GMSWORKS-3 Peace River Side Channel Restoration - BC Hydro

Peace River Project Water Use Plan 

Peace River Trial Side Channels 

Reference: GMSWORKS-3 

Peace River Side Channel Restoration 

Study Period: 2009 

Northwest Hydraulic Consultants Ltd. 

Mainstream Aquatics Ltd. 

M. Miles and Associates Ltd. 

May 10, 2010

GMSWORKS‐3 

Peace River Side Channel Restoration 

Prepared for: 

BC Hydro and Power Authority 

6911 Southpoint Drive 

Burnaby, BC V3N 4X8 

Prepared by: 

Northwest Hydraulic Consultants Ltd. 

30 Gostick Place 

North Vancouver, BC V7M 3G3 

Mainstream Aquatics Ltd. 

6956 Roper Road 

Edmonton, Alberta T6B 3H9 

M. Miles and Associates Ltd. 

645 Island Road 

Victoria, BC V8S 2T7 

May 10 th , 2010

Executive Summary 

This study was initiated by BC Hydro to fulfill the recommendations of the Peace Water Use 

Plan (WUP) Committee to investigate the physical works necessary to maintain habitat 

productivity in side channels below Peace Canyon Dam (PCN), in lieu of increasing base flows 50 

to 100 percent during the summer period. A total of 39 side channel complexes were assessed 

on the Peace River below PCN to allow for the determination of suitable restoration works to 

restore or maintain flows and habitat at the minimum flow of 283 m 3 /s. 

The Peace River has been regulated by W.A.C. Bennett Dam since 1967, and its characteristics 

are influenced by the operation of this dam and PCN. Flow regulation has altered the annual 

hydrograph, daily flow patterns, temperature regime, and water quality of the Peace River. The 

average post‐regulation annual maximum daily flow (under the ‘normal’ operating regime) is 

31% of the pre‐regulation value at Hudson’s Hope and 37% near Taylor. The reduction in peak 

flows is thought to be the primary cause of a loss of side channel area through sediment infilling 

and vegetation encroachment. 

Side channels in the Peace River have been classified as open, ephemeral or closed. Based on 

an overview assessment, a range of side channels exist in the study reach, together totalling 

87.4 km: 21 open, 8 ephemeral, and 6 closed. The total side channel area is estimated at 506.4 

ha, while the mainstem river area is estimated at 3,532.9 ha, thus side channels represent 

about 12.5% of the total area. Permanent open, ephemeral open, and closed side channels 

comprise of 74.9%, 15.6%, and 9.4% of the total side channel area, respectively. 

Potential methods for side channel restoration are reviewed, with a focus on methods that 

could be directly applied to the Peace River. Most of these methods involve deepening or 

excavating the channel to remove accumulated sediment and open side channels. Channel 

inverts and profiles may need to be lowered. Habitat complexing with channel modifications, 

and wood or boulder placement could be used to further restore fish habitat. Site access, 

channel design, habitat complexing and water supply have been identified as key issues. 

Conceptual costs are difficult to estimate as the depth and extent of excavations require survey 

data that is unavailable for the sites. The costs also depend on access and environmental 

requirements, the scope of work at the selected sites, and available budgets. A notional cost of 

$20‐30 per square meter of full constructed channel has been suggested, and lower values 

would apply to channels that require partial or limited excavations. 

Physical characteristics, and fish and fish habitat attributes were examined through both field 

and office studies, and interpreted by the authors. Eleven sites (11) sites were short listed, 

representing predominantly closed side channels that could be excavated into open flowing 

systems. Simple channel excavations and lowering of critical elevations will primarily provide 

re‐watering under base flow conditions. In side channels above the Halfway River, ongoing 

sedimentation and ice effects could be minimal and additional habitat complexing and 

restoration works are suggested. Nine of the eleven sites (all except the lower 2 in the reach) 

Peace River Side Channel Restoration i

would benefit from cold‐clear water fish assemblages including bull trout, rainbow trout and 

Arctic grayling. 

Side Channel 23L and 32L were identified as the sites with the highest overall rating based on 

the overview assessment carried out under this study. The 23L site was selected due to the fact 

that it current dry under the regulated flow regime, and restoration of the area would create 

new back channel habitat. The area is relatively small and accessible. The 32L site was selected 

due to excellent access, sufficient area available, and good potential to create both open 

connected side channel habitat and backwater closed side channel habitat within the same 

area. 

Based on the study team recommendations, the 32L site represents the best opportunity of all 

the sites assessed. Information and data gaps, and implementation issues have been provided 

in the summary section, which will assist in guiding subsequent steps in the process of 

developing a restoration plan for Site 32L. This study recommends ongoing coordination with 

other GMSWORKS projects to better determine other factors that could influence the project or 

scope. 

Peace River Side Channel Restoration ii

Acknowledgements 

The authors would like to thank of BC Hydro for initiating this study, review comments provided 

during the course of the work, and the assistance from: 

Stuart McGregor Project Manager 

Allan Chan‐McLeod Project Lead 

Martin Jasek BC Hydro 

Kyle Robertson. BC Hydro 

The following NHC personnel participated in the study: 

Barry Chilibeck Principal Engineer, Coauthor 

Joe Drechsler GIS Technician 

Dale Muir Senior Engineer 

The following Mainstream Aquatics Ltd. personnel participated in the study: 

Richard Pattenden Fisheries Biologist, Coauthor. 

The following M. Miles and Associates Ltd. personnel participated in the study: 

Mike Mikes Geomorphologist, Coauthor 

Liz Goldsworthy Staff Scientist 

Sandy Allegretto Staff Scientist 

The following individual provided information or assistance with this project: 

Dr. Michael Church Department of Geography, UBC 

Peace River Side Channels Restoration iii

Notification 

This document is for the private information and benefit of the client for whom it was prepared 

and for the particular purpose for which it was developed. The contents of this document are 

not to be relied upon or used, in whole or in part, by or for the benefit of others without 

specific written authorization from Northwest Hydraulic Consultants Ltd. (NHC), Mainstream 

Aquatics Ltd. and M. Miles and Associates Ltd. 

This document represents Northwest Hydraulic Consultants Ltd., Mainstream Aquatics Ltd. and 

M. Miles and Associates Ltd. professional judgments based on the information available at the 

time of its completion, and appropriate for the scope of work engaged. Services performed in 

developing the materials provided in this report have been done in a manner consistent with 

the proficiency and skill of members in professional practice as an engineer or geoscientist 

practicing in similar conditions and environments. 

This report, all text, pictures, data, figures and drawings include herein, are copyright of 

Northwest Hydraulic Consultants Ltd. BC Hydro is permitted to reproduce materials for 

archiving purposes and distribution to third parties only as required to conduct business related 

to the parties. Any other use of these materials without the written permission of NHC is 

prohibited. 

Report prepared by: 

Original signed by Original signed by Original signed by 

Barry Chilibeck, P.Eng. Mike Miles, P.Geo. Rick Pattenden, R.P.Bio. 

Report reviewed by: 

Original signed by 

Bruce Walsh, P.Eng. 

Citation: 

NHC, Mainstream Aquatics and M. Miles and Associates. 2010. Peace River Side Channel 

Restoration. Prepared for BC Hydro. May 10, 2010. 

© copyright 2010 

Peace River Side Channel Restoration iv

Table of Contents 

Executive Summary .............................................................................................................i 

Acknowledgements...........................................................................................................iii 

1 Scope of Work .............................................................................................................1 

2 Data and Methodology................................................................................................2 

3 Background Information..............................................................................................3 

3.1 Setting ........................................................................................................................ 3 

3.2 Hydrology and Hydraulics .......................................................................................... 3 

3.3 Geomorphology ......................................................................................................... 7 

3.4 Fish Habitat and Fish Community .............................................................................. 7 

4 Flow Regulation Impacts on Side Channels..................................................................9 

5 Side Channel Assessment ..........................................................................................11 

5.1 Side Channel Classification....................................................................................... 11 

5.2 Overview Assessment .............................................................................................. 12 

5.3 Physical Information................................................................................................. 13 

5.4 Fish Habitat and Fish Community Information ........................................................ 15 

6 Side Channel Restoration ..........................................................................................16 

6.1 Permanent Open Side Channels............................................................................... 16 

6.2 Ephemeral Open Side Channels ............................................................................... 17 

6.3 Closed Side Channels................................................................................................ 17 

6.4 Restoration Key Issues and Criteria ......................................................................... 18 

6.5 Conceptual Level Costing ......................................................................................... 21 

7 Selected Side Channel Restoration Sites ....................................................................22 

7.1 River KM 5.0R ........................................................................................................... 23 

7.2 River KM 8.1R ........................................................................................................... 24 

7.3 River KM 17.2L ......................................................................................................... 25 

7.4 River Km 23.0L.......................................................................................................... 26 





7.9 River KM 85.5R ......................................................................................................... 30 

7.10 River KM 98.2R ......................................................................................................... 31 

7.11 River KM 102.5R....................................................................................................... 31 

Peace River Side Channel Restoration v

8 Summary and Recommendations ..............................................................................32 

8.1 Site Prioritization...................................................................................................... 32 

8.2 Information and Data Gaps...................................................................................... 32 

8.3 Implementation of Restoration Concepts................................................................ 33 

8.4 Closing ...................................................................................................................... 33 

9 References.................................................................................................................34 

List of Tables 

Table 1. Maximum Daily Discharges on the Peace River................................................................ 6 

Table 2. Side Channel Physical Parameters. ................................................................................. 13 

Table 3. Overview of Peace River Side Channels (PCN to Pine River). ......................................... 14 

Table 4. Side Channels Fish and Fish Habitat Parameters............................................................ 15 

Table 5. Side Channel Restoration Criteria................................................................................... 20 

Table 6. Conceptual Construction Unit Rates and Costs .............................................................. 22 

Table 7. Identified Side Channel Restoration Opportunities (PCN to Pine River). ....................... 22 

List of Figures 

Figure 1: Pre‐Regulation Peace River Discharges ........................................................................... 5 

Figure 2: Post‐Regulation Peace River Discharges.......................................................................... 5 

Figure 3: Maximum Discharges on the Peace River ....................................................................... 6 

Appendices 

Overview Map sheets Index, 1 ‐ 7 

Site Map sheets 1 ‐ 11 

Photo Plates 

Habitat Restoration Typicals 

Peace River Side Channel Restoration vi

1 Scope of Work 

The Peace River’s flows are regulated by Williston Reservoir with power generation at the G.M. 

