378776
PART II: RIVER CHANNELS AND FLUVIAL LANDFORMS
1. Describe the alluvial channel pattern of Kitchi Creek in a single word! Look at the legend on the back
of a newer topographic map to determine what the brown dots adjacent to the river represent. Now
examine Kitchi creek on air photo BC78081: 83. How does the creek on the photograph differ from the
creek depicted by the map?
TIPS: Old map legend doesn’t identify brown dots, but newer maps do – look at new map
But also consider, what we see on map is wide, shallow, straight channel (dots are where water can run)
Different times of the year, there are different amounts of water running through channel
How would channel look after a big rainstorm, vs. during a drought? What about when photo was taken?
ANSWER: Braided.
Brown dots represent gravel and sand in the river channel that were not occupied by water when the
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Geography 103 Lab 4
Exercises: Tips and Answers
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site was mapped.
The photos show the channel full of water, with little gravel visible. The photo was taken in July
when melt-water fills the channel, submerging any mid-channel bars.
2. Consider the McGregor River in the northwest section of the map. What map evidence is there that
meanders have shifted in the past? What further evidence can you see on the air photos?
TIPS: Use map and photo
Look back at notes about meandering rivers – as river moves, as sinuosity changes, what gets left behind?
(Point bars, meander scrolls, floodplains)
Note – what do little plant-like symbols represent? How might that be evidence?
(Swamp, marsh = floodplain)
ANSWER: In the floodplain or valley bottom there are oxbow lakes, marshes and swamps in old
channel depressions. Gravel deposits are evident in point bar position. On the air photos, meander
scrolls and meander cut-offs are evident.
3. Using both the photos and the map, identify the landform at each of the 10 locations listed below.
Select from the following list of 8 landform types. Some types will be used more than once.
TIPS: Warn them this may seem difficult, just do your best
Note that if 2 UTM locations are next to each other (one inside, one outside channel), what could they be?
Inside = deposition = point bar
Outside = erosion = eroded bank or meander scroll
How to identify terraces? On map, look for steep contour lines and higher elevation
How to identify oxbow lake? Remember it is lake formed by meander cutoff – looks like bow
How to identify alluvial fan? Deposition where there is a change in slope (mountain to floodplain, steep to
low gradient, closely to widely spaced contours)
Flood plain
Meander scroll
Point bar
Terrace
Eroding bank
Alluvial fan
Oxbow lake
Mid-channel bar
UTM Location
Landform type:
402794
Point bar
402793
Eroding bank
427816
Alluvial fan
343814
Point bar
496845
Mid-channel bar
375785
Flood plain
344815
Eroding bank
340822
Meander scroll
448827
Terrace
355810
Oxbow
4. Compare the sinuosity, gradient, and channel pattern of two sections of McGregor River.
Section A:
from 475843 to 530836
Section B:
from 450835 to 311850
a. For each section, calculate sinuosity (P). Show your calculations.
TIPS: Use equation of sinuosity (P = lc/lv)
Use method of using string to measure on map and ruler to measure length of string
Always show your work! This is the only way you can get partial credit (applies here and to exams)
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Geography 103 Lab 4
Exercises: Tips and Answers
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ANSWER:
Section A: P = Lc / Lv = 21.5 cm / 19.5 cm = 1.1 = braided channel
Section B: P = Lc / Lv = 71.5 cm / 39.3 cm = 1.8 = meandering channel
b. For each reach, calculate gradient (S). Note that on this map the contour interval is in imperial units.
Show your calculations.
TIPS: Remember, contours are in feet, not meters
Remember, vertical divided by horizontal distance
1. Measure horizontal with string (follow channel)
2. Convert to km using RF ( = 1:50,000)
3. Find contours up and downstream of points, measure vertical change (up-down)
4. Convert vertical (in feet) to meters using conversion 100ft = 30. 48m
5. Divide rise (in m) over run (in km)
ANSWER:
Section A:
Rise
Run
= 2700 – 2590 = 110 feet
110 ft x 0.3408 = 37.5 m
= 21.5 cm on map x 50 000
= 1,075,000 cm on ground
= 10.75 km
110 m / 10.75 km = 10.2 m / km
OR
110 m/ 10750 m x 100 = 1.02 %
Section B:
Rise
Run
= 2590 – 2450 = 140 feet
140 ft x 0.3048 = 47.7 m
= 71.5 cm on map x 50 000
= 3, 575, 000 cm on ground
= 35.75 km
42.7 m / 35.75 km = 1.2 m/km
OR
42.7 m/ 35750 m x 100 = 0.12%
c. Examine air photo BC78081: 81 and refer to answers from 4(a).
