Dr. Dan Smith, PhD

Geography Department, University of Victoria

RIVER BANK EROSION, BEAVER RIVER CROSSING OF THE TRANS CANADA HIGHWAY

GLACIER NATIONAL PARK, BRITISH COLUMBIA

Submitted By:

Laura Card

Keith Bootle

GEOG 477 – FIELD SCHOOL PROJECT

December 2008

i

ABSTRACT

This paper describes an investigation of riverbank erosion at the Trans Canada Highway at the

bridge over the Beaver River. Fieldwork was conducted to gather information about river flow

velocity, estimated discharge, bar pebble distribution and bank sediment size and cohesiveness.

Further information was gathered including a retroactive field assessment, aerial photographs,

historical climate data and discharge trends to help determine why the bank is eroding at this

location, an estimation of a rate of erosion and the potential implications of the bank erosion. The

methodology for the fieldwork was crude and therefore did not provide conclusive results. Results

indicated that the Beaver River bank was eroding due to change in meander characteristics and bank

erosion is exacerbated by high flow events in the summer months (May to July), less cohesive bank

material, debris obstructions and possibly by poor rip-rap construction. Only a rough rate of

erosion could be determined based on aerial photography review but still requires further field work

at a later date for comparison with measurements taken during the field work conducted for this

paper. The potential implications of bank erosion at this location included undermining of the

bridge construction, a wash out of the Trans Canada Highway which would result in impact on BC

tourism and economy as the highway is the main corridor from BC to the east.

ii

TABLE OF CONTENTS

ABSTRACT .................................................................................................................................................... I

1.0 INTRODUCTION AND BACKGROUND ............................................................................................. 4

1.1 GENERAL................................................................................................................................. 4

1.2 SITE DESCRIPTION ................................................................................................................ 4

1.3 SCOPE OF WORK ................................................................................................................... 5

2.0 RIVER BANK EROSION .................................................................................................................... 6

2.1 GENERAL................................................................................................................................. 6

2.2 INFLUENCE OF BRIDGES ...................................................................................................... 6

3.0 METHODOLOGY ................................................................................................................................ 7

3.1 FIELD METHODOLOGY .......................................................................................................... 7

3.1.1 Flow Velocity Measurements ....................................................................................... 7

3.1.2 Discharge Estimates .................................................................................................... 7

3.1.3 Pebble Count ............................................................................................................... 7

3.1.4 Sediment Collection and Sieving ................................................................................. 8

3.2 LABORATORY METHODOLOGY ............................................................................................ 8

3.2.1 Retroactive Channel Stability Assessment .................................................................. 8

3.2.2 Aerial Photograph Review ........................................................................................... 8

3.2.3 Historical Climate and Discharge Trends ..................................................................... 8

3.3 LIMITATIONS OF METHODOLOGY ........................................................................................ 9

4.0 FIELD OBSERVATIONS .................................................................................................................. 10

5.0 RESULTS AND DISCUSSION ......................................................................................................... 13

5.1 FIELD RESULTS AND DISCUSSION .................................................................................... 13

5.1.1 Flow Measurements .................................................................................................. 13

5.1.2 Discharge Estimates .................................................................................................. 13

5.2 LABORATORY RESULTS AND DISCUSSION ...................................................................... 14

5.2.1 Retroactive Channel Stability Assessment ................................................................ 14

5.2.2 Sediment Sieve Analysis ........................................................................................... 15

5.2.3 Pebble Count ............................................................................................................. 16

5.2.4 Aerial Photograph Review ......................................................................................... 17

5.2.5 Historical Climate and Discharge Trends ................................................................... 19

6.0 CONCLUSIONS ................................................................................................................................ 20

7.0 REFERENCES .................................................................................................................................. 20

iii

TABLE OF CONTENTS

APPENDICES

Appendix A River Channel Stability Assessment

Appendix B Flow Rate Data

Appendix C Discharge Data

Appendix D Sediment Sieve Analysis Data

Appendix E Pebble Count Data

4

1.0 INTRODUCTION AND BACKGROUND

1.1 GENERAL

A portion of the right riverbank located near the bridge of the Trans Canada Highway is

being eroded by the Beaver River (Figure 1). Stability of the highway and bridge is

potentially at risk due to the erosion therefore the purpose of this investigation was to

answer the following questions:

1. Why is the Beaver River eroding in the bank in this location?

2. How fast is the bank being eroded?

3. What are the implications of the bank erosion?

Figure 1: Photo showing the erosion of the right bank of the river near the bridge.

1.2 SITE DESCRIPTION

The Beaver River is a tributary of the Columbia River and is a glacier fed meandering river

that empties into the Kinbasket Lake (Wikipedia website). The drainage basin of the river is

bounded to the south and east by the Glacier National Park boundary and is 1,150 km2

(Figure 2) (Water Survey Canada (WSC) website). Figure 3 shows a location map of the

mouth of the river (WSC station “Beaver River at the Mouth”), our site and the source of

the river.

The portion of the Trans Canada Highway that runs through Glacier National Park was

completed in 1962 (Parks Canada) and was the last completed section. Prior to that; the

only access through Rogers Pass was by railway, which was completed in 1885. The railway

does not cross the Beaver River at the same section of the highway so this investigation did

not include the railway. Traffic routing through Glacier National Park along the Trans

5

Canada Highway increases by 1 to 2 % per year (Parks Canada) indicating the significance

of the highway as an important transportation route.

The bridge itself is a concrete structure, 42 metres long with a single abutment mid-span.