Shrum Generating Station (GMS) and Peace Canyon Dam (PCN). These facilities provide 

approximately 29% of British Columbia’s energy. The current minimum flow of 283 m3/s was 

instigated to mitigate fish stranding and habitat dewatering in Peace River side channels 

downstream of the projects.. 

Development of Williston Reservoir and regulation of the Peace River has impacted side 

channel habitat by reducing large flood flows that control vegetation establishment and 

transport fine sediments from the secondary channels along the mainstem (Church, 1995). 

Similar impacts have been observed on the Nechako River above Fort Fraser (Rood and Neill, 

1987; NHC/MMA, 2008) where river regulation has reduced both the number and area of side 

or secondary channels. The regulated flow regime reduces natural water levels that would 

occur during the spring and summer, decreasing both the wetted area and side channel 

connectivity to the mainstem river, which effects its utility and value as fish habitat. 

The Peace Water Use Plan (WUP) Committee recommended a plan to examine the potential to 

mitigate these impacts on the Peace River (Anon, 2003). The Peace WUP committee 

acknowledged the important role of the Peace River generating facilities on the environment 

and recommended the investigation of physical works to maintain habitat productivity in lieu of 

increasing base flows 50 to 100 percent during the summer period. 

The key objective of this study is to inventory and assess Peace River side channels situated 

between PCN and the Pine River, and to collect the information necessary for the 

determination of suitable physical works to restore or maintain flows and habitat at base flows 

of 283 m 3 /s. This assessment examines the biophysical characteristics of side channels, existing 

and potential fish utilization, and existing PCN discharges to develop conceptual restoration 

works for 2 or more sites. These restoration plans will potentially demonstrate a variety of 

restoration opportunities, re‐watering strategies, and habitat complexing methods to meet the 

requirements of diverse fish assemblages in the Peace River. 

This study will also provide an assessment of the potential impacts and benefits to wildlife and 

wildlife habitat, an assessment of site access and constructability, determination of 

construction and maintenance costs, review of public access requirements, and identification of 

regulatory information needed to obtain project approvals. The study will primarily: 

1. Determine fish species utilization by life stage and habitat needs, and how these are 

interrelated to side channel habitat availability and flows; 

2. Determine the types of side channel habitat that are currently utilized, what life stages 

and species utilize these habitats, and the potential for these habitats to be limiting due 

to flow; 

3. Provide an overview assessment and inventory under the current 283 m 3 /s minimum 

flow regime, short‐listing of 10 sites, documentation of biophysical attributes, and 

Peace River Side Channel Restoration 1

identify the opportunities and limitations of each site in terms of the potential to re‐ 

activate, re‐water or restore habitats; 

4. Determine the range of potential engineering works available to provide restoration or 

re‐watering, including ‘hard’ and ‘soft’ options such as invert excavation, pilot channel 

excavation, back channel creation or whole channel lowering. 

5. Select two or more demonstration sites where various restoration methods, including 

habitat recreation, construction and bioengineering, can be used in conjunction with re‐ 

watering options; and 

6. Provide a summary of the construction and operational costs for these conceptual 

options, a decision framework for selection of candidate sites, and rationale for the 

selection of restoration methodologies. 

Coordination and synergy with GMSWORKS‐3,‐4,‐5 and ‐6 are further discussed in the summary 

section of this report. Coordination and data‐sharing between these projects has been enabled 

by the various contractors, and there are significant opportunities to build on the existing body 

of knowledge and information collected to date. 

2 Data and Methodology 

Field investigations were undertaken on May 28 and 29, 2009. This involved an initial helicopter 

survey by the entire study team on May 28. The section of Peace River between Taylor and PCN 

was flown in both directions. The initially identified sites, along with other potential restoration 

sites, were inspected from the air and extensively photographed (using both still and high 

definition video cameras). Selected sites were also investigated on the ground. A second 

inspection by river boat was undertaken on May 29 by Pattenden and Miles. The 18 km section 

of river situated downstream of PCN was traversed and potential restoration sites were 

investigated on the ground. Additional sites were visited by NHC staff during work conducted 

under GMSWORKS‐5 and ‐6. 

BC Hydro’s air photo mosaic was unavailable at project initiation and Google Earth imagery was 

therefore employed. Stream kilometre marks (measured downstream of PCN) and place names 

were added to assist in site identification. The resulting mosaic, which covers 113 km of river, is 

of varying quality. High resolution imagery (obtained in 2006) is available in the area between 

KM 0 to 43 and 49 to 78. Comparatively lower resolution imagery (date unknown) is available 

between KM 43 to 49 and 79 to 113. Additional analyses and data compilation was undertaken 

by NHC for side channel configurations and assessment of restoration opportunities along the 

reach. The mosaics resulting from these additional assessments have been included in the 

Appendices section of this report. This work has utilized orthophoto mosaics and GIS data 

provided by BC Hydro and MMA. 

The basis of the analyses has included an assessment of the physical and biological 

characteristics of the side channel sites, followed by a technical assessment of the methods and 

works that could be utilized to restore flow and/or fish access to the sites. This technical 

information was semi‐qualitative, based on available data, and provided a relative index for 


assessment purposes. Data, analyses, results, and summaries have been provided, with 

relevant information attached. 

3 Background Information 

3.1 Setting 

The Peace River is formed by the junction of the Parsnip and Finlay Rivers, and flows eastward 

through the Rocky Mountains through BC and Alberta to Lake Athabasca. The reach 

downstream of PCN is underlain mostly by the Fort St. John Shale and Gates Sandstone 

sedimentary rocks. The most abundant rock formation is Cretaceous Fort St. John Shale of the 

Shaftsbury formation, which is found frequently exposed along the banks of the Peace River 

and its tributaries. Near Hudson’s Hope, a sequence of sandstone, shale and silty shale of the 

Gates Sandstone formation is exposed as islands and banks along the Peace River. These 

formations are also responsible for the 22 km section of Peace River channel downstream of 

PCN that is vertically controlled by cross channel exposures of bedrock. 

Local soils are a product of in situ weathering of the parent rocks that are exposed along the 

Peace River as well as relic glacial‐derived sediments. The Peace River and tributary valleys have 

entrenched valley walls composed of fine textured shales and glaciolacustrine sediments. The 

glaciolacustrine sediments include sand, gravel, and cobbles in a silty sand matrix, weathered 

fine textured shales and glaciolacustrine slits and clays that were deposited during the recent 

glaciation by proto‐glacial lakes and ice‐dam floods. Other than localized outcropping of 

bedrock, the river channel is composed of alluvial deposits of sand, gravel, cobbles and 

boulders to depths of up to 10 m. More recent alluvial materials within the floodplain area 

consist of fine textured sands and silts. 

The Peace River has an entrenched river channel lower than the surrounding plateau by up to 

300 m. The Peace River channel is approximately 375 m wide and has a bankfull width of 485 m 

with a reach slope 0.22 percent 1 . The main river channel is slightly sinuous and often confined 

by high valley banks. The active channel contains infrequent shoals and bars and relatively 

regular islands that are partially or fully vegetated and form secondary channels. These 

secondary or side channels are either free‐flowing, backwatered or non‐functional within the 

contemporary floodplain. The river morphology and channel processes are further discussed in 

Section 3.3 

3.2 Hydrology and Hydraulics 

The free‐flowing sections of the Peace River downstream of Hudson’s Hope, BC are regulated 

by W.A.C. Bennett Dam that has drainage area of which is 68,900 km². The dam has formed 

Williston Reservoir, which has a live storage capacity of 41,300 Mm³, slightly larger than the 

average annual inflow volume of developed from a mean annual discharge of 1,100 m³/s. With 

1 based on a 2 km cross section spacing from PCN to Fort St. John 


the significant storage relative to annual inflows, uncontrolled spills from Williston Reservoir 

into the lower Peace River are infrequent, thus the magnitude and frequency of peak flows 

have been reduced relative to historical unregulated flows. Seasonally, flows are regulated for 

ice control on the lower Peace River as well as minimum flows for fish and fish habitat in the 

Peace River below PCN. 

Peace River has been regulated by Bennett Dam since 1967, with hydroelectric power 

generated at GMS and PCN. These two stations produce approximately 29% of British 

Columbia’s energy, and also provide critical load following capability to meet hourly power 

demand within the interconnected provincial power transmission system. PCN is located 

approximately 20 km downstream of W.A.C. Bennett Dam and forms Dinosaur Reservoir, which 

extends upstream to the tailwater of W.A.C. Bennett Dam. While the reservoir’s tributary 

drainage area is approximately 12,430 km 2 , it provides for limited storage due to a lack of major 

tributaries, and flow balance is typically achieved within a day. 

Water Survey of Canada [WSC] operates three stream gauging stations between PCN and the 

BC Border. These include Peace River at Hudson Hope (basin area 69,900 km²), Peace River 

above Pine River (basin area 83,900 km²) and Peace River near Taylor (basin area 97,100 km²). 

BC Hydro has also collected data at PCN (basin area 68,900 km²). The period of record at the 

Peace River at Hudson Hope and Peace River near Taylor stations includes data that was 

collected prior to the construction of Bennett Dam. The seasonal variation in stream flow 

observed at the four gauging stations is illustrated in Figure 1 and Figure 2. The data have been 

sub‐divided into the pre‐regulation (≤ 1967) and post‐reservoir filling (≥1973) time periods. This 

comparison illustrates how storage in Williston Reservoir has reduced the snowmelt freshet in 

the spring and resulted in a more regulated hydrograph. 

The historical variation in annual maximum daily discharges observed at the Taylor and Hudson 

Hope WSC gauge sites is illustrated in Figure 3. Pre‐project data (i.e. ≤1967) indicate that the 

annual maximum daily discharges ranged between 4,760 and 8,810 m³/s (average 6,165 m³/s) 

at Hudson Hope and between 5,380 and 11,500 m³/s (average 7,525 m³/s) near Taylor. 

Regulation has substantially decreased the natural range of peak flood magnitudes. Anomalies 

occur in 1972 (spillway test), 1996 (emergency drawdown) and, to a smaller extent, in 1990 

when a spring ‘cold low’ storm resulted in substantial inflow from streams draining the east 

side of the Rockies. Excluding these three events, post‐regulation annual maximum daily 

discharges are presented in Table 1. 


Figure 1: Pre‐Regulation Peace River Discharges 

Figure 2: Post‐Regulation Peace River Discharges 


Figure 3: Maximum Discharges on the Peace River 

Table 1. Maximum Daily Discharges on the Peace River. 