TIPS: Should be able to answer just by looking, but also consider values of P you calculated (high or low)
Is Section A straight, meandering or braided? Explain your answer.
ANSWER: Meandering.
The channel is single-thread and has a sinuosity > 1.5.
Is Section B straight, meandering or braided? Explain your answer.
ANSWER: Braided.
The channel has multiple threads and a sinuosity < 1.5.
3
Geography 103 Lab 5
Teaching Notes
N. Salant
LAB 5: GLACIAL PROCESSES AND LANDFORMS
Preparation
- Write name, email address (optional), lab section, lab time, and personal LAC hours on
board
- Set up overhead projector, check overhead pen
- Get overheads out of binder (diagrams of glacial landforms)
- Get half-sheet grids for making topographic profiles
Introduction
- Pass out attendance sheet
- Ask students if they have questions from previous week
Main points
- Two types of glaciers – alpine and continental – with different forms and features
- Learn to name and identify morphological features of glaciers on maps and photos
1) Glaciers and glacial features and landforms
Essentially large accumulations of ice
Today, they exist only at high elevations or latitudes
In past, they would have covered most of Canada
2 Types:
- Alpine = confined to valleys, small
- Continental = cover most of continent, massive
Different features associated with each:
(As you introduce each feature, draw it on the overhead of the picture, below)
(But get students to do it with you – read the description, then have them guess where it would be)
Alpine glacier features
headwall – upslope limit of the glacier
cirque - bowl-shaped depression at head of glacier
firn – glacial ice, resulting from recrystallized snow
zone of accumulation – upslope zone in which snow accumulation exceeds ablation
zone of ablation – downslope zone in which snow ablation exceeds accumulation
crevasse – crack indicating ice movement and changes in underlying bedrock topography
moraine – sediment transported and deposited by the glacier (lateral, terminal, recessional)
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Geography 103 Lab 5
Teaching Notes
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Different features produce different landforms once glacier recedes (melts)
(As you introduce each landform, draw it on the overheads of the pictures, below)
(Explain that students will need to identify these on a topographic map, based on these descriptions)
Alpine glacier landforms
cirque – bowl-shaped depression at head of glacier
horn – three or more cirques forming a sharp, pointed peak
arête – sharp ridge or walls dividing two cirque basins
col – erosion of an arête by two cirques forming a high elevation pass
tarn – small mountain lake in a cirque
glacial trough – U-shaped, deep, steep-walled trough
hanging valleys – tributary valleys elevated above main trough
fjord – open trough below sea level, inundated with sea water
Continental glacier landforms
moraine – till (sediment) deposited on the outer edge of the ice sheet (lateral,
esker – deposit of sand and gravel in an ice tunnel created by meltwater
outwash plain – stratified drift left by braided streams
drumlin – smooth rounded oval hill consisting of glacial till
till plane – distribution of till between moraines
kame – residual glacial delta of well-sorted sand and gravel, isolated and flat-topped
kettle – basin-like hollow created by ice deposited onto glacial till as the glacier receded
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Geography 103 Lab 5
Teaching Notes
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2) Glacial movement
‘Advancing’ = gain/accumulation of ice > loss/ablation of ice = glacier grows in size
‘Retreating’ = loss/ablation of ice < gain/accumulation of ice = glacier shrinks in size
Effects of glacial movement:
‘Plucking’ of stones – picks up material that moves with glacier and is deposited later
‘Abrasion’ or ‘scouring’ of bedrock – type of erosion, causes grooves or smoothing of rock
Deposition of glacial ‘till’ – sediment in glacier is deposited, may form moraines or ‘erratics’
(Make sure terms are clear:
Till = any sediment transported and deposited by glacier)
Erratics = large individual rocks transported and deposited by glacier)
3) Topographic profiles
Graph of topographic relief and landforms of a landscape
Vertical elevation plotted against distance
(Show example in lab manual)
How to construct topographic profile:
(Demonstrate for class using map and graph paper)
1. Lay graph paper along transect on map
Choose start and end point of transect
(For this lab, use Paradise Valley: Mt. Aberdeen to Mt. Temple)
2. Tick each point where profile stars, ends, and crosses each contour line, stream, or hill top
3. Label each tick point
OK to only label index contours when ticks are close together
4. Make vertical axis
Use 1000 ft = 1 cm (1 box)
(Note that choice of axis will determine how big your mountains look)
Choose your vertical scale based on contours
In this case, minimum = 2000 ft, maximum = 12,000 ft
5. Using a ruler, project each tick mark to the appropriate elevation
6. Connect all points with a smooth line
7. Label features (e.g. hilltops)
8. Label x-axis with RF of map
In this case, RF = 1:50,000
A. Vertical exaggeration
Consider what graph would look like with a different vertical scale
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Geography 103 Lab 5
Teaching Notes
N. Salant
Example) Instead of 1 box = 1000 ft, try 1 box = 500 ft
Would mountains look taller or shorter?
