Fwp 2007 01 rpt hardistyresorationprojectbackfloddingriffleconstruction

REPORT ON

HARDISTY CREEK RESTORATION PROJECTHARDISTY AVENUE CULVERT

BACKFLOODING RIFFLE CONSTRUCTION

Submitted to:

Athabasca Bioregional SocietyBox 5058

Hinton, Alberta, T7V 1X3

DISTRIBUTION:

2 Copies Athabasca Bioregional SocietyHinton, Alberta

1 Copy Golder Associates Ltd.Edmonton, Alberta

January 2007 05-1373-029

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EXECUTIVE SUMMARY

Introduction

In October 2003, Golder Associates Ltd. (Golder) was retained by Foothills Model Forest on

behalf of the Hardisty Creek Restoration Project (HCRP) to undertake an assessment of fish

passage and habitat restoration opportunities on Hardisty Creek, in and near Hinton, Alberta. The

results of this study (Golder 2004) recommended riffle restoration and culvert backflooding in the

Kinsmen Park reach of Hardisty Creek, between Hardisty Avenue and Switzer Drive.

The initial habitat restoration in the Kinsmen Park reach was undertaken in October 2004, and

included construction of eight rock riffles, large woody debris (LWD) placement and woody

plantings. The upper rock riffle, intended to backflood the Hardisty Avenue culverts for fish

passage, was not constructed at that time due to budget limitations.

This report describes the construction of the upper riffle, which was constructed in October 2005.

It documents the detailed design and permitting for the upper riffle construction, the construction

methods, sequence and environmental monitoring. The report also provides an assessment of the

stability of Large Woody Debris (LWD) structures installed in 2004, a preliminary assessment of

restoration alternatives for the reach of Hardisty Creek below Switzer Drive, and a description of

maintenance to the lower riffles in the Kinsmen Park reach of Hardisty Creek.

Detailed Design

A conceptual-level design for backflooding of the Hardisty Avenue culverts was presented in a

previous report (Golder 2004). The design was intended to meet the goal of reducing the mean

flow velocities through the culverts to 1 m/s or less, at discharges of 1.6 m3/s or less. This would

allow passage of fish with swimming modes similar to rainbow trout, bull trout and similar

salmonids. During final design of the riffle, its crest elevation was modified slightly reduce the

downstream gradient and its cross-slope was reduced to create a shallower, slower and less

erosive flow along the downstream face of the riffle. The design slope of the downstream face of

the riffle was steepened slightly to prevent the toe of the riffle from reaching the next downstream

riffle, and two equally-spaced rock vortex weirs and random boulder placement were added to the

downstream face of the riffle for additional grade control.

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The final design for the riffle specified 150 mm minus pit run gravel for use as general fill,

350 mm minus rock fill to provide an armored surface for the riffle, and 750 mm diameter rock

riprap for construction of the riffle crest, vortex weirs and random boulder placement. Additional

materials included impermeable liner and non-woven geotextile installed as a seepage barrier

below the riffle crest and live willow stakes installed in selected locations around the riffle and

upstream pool.

It must be noted that though the riffle structure is designed to withstand a flood with a 100-year

return period, it will not necessarily be maintenance free. Natural transport of bed material would

convey sands and gravels from upstream across the riffle and downstream during high flows. The

presence of the upstream culverts and deep pool could potentially limit the availability of material

from upstream and prevent replacement of smaller material on the face of the riffle. Periodic

monitoring of the riffle is recommended to identify potential future maintenance requirements.

Monitoring should evaluate in-filling of the culvert outlet pool and scour of small material from

the face of the riffle.

Permitting

The stream restoration works described here were performed in accordance with Alberta Water

Act Approval #00211360, Canada Fisheries Act Authorization #ED-04-2284, and the Fish

Collection License held by Foothills Model Forest. Copies of the relevant permits are provided in

Appendix I.

The Fisheries Act Authorization requires that a “post-construction assessment of the project area

shall be conducted and submitted to DFO in the fall of 2006 to identify any problem areas that

require remedial action. The program shall assess the physical stability of the new streambed,

instream remediation prescriptions, and of the creek and banks for 500m upstream and 500m

downstream of the works. Fish passage shall also be assessed. Post-construction monitoring

reports including photos shall be submitted to DFO, referencing file #ED-04-2284, within one

year following completion of the works. The monitoring report shall also include photographic

documentation on the survival of riparian vegetation plantings. If less that 85% of the vegetation

survives, then the Town of Hinton shall replace the lost vegetation.”

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Construction

Construction took place between 10 October and 14 October 2005. It involved participation of

the Town of Hinton, the Athabasca Bioregional Society, Foothills Model Forest, Big Berland

Construction, West Central Construction, Westridge Sand & Gravel, Golder Associates,

Millennium EMS and Hoitsma Ecological.

Prior to the start of instream construction, the Town of Hinton stockpiled 150 mm minus gravel in

the parking lot adjacent to the works. On 10 October 2005, Golder Associates and Millennium

EMS personnel performed construction layout surveys and a fish salvage at the site.

On 11 October 2005, instream construction commenced. A flow diversion channel was

constructed, 150 mm minus fill was placed in the dry channel and the impermeable liner,

geotextile and rock riprap were placed at the riffle crest.

On 12 October 2005, additional 150 mm minus fill was placed and rock riprap was hauled to the

site and placed at the riffle crest and at the two vortex weirs.

On 13 October 2005, additional 150 mm minus fill was placed and 350 mm minus armor material

was hauled and placed. Rock riprap and 350 mm minus armor material were moved to the lower

riffles for maintenance.

On 14 October 2005, a buried diversion pipe was placed to allow full-width construction of the

riffle. Woody plantings were placed along the edges of the riffle and upstream pool. The riffle

was completed by late afternoon with the exception of a small amount of fill on the LDB at the

lower end of the riffle. Material was stockpiled at this location and the work was subsequently

completed by a local contractor with a skid steer loader (Buttazoni).

Environmental Monitoring

Environmental monitoring included a fish salvage prior to commencement of instream works and

turbidity monitoring during construction. Detailed fish salvage data are provided in Appendix III

and turbidity monitoring data are provided in Appendix IV.

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Additional Issues

Ballasting of LWD structures installed in 2004 were assessed for stability. The detailed analysis

is provided in Appendix V, which indicates that 10 of the 20 structures can be classified as stable.

The analysis did not confirm stability for the remaining structures, though the analysis method is

likely conservative and it must be noted that there did not appear to be any movement of these

structures during the high water events of June 2005. For structures that are potentially

underballasted, dimensions and calculations should be confirmed after an additional inspection to

confirm the parameters used in the assessment, and additional ballasting should be considered if

required.

Hardisty Creek Below Switzer Drive is currently being considered for restoration as part of the

next phase of the Hardisty Creek Restoration Project. A site reconnaissance indicated that the

channel in this area has little or no floodplain area and it appears that fill has been placed on the

left and right overbanks to increase the area available to commercial developments on either side

of Hardisty Creek. The channel in this area would benefit from excavation in the overbank area

to provide an adequate floodplain, and that revegetation with native species and placement of

natural materials for grade and erosion control, rather than the concrete rubble that currently

exists in several locations, would be beneficial.

A seep of a hydrocarbon or chemical substance was observed at one location on the LDB of the

creek, and waste, including pieces of metal, were observed in fill on both banks. It is

recommended that, as a minimum, a Phase I Environmental Site Assessment be undertaken on

this site prior to construction of any stream restoration works that could potentially expose

contaminated soils.

Lower Riffle Maintenance and Improvement included replacement of rock riprap boulders and

additional placement of small boulder and cobble material from the 350 mm minus fill material

available on site. Materials were stockpiled on the RDB at each riffle for future placement by

community volunteers, and at some riffles, material was hand placed. The preferred placement

method is to place the largest material first, in the area below the existing boulders, and then

place smaller boulders and cobbles to bridge the gaps and create a rock matrix that will eventually

trap smaller fractions that are carried down the creek.

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TABLE OF CONTENTS

SECTION PAGE

1. INTRODUCTION .....................................................................................................................11.1 Background .........................................................................................................................11.2 Organization of the Report ..................................................................................................1

2. PRECONSTRUCTION .............................................................................................................22.1 Design..................................................................................................................................2

2.1.1 Riffle Geometry ........................................................................................................22.1.2 Riffle Materials .........................................................................................................2

2.2 Permitting ............................................................................................................................6

3. CONSTRUCTION.....................................................................................................................73.1 Methods and Construction Sequence ..................................................................................7

3.1.1 Pre-Construction Staging ..........................................................................................73.1.2 11 October 2005........................................................................................................73.1.3 12 October 2005........................................................................................................83.1.4 13 October 2005........................................................................................................83.1.5 14 October 2005........................................................................................................9

3.2 Environmental Monitoring ................................................................................................103.2.1 Fish..........................................................................................................................103.2.2 Sediment and Turbidity...........................................................................................11

4. ADDITIONAL ISSUES ..........................................................................................................134.1 LWD Installed in 2004 ......................................................................................................134.2 Future Restoration Below Switzer Drive ..........................................................................144.3 Lower Riffle Maintenance and Improvement ...................................................................14

5. CONCLUSION........................................................................................................................16

6. REFERENCES ........................................................................................................................17

LIST OF TABLES

Table 1 – Riffle Armor Layer Sizing Calculations...........................................................................5Table 2 – Regulatory Permits for Stream Restoration Works ..........................................................6Table 3 – Summary of Calculated Factors of Safety for LWD Structures .....................................13

LIST OF FIGURES

Figure 1 – Profile View Showing Riffle Design ..............................................................................3Figure 2 – Elevation View Showing Riffle Design..........................................................................3Figure 3 – Turbidity Monitoring at Switzer Drive and at Upstream Background Site ..................12

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LIST OF APPENDICES

Appendix I Regulatory Permits for Instream ConstructionAppendix II PhotographsAppendix III Fisheries Information Collected Prior to ConstructionAppendix IV Turbidity Data Collected During ConstructionAppendix V LWD Ballasting AssessmentAppendix VI Construction Survey DataAppendix VII July 2006 Inspection and Photo SurveyAppendix VIII Review Comments on Draft Report

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1. INTRODUCTION

1.1 Background

In October 2003, Golder Associates Ltd. (Golder) was retained by Foothills Model Forest on

behalf of the Hardisty Creek Restoration Project (HCRP) to undertake an assessment of fish

passage and habitat restoration opportunities on Hardisty Creek, in and near Hinton, Alberta. The

results of this study (Golder 2004) recommended riffle restoration and culvert backflooding in the

Kinsmen Park reach of Hardisty Creek, between Hardisty Avenue and Switzer Drive.

The initial habitat restoration in the Kinsmen Park reach was undertaken in October 2004, and

included construction of eight rock riffles, large woody debris (LWD) placement and woody

plantings. The upper rock riffle, intended to backflood the Hardisty Avenue culverts for fish

passage, was not constructed at that time due to budget limitations.

This report describes the construction of the upper riffle, which was constructed in October 2005.

1.2 Organization of the Report

Chapter 2 of this report describes pre-construction activities, including detailed design (geometry

and materials) and permitting for the project.

Chapter 3 of the report describes activities taking place during the construction period, including

construction methods and sequence. It also describes environmental monitoring activities

undertaken for regulatory compliance.

Chapter 4 of the report describes additional issues related to the project. These include an

assessment of the stability of LWD structures installed on Hardisty Creek in 2004, and a

reconnaissance of the reach of Hardisty Creek immediately below Switzer Drive, which could

potentially be restored in the next phase of the project.