There is armouring under the bridge of the two outermost abutments as well as some riprap

along the right bank. The actual age of the bridge is unknown however there is some

evidence to suggest that it has been updated at some point and is not the original bridge

structure erected in 1962.

Figure 2: Drainage map of the Beaver River. Figure 3: Map showing WSC station, site and source of river.

1.3 SCOPE OF WORK

The scope of work for the bank erosion investigation included the following:

Visually observing the channel at the erosion location, the bank sediments, channel

morphology and basic bridge construction and conducting a retroactive assessment of

channel stability based on these observations.

Taking flow velocity measurements upstream of the bridge, near the bridge and

downstream of the bridge.

Estimating channel cross-sections at the flow velocity locations in order to determine an

estimated discharge.

Conducting a pebble count at two point bars, one upstream and one near the bridge.

Collecting bank sediment samples at the site of erosion and conducting sieve analysis on

them.

6

Collecting other relevant information including aerial photographs, historical climate

information and local discharge trends from the Water Survey of Canada.

Providing this report that summarises our results.

2.0 RIVER BANK EROSION

2.1 GENERAL

Meandering rivers are often subject to bank erosion as the outer bank of a bend is a zone of

maximum boundary shear stress (Knighton, 1998). Two main mechanisms cause bank

erosion: bank scour and mass failure (Natural Resources Sciences, 2006). Bank scour is the

direct removal of bank materials by the action of the river and the sediment it carries and

flow rate is a major factor. Mass failure is the collapse of a section of the bank into the river

in a single event and is common when the bank has been undercut (Natural Resources

Sciences, 2006). Other factors contribute to the erosion of a bank and include the

following: flooding, land use and stream management, clearing of river bank vegetation,

river straightening, rapid flow drop after flooding, saturation of banks from non-river

sources, redirection and acceleration around infrastructure or debris in the channel, intense

rainfall events, and bank soil characteristics such as easily erodible or poor drainage. Several

of these factors were evident at the Beaver River.

2.2 INFLUENCE OF BRIDGES

If a bridge is constructed at a meander point, or near a migrating bend, the construction of

the bridge itself can change the characteristics of the river as the river adjusts to the

obstructions within the channel (Lagasse et al, 2001). Some of the common hydraulic

problems associated with bridge construction at a migrating meander are shown in Figure 4.

Erosion of the outer bank can create erosion of fill used in construction and breaching of

embankments at the outer abutments. Also bar growth within the channel under the bridge

can result in constriction of the channel and the mid-span abutment acts as an obstruction

and increases scour.

Figure 4: Problems associated with bridge construction at

river meanders. From Lagasse et al, 2001.

7

3.0 METHODOLOGY

3.1 FIELD METHODOLOGY

3.1.1 Flow Velocity Measurements

Flow velocity measurements were taken in three locations along the channel: upstream of

the bridge, near the bridge and downstream of the bridge. At all locations, measurements

were taken for a 10 metre section and a 20 metre section. A floating object was thrown into

the river as close to the thalweg location as possible and the time was recorded for the

object to travel 10 metres and 20 metres. Five time trials were conducted and the results

averaged. According to the following equation, flow velocity could then be estimated.

v = d / t where v = velocity (m/s)

d = distance (m)

t = time (s)

Due to obstructions in the river channel, two sub-locations at the near bridge site were used

for the estimation.

3.1.2 Discharge Estimates

Measurements of the channel width and depth were taken at each of the flow velocity

locations in order to estimate a channel cross-section and therefore, combined with flow

velocity, an estimation of discharge.

Channel width was determined by tying the end of a measuring tape to a rock and throwing

it across the channel and channel depth was estimated by wading and speculation. This

provided a crude estimation of the area of each flow velocity location. According to the

following equations, discharge was estimated.

A = w x D Where A = area (m2)

Q = v x A w = channel width (m)

D = channel depth (m)

Q = discharge (m3/s)

v = velocity (m/s)

A comparison to data provided by the Water Survey of Canada was also included. Real

time data was collected for the station “Beaver River at the Mouth” for the selected days of

September 10th to 11th, 2008, the days that the field measurements were taken. A ratio of

the discharge on those days to the drainage area of the entire Beaver River was compared to

an estimated drainage area for the site (upstream of the bridge), which was able to give an

estimated discharge as compared to known data.

3.1.3 Pebble Count

A pebble count was conducted at two locations, on an upstream bar and on a bar located

near the bridge. Transects were established across each bar and ten random pebbles at five

metre intervals along the transect were measured along the x, y and z-axes to achieve a

8

representation of the bar pebble size. The longest axis (y-axis) data was then used as a

representation of the pebble and the number of pebbles per grain size according to the

Udden-Wentoworth scale were counted. This estimated the grain sizes of the pebbles of

the bars. A correlation between upstream and downstream bars was attempted.

3.1.4 Sediment Collection and Sieving

Three sediment samples were collected along the eroded bank. An organic horizon was

observed so samples were taken from the organic layer, below (near the water line) and

above (near surface) the organic horizon. The sediments were dried in the laboratory and

subjected to a standard set of sieves and each sub-sample was weighed. The sub-sample

with the highest percentage was considered to be indicative of the most common type of

sediment within each layer analysed.

3.2 LABORATORY METHODOLOGY

3.2.1 Retroactive Channel Stability Assessment

A channel stability assessment (Lagasse et al, 2001) was conducted after the fieldwork was

completed and was based on the observations made in the field. The assessment consisted

of 13 stability indicators that were ranked into excellent, good, fair and poor ratings, with

three values in each range and a value was assigned to each indicator based on the field

observations made. Some of the indicators were for regional observations of the channel

and others were for local conditions. The ratings for the indicators were then weighted

based on each indicators impact on stream instability. The sum of the weighted ratings

gives a final rank to the river. This method was based on prior assessments methods and

tested on gravel bed streams and has several advantages including that the assessment does

not have a single indicator that can dominate the rating of channel stability. This method

provides a relative ranking instead of a quantitative ranking; however, it can still be used to

give an idea of potential problems that exist or may arise. The assessment is attached as

Appendix A.