Pre‐Regulation 

Post‐Regulation 

WSC Station 

(m³/s) 

(m³/s) 

Average Low Average High 

Peace Canyon Dam ‐ 1,683 1,926 3,293 

Peace River at Hudson 

Hope 

6,165 1,640 1,940 3,170 

Peace River above Pine 

River 

7,525 1,590 2,225 4,040 

Peace River near Taylor 1,820 2,788 4,470 

The average post‐regulation annual maximum daily flow (under the ‘normal’ operating regime) 

is 31% of the pre‐regulation value at Hudson Hope and 37% near Taylor. Interested readers are 

referred to the more comprehensive discussion of pre‐ and post‐regulation changes in 

hydrology and sediment transport presented in Church (in press). 

Additional hydrometric data is currently being collected at 5 stations along the reach under 

GMSWORKS‐5, a program to provide continuous measurements of discharge at key locations 

from PCN to Fort St John. Data from the remote hydrometric stations is transmitted to BC 


Hydro via telemetry, and will be utilized to better understand how flows and water levels in the 

reach may influence side channel hydrology and function. The locations of hydrometric stations 

operated under GMSWORKS‐6 are included in the overview and on site map sheets 

In addition to the hydrometric work, bathymetric surveys and a hydraulic model of the reach 

are being prepared under GMSWORKS‐6. This modelling is being coordinated with the overall 

hydraulic modelling of the Peace River from PCN to the BC‐Alberta border. The model will help 

to better understand flow magnitude and the effects of ramping within the reach, and provide 

estimates of water elevations between existing hydrometric stations. 

3.3 Geomorphology 

The geomorphology of Peace River has been the subject of on‐going investigations by BC Hydro 

and others. Relevant reports include river regime and morphology studies undertaken for the 

initial investigation of dam sites at Sites C and E (BC Hydro and Power Authority, 1975). Earlier 

studies by Kellerhals and Gill (1973) and Kellerhals (1982) assessed the affect of river regulation 

on channel processes, which included side channels. Professor Michael Church at the UBC 

Department of Geography, along with his colleagues and students, has been systematically 

investigating regulation related changes in channel morphology, ice processes and riparian 

vegetation. Relevant reports include: Church and Rood, 1982; Church, 1995; Church and North, 

1996; Church et al., 1997; Ayles, 2001; Ayles and Church, (in press), and Zu and Church, (in 

press). 

3.4 Fish Habitat and Fish Community 

The success (i.e., abundance and distribution) of existing fish populations in the Peace River are 

a result of the interaction between species‐specific habitat requirements and the influence of 

the regulated flow regime. The fish community that presently resides in the study area is 

composed of fish populations that have adjusted to the regulated flow regime that has been in 

place since 1969 or that have utilized life history strategies that circumvent or exploit the 

effects of the regulated flow regime. 

RL&L (2001) described Peace River fish habitats in British Columbia with particular reference to 

the influence of flow regulation on habitat utilization by small fish. P&E (2002) characterized 

near‐shore fish habitats in the Peace River with particular reference to large fish. RL&L (1992) 

assessed the implications of flow regulation on the Peace River to fish habitat and the fish 

community. The quantity and suitability of side channel habitats are currently being quantified 

under GMSWORKS‐4 for flows between 300‐1800 m 3 /s, to better understand the availability 

and flow characteristics of side channel habitats within the study reach. 

Fish studies within the study area consistently show that the fish community is numerically 

dominated by adults and older juveniles of large‐fish species, with a paucity of younger fish in 

the large‐fish species and most small‐fish species. The mechanism driving this outcome is the 

absence of suitable habitats needed by small‐sized fish in the Peace River, which is caused by 


the regulated flow regime and a life history strategy that relies heavily on tributary habitats for 

critical life requisites such as spawning and early rearing. 

There are exceptions to this general observation. Existing side channels and near‐shore areas 

along the mainstem channel margins that do not dewater provide habitats for younger fish of 

the large‐fish species and small‐fish species. If other basic habitat requirements are met (e.g., 

appropriate water temperatures, water clarity, water velocity, and physical cover) younger fish 

of the large‐fish species and small‐fish species can reside within these areas. One example 

includes the presence of young rainbow trout, Arctic grayling, slimy sculpin, and prickly sculpin 

in near‐shore habitats of the Peace River containing large amounts of physical cover. Another 

example is the presence of viable fish populations belonging to the unique species assemblage 

relying exclusively on selected side channels to provide all habitat requirements 

The Peace River fish community downstream of PCN consists of 31 fish species that can be 

divided into three general fish assemblages based on habitat requirements: cold‐clear water 

(11 species), cool turbid water (15 species), and unique (5 species). 

The cold‐clear water fish assemblage, which consists of salmonid (trout and whitefish) and 

cottid (sculpins) species, dominates the mainstem fish community within the study area. 

Mountain whitefish, Arctic grayling, bull trout and rainbow trout are the numerically dominant 

and most widespread large‐fish species in this assemblage, while slimy sculpin is the most 

abundant species in the small‐fish group. Populations in this group are found in side channels 

and in near‐shore areas along channel margins in the river mainstem. Small‐fish assemblages 

are very flexible in their habitat needs. If appropriate conditions are present, either in side 

channels or river mainstem, species in this group would likely utilize these habitats. 

The cool‐turbid water fish assemblage consists of a diverse group of large‐fish and small‐fish 

species that reside in the river mainstem, but with most of these fish largely restricted to 

tributary confluence areas and/or the extreme lower portion of the study area (i.e., 

downstream of the Moberly River confluence). The only exceptions to this pattern are redside 

shiners, which are abundant and widely distributed throughout the study area. The restricted 

distribution of most cool‐turbid water species is largely due to the requirement for warmer 

water temperatures and low water clarity. Populations of goldeye and walleye, for example, 

primarily reside downstream of the study area, but will use habitats upstream of the Pine River 

confluence opportunistically if appropriate conditions exist (i.e., warm water and high 

turbidity). Others such as suckers, northern pikeminnow, and most of the minnow species rely 

heavily on tributaries to provide appropriate habitats, and do not venture far from these focal 

points. Despite the restricted distribution of most species, side channels are the preferred 

habitat when available, but near‐shore areas along channel margins in the river mainstem can 

also be utilized. 

The unique fish assemblage consists of five species that are almost entirely restricted to side 

channels (i.e., lake whitefish, northern pike, yellow perch, white sucker, and spottail shiner). All 

occur in a select number of side channels that exhibit specific physical characteristics. The side 


channel must be sheltered from high water velocities (i.e., one inlet at the downstream end), 

have low water turbidity during much of the year, and support growth of aquatic vegetation. 

These side channel habitats are restricted in distribution, thus the unique fish populations that 

rely on them are also restricted in distribution. 

4 Flow Regulation Impacts on Side Channels 

The Peace River is a regulated system influenced by the operation of the W.A.C. Bennett Dam 

and PCN. Flow regulation has altered the annual hydrograph, daily flow patterns, water 

temperature regime, and water quality of the Peace River. The strongest influence of regulation 

occurs closest to PCN with progressive decrease of effect in the downstream direction. While 

the effect decreases in the downstream direction in the river mainstem, the influence of flow 

regulation has a strong influence on side channels within the study area and further 

downstream to the BC‐Alberta border. 

4.1.1 Flow Magnitude 

The annual hydrograph is characterized by reduction in spring and summer flood discharges 

and an increase fall and winter discharges, in comparison to the pre‐impoundment condition. 

The most profound effect that the regulated flow regime has had on fish habitat is a loss of or a 

reduced availability of side channels due to a reduction in water elevations. An additional effect 

of significance has been a reduction of habitat complexity created by then infilling and 

sedimentation of channel margins from a reduction of bank/bed erosion and bed material 

movement. The dams and reservoir development have also reduced inputs of large woody 

debris, which is typically associated with annual bank erosion in the upstream floodplains of 

tributary systems. This in turn reduces the presence of large jams that ultimately influence 

channel function, morphology and fish habitat. 

4.1.2 Daily Flow Ramping 

The GMS and PCN are power‐peaking facilities that typically produce fluctuating water levels on 

a daily and hourly basis. This effect extends to the BC‐Alberta boundary, but can be dampened 

by the flow inputs of major tributaries to the Peace River (e.g., Halfway River, Moberly River, 

and Pine River). The regulated flow regime affects the availability of shallow water habitats 

found primarily in side channels and along channel margins. Frequent dewatering results in 

reduced productivity, physical displacement of fish, and fish stranding. Another consequence of 

fluctuating water levels, particularly downstream of the Halfway River confluence, is 

development of shore‐fast ice in winter that can exclude fish from near shore habitats. 

4.1.3 Water Temperature 

Peace River water temperatures have been affected by the operation of the hydroelectric 

facilities and their storage reservoirs. On a seasonal basis, river temperatures are cooler in the 

summer and warmer in the winter in comparison to pre‐impoundment conditions. The river 

surface no longer freezes upstream of the Pine River confluence. The altered water 

temperature regime has a strong influence on the Peace River fish assemblage, and cold water 


species dominate the system. The temperature regime also influences fish life history activities 

(e.g., spawning) by shifting the timing of temperature cues used by fish. As a result, some 

populations (e.g., mountain whitefish) initiate spawning much later than similar populations in 

unregulated systems. 

An important effect of the altered temperature regime is the change in degree days needed for 

egg development and fry growth, the consequence of which is an increase in mortality. Water 

temperatures in shallow water areas of the Peace River are also influenced by the daily flow 

regime. Low flows, particularly in side channels, create shallow water areas that exhibit 

elevated water temperatures during warm summer days. These warmer temperatures can be 

outside the preferred thermal range of fish or can be lethal to fish. 

4.1.4 Fine Sediments, Debris and Ice 

Operation of the hydroelectric facilities and their storage reservoirs has had little effect on fine 

sediment regimes, due to the lithography of upstream basins (Church, 1995). In general, water 

clarity is high upstream of the Halfway River confluence, but can decline dramatically 

downstream of this point during periods of high tributary inflows. The absence of suspended 

sediments upstream of the Halfway River has likely enhanced primary production. 

Downstream of the Halfway River confluence, the effect of elevated fine sediment loads from 

tributary inputs combined with an altered annual hydrograph (i.e., reduced mainstem flood 

discharge) has resulted in an infilling of side channels and channel margins. This influences the 

availability and complexity of fish habitats. Tributary systems also supply wood debris loading 

to the Peace River and provide materials for the formation of jams and debris structures. 

Thermally altered discharge from PCN results in the delayed formation of ice in and along the 

Peace River. Areas above the Halfway River are less affected by ice flows and its effects on the 

channel during break‐up. Shore ice may thicken in areas where flow fluctuations occur more 

frequently, which may be expected to affect potential debris placement and restoration 

opportunities. 