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2. PRECONSTRUCTION

2.1 Design

2.1.1 Riffle Geometry

A conceptual-level design for backflooding of the Hardisty Avenue culverts was presented in a

previous report (Golder 2004). The design was intended to meet the goal of reducing the mean

flow velocities through the culverts to 1 m/s or less, at discharges of 1.6 m3/s or less. This would

allow passage of fish with swimming modes similar to rainbow trout, bull trout and similar

salmonids. It considered a riffle vertex crest elevation of 101.00 m, referenced to the large

culvert outlet invert elevation of 100.00 m. The riffle crest rose at a design slope of 6H:1V from

the riffle vertex towards each bank. The upstream face of the riffle had a design slope of 4H:1V

and the downstream face of the riffle had a design slope of 20H:1V.

During final design of the riffle, the crest vertex elevation was reduced by 0.10 m to 100.90 m to

slightly reduce the downstream gradient. The design slope of the riffle crest from vertex to each

bank was changed from 6H:1V to 20H:1V to reduce the concentrated flow over the riffle crest

and along its downstream face. This will result in a shallower, slower and less erosive flow along

the downstream face of the riffle. The design slope of the upstream face of the riffle was

unchanged at 4H:1V. The design slope of the downstream face of the riffle was steepened

slightly from 20H:1V to 14H:1V to prevent the toe of the riffle from reaching the next

downstream riffle (Riffle #2). The effects of this steeper slope of approximately 7% were offset

by adding two equally-spaced rock vortex weirs and random boulder placement on the

downstream face of the riffle.

Profile and elevation views showing the design of Riffle #1 are shown in Figures 1 and 2,

respectively.

2.1.2 Riffle Materials

The final design for the riffle considered the following materials:

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98.5

99.0

99.5

100.0

100.5

101.0

-20 -10 0 10 20 30 40Distance Downstream of Riffle Crest (m)

Ele

vati

on

(m;

Lo

calD

atu

m)

ThalwegCulvert InvertDesign ThalwegDesign Top of PitrunUpstream Riffle Crest RockDownstream Riffle Crest RockImpermeable Liner

Figure 1 – Profile View Showing Riffle Design

Figure 2 – Elevation View Showing Riffle Design

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

102.5

0 5 10 15 20 25 30

Distance from RDB Reference Point (m)

Ele

vati

on

(m;

Lo

calD

atu

m)

Pre-Construction Bed Elevation

Design Riffle Crest Elevation

Design top of 150 mm minus Fill

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150 mm minus rock fill material was used to bring the existing bed elevation up in the core

of the riffle. This was placed below the armor layer off the riffle and creek bed and

comprised a well-graded mix of cobble, gravel, sand and silt. This material was provided as

a contribution from the Town of Hinton and quantities were stockpiled on site prior to the

start of construction;

350 mm minus rock fill material was used for the upper armor layer of the riffle and creek

bed and comprised a well-graded mix of boulder, cobble, gravel, sand and silt. The upper

armor layer was placed to a thickness of 500 mm. Some of this material was also placed at

the lower riffles to provide supply for future maintenance and improvement, as discussed in

Section 4.3. It was hoped that this material could be sourced from the concurrent East

Hardisty sewer project construction (refer to Photographs 21 and 22 in Appendix II). This

material proved to be unavailable in sufficient quantity, so other sources were considered,

including the West Central yard in Hinton (refer to Photograph 23 in Appendix II), the West

Central Pit across the Athabasca River from Hinton (refer to Photographs 24 to 26 in

Appendix II), and a Town of Hinton waste rock pile (refer to Photograph 33 in Appendix II).

None of these sources could provide large enough material. Adequately sized material was

eventually purchased from the Border Paving pit in Hinton (refer to Photographs 38 to 42

and 51 in Appendix II), and a small quantity of 250 to 300 mm rock was also purchased from

Northland Maintenance and transported from their stockpile at the Town of Hinton yard;

750 mm diameter rock riprap was placed as a double row along the riffle crest, in the two

vortex weirs on the downstream face of the riffle, in random locations on the downstream

face of the riffle, and as additional protection against flow impingement along the upstream

face of the riffle. Some of this material was also placed at the lower riffles to provide supply

for future maintenance and improvement, as discussed in Section 4.3. The source of this

material included salvage material from that placed at Riffle #1 in 2004 and a small quantity

of material purchased from Northland Maintenance. The bulk of the rock riprap was

purchased from the Border Paving pit in Hinton. This material can be seen in Photograph

20, among others, in Appendix II;

Impermeable liner material, fish-friendly with a thickness of 30 mil, and non-woven

geotextile were purchased from Nilex Geosynthetics in Edmonton. This material was placed

vertically, below the crest of Riffle #1, to discourage subsurface flow through the riffle. The

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material and its placement are shown in Photographs 10 and 13 to 15 in Appendix II. Non-

woven geotextile was also placed along the upstream face of the footer stones in each vortex

weir, as shown in Photograph 35 in Appendix II; and

Live willow stakes were also placed in selected locations along Riffle #1, under the

direction of Todd Hoitsma of Hoitsma Ecological. These stakes were locally sourced by

Connie Bresnahan of the Athabasca Bioregional Society. The willow staking is shown in

Photographs 60 and 61, 95 and 96, 103, 112 and 113 in Appendix II.

The specified 350 mm minus armor material was expected to have a d50 of approximately

200 mm. To check on the erodibility of this material, critical velocities corresponding to design

flow depths at the riffle were calculated according to a sediment transport equation presented by

Melville and Coleman (2000). In the equation shown below, the critical velocity for sediment

entrainment, Vc, is a function of the flow depth, y, and median particle diameter, d50:

Vc = 5.67y1/6d501/3

Maximum flow depths and mean flow velocities along the downstream face of the riffle were

calculated based on the design discharges corresponding to return periods of 2, 25 and 100 years.

The calculations summarized in Table 1 are based on the riffle geometry described in Section

2.1.1 and show that during the 100-year flood, bed material with a d50 of 0.200 m (corresponding

to the 350 minus material used for this project) should be stable to a critical velocity of 3.0 m/s.

This is greater than the calculated mean flow velocity of 2.2 m/s and should provide some factor

of safety. Calculated critical velocities for smaller armor material sizes are provided for

comparison purposes.

Table 1 – Riffle Armor Layer Sizing Calculations

Median particle diameter (m)

0.200 0.150 0.100 0.075

ReturnPeriod

DesignDischarge,Q (m3/s)

MaximumFlow Depth,

y (m)

Mean FlowVelocity,V (m/s)

Vcritical

(m/s)Vcritical

(m/s)Vcritical

(m/s)Vcritical

(m/s)

2 year 2.3 0.28 1.4 2.7 2.4 2.1 1.9

25 year 7.8 0.45 2.0 2.9 2.6 2.3 2.1

100 year 11.8 0.52 2.2 3.0 2.7 2.4 2.1

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It must be noted that though the riffle structure is designed to withstand a flood with a 100-year

return period, it will not necessarily be maintenance free. Natural transport of bed material would

convey sands and gravels from upstream across the riffle and downstream during high flows. The

presence of the upstream culverts and deep pool could potentially limit the availability of material

from upstream and prevent replacement of smaller material on the face of the riffle. Periodic

monitoring of the riffle is recommended to identify potential future maintenance requirements.

2.2 Permitting

The stream restoration works described here were performed under the authorizations and

approvals described in Table 2. Copies of the relevant permits are provided in Appendix I.

Table 2 – Regulatory Permits for Stream Restoration Works

Legislation Administered By Permit

AlbertaWater Act

Alberta Environment (AENV) Approval #00211360, amended27 September 2005

CanadaFisheries Act

Alberta Sustainable ResourcesDevelopment (ASRD)

FMF Research Fish Collection License

CanadaFisheries Act

Fisheries and Oceans Canada(DFO)

Authorization #ED-04-2284, amended29 September 2005

The Alberta Water Act Approval requires the approval holder submit a Certificate of Completion

to Alberta Environment when the activity is completed.

The Fisheries Act Authorization requires that a “post-construction assessment of the project area

shall be conducted and submitted to DFO in the fall of 2006 to identify any problem areas that

require remedial action. The program shall assess the physical stability of the new streambed,

instream remediation prescriptions, and of the creek and banks for 500m upstream and 500m

downstream of the works. Fish passage shall also be assessed. Post-construction monitoring

reports including photos shall be submitted to DFO, referencing file #ED-04-2284, within one

year following completion of the works. The monitoring report shall also include photographic

documentation on the survival of riparian vegetation plantings. If less that 85% of the vegetation

survives, then the Town of Hinton shall replace the lost vegetation.”

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3. CONSTRUCTION

3.1 Methods and Construction Sequence

3.1.1 Pre-Construction Staging

Prior to construction, the Town of Hinton stockpiled approximately 400 m3 of 150 mm minus

gravel in the parking lot adjacent to the works.

3.1.2 11 October 2005

On the first day of construction, equipment used included a Komatsu PC200LC excavator with

thumb (Big Berland Construction) and John Deere 240 skid steer loader (Town of Hinton). The

sequence of construction included:

An instream diversion was constructed on the left downstream bank (LDB) of the channel

by excavating a dry, shallow trench, lining it with polyethylene, and then blocking off the

remainder of the channel with 150 mm minus fill (refer to photographs 6 to 8 and 19 in

Appendix II);

150 mm minus was placed to raise the channel bed elevation. This was done “in the dry”

by moving stockpiled material to the right downstream bank with the skid steer loader

and placing it with the excavator (refer to photographs 11, 12 and 18 in Appendix II).

The fill was compacted by tracking and/or compression with the excavator bucket;

An impermeable liner was placed below the riffle crest, by stapling it to 2 x 4 support

posts. Fill was placed incrementally on each side of the liner to prevent its displacement

(refer to photographs 10 and 13 to 15 in Appendix II); and

750 mm rock riprap was placed at the riffle crest (refer to photographs 16 and 20 in

Appendix II).

On the afternoon of 11 October, potential sources of 350 mm minus armor material were

investigated, including the Hinton East Hardisty sewer excavation (refer to photographs 21 and

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22 in Appendix II), the West Central Hinton yard (refer to photograph 23 in Appendix II), and the

West Central pit (refer to photographs 24 to 26 in Appendix II).

3.1.3 12 October 2005

On the second day of construction, use of the Big Berland Construction excavator and Town of

Hinton skid steer loader continued. In addition to this, Town of Hinton and West Central dump

trucks were used to transport materials, an additional excavator (Westridge Sand & Gravel) was

used to load rock riprap at the Border Paving pit, and a John Deere 544 articulated loader (Town

of Hinton) was used to load 150 mm minus material at the Town of Hinton yard. The sequence

of construction included:

Placement of 150 mm minus fill continued;

Approximately 80 pieces of 750 mm minus rock riprap, approximately 10 additional

loads of 150 mm minus material, and small quantities of rock riprap and small boulders

purchased from Northland Maintenance were hauled to the project site; and

750 mm minus rock riprap was placed at the riffle crest and upstream face, as well as at

the lower of two rock weirs (refer to photograph 35 in Appendix II).

On the afternoon of 12 October, it became apparent that the Hinton East Hardisty sewer

excavation would not be able to provide 350 mm minus armor material to the project, and two

additional potential sources were investigated. These included the Town of Hinton waste

stockpile (refer to photograph 33 in Appendix II) and the Border Paving Hinton pit (refer to

photograph 38 in Appendix II).