(Taller - demonstrate with figure)
For a 2000 ft tall mountain:
1000 ft interval
500 ft interval
4000
2000
3000
1500
2000
1000
1000
500
Example of Vertical Exaggeration (VE) = a way to make low relief landforms easier to see
Calculating VE:
VE
=
Vertical scale
Horizontal scale
Vertical scale:
1 cm on figure = 1000 ft in real life
To convert to RF, units must be the same
=
1,000 ft
x1m
3.28 ft
x 100 cm
1m
Units cancel
= 30, 480 cm
So RF = 1:30,480
Horizontal scale:
RF = 1:50,000
VE
=
= 1.6
1:30,480
1:50,000
Mountains exaggerated by a factor of 1.6
Typical VE is ~2
4
Geography 103 Lab 5
Exercises: Tips and Answers
LAB 6: ASSIGNMENT
PART I: INTERPRETATION OF ALPINE GLACIAL LANDFORMS
1. Use the topography map and air photos to identify the landform at each of the 10 locations
listed below. Select from the following list of 8 landform types. Some types will be used more
than once.
TIPS: We do not use air photos, tell students not to worry
‘Name of feature’ is the given cultural name, written on the map
‘Landform type’ is the actual physical feature (e.g. cirque, col)
Use cultural names to help you identify what landform it is – for example, something called a
ridge or a pass would both correspond to very distinct features (arête, col)
cirque
horn
arête
col
tarn
glacial trough
hanging valley
fjord
UTM Location
540866
543877
606858
610822
528857
600940
671995
534868
619039
584839
Name of Feature
Larch Valley
Sentinel Pass
Panorama Ridge
Consolation Pass
Eiffel Lake
Bow Valley
near Baker Creek
Eiffel Peak
Hidden Lake
Mount Babel
Landform type
cirque
col
arête
col
tarn
glacial trough
hanging valley
horn
tarn in a cirque
horn
2. One glacial landform was not included – explain why.
TIP: Tell students to think about where this map is from relative to the ocean
ANSWER: The Lake Louse map does not include an example of a fjord. A fjord is an open
glacial trough that is situated below sea level and becomes inundated with sea water. Due to
the continental or inland location of Lake Louise and the Bow Valley, fjords have not
developed as a result of glaciation.
3. Construct a cross-sectional profile of one of the larger glacial valleys in the Lake Louise map
area. Your profile should cover at least 3km, cross perpendicular to the valley axis, and extend
from a peak or ridge on one side of the valley to a similar topographic high on the opposite side
of the valley. Calculate the vertical exaggeration and indicate it on the diagram. Indicate the UTM
coordinate where your cross section is located. Include the appropriate titles and labels.
TIPS: Tell students to use list of instructions for making a topographic profile
For Paradise Valley, start at Mt. Aberdeen, end at Mt. temple
Set vertical scale to be 1cm = 1000ft, horizontal scale is just RF
Remember RF = 1:50,000
Calculate VE for 1cm = 1000ft, then try 1 cm = 500ft, see how much bigger it would be
UTM coordinate will be two different UTMs, one for start, one for end
ANSWER: Answers will vary.
Geography 103 Lab 5
Teaching Notes
4. Construct another cross-sectional profile, using it to illustrate the topographic setting of one or
more glacial features such as those identified in Question 1. Label the diagram as in Question 3.
ANSWER: Answers will vary.
PART II. CONTINTENTAL GLACIATION
1. What are the elongate hills called? How were they formed? What was the direction of ice
movement?
TIPS: Remind them this is a continental glacier
The elongated hills are drumlins. Drumlins were formed by deformation of till under the
moving Laurentide ice sheet. Drumlins are streamlined in the direction of ice movement.
The Laurentide ice moved from the northeast to the southwest. Note the asymmetrical, long
profiles typical of drumlins:
2. How is an esker formed?
TIPS: Again, remind them this is a continental glacier, and eskers are composed of coarse but
more rounded material.
If you want to point some out to the students, eskers on this map can be found at:
385160 to 362136
106182 to 094164 (the southern portion has been mined for gravel)
030228 to 000195 (parts of this esker have been mined for gravel)
Eskers are formed by deposition of sands and gravels by a subglacial meltwater channel.