4.1.5 Morphology and Physical Characteristics 

In regulated rivers, the isolation of side channels occurs due to hydrological modifications and 

morphological changes. The impacts can include: 

� Downcutting of the primary channel resulting in isolation of secondary channels, 

� Infilling of secondary or side channels with fine sediments from lack of regular high flood 

flows, 

� Channel simplification resulting from reduced sediment or supply of large woody debris, 

� Floodplain impacts from flood protection works, and 

� Vegetation encroachment and growth associated with sediment infilling. 


These impacts have been recognized in the Peace River, among other regulated rivers. Church 

and Rood (1982) investigated the post‐regulation loss in side channel length between 1967 and 

1977 in the area between Hudson’s Hope and the Alberta border. This early study documented 

a loss of 128 km of side channel length (288 to 160 km a 44% decrease). The braiding index 2 

also decreased from 3.26 to 2.25, which represents a simplification of channel habitat. The 

subsequent paper by Ayles and Church (in press) indicates these values “subsequently changed 

very little” (p. 19). The loss of side channels is indicated by “being the immediate consequence 

of the elimination of the highest flows” (p. 19), which results in fine textured sediment 

deposition and infilling with vegetation (see Teversham and North, 1982; North, in press). 

Ayles and Church (in press) have analyzed all available river cross‐section data in the BC section 

of the Peace River and identified sections of net post‐regulation aggradation and degradation. 

The analysis indicates that channel aggradation occurs locally adjacent to the larger tributary 

streams (Halfway River, Moberly River, Pine River), but that much of the river bed is stable due 

to the post‐regulation reduction in bed material transport capacity. The cross‐sectional data 

provide an important resource that would allow for the quantification of sediment deposition 

rates in former side channels (see cross‐sections in Teversham and North, 1982 and Ayles, 

2001). 

5 Side Channel Assessment 

5.1 Side Channel Classification 

Side channel classification is used to describe the role and function of side channels in a 

biological context, or secondary channel classification as these are referred to in a 

geomorphological context 3 . Peterson and Reid (1984) describe three types of side channel 

habitat within a river floodplain: overflow channels, percolation‐fed channels, and wall‐based 

channels. There are three general types of side channels within the study area, which are 

described below: permanent open side channels, ephemeral open side channels, and closed 

side channels. 

5.1.1 Permanent Open Side Channels 

These areas do not dewater under the typical flow regime, the upstream inlet and downstream 

outlet are always open, and the side channels have similar physical characteristics to the river 

mainstem. The side channels can be large and deep, conveying a significant portion of river’s 

flow, and morphological features that can develop with the side channels influence hydraulic 

characteristics. These side channels provide habitat and support fish assemblages that occur in 

the adjacent river mainstem. Fish habitats in these side channels are not typically impacted by 

2 

Braiding Index = (thalweg + secondary or side channel length) ÷ thalweg length. 

3 

The term ‘side channel’ can and will be used interchangeably with ‘secondary channel’, a common morphologic 

term throughout the report. 


dewatering, but habitat complexity has decreased over time due to river processes like fine 

sediment infilling and deposition. 

5.1.2 Ephemeral Open Side Channels 

These areas regularly dewater or partially dewater under the existing regulated flow regime. 

The characteristics of these side channels differ from the adjacent mainstem channel in several 

ways: 1) the upstream inlet contains no surface water except during the highest flows, 2) the 

bed material reflects the long term effects of infilling, 3) surface water that is present is 

subjected to elevated water temperatures in summer, and 4) bed‐fast ice can develop during 

winter. Ephemeral side channels either support very low numbers of fish or no fish. These side 

channels are used opportunistically when surface waters are available. Fish either vacate 

habitats within these side channels when water flow decreases, or become stranded and 

perish. When suitable water flows do occur these side channels have the potential to provide 

good quality habitat, particularly for small‐sized fish (e.g., rearing) due to the abundance of 

shallow water habitat and more benign water velocities. 

5.1.3 Closed Side Channels 

These areas do not dewater under the typical regulated flow regime. The characteristics of 

these side channels differ dramatically from the adjacent mainstem channel: 1) the upstream 

inlet is closed except during extreme flood flows, 2) the bed material primarily consists of fine 

sediments, 3) water clarity is high, and 4) water velocity is very low. These closed side channels 

support viable populations of unique fish assemblages and are used by other fish populations 

opportunistically (e.g., bull trout in spring); these side channels also support emergent and 

submergent aquatic vegetation. Major factors limiting the quality of habitat and fish use in 

these unique side channels are long‐term infilling (some side channels formerly used by fish 

have infilled within the last 20 years) and fluctuating water levels that prevent establishment of 

emergent vegetation. 

5.2 Overview Assessment 

The satellite imagery was initially reviewed and areas where side channel loss had occurred 

were identified. Areas of potential interest were then examined in stereo using 1:5,000 scale 

colour aerial photographs flown on October 26, 2008. Additional photogrammetric analyses 

were used to estimate the type and area of side channels in the Peace River. Orthophotos were 

imported to ARCGIS and MOE “blueline” shapefiles indicating stream thalweg were imported 

and bank lines were digitized. Distances from PCN were scaled to the start of side channels or 

side channel complexes, and the side channels were classified based on the dominant side 

channel type. Standardized naming and classification was implemented for this study to provide 

reference (Table 3). 

Based on the overview assessment, there is a range of side channels in the study reach: 21 

open, 8 ephemeral, and 6 closed, totalling 87.4 km. Based on a mainstem length of 102.5 km, 

the braiding index is 1.85. Note these represent side channel complexes from an assessment 

based on the predominant channel type. The total side channel area was estimated at 506.4 ha, 


while the mainstem river area was estimated at 3,532.9 ha, so side channels represent about 

12.5% of the total area. Permanent open, ephemeral open, and closed side channels comprise 

of 74.9%, 15.6%, and 9.4% of the total side channel area, respectively. 

5.3 Physical InformationEvaluation of the physical characteristics was completed 

through: 

� Visual and/or field identification of characteristics during site inspections; 

� Interpretation of orthophotos and LiDAR data in ARCGIS; and 

� Review of MMA photo mosaics and oblique photography; 

LiDAR data contained digital elevation data that provided some background, however, if more 

detailed designs proceed, additional survey data will be required. The physical parameters are 

presented in Error! Reference source not found. along with the classifications or ratings used in 

this study. 

Table 2. Side Channel Physical Parameters. 

Item Definition Rating / Comment 

Side Channel Distance downstream of PCN km 

Type See Section 5 

Length m 

Area ha 

River Location As viewed downstream Right, Left 

Bar Type 

Mid Channel, Tributary Fan Point 

Complex 

Access Existing, Upgrade, New (m) 

Mainstem Bank Type Steep >30% 

Moderate

Table 3. Overview of Peace River Side Channels (PCN to Pine River). 

PCN Name a 

Side Channel Length 

(km) 

Side Channel Area (ha) b Side Channel 

Classification c 

3.0R 1.8 14.6 Open 

5.0R 2.4 1.8 Open 

8.1R 4.8 45.1 Open 

9.6L 1.3 9.4 Open 

17.2L 0.5 1 Closed 

18.4L 3.4 36 Open 

20.9R 2.4 19.2 Open 

23.0L 0.6 0.2 Closed 

27.2R 3.1 38 Open 

31.2R 1.5 6 Ephemeral 

32.0L 2.6 15.6 Closed 

33.5R 2.5 16.3 Ephemeral 

40.5L 3.0 18 Ephemeral 

47.8R 2.8 12.4 Open 

49.9L 3.9 38.7 Open 

53.2R 1.5 6.8 Open 

56.3L 2.4 26.3 Open 

58.0L 2.8 5 Closed 

58.8R 0.9 4.3 Open 

59.7L 1.0 1.6 Ephemeral 

65.0L 2.8 20.6 Open 

66.2R 3.2 18 Ephemeral 

69.1L 1.8 11 Open 

70.5R 3.4 15 Closed 

73.0L 2.1 23.9 Open 

73.8L 4.6 9.6 Open 

77.5R 1.7 7.7 Open 

82.5R 1.6 0.16 Ephemeral 

83.8L 2.7 24.3 Open 

85.3R 5.7 17 Open 

88.7L 3.2 8.9 Open 

94.1L 1.4 3.8 Open 

94.8R 1.9 11 Closed 

98.2R 3.9 12.5 Closed 

102.5R 2.2 6.6 Closed 

Total 87.4 506.4 

a L/R indicates bank facing the downstream direction; distance is downstream of PCN 

b area estimated at minimum water elevations from photogrammetry 

c based on visual assessment using report methodology 


Physical criteria developed in this process and the habitat classifications and limiting factors 

identified in Table 4, were used to evaluate the side channels with respect to potential 

restoration options. 

5.4 Fish Habitat and Fish Community Information 

This study considered several fish habitat requirements or priorities in its assessment. The 

objective of side channel restoration is to use physical works (as an alternative to increasing 

minimum flows) to ensure adequate water supply, residence time for thermal buffering, and/or 

access at lower flows or deep refugia to maintain fish when isolated at lower flows (BC Hydro, 

2008). 

The decision process to establish restoration targets must incorporate species and life stage 

habitat requirements in order to maximize benefits to the fish community. The following fish 

and fish habitat parameters in Table 4 were incorporated in the side channel assessment. 

Table 4. Side Channels Fish and Fish Habitat Parameters. 

Item Definition Source / Comment 

Dominant fish habitats Ru ‐ run; Gl ‐ glide; Rf ‐ riffle; Pl ‐ pool MOE. 1995. 

Gradient L ‐

6 Side Channel Restoration 

Side channels are generated through cyclic or episodic changes in river planform brought about 

by physical river processes. Continued morphological processes result in the creation, evolution 

and eventual loss of these channels through time, and interruption of one or more of the many 

processes can impact side channels. Side channels have been recognized as critical aquatic 

habitat, and side channel restoration activities for fish habitat restoration have been practiced 

in the Pacific Northwest (PNW) for over 20 years. Many of these projects include: 

� Excavation of inlet channels to re‐water side channel habitats, 

� Construction of small intake and pipe systems to re‐water side channels, 

� Excavation and construction of new open water‐fed connected side channels in the 

floodplain, and 

� Construction of groundwater‐fed side channels in floodplains. 

Within all these works, the complexing of side channels with either wood debris or large 

substrate, and modifications of the channel structure by construction of pools or riffles, have 

been implemented to improve the fish habitat. Most of these works have been implemented 

on relatively small coastal and interior watersheds, and relatively little significant restoration 

has been implemented on rivers of a magnitude similar to the Peace River. Typical restoration 

drawings for habitat complexing and bank protection have been included in the Appendices. 