3.1.4 13 October 2005

On the third day of construction, use of the Big Berland Construction excavator and Town of

Hinton skid steer loader continued. In addition to this, Town of Hinton and West Central dump

trucks were used to transport materials, and the Town of Hinton articulated loader was moved to

the work site to move stockpiled materials into the work area. The sequence of construction

included:

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350 mm minus armor material from the Border Paving Hinton Pit was hauled to the site

and stockpiled (refer to photographs 39 to 42 and 51 in Appendix II);

Placement of 150 mm minus fill continued and placement of 350 mm minus fill

commenced (refer to photographs 47 to 50 and 52 to 56 in Appendix II);

The skid steer loader was used to haul rock riprap and some 350 mm minus material for

lower riffle maintenance (refer to photographs 29 to 32), while the larger loader was used

at the upper riffle; and

A sediment trap was installed at the downstream end of Kinsmen Park, in anticipation of

mobilizing more sediment during riffle construction (refer to photographs 43 to 46 in

Appendix II).

By the end of the day on 13 October, it became apparent that the two 4-inch pumps that were

being used in tandem with the instream flow diversion would not be sufficient to convey all flow

when fill was placed along the LDB, in the instream diversion area. Four lengths of 500 mm

diameter “Big O” pipe were purchased from UMA Engineering in Hinton and transported to the

work site to be used as a temporary buried diversion pipe.

3.1.5 14 October 2005

On the fourth day of construction, use of the Big Berland Construction excavator and Town of

Hinton skid steer and articulated loaders continued. The sequence of construction included:

Placement of the 500 mm “Big O” diversion pipe and placement of 150 mm minus fill on

top of it (refer to photographs 57 to 68 in Appendix II);

Placement of 350 mm minus armor material and rock riprap at lower riffles for

maintenance (refer to photographs 70 to 76 in Appendix II);

The skid steer loader was used to haul rock riprap and some 350 mm minus material for

lower riffle maintenance (refer to photographs 29 to 32), while the larger loader was used

at the upper riffle;

Continued placement of 350 minus armor material and 750 mm rock riprap in the riffle

and two vortex weirs. As lower surfaces were completed, the pumped diversion hoses

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were placed to discharge on the armor layer to enhance the movement of fines

downwards into the rock matrix (refer to photographs 97 to 104 in Appendix II);

The inlet of the diversion pipe was blocked with filter fabric, rock riprap and 150 mm

minus fill and the riffle crest was completed (refer to photographs 105 to 109 and 114 to

119 in Appendix II); and

Woody plantings were placed along the LDB and RDB along the length of the riffle and

in the upstream pool, under the direction of Todd Hoitsma of Hoitsma Ecological Inc.

(refer to photographs 112 and 113 in Appendix II).

At the end of the day on 14 October, construction was complete with the exception of a small

amount of fill on the LDB at the lower end of the riffle. Material was stockpiled at this location

and the work was subsequently completed by a local contractor with a skid steer loader

(Buttazoni). The completed riffle is shown in photographs 120 to 122 and 124 to 126 in

Appendix II.

3.2 Environmental Monitoring

3.2.1 Fish

Prior to construction, on the evening of 11 October 2005, block nets were set approximately 10 m

above the Hardisty Avenue culverts and immediately above Riffle #3, approximately 60 m

downstream of the Hardisty Avenue culvert outlets. This area was electrofished by Golder

Associates Ltd. and Millennium EMS Ltd. personnel on the evening of 10 October 2005 and was

subsequently electrofished by Foothills Model Forest personnel on the morning of 11 October

2005, before the commencement of instream work. A record of fish collected during these fish-

outs is provided in Appendix III and was provided to Alberta Sustainable Resources Development

in compliance with the terms of the Fish Collection License. Several of the largest fish salvaged

during the fish-out on 10 October 2005 are shown in Photographs 1 to 5 in Appendix II.

On the morning of 11 October 2005, prior to electrofishing, the lower block net was moved to just

above Riffle #3, as shown in Photograph 76 in Appendix II. The block nets were removed after

construction, at approximately 1800h on 14 October 2005.

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3.2.2 Sediment and Turbidity

It is not possible to reconstruct a creek bed without releasing some sediment into the creek.

Placing “clean” material, without fines, would leave voids between larger rock fractions, allowing

flow through the rock matrix and resulting in subsurface flow during low flow periods. Indeed,

this was thought to be a problem in several parts of the creek in its Kinsmen Park reach, prior to

the stream restoration. Three types of material were placed in the creek during construction of the

Riffle #1. These included:

clean rock riprap, used as armor for riffle and vortex weir crests;

350 mm minus fill material. This was used for the upper armor layer of the riffle and

creek bed and comprised a well-graded mix of boulder, cobble, gravel, sand and silt.

This material was exposed to flow immediately after construction and fines entered the

creek during the “first flush” of flow over this material; and

150 mm minus fill material. This was used as fill below the armor layer off the riffle and

creek bed and comprised a well-graded mix of cobble, gravel, sand and silt. This

material was completely covered with 350 mm minus fill material material and is not

intended to ever be exposed to flow.

During instream construction, from 11 October to 14 October 2005, turbidity was monitored at

the lower end of the Kinsmen Park reach, at Switzer Drive. The results of turbidity monitoring

are plotted in Figure 1 and detailed data are presented in Appendix IV. Most readings during

construction fell below 25 NTU, with the exception of single-measurement spikes during the late

mornings of 12 October and 14 October, and during the “first flush” period on the afternoon of

14 October, when the armor fill was first exposed to flow.

A sediment trap was installed on Hardisty Creek, just above Switzer Drive, on the morning of

13 October, prior to the “first flush” and remained in place until approximately 1800h on 14

October, approximately 3 hours after the initial pulse of sediment from the introduction of flow to

Riffle #1. The sediment trap is shown in Photographs 43 to 46, 52 to 56, 69 and 94 in

Appendix II.

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0

20

40

60

80

100

120

140

160

Oct 10 12:00 Oct 11 12:00 Oct 12 12:00 Oct 13 12:00 Oct 14 12:00 Oct 15 12:00Date and Time

Tu

rbid

ity

Rea

din

g(N

TU

)Turbidity Measured at Switzer DriveUpstream Background TurbidityInstream Work Period

Start of ConstructionWith Instream Diversion

Sediment TrapInstalled at Switzer Drive

Diversion PipeInstalled

First Flush of ChannelBed Armor Material

Instream WorkCompleted

Sediment Trap atSwitzer Drive Removed

Figure 3 – Turbidity Monitoring at Switzer Drive and at Upstream Background Site

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4. ADDITIONAL ISSUES

4.1 LWD Installed in 2004

A detailed analysis of ballasting for the Large Woody Debris (LWD) structures installed in 2004

is provided in Appendix V, and a summary of the calculations is provided in Table 3, along with

comments and recommendations for each structure. Overall, stability was confirmed for 10 of the

20 LWD structures. The remaining structures had calculated Factors of Safety for Buoyancy,

FSB, of between 0.4 and 1.1. LWD structures with FSB values of 1.0 or less by definition will

have Factors of Safety for Sliding, FSS, of less than zero. These structures may be underballasted;

however, it is possible in some cases that the calculated values are overly conservative. This is

because the ballasting calculations assume full submergence of the LWD structures, and the

relatively low water depths during flood events on Hardisty Creek mean that logs may not be

fully submerged. There did not appear to be any movement of these structures during the high

water events of June 2005.

Table 3 – Summary of Calculated Factors of Safety for LWD Structures

LWDStructure

Factor ofSafety forBuoyancy,

FSB

Factor ofSafety forSliding,

FSS

Comments and Recommendations

1 0.4 -2.5 Confirm dimensions; may be underballasted.

2 4.4 3.1 Stability confirmed.

3 2.2 n/a Stability confirmed.


5 1.6 1.6 Likely stable, FS > 2.0 would be preferred.





10 0.7 n/a Confirm dimensions; may be underballasted.

11 1.1 0.3 May be underballasted but appeared stable in June 2005.


13 1.8 n/a Likely stable, FS > 2.0 would be preferred.





18 0.7 -1.4 Calculations say underballasted, but currently embedded in bed.


20 3.2, 2.2, 1.3 2.4, 1.2, 1.1 Likely stable, FS > 2.0 would be preferred.

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For structures that are potentially underballasted, dimensions and calculations should be

confirmed after an additional inspection to confirm the parameters used in the assessment, and

additional ballasting should be considered if required.

4.2 Future Restoration Below Switzer Drive

The reach of Hardisty Creek located below Switzer Drive and above the West Fraser property is

currently being considered for restoration as part of the next phase of the Hardisty Creek

Restoration Project. On the morning of 14 October 2005, a site reconnaissance of this area was

undertaken by Nathan Schmidt of Golder Associates Ltd. and Todd Hoitsma of Hoitsma

Ecological Inc. Photographs 77 to 93 in Appendix II were taken during this reconnaissance.

The channel in this area has little or no floodplain area and it appears that fill has been placed on

the left and right overbanks to increase the area available to commercial developments on either

side of Hardisty Creek. It was agreed that the channel in this area would benefit from excavation

in the overbank area to provide an adequate floodplain, and that revegetation with native species

and placement of natural materials for grade and erosion control, rather than the concrete rubble

that currently exists in several locations, would be beneficial.

A seep of a hydrocarbon or chemical substance was observed on the LDB of the creek, as shown

in Photograph 87 in Appendix II. Waste, including pieces of metal, was observed in fill on both

banks, as shown in Photographs 85 and 93. It is recommended that, as a minimum, a Phase I

Environmental Site Assessment be undertaken on this site prior to construction of any stream

restoration works that could potentially expose contaminated soils.

4.3 Lower Riffle Maintenance and Improvement

A site reconnaissance undertaken on 20 August 2005 showed that some undersized cobble-gravel

material that had been used to construct the downstream faces of the lower riffles (Riffle #2

through Riffle #9) on Hardisty Creek had been washed away during summer floods. In some

locations, scouring of gravel from below the riffle resulted in toppling of riffle boulders and

downstream movement. The pre-construction condition of each riffle is shown in Photographs

The recommended remedial action was replacement of rock riprap boulders and additional

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placement of small boulder and cobble material from the 350 mm minus fill material available on

site.

Some maintenance was performed at Riffle #2 using the excavator while it was working at the

lower end of Riffle #1. Equipment access to the lower riffles (Riffle #3 to Riffle #9) was limited

because of height restrictions on land and the desire not to walk the tracked excavator across

existing riffles. At these riffles, 350 minus material was stockpiled on the RDB for future

placement by community volunteers, as shown in Photographs 70 to 76 in Appendix II. Material

was hand placed at Riffle #8, as shown in Photographs 30 to 32 in Appendix II. The preferred

placement method is to place the largest material first, in the area below the existing boulders,

and then place smaller boulders and cobbles to bridge the gaps and create a rock matrix that will

eventually trap smaller fractions that are carried down the creek.

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5. CONCLUSION

This report documents the detailed design and construction of the upper riffle in the Kinsmen

Park reach of Hardisty Creek, which was built in October 2005. It also presents additional

assessments of the LWD structures that were installed in October 2004, of the potential future

restoration area below Switzer Drive, and of the maintenance activities prescribed for the lower

riffles in the Kinsmen Park reach.

We trust the above meets your present requirements. If you have any questions or require

additional details, please contact the undersigned.

GOLDER ASSOCIATES LTD.