3.2.2 Aerial Photograph Review

Aerial photographs from 1986, 1994 and 2004 were obtained in attempt to measure bank

erosion rate. Measurements of common features to each photo such as upstream

meanders, upstream channel width, and bar length were compared. Observations were

made regarding historical bar migration and alterations to the upstream flow patterns. A

crude erosion rate was obtained by relating the river shape observed in September 2008, to

that in the 2004 aerial photo. Estimations of the area eroded to the east of the bridge will be

used.

3.2.3 Historical Climate and Discharge Trends

Historical precipitation data from the National Archive of Climate Normals and Averages

was collected and maximum instantaneous discharge records from the Water Survey of

Canada website were compared to determine the impact of precipitation sources on

discharge. The data came from regionally local sources: climate data used was from

Golden, and the discharge data was from a downstream location on the Beaver River. All

the maximum instantaneous flow occurred in the late spring (May/June) throughout the

record, therefore the precipitation data was needed to reflect the available runoff. Total

9

precipitation data was calculated by combining snow accumulation from the preceding

fall/winter (October-December), snow accumulation for the winter/spring (January-April)

of the year of comparison, and annual precipitation of the year of comparison. It is

assumed that all the snow stayed solid until runoff the following year (year of comparison),

consequently the fall/winter values of the year in comparison were excluded. Precipitation

is assumed to exist as surface flow, and is assumed to have a low residence time in the

drainage area, therefore annual values of the year in comparison are used. Associated issues

with this calculation include the effect of snow and rainfall on glacial melt, the impact of

other climatic factors runoff such as weather events and systems, and the relevance of this

data to the specific study location.

3.3 LIMITATIONS OF METHODOLOGY

The main limitation to the methodologies used was lack of proper field equipment;

however, attempts were made to estimate channel conditions to the best of our ability with

the equipment at hand. The following table summarises the limitations and potential

sources for error for each method conducted as well as what could have been done to

achieve better results.

TABLE 1 – LIMITATIONS OF METHODOLOGY

Methodology Limitation What Could Have Been Done

Flow Velocity Placement of object in river not

always consistent, mass of object

not consistent, obstructions in

channel, human error

Use of flow meter

Discharge Estimates Trajectory of rock not straight or

from bank to bank for width

measurements, distortion of

looking through water to channel

bed for depth measurements,

human error

Use of measuring tape and ruler

with waders to cross channel

Pebble Count Not enough samples taken from

various bars, human error

More locations upstream and

definitely a downstream bar

should be sampled to achieve a

correlation of results

Sediment Collection & Sieving Loss of sediment in weighing,

clumps of sand or fine materials

not being properly sieved, high

amount of fines, human error

Use of a hydrometer to determine

amounts of fine materials present

Retroactive Channel Stability

Assessment

Conducted after fieldwork,

quantitative indicator was assumed

not calculated due to lack of

measurements

Use the assessment during the

fieldwork to ensure measurements

were taken and proper

observations made

Aerial Photo Review Scale too small to see much detail,

human error in interpretation and

measuring

Attempt to acquire better aerial

photos

Historical Climate and Discharge

Trends

Too many possible causes for high

discharge, can’t quantify or

distinguish between major events,

not representative of the exact

One year proved to be an

anomaly, how to incorporate this

10

bridge crossing

4.0 FIELD OBSERVATIONS

On September 10 to 11, 2008, Keith Bootle and Laura Card were onsite to make

observations of channel morphology, riverbank condition and general site conditions at the

Trans Canada Highway as it crosses the Beaver River. Below is a summary of particular

observations made that were used in the overall assessment of the channel and the bank

erosion (Figures 5 to 11 show the observations and Figure 12 shows a site diagram based on

observations and measurements made onsite):

Significant erosion of the right river bank near the bridge construction from bank

scour and mass wasting events

Three main sediment layers in the eroded bank including a near water level sandy

silt layer, an organic layer and a silty surface layer

Armouring of the right bank using riprap that appeared to be non-engineered (an

opinion based on the placement of some riprap on the flat portion of the bank and

within the river bed as opposed direct placement on the bank) and flow beginning

to move upbank and behind of the riprap

Placement of stakes at the right bank at measured distances from the highway, likely

by Ministry of Transportation or Parks Canada personnel in order to monitor the

bank erosion

Coarse woody debris within the scour pool near the eroded bank

Several log jams upstream at the point bars as well as coarse woody debris within

the channel and at the mid-span abutment of the bridge

Extensive gravelly point bars, partially vegetated near the middle; however some

vegetation had been flattened in one direction indicating a high flow event that

overtopped the point bars

A silt veneer on the boulders underneath the bridge indicating a high flow event

11

Figure 5: Photo showing bank erosion and stakes

placed by others

Figure 8: Photo showing log jams

Figure 9: Photo showing coarse woody debris and riprap

Figure 6: Photo showing sediment layers

Figure 7: Photo showing stakes, riprap and erosion behind

riprap

Figure 10: Photo showing point bar

12

Figure 11: Photo showing silt on armouring boulders

Figure 12: Site diagram

13

5.0 RESULTS AND DISCUSSION

5.1 FIELD RESULTS AND DISCUSSION

5.1.1 Flow Measurements

The following graph shows the results for the flow velocity measurements. The table of

values and the field calculations are attached as Appendix B.