A contemporary analogue is the lower Fraser River, where channel modifications and gravel 

removal for the purpose of maintaining flood capacity have been implemented. These works 

have involved opening relic channels to flow and constructing large channels through bars. 

These works are temporary, however, and have not been constructed as permanent features. 

Another example is the Nechako River, where the construction and assessment of habitat 

complexing works for compensation of lost productivity resulting from a reduction in flows has 

been studied (NFCP, 1996). These works have been constructed on a river system dissimilar 

from the Peace River as it not is subject to a highly variable flow regime, and has much lower 

peak flows and mean annual flow. 

Following the classification of side channels in the study reach, the following potential 

restoration options have been identified. These options are used in the individual assessment 

of sites identified in Section 7. 

6.1 Permanent Open Side Channels 

These channels contain flow through the current range of flows from PCN, but regulation 

impacts may have reduced the productive capacity of habitats. The following options can be 

considered: 


a) Inlet improvements for additional flow capacity or range: 

Existing inlet area can be widened and/or deepened through the thalweg to provide 

additional flows to increase velocities and depths (e.g. suitability) of side channel habitat 

for fish. 

b) Channel improvements: 

Excavation of deeper pools in the bed, alcoves along the margin of the channel, or 

channel fills to form riffles to improve the hydraulic conditions for fish. 

a) Channel construction: 

These channels can be extended within the floodplain with excavations, and made 

longer or wider to increase the amount of available wetted area and habitat. 

b) Habitat complexing: 

Wood debris, jams and cover or channel modifications (e.g., spawning substrate, pools, 

riffles, alcoves) added to the side channel to restore or improve the rearing and/or 

spawning habitat for fish. 

6.2 Ephemeral Open Side Channels 

These channels are largely affected by partial or complete dewatering of the channel, resulting 

in dewatered fish habitats, reduced productive capacity, and potential fish stranding. The 

following additional actions (including those listed above) can be considered for these channels 

that fully or partially dewater through the current range of PCN flows. 

c) Excavation of inverts throughout the channel: 

High spots in the channel invert or bed are lowered, connecting isolated sections of 

channel to provide connectivity and flowing conditions through the side channel. This 

improves access for fish, prevents fish stranding, and improves fish habitat conditions. 

d) Excavation and lowering of the entire channel: 

The entire channel is excavated and the thalweg elevation is lowered to ensure that the 

wetted channel does not dewater through the range of flows. 

6.3 Closed Side Channels 

Closed side channels have no direct flow from the river mainstem, and rely on backwatering, 

local inflows, or groundwater to sustain pooled or flowing water. Although largely affected by 

regulation, these side channels also provide unique habitats for aquatic species along the Peace 

River. The following additional restoration actions (including those listed above) can be 

considered for these systems: 

e) Installation of water intake and supply pipe: 

A small piped or open channel intake can provide base flows through these features to 

ensure water supply through critical periods. 

f) Beaver Dam Removal: 

Many side channels are dammed by beavers and may benefit from seasonal removal of 

dams to facilitate improved fish access. 


6.4 Restoration Key Issues and Criteria 

Based on the overview assessment conducted by both field and office examination of the 

potential side channel sites, the following items are considered key or critical factors in the 

restoration of side channels in the Peace River. 

6.4.1 Access 

Side channels situated along the south bank of the Peace River have little to no road access 

except near PCN and close to Fort St. John at the Pine River. All other potential sites will require 

boat or barge access for equipment, unless extensive road development (now or in the future) 

provides greater local access. Many of the sites are also located in the deeper valley profile 

along the river, and would require long haul or access roads if materials were to be imported or 

removed from sites. 

6.4.2 Channel Design 

Restoration efforts results in open and partially connected side channels being exposed to flow, 

and channel design must adequately address hydraulic issues like bank and channel stability 

and flow conveyance. Channel design concepts should reflect natural conditions by using pre‐ 

existing channels as an example, and by replicating similar channel and habitat forms found 

locally along the river. Existing coarse bed materials (large gravels and cobbles) are sufficient to 

provide adequate stability for the channel bed and banks. Graded open channels with natural 

form and materials will provide adequate fish passage over a range of flow conditions. The 

channel bed and banks should not be left uniform and variation is preferred to provide a range 

of hydraulic conditions and habitats within the channel. 

6.4.3 Intake Design 

Any side channel on the Peace River is subject to ongoing sedimentation, ice effects, and 

damming by beavers. The effects of sedimentation increase with distance downstream from 

PCN, especially as larger tributaries enter the mainstem Peace River. In consideration of the 

potential impacts, simple, wide open channels may be both economical and reliable in 

comparison to piped intakes with formal intakes and control works. Wider channel openings 

with moderate depths of flow will be more difficult for beavers to dam than smaller pilot 

channels intended to re‐water closed side channels. Where feasible, however, simple pipe 

intakes may prove to be cost effective if a relatively small range of flows is required. This study 

did not identify any tributary systems that could be considered to be reliable for the purposes 

of surface water supply for a restored or constructed side channel along the Peace River. 

6.4.4 Habitat Complexing 

Large wood recruitment in the Peace River has been limited through construction of upstream 

dams and reservoirs. Without an ongoing supply or source of wood, the construction of wood 

jams and debris structures could be under taken, as long as the effects of ice and flow 

regulation are accounted for. 


Studies on the Nechako River indicate that both recruitment and sufficient anchoring to 

account for fluctuating flows is critical to the design and structural stability of debris structures 

on the river (NFCP, 2003). An assessment conducted on debris bundles and sweepers indicated 

a loss of complexity that was assumed to occur during winter when ice stripped branches from 

the debris complexes. The studies also identified several parameters important for biological 

success of juvenile chinook rearing habitat, namely: 1) the provision of appropriate shear 

velocities, 2) cover area, and 3) substrate in complexing structures. These provisions would also 

likely apply for salmonid rearing within the upper Peace River. 

In 2006, NHC constructed several large wood jams on the Pine River as compensation for loss of 

wood resulting from an oil spill remediation. These jams were large un‐ballasted log jams 

secured by steel H‐piles driven into the bed of the river. The large jams proved effective in 

mitigating the loss of wood within the channel and helped to stabilize sections of the channel. 

Several of the jams recruited wood and maintained their purpose and function. Loss of jam 

structural integrity was primarily due to scour under the jams, and loss of the H‐piles. In the 

Peace River side channels, the installation of engineered log jams (ELJ) and wood debris 

structures should be undertaken using un‐ballasted techniques utilizing embedment and piling 

to secure the wood in the channel. Jams sizes could range from 25‐100 m 2 and installed 

laterally along the channel or at the head of bar complexes. 

Mainstream Aquatics (MA) has noted the existing use of limited instream boulder cover by fish 

in open side channels (Rick Pattenden, pers. comm.). Within the channel margin of open side 

channels, boulder cover could be installed to provide additional cover for juvenile and adult 

fish. This may be effective where overhead cover is limited or wood debris placement is not 

viable, such as along steep banks. If overwintering or refuge habitats are sought, localized 

deepening of channel areas or the construction of side alcoves may be useful, as long as flows 

are provided and pool areas remain functional throughout the current range of PCN flows. Pool 

or alcove areas would be sensitive to ongoing sediment deposition and would therefore be 

ideally suited to sites in the upper river (above the Halfway River), or multiple areas could be 

constructed acknowledging attrition and loss of these areas through time. 

6.4.5 Materials and Construction 

Due to the isolated locations of most of these potential sites, the import of materials will be 

limited and expensive. Potential designs will have to incorporate local placement of fills, 

utilization of existing materials and limited access. These channels will not use formal rock bank 

protection or armouring to reduce channel movement. 

Sediments that are excavated from infilled channels can be placed along the bars to form 

additional higher elevation bar habitat or adjacent higher floodplains. These areas will rapidly 

re‐vegetate with grass and brush, or may be treed if simple site restoration principles are used. 

Sources for wood and rock include material from clearing for access and tote roads, and 

existing slopes and local pits if available. Sourcing for materials should be undertaken prior to 

detailed design. 


Table 5 presents the restoration criteria and factors used in the site assessment, along with the 

physical attributes, and fish and fish habitat information. 

Table 5. Side Channel Restoration Criteria. 

Item Definition Rating / Comment 

Channel Extend ‐ New Area (m 2 ) 

Widen Area (m 2 ) 

Excavate ‐ Depth Depth (m) 

Spot Excavate ‐ Thalweg Depth (m) 

Spot Excavate ‐ Pool Depth (m) 

Inlet Excavate ‐ Depth Depth (m) 


Outlet Excavate ‐ Depth Depth (m) 


Water Supply New Inlet Area (m 2 ) 

Piped Inlet 

Habitat Complexing Cover Overhead, Instream, None 

Boulder Cover Area (m 2 ) 

Riffle Construction Area (m 2 ) 

ELJ/Wood Debris Structures (LWD) Area (m 2 ) 

Fish Access Beaver Dam Removal n.a. 

Cold / Clear Water Fish Benefit L, M, H 

Cool / Turbid Water Fish Benefit L, M, H 

Priority L, M, H 

6.4.6 Design and Construction Mitigation 

Without mitigation during design and construction, development of aquatic habitat restoration 

projects within the floodplain of the Peace River could impact water quality, terrestrial and 

wildlife values. This section provides an overview of the mitigation that could be provided to 

ensure potential impacts do not occur, and full benefits of the restoration work is realized. 

Water quality impacts include the discharge of fine sediment into the water that could impact 

fish and fish habitat. These impacts could occur during instream construction works, surface 

erosion from bare surfaces exposed during construction and the discharge of drainage and 

dewatering flows. Mitigation from these impacts include: 

� Work timing and development of proper access, 

� Hydraulic site isolation of instream works areas including channel inlets and outlets, 

� Proper erosion and sediment control, and 

� Treatment and proper discharge of dewatering flows. 


Site isolation costs and contingency costs for dewatering and mitigation have been included in 

the site costing to reflect these requirements. 

Sediment 

Wildlife 

6.5 Conceptual Level Costing 

In developing rough conceptual costing, a value of $10‐$30 per m 2 was developed for major 

restoration and development of new side channel habitat. The higher end of the range includes 

complexing with wood or boulders, hauling and removal of excavated materials, and sites with 

multiple instream works or significant access development. The lower end of the range 

considers simple channel excavations with local placement and grading of fills, utilization of 

existing complexing materials, or areas that have simple access. 

These values are conceptual and based on existing information and professional experience in 

developing habitat restoration projects, and further feasibility and technical assessment is 

required to develop more accurate costs estimates. 