The sands and gravels are deposited on the channel bed. When the meltwater and glacial
ice have been removed, a mound of sediment remains, showing the former subglacial course
of the channel.
6
Geography 103 Lab 6
Teaching Notes
LAB 6: FIELD TRIP TO THE POINT GREY CLIFFS
Preparation
- Bring backpack, raincoat, gloves, good shoes
- Prepare three samples, in bags, to show students different material types
Introduction
- Pass out attendance sheet
- Ask students if they have questions from previous week
- Explain that ~10 minutes of explanation and notes before field trip will help answer
questions and explain what we see
1) (Brief) Geomorphic History of Point Grey Cliffs
Glacial history - 3 formations:
Vashon Till (youngest, at top)
– formed by glacial till, at base of glacier, moved by ice, compressed
Upper Quadra
– formed by glacial outwash, at front of glacier, moved by meltwater
Lower Quadra
– formed by glacial till, at base of glacier, moved by ice
Template for stratigraphic profile:
Vashon Till
Upper Quadra
Each layer/formation has a different:
- Age
- Thickness
- Slope angle
– indicates resistance to erosion
Gradual = less resistant, more permeable, coarser material (water percolates)
Steep = highly resistant, less permeable, finer material
Lower Quadra
Upper Quadra
Water
Colluvium
Water stops at impermeable layer and is
forced laterally = seepage
Lower Quadra
1
Geography 102 Lab 6
Teaching Notes
N. Salant
Recent history Cliffs eroded by runoff, landslides and wave action
Human activity to reduce natural erosion
(Tell students to look for evidence of all these things along the way)
Introduce assignment:
Review questions
Sketch topographic profile (see template)
Table – characteristics of the 3 formations
Clast size
Texture
Bedding
- outwash = meltwater = bedded
- till = ice transport = not bedded
Sorting
- outwash = water = sorted, rounded
- till = ice = unsorted, angular
Compaction
- Lower underneath Upper = high compaction
- till underneath ice = compaction
Permeability
- related to clast size
Resistance (vs. erodibility) - related to permeability and clast size
2) Field trip
1st stop: Satellite photo next to room 130
Point out location of UBC and location of glacier (Northwest of UBC)
Transport of meltwater was first Southward  Lower Quadra
Transport shifted Southeast  Upper Quadra
2nd stop: Top of trail
Point out Upper Quadra sand near tree
Note that in this location, Vashon Till is not at surface (eroded) –will see at end of walk
Discuss erosion processes acting on hillslope (get students to suggest mechanisms)
Mechanical erosion processes
Sheetwash, gully erosion, seeps, waves, freeze-thaw, landslides, soil creep
Point out that trail goes down centre of gully. What produced this? Landslide
Biological erosion processes
Tree-throw
Human walking
3rd stop: At bench, next to seepage
Talk about evidence for boundary between Upper and Lower Quadra
1. Seepage – indicates where two layers meet, permeable hits impermeable
2. Change in slope – Upper = less steep (~30%), Lower = more steep (~75%)
Why? Upper – sandy loam = coarse = permeable = less resistant
Lower – clay loam = fine = impermeable = more resistant
4th stop: Beach
Note that material on beach is eroded Quadra sand, ‘slumping’ from mass-wasting
= colluvium or alluvium, debris fan
Walk along beach
5th stop: First groyne
1
Geography 102 Lab 6
Teaching Notes
N. Salant
Point out steep exposed face of cliff
Talk briefly about human intervention, attempts to reduce erosion:
1. Built groynes – perpendicular to beach, decrease wave action erosion
2. Built berms – parallel to beach, decrease wave action erosion (brought in cobbles
from Cascade Mountains, WA – metamorphic composition, not local)
3. Built trails and stairs – reduce human impact
4. Increase vegetative cover – seed and plant; roots increase stability, capture water,
reduce runoff
Take footpath behind beach – point out berms
Continue on beach to first tower, then take footpath again
6th stop: Just past tower on footpath
Show landslide scar – bent trees, gentler slope
Age of trees indicates date of landslide (smallish trees ~ 20-30 year old)
Continue along path to trailhead, at base of large landslide gully
Point out upside down tree!