Flow Rate Estimations

1.95

1.301.14

0

0.5

1

1.5

2

2.5

Upstream of bridge Just before bridge Downstream of bridge

Location

Flo

w R

ate

(m

/s)

The flow velocity appears to decrease from upstream of the bridge to downstream of the

bridge possibly indicating a channel deepening, channel widening or subsurface flow into

the bed or banks of the river. However, as these locations are all relatively close to each

other and due to the crudeness of the methodology, one cannot use the information

individually and should average the results of the three locations to get a general idea of the

flow velocity in this area. The average of these velocities is 1.46 m/s and this value likely

gives a slightly better representation of the velocity in the area around the bridge.

5.1.2 Discharge Estimates

An estimate of a channel cross-section was attempted in order to calculate an estimated

discharge in the area around the bridge. Based on the field measurements, the average

discharge was 19.99 m3/s. As the methodology was crude, we attempted to make a

comparison with data from the Water Survey of Canada for the station “Beaver River at the

Mouth” which resulted in an estimated discharge of 12.68 m3/s. Calculations and data are

attached as Appendix C.

The measured discharge is significantly higher than the compared discharge of the WSC

likely due to the methodology used.

14

5.2 LABORATORY RESULTS AND DISCUSSION

5.2.1 Retroactive Channel Stability Assessment

The table below shows the ratings given to each stability indicator and the weighted value

which in turn determines the stability rating of the channel.

TABLE 2 – RAPID ASSESSMENT OF CHANNEL STABILITY

Stability Indicator Rating Weight Weighted Value

Bank soil texture and coherence 6 0.6 3.6

Average bank slope angle 11 0.6 6.6

Vegetative bank protection 8 0.8 6.4

Bank cutting 9 0.4 3.6

Mass wasting or bank failure 9 0.8 7.2

Bar development 6 0.6 3.6

Debris jam potential 11 0.2 2.2

Obstructions, flow deflectors and sediment traps 9 0.2 1.8

Channel bed material consolidation and armouring 3 0.8 2.4

Shear stress ratio 8 1 8

High flow angle of approach to bridge 2 0.8 1.6

Bridge distance from meander to impact point 10 0.8 8

Percentage of channel constriction 2 0.8 1.6

Total - - 56.6

Overall Rating (R) - - Fair

Ratings Values Overall R

Excellent 1-3 R < 32

Good 4-6 32 <= R < 55

Fair 7-9 55 <= R < 78

Poor 10-12 R >= 78

The overall rating for the channel was fair which indicates that the bed and banks are

somewhat unstable.

The rating for the shear stress ratio was assumed rather than calculated. The shear stress

ratio is the ratio between the boundary shear stress and the critical shear stress under which

the bed materials begin to move at bankfull flow conditions for rivers with a slope less than

0.02 m/m (Legasse et al, 2001). At shear stress ratio > 1, sediment begins to move at the

bed (for a gravel bed stream), at shear stress ratio > 2, most the bed material is in motion

and for shear stress ratio > 3, the entire bed is in motion (Legasse et al, 2001). It was

assumed that for this channel, with a slope of less than 5%, under bankfull flow conditions

that most of the bed material would be in motion; therefore a rating of 8, or fair, was

assigned. It is noted that this indicator has the highest rating and an actual calculation for

this ratio would better describe the channel, however, this assessment was conducted after

the fieldwork and some of the measurements required to calculate the shear stress ratio

were not taken. Appendix A shows the table of the stability indicators and the descriptions

of the ratings.

15

5.2.2 Sediment Sieve Analysis

The results of the sediment sieve analysis of the samples collected along the eroded bank

are summarised in the following graphs. Sample A is closest to the water line, Sample B

was taken from the organic layer and Sample C was collected above the organic layer

(therefore closest to surface).

Sample C (0.8 m below surface)

8.74.6 4.6 4.8 4.7 4.6 4.5 4.7

8.212.0

38.6

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

2.000 1.700 1.400 1.000 0.710 0.595 0.500 0.355 0.125 0.075 <

0.075

Sieve Size (mm)

Pe

rce

nt

(%)

Sample B (1.2 m below surface)

5.4 5.2 5.3 6.2 6.0 5.6 5.5 6.1

13.4 12.6

28.6

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

2.000 1.700 1.400 1.000 0.710 0.595 0.500 0.355 0.125 0.075 <

0.075

Sieve Size (mm)

Pe

rce

nt

(%)

16

Sample A (1.7 m below surface)

4.7 4.7 4.7 4.8 4.8 4.7 4.8 5.2

31.3

16.114.3

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

2.000 1.700 1.400 1.000 0.710 0.595 0.500 0.355 0.125 0.075 <

0.075

Sieve Size (mm)

Perc

en

t (%

)

Sample C contained the highest amount of fine material and some coarse sand or larger

grains, which was observed in the field. The organic layer represented by Sample B

contained mainly muds and some very fine sand that makes it slightly less cohesive. The

sample closest to the water line, Sample C, consisted mainly of very fine-grained sand

making this layer of the bank less cohesive and most likely to erode. This is likely why the

bank is undercut. The field data is attached in Appendix D.

5.2.3 Pebble Count

The tables below show the results of the pebble counts conducted on the two bars. The

data from the field is attached in Appendix E.