In developing conceptual costing, basic unit costs were assumed and used with estimated 

quantities and measurements derived from site restoration plans. Site restoration costs were 

estimate to conceptual level assigned as AACE Class 4, +65%/‐35% accuracy 4 . Estimated costs 

included a contingency item for detailed design, and permitting and environmental, which is 

estimated at 30% of total construction costs. 

Habitat complexing was assumed to be applied to sites requiring the following: 

� Complexing Wood for ELJ and debris structures: 1 m 3 /s per 10 m 2 channel area; 

� Complexing Boulder Cover: Use 0.5 m 3 per 2.5 m 2 area; and 

� Live Staking: 2 stakes per m 2 . 

As described earlier, preliminary take‐off volumes and data were estimated from conceptual 

lay‐out drawings at each site. This data was combined with conceptual unit rate values to 

develop cost estimates. These values were cross‐checked with estimates of total daily 

equipment and labour costs, and an estimate of the time required to complete the work based 

on assumed productivity and volumes. Estimated unit rates are provided in Table 6, which is 

based on adjusted MOT Blue Book values. 

4 Advancement of Cost Engineering Recommended Practice No. IOS‐090, Cost Engineering Technology, 20 May 

2009. 


Table 6. Conceptual Construction Unit Rates and Costs 

Item Cost Rate/Notes 

15T Track Hydraulic Excavator $125/hr all found 35‐85 m 3 /s hr 

20T Track Hydraulic Excavator $150/hr all found 50‐100 m 3 /hr 

25T 6W Off‐road Truck $100/hr all found 25‐50 m 3 /s short haul 

75 kW Bulldozer $100/hr all found Grading, finishing 

Labourer $650/d Includes per diem 

Foreman $900/d Includes per diem 

Site Engineer / Environmental Monitor $1150/d Includes per diem 

Excavate and place $5/m 3 20T Excavator, single pass 

Excavate and short haul $10/m 3 Haul less than 500 m 

Excavate and long haul $15/m 3 Haul off site 

Access and tote road construction $10,000/km Clearing and rough grading 

Full bench graded road construction $100,000/km Cut/fill, grade and ballast 

Complexing wood debris – installed $150/m 3 Use 1 m 3 per m 2 structure area 

Live staking ‐ installed $7.50/m 2 Use 2 stakes per m 2 area 

Complexing boulders ‐ installed (1000 mm dia. = 1 m 3 ) $100/m 3 Use 0.5 m 3 per 2.5 m 2 area 

Site Isolation and Dewatering ‐ small $5,000 Site < 100 m 2 

Site Isolation and Dewatering ‐ large $25,000 Site < 500 m 2 

Channel Crossing (3‐1500 mm CMP) $10,000 Per site 

7 Selected Side Channel Restoration Sites 

On this basis an initial selection of preferred restoration sites were identified prior to field 

inspection. This assessment was verified or modified based on field examination results. For the 

pre‐field assessment, areas within the side channels were digitized with polygons to provide 

areas based on defined channel widths. Road and access distances were scaled from 

orthophotos and based on existing roads and distances to sites. The locations of these areas are 

indicated on the appended overview map sheets and are listed in Table 7. A brief description of 

each of these sites and conceptual remedial options are presented below. 

Table 7. Identified Side Channel Restoration Opportunities (PCN to Pine River). 

PCN Name a 

Side Channel 

Length (km) 

Side Channel Area b 

(ha) 

Side Channel Type Priority 

5.0R 2.4 1.8 Open Low 

8.1R 4.8 45.1 Open Low 

17.2L 0.5 1.0 Closed High 

23L 0.6 0.2 Closed High 



40.5L 3.0 18.0 Ephemeral Medium 


73.8L 4.6 9.6 Open High 

85.3R 5.7 17.1 Open Medium 

98.2R 3.9 12.5 Ephemeral Medium 

102.5R 2.2 6.6 Closed Medium 

a L/R indicates bank looking downstream; distance is downstream of PCN 

b area estimated at minimum water elevations from photogrammetry 

c assessment based on collaboration of principal authors and report methodology 

7.1 River KM 5.0R 

The site at River KM 5.0R consists of a 2.4 km long right bank 5 side channel located opposite 

Hudson’s Hope and upstream of Maurice Creek. This area is shown on Map sheet 1 of 11, which 

is appended to the report. This side channel complex contains three primary channels. The 

most northerly channel (closest to the main stem) is infilled with sediment and colonizing 

vegetation. The middle channel is seasonally active but was found to contain little flow in May 

2009. The largest third channel is an open channel along the right bank. Localized bank erosion 

is occurring along the mid‐ to lower section of the third channel, and sedimentation is forming 

an obstruction that extends into the larger southern secondary channel. These materials, along 

with sediment supplied from Maurice Creek form a hydraulically smooth series of bars at the 

outlet of the largest secondary channel. Sediment accumulation also occurs at the inlet of this 

large channel and these materials have been observed to go dry during periods of low flow 

(Rick Pattenden, pers. comm.). This area is illustrated on Plate 4.2.2. 

The three side channels at this site mimic fish habitats provided in the main side channel 

(run/riffle complexes). Due to frequent dewatering, the secondary channels provide minimal 

fish habitat and are used only opportunistically when sufficient flows are present. The area is 

dominated by the cold‐clear water fish assemblage. Bull trout (juveniles), mountain whitefish 

(juveniles), and rainbow trout (juveniles), and slimy sculpin (adults) are the fish species that are 

most likely to use the area at present. Cold water temperatures may preclude use of this area 

for spawning/egg incubation by most species (mountain whitefish is the exception). 

The conceptual restoration plan is show on the Site Map 5.0R. Road access is available to 

Maurice Creek and excavation equipment could access the site during periods of low river flow. 

Approximately 750 m of road is required for access, of which half requires road improvement 

and the other half is open tote road across gravel bars. A water crossing at the side channel 

outlet will be required to access the site. 

5 Right bank while looking downstream. 


The middle side channel is ephemeral and subject to dewatering, and the north channel is 

inactive within the current flow regime. Restoration would include deepening sections of the 

middle channel to make it free flowing and open. Wood complexes could be installed to benefit 

rearing habitat for salmonids in this cold water reach. The north channel would be excavated 

into a closed channel providing backchannel refuge and rearing habitat. The close proximity of 

this site to PCN will limit sediment infilling. Localized sediment removal at the outlet of the third 

channel could increase flows. 

Proposed restoration for this site includes: 

1. Excavation of a closed channel 10‐25 m wide, 1‐2 m deep on the north side of the bar; 

2. Excavation of the inlet bar and selective thalweg excavations in the middle secondary 

channel; 

3. Large wood complexing of the middle channel at 10‐15 sites along the channel with 25‐ 

40 m 2 jams; and 

4. Boulder complexing of the main south secondary channel. 

Total estimated excavation and fills are approximately 74,000 m 3 depending on the depth of 

cut, and would result in the development of 50,000 m 2 of open continuous side channel 

habitat. Fills would be placed along bar edges to form raised bar areas that would be live staked 

and allowed to re‐vegetate naturally. Estimated costs for the KM 5.0R site in concept are 

$1.54M including contingencies. 


The side channel at River KM 8.1R is shown on Map sheet 2 of 11. The main side channel at this 

site is presently used by fish populations belonging to the cold water fish assemblage and 

habitat limitations are minimal. The ephemeral secondary channels do not appear to provide 

access to fish at most flows and appear to dewater regularly, fish use is therefore unlikely. 

If the secondary channels were targeted for restoration the sites would mimic fish habitats 

provided in the main side channel (run/riffle complexes). The area is dominated by the cold‐ 

clear water fish assemblage; therefore, bull trout (juveniles and adults), mountain whitefish 

(all), rainbow trout (juveniles and adults), and slimy sculpin (fry, juveniles, and adults) would 

benefit from restoration. With restoration of the secondary side channels, cold water 

temperatures may preclude the use of this area for spawning/egg incubation by most species 

(mountain whitefish is the exception). 

Access to the site is provided from the upstream property and would cross the upstream end of 

the bar with a culvert crossing or small‐span bridge. The larger secondary channel on the south 

side of this bar complex may be subject to low flows and excavation of sediment infilling at the 

inlet may help increase flow input and habitat area. The smaller secondary channel to the north 

is ephemeral and would be excavated and lowered to form an open side channel. In the cold‐ 

clear water reach of the Peace River, wood complexing will improve rearing habitat for bull and 

rainbow trout. 


The restoration concept includes: 

1. Excavation of 5,000‐7,500 m 3 of sediment from the inlet thalweg of the main secondary 

channel to increase flows at reduced Peace River discharges; 

2. Excavation of 100,000‐120,000 m 3 of sediment to form an open side channel 10‐15 m 

wide, approximately 1‐1.5 m deep; and 

3. Large wood complexing of the new channel at 10‐15 sites along the channel with 25‐ 

40 m 2 jams. 

The area to be developed for the new open channel is estimated at 30‐60,000 m 2 . Fills would be 

placed at the upstream and middle portions of the existing river bar and re‐vegetated. The total 

restored channel area is approximately 130,000 m 2 . Estimated costs for the 8.1R site in concept 

are $2.30M including contingencies. 

7.3 River KM 17.2L 

The potential restoration site at River KM 17.2L consists of a 0.5 km long, small left bank side 

channel that has been extensively infilled with fine sediment and vegetation. This area is 

shown on Map sheet 3 of 11. Oblique aerial imagery is presented on Plate 4.3.1. A channel 

spanning beaver dam occurs in the central section of this site and has caused the formation of a 

small pond. Sediment deposition has blocked off the entrance to this channel at most flows. 

The outlet is also heavily infilled with sediment and there was only a narrow wetted connection 

to the river mainstem in May 2009. This area is illustrated on Plate 4.3.2. 

This side channel has severe limitations for fish use. Access is restricted and elevated water 

temperatures in summer likely exceed the tolerance levels of most species. Longnose sucker fry 

and lake chub, however, were observed in the ponded area of this site indicating some fish use. 

Of note was the presence of several amphibian tadpoles (likely Western Toad (Bufo boreas)) in 

the beaver pond portion of the side channel at the time of the field survey. The Western Toad 

is protected under the federal Species at Risk Act (SARA) under which it has Schedule 1, Special 

Concern status. The Western Toad is also protected under the BC Wildlife Act and is listed as 

endangered under the World Conservation Union (IUCN). Amphibious species at this site will 

need to be identified and potential impacts to these species will need to be adequately 

addressed prior to proceeding with restoration. 