Nathan Schmidt, Ph.D., P.Eng.Associate, Senior Water Resources Engineer

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6. REFERENCES

D’Aoust, S.G. and R.G. Millar. 1999. Large Woody Debris Fish Habitat Structure Performance

and Ballasting Requirements. British Columbia Ministry of Water, Land and Air

Protection, Watershed Restoration Management Report No. 8, 119 p.

Golder 2004. Hardisty Creek Fish Habitat and Fish Passage Assessments and Corrective

Designs. Prepared by Golder Associates Ltd. for Foothills Model Forest, May 2004, 56 p.

Melville, B.W. and S.E. Coleman. 2000. Bridge Scour. Water Resources Publications, LLC,

Highlands Ranch, Colorado, 550 p.

Slaney, P.A. and D. Zaldokas, eds. 1997. Fish habitat rehabilitation procedures. Watershed

Restoration Technical Circular No. 9. Watershed Restoration Program, Ministry of

Environment, Lands and Parks, Vancouver, B.C.

APPENDIX I

REGULATORY PERMITS FORINSTREAM CONSTRUCTION

APPENDIX II

PHOTOGRAPHS

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Photograph Description

Photograph 1: 10-Oct-05 1712h

222 mm long Rainbow Trout (RNTR) salvaged during the fish-outon the evening prior to construction.


190 mm long Brook Trout (BRTR) salvaged during the fish-out onthe evening prior to construction.


168 mm long Bull Trout (BLTR) salvaged during the fish-out onthe evening prior to construction.


87 mm long Mountain Whitefish (MNWH) salvaged during the fish-out on the evening prior to construction.


200 mm long Bull Trout (BLTR) salvaged during the fish-out onthe evening prior to construction.

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View of left downstream bank (LDB) diversion from upstream.The temporary diversion was lined with heavy polyethylene andwas completely within the existing channel.


Placement of fill at upstream riffle to bring up the water level in theupstream pool and to force all flow through the instream diversion.


Minor excavation at the upper end of the diversion to enhanceflow through the diversion.


Movement of 150 mm minus granular fill material with the Town ofHinton bobcat. The material was moved from the stockpile in theKinsmen Park parking lot to the edge of the creek bank, to allowthe excavator to reach it without climbing out of the channel.


Photograph of the impermeable liner used in the upstream riffle.This material was fish-friendly non-woven geotextile was placedagainst it on the downstream side to provide some protectionagainst rock during placement.

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Placement of 150 mm minus granular fill material below theupstream riffle. A small amount of flow through the rightdownstream bank (RDB) area remained after construction of theinstream diversion, and the initial placement of this material wasused to block all flow through the area outside of the diversion. Allpractical efforts were made to prevent water from flowing againstthis material to prevent erosion and transport of sediment into thedownstream reach of Hardisty Creek.


This picture shows complete diversion of flow through theinstream diversion. Some rock riprap has been placed against theupstream portion of the upper riffle.


The impermeable liner and accompanying non-woven geotextilewere initially placed across two-thirds of the channel, at the designriffle crest location, by stapling them to 2x4 timber supports.


The impermeable liner and accompanying non-woven geotextilewere initially placed across two-thirds of the channel, at the designriffle crest location, by stapling them to 2x4 timber supports.

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The liner material was tied into the RDB by laying it against thebank upstream of the riffle and placing granular fill on top of it.


Rock riprap was placed at the crest of the upstream riffle. Tworows of rock were placed and knitted together by selecting piecesthat interlocked in the best possible fashion.


At the downstream end of the instream diversion, clean water canbe observed flowing against the LDB, through turbid, pondedwater at the downstream end of the work area.


Continued placement of 150 mm minus granular fill material “inthe dry” outside of the instream diversion area.


Instream diversion as viewed from downstream.

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View from upstream of first riffle, showing rock riprap being placedat the riffle crest elevation.


Large diameter granular material excavated from the Hinton EastHardisty sewer construction project. This material was beingconsidered as 350 mm minus granular fill to provide an armorlayer for the downstream riffle surface. This material source wasultimately not used as material of sufficient quantity and qualitywas not available during the riffle construction period.


Large diameter granular material excavated from the Hinton EastHardisty sewer construction project. This material was beingconsidered as 350 mm minus granular fill to provide an armorlayer for the downstream riffle surface. This material source wasultimately not used as material of sufficient quantity and qualitywas not available during the riffle construction period.


Large diameter granular material from the West Central yard inHinton. This material was being considered as 350 mm minusgranular fill to provide an armor layer for the downstream rifflesurface. This material source was ultimately not used as materialof sufficient quantity and size was not available during the riffleconstruction period.


Large diameter granular material from the West Central pit acrossthe Athabasca River from Hinton. This material was beingconsidered as 350 mm minus granular fill to provide an armorlayer for the downstream riffle surface. This material source wasultimately not used as material of sufficient size was not availablefrom this source.

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End of the first day of construction, showing progress onplacement of 150 mm minus granular fill and riffle crest rockriprap.


Typical 150 mm minus granular fill material in the stockpile onsite.

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View of Riffle #9 from RDB, prior to placement of any boulders formaintenance.




View of Riffle #8 from RDB, during placement of boulders formaintenance.


View of Riffle #8 from RDB, after placement of boulders formaintenance.

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Large diameter granular material from the Town of Hintonwaste/borrow stockpile. This material was being considered as350 mm minus granular fill to provide an armor layer for thedownstream riffle surface. This material source was ultimately notused as material of sufficient size was not available from thissource.




Placement of rock riprap at the lower rock vortex weir.

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End of the second day of construction, showing progress onplacement of 150 mm minus granular fill, riffle crest rock riprapand vortex weir rock riprap.


End of the second day of construction, showing progress onplacement of 150 mm minus granular fill, riffle crest rock riprapand vortex weir rock riprap.


Large diameter granular material from the Border Paving HintonPit. This material was ultimately selected as 350 mm minusgranular fill to provide an armor layer for the downstream rifflesurface.


First load of 350 mm minus granular fill arriving on site. This loadappears slightly undersized with a higher than acceptable finescontent.


Additional loads of 350 mm minus granular fill from the BorderPaving pit. The material size is up to acceptable levels, thoughstill marginal.

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Additional loads of 350 mm minus granular fill material arriving onsite from the Border Paving pit. This material is well into theacceptable size range.


Additional loads of 350 mm minus granular fill material arriving onsite from the Border Paving pit. This material is well into theacceptable size range and is representative of the bulk of thematerial placed in the channel.


Installation of the downstream sediment trap on Hardisty Creek atSwitzer Avenue.





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Placement of material and grade survey on the lower vortex weirat the riffle construction.


Placement of material and grade survey on the lower vortex weirat the riffle construction.


End of the third day of construction, showing progress onplacement of 150 mm minus granular fill, riffle crest rock riprapand vortex weir rock riprap.


End of the third day of construction, showing progress onplacement of 150 mm minus granular fill, riffle crest rock riprapand vortex weir rock riprap.

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Stockpiled 350 mm minus granular fill material for use as channelbed armor.


Check on the sediment trap on Hardisty Creek at Switzer Drive.Rising water levels in the pond are due to deposition of leavesand sediment on the non-woven geotextile.


Check on the sediment trap on Hardisty Creek at Switzer Drive.Rising water levels in the pond are due to deposition of leavesand sediment on the non-woven geotextile. Water can be seenspilling through the non-woven geotextile on the downstream side.


Check on the sediment trap on Hardisty Creek at Switzer Drive.Rising water levels in the pond are due to deposition of leavesand sediment on the non-woven geotextile. Water can be seenspilling through the non-woven geotextile on the downstream side.

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Installation of buried temporary diversion pipe in the instreamdiversion, to allow fill placement along the LDB of the channel. A500 mm diameter, corrugated “Big O” pipe was used.


Inlet of the buried diversion pipe.


Mainly dry channel along the diversion pipe, prior to placement of150 mm minus granular fill material.

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Placement of 150 mm minus granular fill material and live willowstakes along the downstream diversion pipe.


Placement of 150 mm minus granular fill material and live willowstakes along the downstream diversion pipe.


Placement of 150 mm minus granular fill material and live willowstakes along the downstream diversion pipe. Also visible ispolyethylene sheeting that was placed on the creek bank at theoutlet of two 4-inch pumped diversion hoses.


Inlet of diversion pipe, and 150 mm diameter granular fill materialplaced above the pipe inlet.



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The diversion pipe inlet was extended upstream by placing anadditional section of pipe, to allow placement of additional fillmaterial in this area.


The diversion pipe inlet was extended upstream by placing anadditional section of pipe, to allow placement of additional fillmaterial in this area.



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Rock riprap and 350 mm minus granular material stockpiled atRiffle #9 to allow future maintenance/improvement of the riffle. 3pieces of 750 mm rock riprap and 2.5 m3 of 350 mm minusgranular material were placed at this location.


350 mm minus granular material stockpiled at Riffle #8 to allowfuture maintenance/improvement of the riffle. 3 pieces of 750 mmrock riprap and 2 m3 of 350 mm minus granular material wereplaced at this location.


350 mm minus granular material stockpiled at Riffle #7 to allowfuture maintenance/improvement of the riffle. 2 m3 of 350 mmminus granular material were placed at this location.





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View downstream on Hardisty Creek from just below SwitzerDrive. This series of photos was taken to prepare for potentialfuture restoration of the reach between Switzer Avenue and theWest Fraser property.


View downstream on Hardisty Creek from just below thepreceding photograph. This series of photos was taken toprepare for potential future restoration of the reach betweenSwitzer Avenue and the West Fraser property.



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View upstream on Hardisty Creek from the location of thepreceding photograph. This series of photos was taken toprepare for potential future restoration of the reach betweenSwitzer Avenue and the West Fraser property.







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Fill material in LDB of Hardisty Creek, just below the precedingphotograph. This series of photos was taken to prepare forpotential future restoration of the reach between Switzer Avenueand the West Fraser property.




Seepage zone in LDB of Hardisty Creek, just below the precedingphotograph. This seep did not appear to be natural and should beinvestigated prior to any stream restoration work in this area. Thisseries of photos was taken to prepare for potential futurerestoration of the reach between Switzer Avenue and the WestFraser property.





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View downstream on Hardisty Creek from just below thepreceding photograph. A trash pump / water intake is visible onthe LDB. This series of photos was taken to prepare for potentialfuture restoration of the reach between Switzer Avenue and theWest Fraser property.


View downstream on Hardisty Creek from just below thepreceding photograph. The West Fraser mill boundary fence isvisible in the downstream portion of the photograph. This seriesof photos was taken to prepare for potential future restoration ofthe reach between Switzer Avenue and the West Fraser property.


Trash pump / water intake is located on the LDB of HardistyCreek, just upstream of the West Fraser property. This series ofphotos was taken to prepare for potential future restoration of thereach between Switzer Avenue and the West Fraser property.


Fill on the RDB of Hardisty Creek, just upstream of the WestFraser property. This series of photos was taken to prepare forpotential future restoration of the reach between Switzer Avenueand the West Fraser property.

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Inlet of the instream diversion, showing pumped diversion lines.


Outlets of piped instream diversion and pumped diversions.


Pumped diversion hoses were placed on completed armor layer toenhance movement of fines into the interstices between largerrock fractions.



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Sediment entering the channel from the first flush of well-gradedarmor material.



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Pumped diversion hoses were placed on completed armor layer toenhance movement of fines into the interstices between largerrock fractions. This photograph also shows the lower vortex weir.