Pebble Count for Upstream Bar

5

38

57

00

10

20

30

40

50

60

< 3 (medium pebble) > 3 < 6.4 (large

pebble)

> 6.4 < 26 (cobble) > 26 (boulder)

Grain Size (cm)

Nu

mb

er

of

Peb

ble

s

17

There appears to be a slightly smaller pebble size in the more downstream bar, which may

be due to lower flow rates however, it is quite likely that the data is incomplete and

inconclusive. More pebble counts would need to be conducted in more locations (both

upstream and downstream) to be able to truly make a correlation between pebble sizes on

the bars. Also, this data looks at the bar as a whole as opposed to looking at where the

larger pebble sizes on the bar itself maybe located which may give insight into the width of

the channel during higher flows.

5.2.4 Aerial Photograph Review

Air photo interpretation revealed various changes over the years that photos were obtained

(1986, 1994, and 2004). Aerials are attached as Appendix F. The erosion of concern

observed in the field doesn't appear in any of the air photos, indicating that the erosion

developed since 2004. In order to quantify the amount of change observed, stream width

measurements were attempted approximately 70-80 m upstream of the bridge (Figure 13).

This location is upstream of the observed erosion, but useful in quantifying local rates of

erosion and change.

Figure 13: 1994 photo, scale 1:5 000. Yellow line represents upstream extent of bar, blue line represents

upstream bend, green line represents tail of bar measurement and red line represents the width of channel.

Pebble Count for Bar Closest to Bridge

6

75

58

1

0

10

20

30

40

50

60

70

80

< 3 (medium pebble) > 3 < 6.4 (large

pebble)

> 6.4 < 26 (cobble) > 26 (boulder)

Grain Size (cm)

Nu

mb

er

of

Peb

ble

s

18

Notably, in each air photo there appeared to only be one single bar, which was located

further upstream than the current bar locations. It was measured that the river channel

became slightly wider between 1986 and 1994, but by 2004 the bar had migrated, thinned,

and shifted upstream though decreasing the stream width. Table 3 summarises the

measurements made. This most recent migration would have allowed for a higher localized

flow rate in a straighter and narrower channel. This could have allowed for increased flow

rate, which could have deposited the observed obstructions that are causing the channel to

be forced to the east.

TABLE 3 – AIR PHOTOGRAPH MEASUREMENTS

Measurement

1986

(1:20 000)

1994

(1:5 000)

2004

(1:30 000)

Distance to upstream extent of bar (m) 130 132.5 75

Distance to instream point of upstream bend (m) 200 210 165

Width of channel (m) 40 60 36

Tail of bar (m) n/a 37.5 n/a

Thalweg width (m) n/a 11.5 n/a

Number of observed bars 1 1 1 (fragmented)

The area estimated to have eroded in the area of concern since 2004 is 285 m2 (Figure 14).

This gives a rate of erosion of 71.25 m2/yr. More importantly in the north direction (most

direct path to the Trans Canada Highway) approximately 9.7 m of soil has been eroded

since 2004, which is an average of 2.4 m per year. At this conservative rate, erosion would

reach the highway barriers in approximately 6.25 years.

The air photos needed to be more recent to provide an indication of a start date of erosion

because rates were calculated assuming that the erosion of concern started in 2004

immediately following the last obtained air photo. The scale was poor on the photos that

were available, therefore measurements were likely inaccurate and misleading.

Figure 14: Erosion rate estimation.

19

5.2.5 Historical Climate and Discharge Trends

When examining all years of record and gaps removed (2002), there seemed to be a limited

relationship between increased years of high precipitation and increased discharge (Figure

15). The first year of record, 1985, appeared to be an outlier, therefore was interpreted as

an anomaly. With the data from that year removed from the graph the relationship is

clearer. The largest difference between precipitation and flow was in 1997 and 2004 as

precipitation was low, but flow stayed relatively high. This indicated that some other event

caused the increased flow other than precipitation. Years 1989-1993, and 1998-2000 show a

correlation between precipitation and discharge, indicating that precipitation may have

caused the peak discharge rate those years. These years also represent very average

precipitation values, with no extremes, which indicates that precipitation extremes in the

Beaver River system are dominated by other climatic and physical factors affecting

discharge (ie. precipitation effect on glacier, temperature variations, and flash floods or large

events). This data shows that the discharge of Beaver River is greatly affected by other

climatic factors than only precipitation.

More accurate discharge, flow, precipitation, climate, and weather data is required to

determine the when periods of high flow would be expected at the bridge crossing leading

to increased erosion.

Figure 15: Graph showing the relationships between discharge, precipitation and the average relationship.

Beaver River (at mouth) - Flow and Precipitation

0

50

100

150

200

250

300

350

400

450

1988 1991 1994 1997 2000 2004Year

Dis

char

ge R

ate

(m3 /s

)

0

100

200

300

400

500

600

700

Tota

l Pre

cipi

tatio

n (m

m)

WSC

Discharge

Rate

Average

relationship

Annual

Precipitation*

Golden

20

6.0 CONCLUSIONS

Based on the observations made at the site and the results of the field and laboratory

analysis, the Beaver River is eroding the right bank near the bridge crossing of the Trans

Canada Highway because of changes in meander characteristics and bank erosion is

exacerbated by high flow events in the summer months (May to July), less cohesive bank

material, debris obstructions and possibly by poor rip-rap construction. Only a rough rate

of erosion could be determined based on aerial photography review but still requires further

field work at a later date for comparison with measurements taken during the field work

conducted for this paper. The potential implications of bank erosion at this location

include undermining of the bridge construction, a wash out of the Trans Canada Highway

which would result in impact on BC tourism and economy as the highway is the main

corridor from BC to the east.