7th stop: At base of trail up to top
Point out how gradual trail is compared to trail coming down
Evidence of landslide – wide gully
Tell students to stop at top
Last stop: Top of trailhead
Point out topsoil – podzol formed from parent material
Point out parent material
- glaciomarine deposit (deposited beneath the ocean, then affected by waves as cliffs emerged
from sea, as sea level dropped)
- composed of pebbles, cobbles, some sand; less compact than Vashon Till below it
- well-drained, but water collects below it at top of Vashon Till
2
Geography 102 Lab 6
Exercises: Tips and Answers
N. Salant
LAB 3: FIELD TRIP TO THE POINT GREY CLIFFS
ASSIGNMENT
ANSWERS
1. Draw a full-page vertical section of the Point Grey Cliffs from the top to beach level. Be sure to
illustrate the three main formations resulting from glacial-related deposition.
Refer to figure at end of document
2. Record details about each stratum in the accompanying data table.
See answers in the table below.
3. Note the degree of compaction of the Vashon Till. Compare it with the underlying formation. Why is
the till so compact? How does this affect water infiltration?
The Vashon till is basal till that was deposited at the base of the glacier and was over-ridden by ice.
The weight of the ice compacted the material making it relatively impermeable to water (low
infiltration).
4. When were the Quadra Sands deposited? How were these dates determined?
The Quadra Sands were deposited prior to the last glacial maximum between 26,000 and 18,000
years before present using radiocarbon techniques on organic matter found within the stratified
layers of the lower sands.
TIPS: Organic material at the base of the formation has been dated using radiocarbon techniques. Specific
dates from the lower unit are 26,100 320 and 25,100 600 years before present.
5. Identify three forms of erosion affecting the Cliffs. Note the physical features that you used to identify
each form of erosion.
Mass movements – colluvium and debris fans at the base of eroded gullies; distorted tree stems and
“buttsweep” or downslope curvature of tree stems
Wave action – undercutting of banks along the beach; deposition redistribution of logs, rock and
debris along the beach
Water – slumps where seeps cause instability
Vegetation disturbance – individual tree-falls create exposed root mounds and pits
Humans – trail building and off-trail hiking, development and construction at the top of the cliffs
6. Explain three ways that water contributes to the erosion of the Point Grey Cliffs.
Water contributes to erosion via (1) sheetwash (overland flow), (2) gulley erosion (streamflow), (3)
seeps that undermine strata, (4) waves, and (5) freeze-thaw action.
7. Describe the beach material near Graham’s Gulley on Tower Beach. Is this material derived from the
Point Grey Cliffs? Consider three lines of evidence: mineral composition, clast size and shape. Explain the
origin of these materials.
The dominant clasts on Tower Beach are rounded pebbles and cobbles. Some rocks are granites and
diorites and could be of local origin. However, metamorphic rocks, sandstones and mafic igneous
rocks are more numerous. Their mineral composition indicates they are not of local origin. The
pebbles and cobbles were brought in by barge from the northern Cascades and deposited on the
beach to control erosion due to wave action and long shore drift. In contrast with Tower Beach,
1
Geography 102 Lab 6
Exercises: Tips and Answers
N. Salant
Wreck Beach is more natural and includes sand with larger clasts of local origin along the base of the
cliffs.
8. Explain three ways that people have attempted to stabilize the cliffs and reduce erosion.
1) Groynes and berms on the beach have been created using boulders, cobbles and pebbles. Theses
structures reduce erosion due to waves and longshore drift. 2) Trees and other vegetation have been
planted along the cliffs to help stabilize the soil. 3) Upslope, terraces have been created. 4) Human
access is limited to designated areas and trails. 5) Development at the top of the cliffs is carefully
planned and infrastructure impacts are monitored.
2
Geography 103 Lab 5
Exercises: Tips and Answers
STRATIGRAPHY OF THE POINT GREY CLIFFS: PHYSICAL CHARACTERISTICS OF THREE STRATA
Stratum
Clast
size(s)
Texture of
matrix
Bedded
(Yes/No)
Sorted
(Yes/No)
Vashon
Drift
(Till)
silt
sand
pebbles
cobbles
sand or
loamy sand
no
no
Upper
Quadra
Sand
silt
sand
loamy sand
or sandy
loam
yes
yes
(within
beds)
Lower
Quadra
Sand
sand
silt
clay
sandy clay
loam or
clay loam
yes
yes
(within
beds)
Shape
Depositional
environment
Compaction or
consolidation
Permeability
Resistance
Erodibility
rounded
to
angular
basal till of
glacier
high: due to
direct weight of
glacial ice
low
(forms a
perched
aquifer)
high
low
NA
fast moving
water
moderate to low
high
low
high
NA
slow moving
water
high: due to fine
material + weight
of glacial ice
low
(seeps form
between strata)
high
low
Geography 102 Lab 6
Exercises: Tips and Answers
N. Salant
4