Remaining breach in the riffle that allows flow through the pipeddiversion.


Inlet of instream diversion pipe prior to placement of material toblock the inlet.


Inlet of instream diversion pipe during placement of material toblock the inlet.


Inlet of instream diversion pipe after placement of material toblock the inlet. Note the increase in upstream pond water surfaceelevation after less than seven minutes. The non-wovengeotextile material was placed over the inlet prior to placement of150 mm minus granular fill material, to prevent loss of fill into thepipe inlet and potential failure of the riffle structure.

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Rapid placement of 150 mm minus granular fill material and rockriprap material on the riffle crest, as the upstream pond elevationincreased.


Visible movement of clean water through the Hardisty Avenueculverts into the upstream pond.


Visible movement of clean water through the Hardisty Avenueculverts into the upstream pond.


Placement of live willow plantings along the borders of theupstream pond.


Placement of live willow plantings along the borders of theupstream pond.

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Rapid placement of 350 mm minus armor layer below the crest ofthe riffle.


Rapid placement of 350 mm minus armor layer below the crest ofthe riffle, and first spill of water over the crest of the riffle.


Rapid placement of 350 mm minus armor layer below the crest ofthe riffle, and continued spill of water over the crest of the riffle.


Rapid placement of 350 mm minus armor layer below the crest ofthe riffle, and movement of water down the riffle.



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View of completed riffle from upstream, showing clean waterentering the upstream pool from the Hardisty Avenue culverts.






Natural riffle located just upstream of Hardisty Avenue, showingsimilar geometry and bed material characteristics to completedriffle.

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View of completed riffle from upstream, showing clean waterentering the upstream pool from the Hardisty Avenue culverts.Submergence of the Hardisty Avenue culverts is visible.




Inlet of larger Hardisty Avenue culvert, showing the extent ofbackflooding during low flow.


Inlet of larger Hardisty Avenue culvert, showing the extent ofbackflooding during low flow.

APPENDIX III

FISHERIES INFORMATION COLLECTEDPRIOR TO CONSTRUCTION

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Table III.1 – Record of Fish Collected, Evening of 10 October 2005

Speciesa Weight(g)

Fork Length(mm) Notes

RNTR 142 222 Photograph takenBRTR 98 190 Photograph takenBLTR 60 168 Photograph taken

MNWH 12 87 Photograph takenBLTR 120 200 Photograph taken

MNWH 64 161 -MNWH 16 97 -MNWH 22 121 -MNWH 42 128 -MNWH 22 108 -MNWH 38 133 -MNWH 40 119 -MNWH 36 120 -MNWH 26 98 -MNWH 18 99 -MNWH 20 105 -MNWH 28 121 -MNWH 36 131 -MNWH 36 131 -MNWH 12 112 -MNWH 30 135 -MNWH 18 106 -MNWH 12 100 -MNWH 20 120 -MNWH 12 97 -MNWH 18 92 -MNWH 14 92 -MNWH 22 98 -MNWH 22 101 -MNWH 18 101 -MNWH 14 90 -MNWH 8 94 -MNWH 10 98 DeadMNWH 6 89 Dead

(a) RNTR = Rainbow Trout; BRTR = Brook Trout; BLTR =Bull Trout; MNWH = Mountain Whitefish.

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Table III.2 – Record of Fish Collected, Morning of 11 October 2005

SpeciesaWeight

(g)Fork Length

(mm) Notes

BKTR 165 56 -BKTR 201 94 -BLTR 204 110 -BLTR 222 125 -BLTR 245 180 -RNTR 195 70 -RNTR 212 140 -RNTR 221 134 -MNWH 75 6 -MNWH 79 6 -MNWH 85 6 -MNWH 86 8 -MNWH 90 6 -MNWH 90 14 -MNWH 91 8 -MNWH 91 8 -MNWH 91 6 -MNWH 93 6 -MNWH 95 6 -MNWH 98 6 -MNWH 110 12 -MNWH 112 14 -MNWH 113 15 -MNWH 118 14.2 -MNWH 120 17 -MNWH 123 18 -MNWH 125 20 -MNWH 126 16 -MNWH 126 20 -MNWH 127 18 -MNWH 128 20 -MNWH 142 24 -MNWH 155 44 -

(a) RNTR = Rainbow Trout; BRTR = Brook Trout; BLTR =Bull Trout; MNWH = Mountain Whitefish.

APPENDIX IV

TURBIDITY DATA COLLECTEDDURING CONSTRUCTION

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Samples were collected at Switzer Drive Bridge, downstream of the sediment trap, unlessotherwise noted. Samples were tested using a Lamotte 2020 Turbidity Meter.

Date & Time Note Rdg 1 Rdg 2 Rdg 3 Mean

10/11/2005 10:29 20.9 21.2 21.1 21.110/11/2005 11:35 16.8 17.6 16.9 17.110/11/2005 12:38 Riffle 7.61 7.81 10.05 8.510/11/2005 12:41 Pool 7.68 7.72 7.77 7.710/11/2005 13:38 15.6 15.4 16.2 15.710/11/2005 14:20 23.3 23 22.8 23.010/11/2005 16:02 9.75 10.27 9.79 9.910/11/2005 17:01 2.43 2.43 2.13 2.3

10/12/2005 8:03 1.09 1.11 1.36 1.210/12/2005 9:34 21 20 14 18.3

10/12/2005 10:30 3.8 3.7 3.8 3.810/12/2005 11:30 85 80 75 80.010/12/2005 12:35 24.4 24.2 23.9 24.210/12/2005 12:48 9.66 9.14 9.68 9.510/12/2005 13:33 3.77 3.79 3.78 3.810/12/2005 14:35 5.89 5.18 5.15 5.410/12/2005 15:33 12.5 10.44 10.78 11.210/12/2005 15:50 Background upstream 0.93 1 0.67 0.910/12/2005 17:01 4.44 4.41 4.53 4.510/12/2005 18:03 2.19 2.18 2.22 2.2

10/13/2005 8:13 1.07 0.89 0.86 0.910/13/2005 9:17 1.43 1.43 1.46 1.410/13/2005 9:57 6.44 6.88 6.88 6.7

10/13/2005 11:02 22 21.6 21.6 21.710/13/2005 12:14 Sediment trap installed 4.21 4.37 4.09 4.210/13/2005 13:15 5.86 5.99 6.27 6.010/13/2005 14:02 2.85 2.78 2.97 2.910/13/2005 14:38 2.82 2.32 2.32 2.510/13/2005 15:14 1.9 1.71 1.73 1.810/13/2005 16:26 1.61 1.56 1.51 1.610/13/2005 17:21 3.11 2.61 2.55 2.8

10/14/2005 8:20 1.42 1.36 1.31 1.410/14/2005 9:24 3.51 3.3 3.32 3.4

10/14/2005 10:15 20.4 20.5 20.5 20.510/14/2005 11:35 50.2 50.3 49.7 50.110/14/2005 12:09 6.34 6.41 6.47 6.410/14/2005 12:14 Sample from 2nd riffle 20.8 21 20.9 20.910/14/2005 13:20 12.5 12.4 12.5 12.510/14/2005 14:26 3.92 3.91 3.91 3.910/14/2005 15:05 79.7 80.5 80.2 80.110/14/2005 17:00 Sample too high to read

APPENDIX V

LWD BALLASTINGASSESSMENT

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In October 2004, 20 Large Woody Debris (LWD) structures were installed in the Kinsmen Park

reach of Hardisty Creek. Details of these structures are provided in Table V1 and their locations

are shown in Figure V1.

Table V1 – Description of LWD Structures in Kinsmen Park Reach of Hardisty Creek

LWDNo.

StructureType

Root WadDiameter

(m)

LogDiameter

(m)

LogLength

(m)Boulder

No.

BoulderIntermediate

Axis (m)

EstimatedBallast

(kg)

1 Single Log n/a 0.43 14.7 1 0.5 1842 0.6 3053 0.6 364

total 853

2 Single Log n/a 0.125 8.5 1 0.7 418total 418

3Multi-Log with

Intact Root Wad 1.6 0.24 13.4 1 0.7 541Multi-Log 0.16 6.6 2 0.8 610

3 0.6 293total 1444

4Single Log withIntact Root Wad 2.3 0.18 10.0 1 0.6 244

2 0.8 685total 929

5 Root Wad 2.4 0.35 1.2 1 0.5 1792 0.5 164

total 343

6Multi-Log with

Intact Root Wad 1.0 0.20 12.6 1 0.5 195Multi-Log 0.19 15.8 2 0.4 111

3 0.7 4004 0.6 316

total 1021


2 0.6 2713 0.5 174

total 619


2 0.5 169total 287

9Multi-Log with

Intact Root Wad 1.2 0.26 8.5 1 0.5 174Multi-Log 0.325 2.7 2 0.6 331Multi-Log 0.16 9.0 3 0.7 541

total 1046

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Table V1 – Description of LWD Structures in Kinsmen Park Reach of Hardisty Creek(continued)

LWDNo.

StructureType

Root WadDiameter

(m)

LogDiameter

(m)

LogLength

(m)Boulder

No.

BoulderIntermediate

Axis (m)

EstimatedBallast

(kg)

10 Multi-Log 0.27 4.3 1 0.4 83Multi-Log 0.225 14.5 2 0.5 144

total 227

11 Root Wad 2.75 0.54 0.76 1 0.4 1112 0.5 195

total 306


2 0.6 348total 605

13 Multi-Log 0.165 4.0 1 0.5 195Multi-Log 0.255 6.5 2 0.5 207

total 402

14 Single Log 0.295 12.7 1 0.3 412 0.5 1313 0.5 1694 0.4 83

total 423

15 Single Log 0.305 15.5 1 0.5 2192 0.5 1313 0.6 244

total 594

16 Root Wad 2.9 0.52 1.0 1 0.7 4002 0.5 174

total 573

17 Single Log 0.325 7.5 1 0.6 2312 0.5 174

total 405

18 Root Wad 3.5 0.44 0.55 1 0.5 174total 174

19 Multi-Log 0.37 6.8 1 0.6 3160.22 7.3 2 0.4 830.20 3.6 3 0.4 70

total 468

20 a- Single Log 0.18 5.9 1 0.7 457b- Single Log 0.175 6.1 1 0.6 331c- Single Log 0.175 12.0 1 0.5 174

total 962

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Figure V1 – Layout of LWD Structures at Kinsmen Park Reach of Hardisty Creek

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Ballasting requirements for the log-boulder LWD structures were assessed based on the updated

methods presented by D’Aoust and Millar (1999). Ballasting requirements for single log

structures, multi-log structures and root wads are presented below.

The design flow velocity for the Kinsmen Park reach of Hardisty Creek is calculated using the

Manning equation and the 100-year design discharge:

Q = A R2/3 S1/2 / n; therefore, A R2/3 = Q n / S1/2

Based on the design discharge, Q, of 11.8 m3/s, the mean channel slope, S, of 0.02 m/m and an

assumed channel roughness, n, of 0.050, and mean channel geometry represented by a bed width

of 8 m and 1H:1V sideslopes, this equation returns a mean flow depth of 0.68 m and a mean flow

velocity of 2.0 m/s.

Single Log LWD Structures

Single log structures include LWD structures 1, 2, 14, 15, 20a, 20b and 20c. Single log structures

with intact root wads include LWD structures 4, 7, 8 and 12. LWD structures 7 and 8 were

treated as single log structures, because in these cases, the root wad was placed against the creek

bank and the log placed into the stream.