7.0 REFERENCES

Fahnestock, R.K., Morphology and Hydrology of a Glacial Stream – White River, Mount Rainer Washington

(1963), Geological Survey Professional Paper 422-A

Lagasse, P.F., Schall, J.D., Richardson, E.V., Stream Stability at Highway Structures Third Edition,

(2001), National Highway Institute, US Department of Transportation, Publication No. FHWA

NHI 01-002

Woods, J.G., Glacier Country, (2004), Friends of Mount Revelstoke and Glacier, BC, ISBN 0-921-

806-16-7

http://www.wsc.ec.gc.ca/hydat/H2O/index_e.cfm?cname=WEBfrmPeakReport_e.cfm

http://www.wsc.ec.gc.ca

http://www12.statcan.ca/english/census06/data/trends/Table_1.cfm?T=CSD&PRCODE=59&G

eoCode=39019&GEOLVL=CSD

http://www.th.gov.bc.ca/trafficData/tradas/inset3.asp

http://www.transcanadahighway.com/britishcolumbia/TCH-BC-E5.htm

http://atlas.nrcan.gc.ca/site/english/maps/archives/national_park/mcr_0219?maxwidth=800&ma

xheight=800&mode=navigator&upperleftx=4160&upperlefty=464&lowerrightx=7360&lowerrighty

=3664&mag=0.125

Google Earth

Canadian Meteorological Survey – Historical Climate Data

http://images.google.com/imgres?imgurl=http://www.glossary.oilfield.slb.com/files/OGL98036.jp

g&imgrefurl=http://www.glossary.oilfield.slb.com/DisplayImage.cfm%3FID%3D202&usg=__Ki

KSL2fQG-

t5i2scmDiz4iWGsxI=&h=400&w=393&sz=69&hl=en&start=1&um=1&tbnid=cGZW6haL7-

ve7M:&tbnh=124&tbnw=122&prev=/images%3Fq%3Dudden%2Bwentworth%2Bscale%26um%

3D1%26hl%3Den%26rls%3Dcom.microsoft:en-ca:IE-

SearchBox%26rlz%3D1I7GGLR%26sa%3DN

21

http://www.pc.gc.ca/docs/v-g/bc/glacier/pd-mp/sec8/page1_E.asp

www.arcc.osmre.gov/HydroToys.asp

http://www.usbr.gov/pmts/hydraulics_lab/workshops/flowmeasurementworkshop_files/swoffer.j

pg

Environment Canada. (1987) Mount Revelstoke and Glac ier National Parks. [map]. 1st ed. 1:50 000.

Ottawa, Canada. Environment Canada Parks.

Surveyor General. (1934) Glacier Park. [map] 1st ed. 1:126 720. Ottawa Canada. Surveys and

Mapping Branch Canada.

Surveyor General. (1955) Glacier Park. [map] 3rd ed. 1:126 720. Ottawa Canada. Surveys and

Mapping Branch Canada.

Surveyor General. (1974) Glacier Park. [map] 4th ed. 1:126 720. Ottawa Canada. Surveys and

Mapping Branch Canada.

Aerial Photographs, Government of BC:

1986 – 15BC86088 photos 225, 226

1994 – 15BCB94087 photos 12, 13

2004 – 15BCC04044 photo 172

APPENDIX APPENDIX A RIVER CHANNEL STABILITY ASSESSMENT

APPENDIX APPENDIX B FLOW RATE DATA

Upstream of Bridge

Distance (m) Trial Time (s) Distance (m) Trial Time (s)

10 1 4.91 20 1 11.31

2 4.40 2 9.72

3 5.07 3 9.30

4 5.07 4 11.80

5 5.75 5 10.08

Average 5.04 Average 10.44

Flow (m/s) 1.98 Flow (m/s) 1.92

Average Flow 1.95 m/s

Just Before Bridge

Location A

Distance (m) Trial Time (s) Distance (m) Trial Time (s)

10 1 5.73 20 1 9.42

2 6.69 2 12.62

3 6.04 3 9.30

4 5.65 4 15.00

5 4.20 5 10.70

Average 5.66 Average 11.41

Flow (m/s) 1.77 Flow (m/s) 1.75

Average Flow 1.76 m/s

Location B

Distance (m) Trial Time (s) Distance (m) Trial Time (s)

10 1 12.28 20 1 23.95

2 12.20 2 36.44

3 9.15 3 22.36

4 8.50 4 26.54

5 11.60 5 26.37

Average 10.75 Average 27.13

Flow (m/s) 0.93 Flow (m/s) 0.74

Average Flow 0.83 m/s

Average flow

between

Location A and

B

1.30 m/s

Downstream of Bridge

Distance (m) Trial Time (s) Distance (m) Trial Time (s)

10 1 6.61 20 1 14.32

2 7.89 2 19.60

3 11.40 3 15.08

4 6.89 4 23.13

5 8.14 5 21.80

Average 8.19 Average 18.79

Flow (m/s) 1.22 Flow (m/s) 1.06

Average Flow 1.14 m/s

APPENDIX APPENDIX C DISCHARGE DATA

Discharge Estimate (based on field measurements)

Upstream of Bridge

Flow Velocity 1.95 m/s

Area 10.5 m2

Discharge 20.48 m3/s

Just Before Bridge

Flow Velocity 1.30 m/s

Area 16.88 m2

Discharge 21.94 m3/s

Downstream of Bridge

Flow Velocity 1.14 m/s

Area 15.4 m2

Discharge 17.56 m3/s

Average Discharge 19.99 m3/s

Discharge Estimate (Comparison to WSC)