This site is readily accessible from Highway 29 and the upstream farm yard, and would require 

construction of approximately 100 m of tote road to access the channel. Restoration of this side 

channel would be to restore it from a closed to an open side channel with continuous flow. 

Proposed restoration for this site includes: 

1. Excavate 45,000 m 3 of sediment and fill the existing bar forming an open side channel 1‐ 

2 m deep, 15‐25 m wide; and 

2. Large wood complexing of the new channel at 5‐10 sites along the channel with jams 

25‐40 m 2 . 


The concept provides 32,000 m 2 of open complexed cold water side channel. Note that this 

option may impact some wildlife habitat associated with the current wetted area. The concept 

costs for 17.2L are $0.82M. 

7.4 River Km 23.0L 

The site at River KM 23.0L located just upstream of Farrell Creek, consists of an extensively 

infilled, 0.6 km long left bank side channel. The proposed site is shown on Map sheet 4 of 11, 

with oblique aerial imagery compiled on Plate 4.4.1. A small residual wetted area was observed 

at the channel outlet in May 2009. The upstream channel was found to be dry and no water 

was being diverted into this area. The side channel presently has no value to fish due to a lack 

of water. Restoration of the channel would provide additional habitat for the cold water fish 

assemblage that occurs in the area, with limited benefits incurred by younger life stages (i.e. 

fry) that originate from Farrell Creek. 

Site 23.0L is readily accessed from Highway 28 and the adjacent farm, and approximately 140 m 

of access road is required to the site. The rationale for this site is the conversion of a dry closed 

relic channel into a closed wetted side channel providing off channel rearing and refuge habitat. 

The proposed work at the site includes: 

1. Excavate 27,000 m 3 of sediment and fill the existing upstream bar forming a closed side 

channel 1‐2 m deep, 15‐25 m wide; and 

2. Large wood complexing of the new channel at 4‐8 sites along the channel with 25‐40 m 2 

jams. 

Excavation of a deepened pool at the exit or head of the channel may provide refuge habitat 

and improve subsurface flow into the channel. The total restored closed channel area provides 

19,000 m 2 of habitat for cold‐clear water fish assemblage. The total estimated conceptual costs 

for this option at 23.0L are $0.51M. 


Site 32.0L consists of a 2.4 km long left bank side channel located between an island and the 

base of the left bank valley wall. Plans for this site are presented on Map sheet 5 of 11. Oblique 

imagery is compiled on Plate 4.5.1. 

This side channel contained a wetted channel open at the downstream end, and a series of 

large wetland or ponds in May 2009. The satellite imagery, however, indicates that the wetted 

channel becomes discontinuous at low flow. Ground photos, shown on Plate 4.5.2, illustrate 

how post‐regulation sediment deposition and vegetation growth has infilled the former side 

channel area. This side channel represents habitat that can be utilized by unique fish 

assemblages. This side channel is open only at the lower end, the lowermost portion contains 

deep water that can support fish year round, and there is an abundance of emergent 


vegetation. The most serious limitation at the existing site is dewatering of the upper portion 

and infilling. 

Northern pike have been known to use this site (unique fish assemblage), but it is presently 

used opportunistically by bull trout (adults), mountain whitefish (juvenile and adults), and 

longnose sucker (juveniles and adults). Small fish species such as redside shiner and lake chub 

are likely permanent residents. The abundance of standing water and emergent vegetation 

indicates that this site may be important amphibian habitat. Habitat restoration could target 

enhancement of the existing unique fish habitat, which would benefit this fish assemblage. 

Conversely, the upstream inlet of the site could be reactivated to flush the side channel thereby 

enhancing habitats used by the cold‐clear water fish assemblage. 

Site 34.0L is readily accessed from Highway 28 and the upstream local access road. Access of 

the upper road would require improvements to 250 m of road. An access road further 

downstream of the site would require 300 m of access road built to the site and a crossing over 

the existing wetted channel. Restoration would result in opening up the middle channel, and 

providing more flow to the upper site through construction of a small side channel in the pond 

structure at the upstream end. Fills would be placed downstream of the vegetated island to 

form a new bar along the river and re‐vegetated. 

The proposed restoration concept for this site is: 

1. Excavate 19,000 m 3 of sediment to form a 3‐5 m wide inlet channel to the upper pond 

providing continuous flow through the channel complex; 

2. Excavate 11,000 m 3 of sediment from the inlet channel situated midway down the 

channel complex to supply flow to the lower portion of the channel; and 

3. Large wood complexing of the new channel at 10‐15 sites along the channel with 25‐ 

40 m 2 jams. 

The proposed scheme would replace the unique fish assemblage with a cold water assemblage. 

The alternative scenario will leave the existing channel system closed and extend the existing 

channel upstream with a deepening of the outlet. This will extend and restore the unique fish 

assemblage at the site. The conceptual costs for this site are estimated at $0.63M. 


Site 40.5L consists of a complex of three left bank side channels totalling 4.9 km in length 

located on what is now becoming a large island. A site plan is provided on Map sheet 6 of 11. 

Oblique aerial imagery is compiled on Plate 4.6.1. The largest channel (which is 3 km long) is 

located at the base of a left bank scarp. Much of the left side of this channel is composed of 

bedrock, while the right bank side consists of a low gradient vegetation covered bar. The inlet 

and outlet of this channel were well connected to the main stem channel in May 2009. The 

middle channel (labelled A on Figure 4.6.1) is 1 km long and heavily infilled with sediment. The 

inlet is well vegetated and the outlet (which connects with the main left bank channel) was 

completely dry in May 2009. The third channel (labelled B on Figure 4.6.1) is 1 km long and 


wider than the other two, but appears to have been extensively infilled with post‐regulation 

sediment deposits. The inlet is connected to the main channel at high flow, but becomes 

disconnected at low flow. The outlet connects with the left bank channel. 

This side channel represents habitat that has been historically utilized by the unique fish 

assemblage, but has subsequently infilled (within the last 20 years) to the point where it is 

provides minimal habitat. The side channel is permanently open only at the lower end, and the 

entire area is dominated by shallow water with little cover. The abundance of standing water 

and emergent vegetation indicates that the site may be important amphibian habitat. The area 

is presently used opportunistically by the fish populations that belong to the cold water fish 

assemblage that dominates the area. Given its close proximity to the Halfway River, the site 

may also be used as a feeding area for pre‐spawning adult bull trout. Historically, the site was 

used extensively by northern pike and lake whitefish. 

Similar to Site 32.0L, the restoration can target unique or cold water fish assemblages in the 

Peace River. Deepening and extending the existing closed channels will restore unique fish 

habitat, benefiting this fish assemblage. Excavating and deepening the upstream inlet of the 

two channels on the plan will create open flowing channels likely benefiting the cold‐clear 

water fish assemblage. 

Proposed work at this site includes: 

1. Excavation of 70,000 m 3 of sediment from the inlet thalweg and channel of the main 

(north) secondary channel to increase flows at reduced Peace River discharges; 

2. Excavation of 97,000 m 3 of sediment to form two inlet channel and an open side 

channels 15‐20 m wide, approximately 1‐1.5 m deep; and 

3. Large wood complexing of the new channel at 20‐30 sites along the main secondary 

channel with 25‐40 m 2 jams. 

Fills would be located as indicated on the plans, creating high bar habitat that will be live staked 

and allowed to re‐vegetate. Approximately 1.5 km of access road is required along steep slopes 

to access the lower part of the side channel complex. Fording, culvert crossings or short span 

bridges will be required to access the channels on the bar. A total of 137,000 m 2 of habitat will 

be restored and the conceptual costs are $3.1M. 


Site 58.0L consists of a 2.8 km long left bank side channel complex located immediately 

upstream of Cache Creek, as shown on both the overview map sheet and Map sheet 7 of 11. 

Oblique aerial imagery is compiled on Plate 4.7.1. Site 58.0L includes a 3.3 km long channel 

[labelled A on Figure 4.7.1in the Plates] which is located at the base of the left bank valley wall. 

The entrance to this channel is infilled with sediment and vegetation; the outlet joins Cache 

Creek 980 m upstream of the Peace River confluence. 


A series of extensively infilled channels occurs in the central portion of this bar [see B, C and D 

on Figure 4.7.1], with channel lengths 1.1, 1.2 and 1.9 km, respectively. These channels no 

longer have well defined inlets or outlet connections to the Peace River. There are also two 

remnant channels located close to the left bank of Peace River. One is a recently abandoned 0.9 

km long channel [E], which is likely connected at both the inlet and outlet during high flow. An 

area of recent sediment deposition occurs on the left bank upstream of the Cache Creek 

confluence [F], and one or more secondary channels may have previously occurred in this area. 

This site presently has no habitat value and is not used by fish due to the absence of water. If 

connected directly to the Peace River, restoration of this site would create additional habitat 

for the cold‐clear water fish assemblage. The detrimental effects of ice formation and high 

suspended sediment loads that originate from the Halfway River, however, may limit its long‐ 

term function and utility. 

There does not appear to be any existing road access to Site 58.0L directly, however 200 m of 

access down a steep bank would be required at the upper end from the borrow pit at the 

upstream end of the project area. 

The site restoration proposed for 58.0L is: 

1. Excavation of the inlet and infilled channels in the central part of the bar [A to D] 

totalling 30,000 m 3 ; and 

2. Excavation of 38,000 m 3 of sediment at the inlet and outlet [E and F] to open the side 

channels with a 15‐20 m width, and approximately 1‐1.5 m depth. 

Further inspection of this site is warranted to better determine the potential for groundwater, 

as noted by the presence of upslope water and wetted channel situated a significant distance 

from the mainstem. If the potential for groundwater is confirmed, a closed groundwater 

channel along the valley wall, connecting several ponds and channels, may be a high priority. 

Cover and re‐vegetation is not required at this site. The total area that would restored at this 

site is approximately 44,000 m 2 and the conceptual costs are $1.0M. 


Site 73.8L consists of a complex of left bank side channels located 9 km upstream of the 

Moberly River confluence, as shown on Map sheet 8 of 11. Oblique aerial imagery is compiled 

on Plate 4.8.1. The largest, and most active, side channel at this site is located near the base of 

the left bank valley wall and is 4.2 km long [A on Figure 4.8.1.]. The inlet appears to be 

connected to the Peace River at high flow but becomes isolated at low flow. The outlet is 

wetted over a larger range of flow conditions, but appears to be subject to ongoing 

sedimentation. A series of former secondary channels occurs in the central and southern 

portion of this site. These areas appear to be extensively infilled with sediment and vegetation. 