Standard practice is to check the design Factor of Safety for sliding (FSS) and buoyancy (FSB), as

calculated below:

Where FF equals the frictional resistance of boulder(s), based on the submerged weight of the

boulder(s), W’, the vertical buoyant force exerted by the LWD on the boulder(s), FBL, the vertical

lift force on the boulder(s), FLB, and the angle of repose of the boulder(s), :

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The submerged weight of each boulder is calculated based on the boulder diameter, DB, the

density of water, = 1000 kg/m3, the gravitational constant, g = 9.81 N/kg, and the specific

gravity of the boulder material, SS = 2.65:

The vertical lift force exerted on the boulder(s) by the LWD, FBL, is calculated based on a ballast

factor, BF = 1 for LWD anchored to the bank or BF = 2 for LWD not anchored to the bank, the

length, L, and diameter, DL, of the log, as well as the density of water, = 1000 kg/m3, the

gravitational constant, g = 9.81 N/kg, and the specific density of the timber, SL = 0.48 for

jackpine, lodgepole pine and black spruce:

The vertical lift force acting directly on the boulder(s), FLB, is calculated based on a lift

coefficient, CLB = 0.17, the density of water, = 1000 kg/m3, the flow velocity, V, and the

boulder diameter, DB:

The horizontal drag force exerted on the boulder(s) by the LWD, FDL, is calculated based on the

aforementioned Ballast Factor, BF, a drag coefficient, CDL = 0.3, and the aforementioned density

of water, = 1000 kg/m3, the flow velocity, V, the log length, L, and diameter, DL, and the angle

between the log and stream bank, :

The horizontal drag force exerted on each anchor boulder, FDB, is calculated based on a

coefficient, CDB = 0.20, the density of water, = 1000 kg/m3, the flow velocity, V, and the

boulder diameter, DB:

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Calculations for the single log LWD structures 1, 2, 7, 8, 14, 15, 20a, 20b and 20c are shown in

Table V2 (Factors of Safety for Buoyancy) and Table V3 (Factors of Safety for Sliding).

Table V2 – Factors of Safety for Buoyancy (FSB) for Single Log LWD Structures

Boulder Immersed Weight, W' Log Buoyant Force, FBL Boulder Lift Force, FLB

LWDStructure

DB

(m)SS

( - )FDL

(N)BF( - )

L(m)

DL

(m)SL

( - )FBL

( - )CDB

( - )V

(m/s)DB

(m)FDL

( - )FSB

0.5 2.65 1059 0.17 2 0.5 67

0.6 2.65 1831 0.17 2 0.6 96

0.6 2.65 1831 0.17 2 0.6 961

Total 4721 2 14.7 0.43 0.48 10890 Total 259 0.4

2 0.7 2.65 2907 2 8.5 0.125 0.48 532 0.17 2 0.7 131 4.4

0.5 2.65 1059 0.17 2 0.5 67

0.6 2.65 1831 0.17 2 0.6 96

0.5 2.65 1059 0.17 2 0.5 677

Total 3949 2 17.3 0.24 0.48 3992 Total 230 0.9

0.4 2.65 542 0.17 2 0.4 43

0.5 2.65 1059 0.17 2 0.5 678

Total 1602 2 12.4 0.08 0.48 318 Total 109 3.7

0.3 2.65 229 0.17 2 0.3 24

0.5 2.65 1059 0.17 2 0.5 67

0.5 2.65 1059 0.17 2 0.5 67

0.4 2.65 542 0.17 2 0.4 43

14

Total 2890 2 12.7 0.295 0.48 4428 Total 200 0.6

0.5 2.65 1059 0.17 2 0.5 67

0.5 2.65 1059 0.17 2 0.5 67

0.6 2.65 1831 0.17 2 0.6 9615

Total 3949 2 15.5 0.305 0.48 5777 Total 230 0.7

0.6 2.65 1831 0.17 2 0.6 960.5 2.65 1059 0.17 2 0.5 6717

Total 2890 2 7.5 0.325 0.48 3174 Total 163 0.9

20a 0.7 2.65 2907 2 5.9 0.18 0.48 766 0.17 2 0.7 131 3.2

20b 0.6 2.65 1831 2 6.1 0.175 0.48 748 0.17 2 0.6 96 2.2

20c 0.5 2.65 1059 1 12 0.175 0.48 736 0.17 2 0.5 67 1.3

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Table V3 – Factors of Safety for Sliding (FSS) for Single Log LWD Structures

Frictional Sliding Resistance, FF Log Drag Force, FDL Boulder Drag Force, FDB

LWDStr

W'( - )

FBL

(N)FLB

(N)

(deg)FF

(N)BF( - )

CDL

( - )V

(m/s)L

(m)DL

(m)

(deg)FDL

( - )CDB

( - )DB

(m)FDL

(N)FSS

0.2 0.5 79

0.2 0.6 113

0.2 0.6 1131

4721 10890 259 40 -5394 2 0.3 2 14.7 0.43 30 1896 Total 305 -2.5

2 2907 532 131 40 1883 2 0.3 2 8.5 0.125 45 451 0.2 0.7 154 3.1

0.2 0.5 79

0.2 0.6 113

0.2 0.5 797

3949 3992 230 40 -229 2 0.3 2 17.3 0.24 35 1429 Total 270 -0.1

0.2 0.4 50

0.2 0.5 798

1602 318 109 40 985 2 0.3 2 12.4 0.08 35 341 Total 129 2.1

0.2 0.3 28

0.2 0.5 79

0.2 0.5 79

0.2 0.4 50

14

2890 4428 200 40 -1459 2 0.3 2 12.7 0.295 10 390 Total 236 -2.3

0.2 0.5 79

0.2 0.5 79

0.2 0.6 11315

3949 5777 230 40 -1726 2 0.3 2 15.5 0.305 40 1823 Total 270 -0.8

0.2 0.6 113

0.2 0.5 7917

2890 3174 163 40 -375 2 0.3 2 7.5 0.325 30 731 Total 192 -0.4

20a 2907 766 131 40 1687 2 0.3 2 5.9 0.18 60 552 0.2 0.7 154 2.4

20b 1831 748 96 40 827 2 0.3 2 6.1 0.175 60 555 0.2 0.6 113 1.2

20c 1059 736 67 40 215 1 0.3 2 12 0.175 10 109 0.2 0.5 79 1.1

LWD Structure 1 has a calculated FSB of 0.4 and

FSS below zero and this indicates underballasting.

However, this is based on a reported length of 14.7

m and mean diameter of 0.43 m. The reported

diameter may be a maximum diameter and may

result in an overestimate of both buoyant and drag

forces on the log. The ballasting may be adequate

for this reason and also because of the low design

flow depth of 0.68 m and the fact that the LWD

does not appear to have moved during the high water events of June 2005.

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FSS of 3.1 and this indicates adequate ballasting.


FSS below zero and this indicates that it may be

slightly underballasted. This is based on a

reported length of 17.3 m and mean diameter of

0.24 m. The reported diameter may be a

maximum diameter and may result in an

overestimate of both buoyant and drag forces on

the log. The ballasting may be adequate for this

reason and also because of the low design flow

depth of 0.68 m and the fact that the LWD does not appear to have moved during the high water

events of June 2005.


FSS of 2.1 and this indicates adequate ballasting.

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LWD Structure 14 has a calculated FSB of 0.6

and FSS below zero and this indicates that it may

be slightly underballasted. This is based on a





























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LWD Structure 20 has a calculated FSB values of

3.2, 2.2 and 1.3 for each of the three logs and

calculated FSS values of 2.4, 1.2 and 1.1. These

logs were reset during construction of the upper

riffle in 2005, and were embedded into the bank

under cobble and gravel. The ballasting is

considered to be adequate, given that they did not

move during the flood events of June 2005, prior

to embedment in the creek bank.

Single Log LWD Structures with Exposed Intact Root Wads

Single log structures with exposed intact root wads include LWD structures 4 and 12.

Consideration of the forces due to flow impingement on the root wad require that the design

Factor of Safety for sliding (FSS) be modified, as shown below, while the Factor of Safety for

buoyancy (FSB) remains the same as previously presented:

All parameters in the preceding equation may be calculated as previously presented, except as

follows.

The drag forces on the root wad, FDRW, is calculated based on a drag coefficient, CDRW = 1.2, the

diameter of the root wad, DRW, the flow velocity, V, the density of water, = 1000 kg/m3, and the

angle between the root wad face and flow, , assumed to be 90 degrees.

The frictional force exerted by the flow on the log, FFL, is assumed to be negligible, because it is

located in the lee of the root wad.

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The buoyancy force exerted by the LWD on the boulder(s) must now consider the root wad, and

is calculated based on the length, L, and diameter, DL, of the log, the length, LRW, and diameter,

DRW, of the root wad, as well as the density of water, = 1000 kg/m3, the gravitational constant,

g = 9.81 N/kg, and the specific density of the timber, SL = 0.48 for jackpine, lodgepole pine and

black spruce:

Calculations for the single log LWD structures 4 and 12 are shown in Table V4 (Factors of Safety

for Buoyancy) and Table V5 (Factors of Safety for Sliding).

Table V4 – Factors of Safety for Buoyancy (FSB) for Single Log LWD Structures withExposed Intact Root Wads

Boulder Immersed Weight, W' Total Buoyant Force, FBL Boulder Lift Force, FLB

LWDStructure

DB

(m)SS

( - )FDL

(N)DL

(m)L

(m)DRW

(m)LRW

(m)SL

( - )FBL

(N)CDB

( - )V

(m/s)DB

(m)FLB

(N)FSB

0.6 2.65 1831 0.17 2 0.6 96

0.8 2.65 4339 0.17 2 0.8 1714

Total 6170 0.18 14.7 1 0.5 0.48 2442 Total 267 2.3

0.6 2.65 1831 0.17 2 0.6 96

0.6 2.65 1831 0.17 2 0.6 9612

Total 3661 0.23 15.5 0.8 0.5 0.48 3627 Total 192 1.0

Table V5 – Factors of Safety for Buoyancy (FSS) for Single Log LWD Structures withExposed Intact Root Wads

Frictional Sliding Resistance, FF

LogDragForce

Root Wad Drag Force, FDRW Boulder Drag Force, FDB

LWDStr.

W'(N)

FBL

(N)FLB

(N)

(deg)FF

(N)FFL

(N)CDRW

( - )DRW

(m)V

(m/s)L

(m)DL

(m)

(deg)FDRW

(N)CDB

( - )V

(m/s)DB

(m) FDL

FSS

0.2 2 0.6 113

0.2 2 0.8 201

4 6170 2442 267 40 2904 0 1.2 1 2 14.7 0.43 90 1885 Total 314 1.3

0.2 2 0.6 113

0.2 2 0.6 113

12 3661 3627 192 40 -133 0 1.2 0.8 2 15.5 0.305 90 1206 Total 226 -0.1

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FSS of 1.3. Though the value of FSS is somewhat

low, this ballasting is likely adequate. The

reported root wad diameter was 2.3 m, but an

effective diameter of 1.0 m was used for

calculation purposes.



be underballasted. This is based on a reported

length of 14.5 m and mean diameter of 0.23 m.

The reported diameter may be a maximum

diameter and may result in an overestimate of both

buoyant and drag forces on the log. The ballasting

may be adequate for this reason and also because

of the low design flow depth of 0.68 m and the

fact that the LWD does not appear to have moved during the high water events of June 2005. The

reported root wad diameter was 1.8 m, but an effective diameter of 0.8 m was used for calculation

purposes.