Discharge (Sept 10th avg) 35.00 m3/s

Discharge (Sept 11th avg) 31.75 m3/s

Discharge (Sept 10-11th) 33.38 m3/s

Total drainage area 1150 km2

Our estimated drainage area 437 km2

Estimated discharge (x) 12.68 m3/s

APPENDIX APPENDIX D SEDIMENT SIEVE ANALYSIS DATA

Sample A (1.7 m below surface)

Dry mass (g) 601.6

Sieve #

Sieve size

(mm)

Mass of

Sediment (g)

Percent

(%)

Cumulative

%

10 2.000 66.80 4.7 4.7

12 1.700 66.72 4.7 9.4

14 1.400 66.71 4.7 14.2

18 1.000 67.39 4.8 18.9

25 0.710 67.54 4.8 23.7

30 0.595 67.08 4.7 28.5

35 0.500 67.22 4.8 33.2

45 0.355 73.43 5.2 38.4

120 0.125 442.00 31.3 69.7

200 0.075 226.91 16.1 85.7

bottom tray < 0.075 201.90 14.3 100.0

Total 1413.70

Sample B (1.2 m below surface)

Dry mass (g) 505.98

Sieve #

Sieve size

(mm)

Mass of

Sediment (g)

Percent

(%)

Cumulative

%

10 2.000 71.18 5.4 5.4

12 1.700 68.23 5.2 10.6

14 1.400 70.07 5.3 16.0

18 1.000 81.45 6.2 22.2

25 0.710 78.81 6.0 28.2

30 0.595 73.60 5.6 33.8

35 0.500 71.70 5.5 39.2

45 0.355 80.57 6.1 45.4

120 0.125 176.21 13.4 58.8

200 0.075 165.20 12.6 71.4

bottom tray < 0.075 376.09 28.6 100.0

Total 1313.11

Sample C (0.8 m below surface)

Dry mass (g) 607.07

Sieve #

Sieve size

(mm)

Mass of

Sediment (g)

Percent

(%)

Cumulative

%

10 2.000 129.07 8.7 8.7

12 1.700 67.9 4.6 13.3

14 1.400 68.24 4.6 17.9

18 1.000 70.83 4.8 22.7

25 0.710 69.58 4.7 27.4

30 0.595 67.39 4.6 31.9

35 0.500 67.31 4.5 36.5

45 0.355 70.19 4.7 41.2

120 0.125 121.80 8.2 49.4

200 0.075 177.63 12.0 61.4

bottom tray < 0.075 571.09 38.6 100.0

Total 1481.03

APPENDIX APPENDIX E PEBBLE COUNT DATA

Closest to bridge (north bar)