Fish habitat at this site is severely limited and is not used extensively by fish. This is due to 

extensive areas of shallow water, high water temperatures in summer, and sedimentation. If 


the site is restored it could create additional habitat for the cold‐clear water fish assemblage, 

which would include juvenile and adult Arctic grayling. The detrimental effects of ice formation 

and high suspended sediment loads that originate from the Halfway River, however, may limit 

the longevity of restored channels and their long term value to fish. 

The proposed work consists of: 

1. Excavation of the inlet and infilled channel in the main north channel totalling 15‐20,000 

m 3 ; and 

2. Lowering and construction of an open channel by excavation of 15‐40,000 m 3 of 

sediment for a channel 20 m wide, approximately 1.5‐2.0 m deep. 

Access to this site would need to be provided by a short steep 200 m access road from private 

property located at the upper end of the project site. As discussed, the ephemeral main 

secondary channel along the base of the valley wall would be locally deepened. A larger open 

channel could be constructed midway down the bar. No cover or complexing is proposed for 

this site. A total channel area of 74,000 m 2 is provided by restoration and conceptual costs are 

$1.53M. 


Site 85.5R consists of a 5.6 km long right bank island located immediately downstream of 

Moberly River as illustrated on Map sheet 9 of 11. Oblique aerial imagery is compiled on Plates 

4.9.1 and 4.9.2. The upstream side channel entrance likely goes dry at low flow as does the 

infilled channel in the center of the island. The uppermost section of the channel goes dry 

during low flows in the Peace River. The lower portion of this side channel represents an area 

that currently provides important habitats for the unique fish assemblage. Viable populations of 

northern pike, lake whitefish, yellow perch, white sucker, and spottail shiner reside at this site. 

The upper portion of this side channel provides ephemeral habitat and is used opportunistically 

by fish that originate from the unique fish assemblage. Access to this site would need to be 

undertaken by barge or by road if the area is developed in the future. Side channel restoration 

efforts would target restoration of unique fish habitat. 

The proposed work at 85.5R includes: 

1. Extension of closed side channels into the lateral bar from the existing main closed 

channel by excavating 100‐120,000 m 3 of sediments; and 

2. Creation of multiple channels varying from 10‐20 m width and depths of 1.5 – 2.0 m. 

As shown in the drawing excavation of the inlet to the side channel could be considered, 

however, this could alter the current utilization of the area by the unique fish assemblage and 

would be subject to ongoing sedimentation from the Moberly River. The conceptual project has 

an estimated cost of $3.14M and would restore 74,000 m 2 of side channel habitat. 



Site 98.2R consist of a 3.8 km long side channel immediately upstream of the Pine River on the 

right bank. It extends from the pipeline bridge at KM 98 downstream to the Pine River, 

immediately above its confluence with the Peace River. Sediment accumulations at the inlet 

and outlet currently restrict flows in the side channel. Plate 4.11.1 shows both the inlet and 

outlet conditions. There is good access to the area via existing roads and cleared areas along 

the channel. 

As illustrated on Map sheet 10 of 11, the proposed restoration of this channel would include 

excavation of a new inlet channel, or installation of a piped intake, if this proves to be feasible. 

An open channel would require 40,000‐60,000 m 3 of excavation and minor armouring. One or 

two 1.5‐2.0 m diameter CMP culverts could be installed without controls to provide flows to the 

side channel. At the outlet, approximately 20,000 m 3 of excavation is required to daylight the 

channel to the Pine River. A small access bridge will require re‐construction over the channel 

for landowner access. The total restored area is 40,000 m 2 and conceptual costs are $1.12M. 


Site 102.5R consists of a 2.1 km long side channel complex located on the right bank 

immediately downstream of the Pine River confluence and upstream of the Taylor bridge as 

shown on Map sheet 11 of 11. Oblique aerial imagery is compiled on Plate 4.10.1. Site 102.5R 

contains a series of roads and dykes that isolate the upstream end of the ‘blue water’ remnant 

channel shown on Plate 4.10.1. This site currently provides habitat for a unique fish 

assemblage. Viable populations of northern pike, yellow perch, white sucker, and spottail 

shiner reside in this side channel. 

The abundance of standing water and emergent vegetation in the southernmost ‘blue water’ 

channel indicates that this site may be important amphibian habitat and may provide the best 

quality fish habitat. The remaining side channels are subject to annual flood discharges from 

the Pine River, which introduces large amounts of sediment. 

Restoration activities would excavate and extend closed side channels currently providing 

unique fish habitat. Infilling of the downstream outlet ‘blue water’ side channel outlet and 

development of deep‐water areas for overwintering would provide the most benefit. As shown 

on Map sheet 11 of 11, the head end of the closed channels would be extended towards the 

Pine River with a suitable set‐back to prevent overtopping and flooding. 

The total excavation for the channel extensions is estimated at 75,000 m 3 to provide channels 

with similar characteristics to the existing sites. No habitat complexing would be required at 

these sites, however, pools and alcoves could be developed into the new and existing channels 

to increase cover and habitat complexity. Road access is readily available to most of Site 

102.5R. The restored area is 36,000 m 2 and the conceptual costs are estimated to be $1.03M. 


8 Summary and Recommendations 

8.1 Site Prioritization 

A short list of side channel restoration sites has been developed, with a preliminary rating 

provided for each site and two side channels were identified with the highest rating. A 

summary table for the site assessments and conceptual costing tables are provided in the 

Appendices. The costs presented are at a conceptual level based on the assumed size of the 

restored channel and assumed unit rates. 

Side Channel 23L and 32L were identified as the sites with the highest overall rating based on 

the overview assessment carried out under this study. The 23L site was selected due to the fact 

that it current dry under the regulated flow regime, and restoration of the area would create 

new back channel habitat. The area is relatively small and accessible. The 32L site was selected 

due to excellent access, sufficient area available, and good potential to create both open 

connected side channel habitat and backwater closed side channel habitat within the same 

area. 

Based on the study team recommendations, the 32L site represents the best opportunity of all 

the sites assessed. If restoration opportunities are pursued in the future, and concepts for this 

site should be developed further. The sites should be reviewed, and prioritized in terms of: 

1. Review of conceptual costing and available budget to undertake restoration projects in 

2010/2011; 

2. Review of existing land tenure and available access to the proposed sites; and 

3. Permitting and regulatory approvals required in 2010/2011 for project construction. 

8.2 Information and Data Gaps 

Considerable gaps exist in the physical data available to assess and evaluate side channel sites 

along the Peace River. Some of these gaps can be addressed in the short term through existing 

programs (e.g., GMSWORKS‐5 and ‐6) or through dedicated surveys and studies. The following 

list identifies these items: 

1. Stage‐discharge rating curves and a hydraulic model of the reach will be available 

to estimate water surface elevations along the Peace River reach where the 

proposed side channels are situated. The rating curves and model could be used 

with existing survey data to determine the invert and channel elevations 

required to re‐water existing and restored side channels under the current PCN 

flow regime. This data may influence the priority of site selection. 

2. BC Hydro has recently flown three sets of aerial photographs to document fish 

habitat conditions on Peace River at varying river discharges (GMSWORKS‐4). 

Two or more sets of air photos are scheduled for 2010. These aerial photos 

should be obtained for each candidate restoration site, digitally scanned, and 


compiled at a common scale to document the effects of varying discharge and 

water levels on site conditions. 

8.3 Implementation of Restoration Concepts 

Prior to the implementation of detailed design and construction of a side channel restoration 

project: 

1. Site surveys and elevation data are required at the side channel sites to 

determine –at a minimum– inlet, outlet and channel elevations. Additional 

channel section and profile survey data would allow for the calculation of 

material volumes and preliminary engineering design information. 

2. Ground Investigations and subsurface sampling should be undertaken at multiple 

locations along and within the side channel sites to document surficial materials, 

groundwater conditions, and access limitations. Ground‐truthing of stockpile, 

lay‐down, and fill sites should also be completed prior to detailed design. 

3. A seasonal fish and habitat inventory should be completed prior to the 

restoration of targeted side channels. This information is needed to confirm the 

predicted fish use and habitat limitations of the current assessment and to 

quantify pre‐development conditions. The pre‐development information is 

important to quantify the benefits of the restoration activities and to guide 

future restoration activities. 

4. Terrestrial vegetation and wildlife use values need to be assessed so appropriate 

design and mitigation can be implemented during development of the aquatic 

components of the restoration work to unsure no impacts. 

5. Long term monitoring of restoration sites should be implemented. These 

programs should incorporate information and study designs from other ongoing 

BC Hydro monitoring programs in order to maximize the benefits of the 

monitoring results. 

8.4 Closing 

BC Hydro initiated this study to fulfill Peace WUP Committee recommendations to investigate 

the physical works necessary to maintain habitat productivity in side channels below PCN in lieu 

of increasing base flows 50 to 100 percent during the summer period. A total of 39 side channel 

complexes on the Peace River below PCN were assessed to allow for the determination of 

suitable restoration works to restore or maintain flows and habitat at the minimum flow of 

283 m 3 /s. 

Conceptually, simple channel excavations and lowering of critical elevations may allow for re‐ 

watering under base flow conditions. Conceptual costs are difficult to estimate as the depth 

and extent of excavations require survey data that is unavailable for the sites. The costs also 

depend on access and environmental requirements, scope of work at the selected sites, and 

available budgets. A notional cost of $20‐$30 per square meter of fully constructed channel has 


een suggested, and lower values would apply to channels that require partial or limited 

excavations. 

Eleven sites (11) sites were short listed, predominantly consisting of closed side channels that 

could be excavated into open flowing systems. In side channels above the Halfway River, 

ongoing sedimentation and ice effects could be minimal and additional habitat complexing and 

restoration works are suggested. Nine of the eleven sites (all except the lower 2 in the reach) 

would benefit cold‐clear water fish assemblages including bull trout, rainbow trout and Arctic 

grayling. 

Side channel locations Site 23L and 32L were rated the highest of the assessed channel sites, 

with site 32L selected as the best opportunity for implementation of side restoration objectives 

in this study. Information and data gaps, and implementation issues have been provided in the 

summary section, which will assist in guiding subsequent steps in the process of developing a 

restoration plan for Site 32L. This study recommends ongoing coordination with other 

GMSWORKS projects to better determine other factors that could influence the project or 

scope. 

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Van Metre, P.C., E. Callender and C.C. Fuller. 1997. Historical trends in organochlorine 

compounds in river basins identified using sediment cores from reservoirs. 

Environmental Science and Technology. V. 31, No. 8, p. 2339‐2344. 

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River. Submitted to River Research and Applications. 


Site Summary and Cost Tables 


Appendices

GMSWORKS-3 Peace River Side Channel Restoration - BC Hydro

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