Multi-Log LWD Structures

D’Aoust and Millar (1999) recommends that for multi-log LWD structures, lateral stability is

provided by triangular construction and that it is only necessary to calculate the Factor of Safety

for buoyancy (FSB), using the following equation:

As with the single log LWD structures, the Ballast Factor, BF, for each log is specified as 1.0 for

those anchored to the bank and 2.0 for those in the stream only. Calculations for the buoyant

stability of multiple log LWD structures 3, 6, 9, 10, 13 and 19 are shown in Table V6 (Factors of

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Safety for Buoyancy). Intact root wads were present on LWD structures 3, 6, and 9, but these

were relatively small and located on or against the creek bank, so these were neglected in the

calculations.

Table V6 – Factors of Safety for Buoyancy (FSB) for Multiple Log LWD Structures

Boulder Immersed Weight, W' Log Buoyant Force, FBL Boulder Lift Force, FLB

LWDStructure

DB

(m)SS

( - )FDL

(N)BF( - )

L(m)

DL

(m)SL

( - )FBL

(N) CDB

V(m/s)

DB

(m)FDL

(N)

FSB

0.7 2.65 2907 2 13.4 0.24 0.48 3092 0.17 2 0.7 131

0.8 2.65 4339 2 6.6 0.16 0.48 677 0.17 2 0.8 171

0.6 2.65 1831 0.17 2 0.6 963

Total 9077 Total 3769 Total 398 2.2

0.5 2.65 1059 1 12.6 0.20 0.48 1010 0.17 2 0.5 67

0.4 2.65 542 1 15.8 0.19 0.48 1143 0.17 2 0.4 43

0.7 2.65 2907 0.17 2 0.7 131

0.6 2.65 1831 0.17 2 0.6 96

6


0.5 2.65 1059 1 8.5 0.26 0.48 1151 0.17 2 0.5 67

0.6 2.65 1831 1 2.7 0.325 0.48 571 0.17 2 0.6 96

0.7 2.65 2907 1 9.0 0.16 0.48 462 0.17 2 0.7 1319


0.4 2.65 542 1 4.3 0.27 0.48 628 0.17 2 0.4 43

0.5 2.65 1059 1 14.5 0.225 0.48 1471 0.17 2 0.5 6710


0.5 2.65 1059 1 4.0 0.165 0.48 218 0.17 2 0.5 67

0.5 2.65 1059 1 6.5 0.255 0.48 847 0.17 2 0.5 6713


0.6 2.65 1831 2 6.8 0.37 0.48 3730 0.17 2 0.6 96

0.4 2.65 542 1 7.3 0.22 0.48 708 0.17 2 0.4 43

0.4 2.65 542 1 3.6 0.20 0.48 288 0.17 2 0.4 4319



it appears that it is adequately ballasted.

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and may be underballasted. Dimensions should be

reconfirmed, as it appears that this LWD structure

remained stable during the flood events of June

2005.


and it appears that it is adequately ballasted,

though a Factor of Safety of 2.0 would be

preferred.

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and may be underballasted. Dimensions should be

reconfirmed, as it appears that this LWD structure

remained stable during the flood events of June

2005.

Root Wad LWD Structures

All of the root wads installed in October 2004 were installed vertically, with short trunks

extending upwards. The method for single log LWD structures with root wads, as presented by

D’Aoust and Millar (1999), is not appropriate for analyzing the stability of this type of

installation. However, the method can be used to check for the Factor of Safety for buoyancy

(FSB) can be approximated using the method described for the single log LWD structure with root

wad and the Factor of Safety for sliding (FSS) can be approximated using the steps described for

the single log LWD structure.

Calculations for the buoyant stability of root wad LWD structures 5, 11, 16 and 18 are shown in

Table V7 (Factors of Safety for Buoyancy) and Table V8 (Factors of Safety for Sliding). In

calculations for sliding, the effective length of the LWD has been taken as double its actual length

(BF = 2, despite bed anchorage) to account for the presence of the wider root area against the

creek bed, and the angle has been specified as 90 degrees. It must be noted that “effective” root

wad diameters were used in the calculations, rather than those recorded in the field. This is

because the equations used here are based on dense root wad structures with only 20% porosity,

rather than the much less dense root wads that were used here.

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Table V7 – Factors of Safety for Buoyancy (FSB) for Root Wad LWD Structures

Boulder Immersed Weight, W' Total Buoyant Force, FBL Boulder Lift Force, FLB

LWDStructure

DB

(m)SS

( - )W'(N)

DL

(m)L

(m)DRW

(m)LRW

(m)SL

( - )FBL

(N)CDB

( - )V

(m/s)DB

(m)FDL

(N)FSB

0.5 2.65 1059 0.17 2 0.5 67

0.5 2.65 1059 0.17 2 0.5 675

Total 2119 0.35 0.6 1.2 0.6 0.48 1218 Total 134 1.6

0.4 2.65 542 0.17 2 0.4 43

0.5 2.65 1059 0.17 2 0.5 6711

Total 1602 0.54 0.76 1.5 0.2 0.48 1369 Total 109 1.1

0.7 2.65 2907 0.17 2 0.7 131

0.5 2.65 1059 0.17 2 0.5 6716

Total 3966 0.52 0.6 1.5 0.4 0.48 1612 Total 198 2.2

18 0.5 2.65 1059 0.44 0.2 1.8 0.35 0.48 1367 0.17 2 0.5 67 0.7

Table V8 – Factors of Safety for Sliding (FSS) for Root Wad LWD Structures

Frictional Sliding Resistance, FF Log Drag Force, FDL Boulder Drag Force, FDB

LWDStr.

W'( - )

FBL

(N)FLB

(N)

(deg)FF

(N)BF( - )

CDL

( - )V

(m/s)L

(m)DL

(m)

(deg)FDL

( - )CDB

( - )DB

(m)FDL

(N)FSS

0.2 0.5 79

0.2 0.5 795

2119 1218 134 40 644 2 0.3 2 1.2 0.35 90 252 Total 157 1.6

0.2 0.4 50

0.2 0.5 7911

1602 1369 109 40 104 2 0.3 2 0.76 0.54 90 246 Total 129 0.3

0.2 0.7 154

0.2 0.5 7916

3966 1612 198 40 1810 2 0.3 2 1.0 0.52 90 312 Total 232 3.3

18 1059 1367 67 40 -314 2 0.3 2 0.55 0.44 90 145 0.2 0.5 79 -1.4


FSS of 1.6 and though values of 2.0 would be

preferred, this structure can be considered as

adequately ballasted. The reported root wad

diameter was 1.6 m, but an effective diameter of

1.2 m was used for calculation purposes.

January 2007 -V-17- 05-1373-029

Golder Associates


and FSS of 0.3 and this indicates that it may be

underballasted. However, the ballasting may be

adequate because of conservative assumptions in

the calculations and the fact that the LWD does

not appear to have moved during the high water

events of June 2005. The reported root wad




and FSS of 3.3 and this indicates that it is

adequately ballasted. The reported root wad




and FSS of less than zero, and this indicates that it

is likely underballasted. However, the ballasting

may be adequate because of the fact that the LWD

does not appear to have moved during the high

water events of June 2005, and that there was

significant sediment deposition around the

structure at that time, meaning that it is currently

embedded in the creek bed. The reported root wad

diameter was 3.5 m, but an effective diameter of 1.8 m was used for calculation purposes.

Summary

A summary of the calculated Factors of Safety for Buoyancy and Sliding for each LWD structure

is provided in Table V9, along with comments and recommendations for each structure. Overall,

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stability was confirmed for 10 of the 20 LWD structures. The remaining structures had calculated

Factors of Safety for Buoyancy, FSB, of between 0.4 and 1.1. LWD structures with FSB values of

1.0 or less by definition will have Factors of Safety for Sliding, FSS, of less than zero. These

structures may be underballasted; however, it is possible in some cases that the calculated values

are overly conservative. This is because the ballasting calculations assume full submergence of

the LWD structures, and the relatively low water depths during flood events on Hardisty Creek

mean that logs may not be fully submerged. There did not appear to be any movement of these

structures during the high water events of June 2005. For these structures, dimensions and

calculations should be confirmed after an additional inspection to confirm the parameters used in

the assessment, and additional ballasting should be considered if required.

Table V9 – Summary of Calculated Factors of Safety for LWD Structures

LWDStructure

Factor ofSafety forBuoyancy,

FSB

Factor ofSafety forSliding,

FSS

Comments and Recommendations





5 1.6 1.6 Likely stable, FS > 2.0 would be preferred.






11 1.1 0.3 May be underballasted but appeared stable in June 2005.


13 1.8 n/a Likely stable, FS > 2.0 would be preferred.





18 0.7 -1.4 Calculations say underballasted, but currently embedded in bed.


20 3.2, 2.2, 1.3 2.4, 1.2, 1.1 Likely stable, FS > 2.0 would be preferred.

APPENDIX VI

CONSTRUCTIONSURVEY DATA

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Prior to construction, temporary benchmarks were established and surveyed to assist with the

final field-fit design and construction of the backflooding riffle. Surveys were not referenced to a

geodetic datum and lateral control was based on cloth-tape distance measurements. This method

was sufficient for layout of the rock fill structures.

Vertical Control Surveys

Point BS HI FS Elev Notes

Lg Culv Inv 2.129 102.129 - 100.000 Invert of Large Culvert Outlet; assumed elevationLg Culv Crn - 0.487 101.642 Crown of Large Culvert OutletSm Culv Inv - 1.878 100.251 Invert of Small Culvert OutletSm Culv Crn - 0.684 101.445 Crown of Small Culvert Outlet

Pool - 2.283 99.846 Water surface elevation in downstream pool

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PRE-CONSTRUCTION SURVEY AND DESIGN ELEVATIONS

Boxed entries denote final elevation checks during construction. Other checks were performedas fill material was being placed.