Section 1

x y Z

1 3.8 5.2 1.6

2 3.4 4.4 0.8

3 5.8 8 1

4 3.8 4.4 0.6

5 4.2 4.6 1.4

6 3.2 3.8 1

7 2.8 4.6 1.2

8 3.6 4.4 1.4

9 3 3.8 1.6

10 3.6 4.6 1

Section 2

x y Z

1 3 4 1.2

2 4.6 5.8 3.4

3 4.2 4.4 1.4

4 2.4 4 1.6

5 1.8 3.4 2

6 6.6 8.8 4.4

7 2.8 3.6 1.4

8 7.6 7.6 1.8

9 6 7.8 0.4

10 2.2 3 1.2

Section 3

x y Z

1 2.4 4.8 1.6

2 1.4 3 1

3 2 2.6 1.2

4 1 1.2 0.4

5 2.6 3.2 0.6

6 1 1.8 0.4

7 1.8 4.4 0.8

8 1.2 1.6 0.6

9 2.4 3.6 0.2

10 2.2 3.4 1.2

Section 4

x y Z

1 6.8 10.8 3.6

2 2.6 3.6 1.2

3 5 6 1.2

4 3.8 4 1.4

5 5 5.8 1.6

6 6.6 9 3.8

7 6.2 7.8 2.2

8 2.4 9.4 1.2

9 4.8 6.6 1.8

10 3.2 5 2.2

Section 5

x y Z

1 6.4 7.2 3

2 6.2 9.8 1.8

3 5.2 5.2 3.6

4 4.6 7 2

5 4.2 4.6 1.8

6 5.8 8.6 3.2

7 4 7.8 1.2

8 6.4 9.8 2.8

9 3.4 4.4 1.4

10 3.8 8.4 2.2

Section 6

x y Z

1 4.2 7.6 2.6

2 2.4 3.6 1.4

3 6.2 9.2 4

4 4.8 8.2 1.8

5 6.4 7.2 2.4

6 4.6 7.2 2.4

7 4 6.8 2.2

8 5.2 6.8 2.2

9 3.2 3.6 2

10 9.6 9.8 3.2

Section 7

x y Z

1 5.4 5.6 2.4

2 4.2 8.8 3.2

3 3.2 4.6 1.8

4 7.2 8.4 3.2

5 5.8 7.8 1.2

6 5.2 8.6 3.2

7 4.4 7.2 21.2

8 4 6.2 1

9 4.8 8 1.8

10 2 2.8 1.2

Section 8

x y Z

1 4 7 0.8

2 2.4 2.8 0.8

3 5.2 7 1.2

4 2.2 3 0.8

5 4.8 6.6 3

6 5.6 6.4 1.8

7 4.6 5.8 1.4

8 3.8 5.4 1

9 3.2 5.6 1.2

10 3 5 1.4

Section 9

x y Z

1 4.6 6.8 3.8

2 3.8 5.2 2.6

3 3.4 4.2 1.4

4 7.4 8.8 4.6

5 5.4 6.2 2.4

6 2.6 4 1.4

7 2.4 4.2 2

8 3.6 5.2 2.8

9 6.8 8.2 1.2

10 3.4 4.8 1

Section 10

x y Z

1 6.6 7.2 3.4

2 4.2 7.4 2.4

3 4.2 5.6 0.8

4 4.2 6.2 2

5 5.4 7.38 1

6 2.6 4 0.6

7 4.6 6.8 2.2

8 4.2 5.4 0.8

9 5 5.6 2

10 3.8 8.2 2

Section 11

x y Z

1 3.8 7.4 1.2

2 6 10.4 4.6

3 7.2 9.4 5.4

4 3 6.6 1.4

5 5.2 7.8 2.2

6 4.2 4.8 3.4

7 4.2 5.2 2.2

8 4 32.4 2.6

9 4 6 2

10 3 5.2 2.4

Section 12

x y Z

1 3.8 5.6 1.6

2 2.2 3.2 1.4

3 5.4 8.2 3.4

4 2.6 4 0.8

5 3.8 6.4 2

6 6.4 10.2 4.6

7 2.4 3.8 0.8

8 5.4 5.8 1.4

9 4 4.4 1

10 2.4 3 1.2

Section 13

x y Z

1 3.8 4.8 1.2

2 4.2 5.8 1.8

3 5.4 10 2.4

4 4.4 5.2 1.4

5 4.4 5.6 2

6 5 7 2.4

7 5.4 6.2 3.2

8 3.6 5 1.6

9 4.2 7.4 1.6

10 6.4 7.2 2.2

Section 14

x y Z

1 5.6 4.2 2.8

2 4.8 14.2 4.6

3 4.2 6.2 3.4

4 3 4 2

5 7.4 10 4.6

6 3.8 4.6 2.8

7 2.4 4.8 1.2

8 6.2 10 4.2

9 4.2 5.4 2.6

10 7.8 8 3.4

Furthest Upstream (south bar)

Section 1

x y Z

1 6.6 13.6 4.2

2 6.4 11.2 2.2

3 9.4 10.2 4.4

4 4.6 7 3.2

5 6.4 8.2 2.8

6 4.8 5.4 3.8

7 6.4 6.8 3

8 6 8.2 4.2

9 5.2 7.8 2.6

10 5.4 6.4 2.8

Section 2

x y Z

1 3.4 6.2 1

2 5.2 6.4 3.6

3 2.2 3.4 0.8

4 8.2 16.8 7.8

5 5.2 9.6 4.4

6 3.4 4.2 2.4

7 6.4 10 3.2

8 4.2 5.2 0.8

9 4.2 5.4 2.6

10 5.2 6.2 2.2

Section 3

x y Z

1 3.6 5.4 1.8

2 4.6 6.4 2

3 6.2 9.2 1.8

4 6.8 11 3.2

5 4.6 6.8 2.4

6 7.2 11.4 6.2

7 2.6 4.2 1.6

8 10 12.2 8.4

9 7.2 11.2 5

10 4.8 10.6 3.6

Section 4

x y Z

1 10.8 14.2 5

2 5.2 7.6 2.6

3 2.2 5.2 0.8

4 3.4 5 0.8

5 7.4 9.6 2.8

6 6.6 7.2 3.4

7 4.2 4.8 1.4

8 7.2 9.4 3.4

9 3.6 5.4 2.8

10 7.4 9.6 4.2

Section 5

x y Z

1 4.4 6.4 2.4

2 6.8 13.2 5.2

3 2.4 4.2 1.8

4 3.8 5.4 2

5 5.6 7.8 1.8

6 5.2 7 1.6

7 4.2 4.2 2

8 6 9.8 2.2

9 4.2 6.8 2.6

10 6.4 11.2 4.6

Section 6

x y z

1 4.8 6.4 2.4

2 6.8 10.2 1.6

3 5.2 10 1.6

4 3.2 5.4 1.8

5 4.2 5.6 3

6 5.8 6.6 2.4

7 5.8 6 1.8

8 2.6 3.8 1

9 7.6 10.8 3.4

10 5.6 8 2.2

Section 7

x y z

1 5.2 8.8 3.4

2 6.2 8.2 3.4

3 1.8 2.2 1.2

4 1.8 2.6 1.2

5 8.4 8.6 3.2

6 3.8 5.2 1.2

7 3.4 4.6 1.8

8 4.8 6.2 3.2

9 7.6 9.2 5

10 2.4 4.6 1.6

Section 8

x y z

1 5.6 8.8 3.4

2 6.8 8.2 3.4

3 2.2 2.4 1.2

4 2.6 4.4 1.2

5 8.2 8.6 3.2

6 2 5.2 1.2

7 2.8 4.6 1.8

8 4.8 6.2 3.2

9 2.6 9.2 5

10 5.6 4.6 1.6

Section 9

x y z

1 8.2 10.2 3.8

2 3.6 4.4 1.2

3 8.4 10.4 2.6

4 4.6 6.2 3.2

5 4.4 5.2 3.6

6 5.4 6.6 2.8

7 5 6.2 1.8

8 5.4 6.6 2

9 8.4 10.8 3.2

10 1 1.8 0.3

Section 10

x y z

1 6.2 6.4 2

2 1.2 1.8 0.8

3 2.8 3.2 2

4 4.4 7.2 1.8

5 4 4.4 2.4

6 5.4 7.6 4.4

7 2.4 4.4 2.2

8 4.2 5.8 4

9 1.6 5.8 0.8

10 5 11.2 4.2

APPENDIX AP APPENDIX F AERIAL PHOTOGRAPHS

1986 – 1:20,000

1994 – 1:5,000

2004 – 1:30,000