Transect 0+00 (Centreline of Riffle 1 Crest)

PointPre-

Construction

Design350

minus

Design150

Minus

150Minus Fill

Depth Check Notes

0 102.07 101.571.3 101.17 101.511.7 100.98 101.49 101.09 0.11 Interpolated survey elevation3 100.37 101.42 101.02 0.65

4.2 100.25 101.36 100.96 0.714.5 99.31 101.35 100.95 1.636.7 98.97 101.24 100.84 1.869.5 99.45 101.10 100.70 1.25

11.2 99.59 101.01 100.61 1.02

13.4 99.48 100.90 100.50 1.02 100.92 Design thalweg

16.4 99.80 101.05 100.65 0.8518.4 100.12 101.15 100.75 0.6321.1 100.78 101.29 100.89 0.11 Interpolated survey elevation22.8 101.20 101.3726.1 102.06 101.54

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

102.5

0 5 10 15 20 25 30Distance from RDB (m)

Ele

vatio

n(m

)

Top of 350mm MinusTop of 150mm MinusPre-Construction Bed

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Transect 0+10 (10m Downstream of Centreline of Riffle 1 Crest)

PointPre-

Construction

Design350

minus

Design150

Minus

150Minus Fill

Depth Check Notes

34.9 101.62 101.1825 100.56 100.69 Interpolated survey elevation

23.8 100.43 100.6322.5 100.19 100.56 100.16 -0.03 Interpolated survey elevation20.6 99.83 100.47 100.07 0.24

19.8 99.45 100.43 100.03 0.57 100.12

18.8 99.32 100.38 99.98 0.6515.9 99.42 100.23 99.83 0.4115 99.36 100.19 99.79 0.43 Interpolated survey elevation

12.3 99.17 100.05 99.65 0.48 99.65 Design thalweg

11 99.20 100.12 99.72 0.51 100.16 Interpolated survey elevation

9.9 99.23 100.17 99.77 0.54 99.91

9 99.12 100.22 99.82 0.69 99.79

5.9 99.29 100.37 99.97 0.68

5 99.51 100.42 100.02 0.51 99.99 Interpolated survey elevation

4.1 99.72 100.46 100.06 0.34

3.1 100.14 100.51 100.11 -0.03 100.43 Interpolated survey elevation

2.4 100.43 100.550 101.57 100.67

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

0 5 10 15 20 25 30 35 40Distance from RDB (m)

Ele

vatio

n(m

)


January 2007 -VI-4- 05-1373-029

Golder Associates



Transect 0+20 (20m Downstream of Centreline of Riffle 1 Crest)

PointPre-

Construction

Design350

minus

Design150

Minus

150Minus Fill

Depth Check Notes

0 101.19 99.920.5 100.57 99.893.5 99.45 99.74 99.34 0.004.8 99.01 99.68 99.28 0.277.8 98.95 99.53 99.13 0.1710.5 99.07 99.39 98.99 0.00 Interpolated survey elevation12.3 99.15 99.30 Design thalweg17.8 99.18 99.5819.4 99.43 99.6621.2 99.76 99.7524 100.34 99.8930 100.81 100.19

98.5

99.0

99.5

100.0

100.5

101.0

101.5

0 5 10 15 20 25 30 35

Distance from RDB (m)

Ele

vatio

n(m

)


APPENDIX VII

JULY 2006 INSPECTIONAND PHOTO SURVEY

January 2007 -VII-1- 05-1373-029

Golder Associates

The project site was visited by Nathan Schmidt on 1 July 2006 and photographs of key features

were taken. These are presented below, with comments. It is understood that the spring runoff in

2006 was not high and that the constructed riffle has not experienced deep or rapid flows.

Photo 1 – Riffle 1 from RDB. Photo 2 – Backflood pool from RDB.

Photo 3 – Backflood pool from upstream. Photo 4 – Riffle 1 from LDB.

Photo 5 – Backflood pool from LDB. Photo 6 – Excavated holes at Riffle 1 LDB.

January 2007 -VII-2- 05-1373-029

Golder Associates

Photo 7 – Riffle 1 front face from downstream. Photo 8 – First grade control below Riffle 1from LDB.

Photo 9 – Second grade control below Riffle 1from LDB.

Photo 10 – Successful willow staking in secondgrade control.

Photo 11 – Successful willow staking alongRDB.

Photo 12 – Successful willow staking alongRDB.

January 2007 -VII-3- 05-1373-029

Golder Associates

Photo 13 – First grade control below Riffle 1from RDB.

Photo 14 – Second grade control below Riffle 1from RDB.

Photo 15 – Toe of large diameter fill from RDB.

January 2007 -VII-4- 05-1373-029

Golder Associates

Photo 16 – Riffle 2 from RDB. Photo 17 – Riffle 1 viewed from Riffle 2.

Photo 18 – Successful willow staking on LDBbelow Riffle 2.

Photo 19 – Successful willow staking on LDBbelow Riffle 2.

Photo 20 – Riffle 3 from RDB. Photo 21 – Riffle 3 and reconstructed RDBfrom downstream.

January 2007 -VII-5- 05-1373-029

Golder Associates

Photo 22 – View upstream from below Riffle 3. Photo 23 – Riffle 1 from RDB downstream.

Photo 24 – Riffle 1 from RDB downstream. Photo 25 – Crest and face of Riffle 1 from RDB.

APPENDIX VIII

REVIEW COMMENTS ONDRAFT REPORT

January 2007 -VIII-1- 05-1373-029

Golder Associates

The draft report for this project was issued on 14 March 2006 and review comments were

received from Mr. Rich McCleary of Foothills Model Forest on 30 May 2006. Annotated

comments are provided below:

-Comment: The report provided rationale for adjustments that were made to the initialproject plan and thoroughly described the construction procedure. My questions mainlypertain to some aspects of the final layout and follow-up including monitoring.

Comment: Town of Hinton needs to send completed forms to Alberta Environment.

1 Response: It is assumed that this was done using the Certificate of Completion includedin Appendix I of the draft and final reports. If not, this should be done as soon aspossible.

Comment: Did Nathan survey and post-construction cross-sections for monitoring? Ifso, can the FMF get a copy of that data for future monitoring?

2 Response: Cross-sectional survey data have been provided in Appendix VI of thisreport.

Comment: Page i – need to add verb in 5th line from bottom (i.e. “cross-section wasreduced”).3Response: This edit has been made in the final report.

Comment: page ii – At end of second paragraph, consider adding: Monitoring shouldevaluate in-filling of culvert outlet pool and scour of small material from the face of theriffle.4

Response: This edit has been made in the final report.

Comment: Town of Hinton needs to arrange Phase I Environmental Site Assessment asper page iv.

5 Response: It is strongly recommended that potential contamination of the area belowSwitzer Drive be assessed prior to any construction.

Comment: A number of changes to the original plan were made to preserve the poolcreated by the damming effect upstream of riffle #2. Does Nathan expect that this poolwill be maintained by scouring over the longer term? Is there any need of a gradecontrol structure at the transition between the tail of riffle 1 and the upstream pool of riffle2?

6

Response: During the floods of June 2005, downstream movement of fine gravelsresulted in deposition along the margins of the channel but did not cause pools abovethe riffles to infill. During high flows, the rise in elevation away from the channelcenterline at each riffle concentrates the flow in the center of the channel, increasesvelocities in that area and may create a vortex that scours the pool and maintains itsdepth. Thus it is expected that pools will be maintained over the long term.Response: With regards to a grade control structure at the transition from the tail ofriffle 1 and the upstream pool of riffle 2 (the area shown in Photo 16 of Appendix VII), itwould certainly not hurt to provide some sort of grade control in this area; however, it isexpected that the backwater provided by the downstream riffle will control water depthand flow velocity in this area during high flows and thus limit scour potential. This areashould be a focus of monitoring, especially after high flow events.

January 2007 -VIII-2- 05-1373-029

Golder Associates

Comment: Page 5 – riffle armoring: Are mean flow velocities from Table 1 adjusted for7% slope of riffle verses 5% slope in initial design? Is this an important consideration inthe design?

7 Response: Yes, the mean flow velocities in Table 1 considered the as-built 7% riffleslope. The design is not very sensitive to the slope changes. A check on thecalculations indicates that decreasing the slope to 5% would increase the design flowdepths by approximately 7%, decrease the mean flow velocities by approximately 12%,and increase the critical flow velocities presented in Table 1 by approximately 1%.

Comment: Page 5 – riffle armoring: Are the particles in the vicinity of the vortex weirslarge enough to compensate for increased scour around key boulders due size of rocksand flow constriction between boulders? The elevation of the boulder top in the vortexweirs increased towards channel margins and out onto floodplain. This seems similar tothe configuration used in 2004 that contributed to erosion of backside of riffles. Is this anissue?

8

Response: The vortex weirs are shown in Photos 47 and 48 of Appendix II and Photos8, 9, 13 and 14 of Appendix VII. Flow around the protruding boulders of the weir will becomplex and it is expected that during flood events more of the smaller bed materialfractions will be removed than at other locations. However, this situation is much lesscritical than that of the downstream riffles during the 2005 floods, for the followingreasons:

The likely mechanism for movement of individual boulders at the lower riffles duringthe 2005 floods was scour of downstream material and then shifting due tounbalanced hydrostatic forces. The downstream material was substantially smallerand more scour-prone than the 350 minus material that was placed duringconstruction of the upper riffle.

The vortex weirs were constructed in two layers, with completely buried footerboulders (currently not visible) located downstream and supporting the half-buriedtop layer of boulders. The upper layer of boulders occupies less than 50% of thechannel width at the bed, in contrast to the downstream riffles where the upper layeroccupies close to 100% of the channel width at the bed. This will create less of a“plunging” flow pattern, as occurs at the downstream riffles, as flow passes throughthe weir. Local flow velocities due to flow constriction at peak discharges areexpected to increase by less than 50%, and local scour may occur downstream ofthe weir. However, they are expected to increase local bed roughness (increasingflow depth and decreasing velocity) and limit upstream scour.

Comment: The Foothills Model Forest is planning to continue with floodplain restorationin Kinsmen Park during summer of 2007. This entails construction of a fabricencapsulated soil lift which would increase the elevation of the floodplain by 15-20 cm.Is the left downstream side of the backflooding area appropriate for this activity? Thework would take place outside the boundary of the new channel, as indicated by thewillows that were planted in a trench.

9 Response: Either bank would be appropriate, though as noted in discussions a keyfactor may be to do the work in an area that is likely to be sheltered from human traffic.Two additional factors to consider are:

The channel bankfull width should not be reduced to less than 12 m.

The elevation of the local water table should be determined to ensure that adequatewater supply is available for vegetation.

January 2007 -VIII-3- 05-1373-029

Golder Associates

Comment: Who does Nathan recommend should complete the additional inspection ofthe LWD structures to confirm whether or not additional ballast is required?

10

Response: The additional inspection/assessment could be done during the next phaseof work at the project. As noted in Appendix V, calculated factors of safety may beconservative and some judgment might be applied to the calculated values based onlocal conditions. The assessment considered a design mean flow velocity of 2.0 m/s andmean flow depth of 0.68 m. Factors to consider include:

The calculations assume full submergence of woody debris, while the design meanflow depth of 0.68 m may not allow full submergence. This would reduce buoyantand drag forces on woody debris.

Actual flow velocities on LWD structures located in pools or in sheltered areas maybe lower than the calculated mean channel velocity of 2.0 m/s. This would reducedrag forces on woody debris.

Comment: Are there any recommended procedures for future monitoring? i.e. Howmany cross-sections should be surveyed? Should we use D50 to track changes in bedmaterial size down backside of riffle? The bed of the stream makes a subtle transition tothe floodplain. What should we use to delineate the outer boundaries of the channelwhen completing the bed material monitoring?

11

Response: Recommendations for future monitoring include:

A consistent roster of locations should be defined for long-term monitoring. The siteis sufficiently small that it should be possible to monitor all riffle crests, locations ofLWD and boulder structures, and bed and bank characteristics at selected locations.It is recommended that photographs be taken at key locations from a consistent pointof view to qualitatively track changes.

Cross-section surveys may be limited to riffle/weir crests and perhaps representativetransects across pools or riffles. In particular, channel bank formation upstream ofriffles (as observed in June 2005) may be of interest. A channel thalweg surveyalong the length of the reach would be a good way to track scour, deposition andpotential settlement of weir crests.

D50 could be used to track changes to bed material along the backside of riffles. Atriffle #1, the bed material appears to be well-graded with good particle embedment,but it is expected that some armoring will occur during flood events. Monitoring in thisarea and any others of interest is recommended, using a quantitative method suchas pebble counting or grid methods. Photographs should be taken to compile avisual record at each location.

The streambed makes a subtle transition to floodplain on the lower face of riffle #1. Itis expected that over time, deposition of sediment and organics may create a better-defined boundary. It may be effective to track this by selecting sample locations atvarious distances from the centerline of the channel at this location.

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