rev date description designed drawn chk'd app'd figure … · 2012-05-10 · knight piésold ltd....

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CLARY LAKE

PATSY LAKE

LAKE 901

LAKE 493

PROJECT LOCATION

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REV DATE DESCRIPTION DRAWNDESIGNED CHK'D APP'D

AVANTI KITSAULT MINE LTD.

KITSAULT PROJECT

LAKE 493 DIVERSION TO LAKE 901

PROJECT LOCATION

VA101-343/9 VA11-00935

0FIGURE 1

0 05JUL'11 ISSUED WITH LETTER AS PP VM SRM

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PIPE INLET

STRUCTURE

LAKE 901

(W.L. 746)

LAKE 493

(W.L. 756)

6 144 100 N

476 800

E

OVERLAND HDPE

PIPELINE ROUTE

CULVERT

CULVERT

EXISTING ACCESS

ROAD, TYP.

PIPE OUTLET

INTO LAKE 901

EXISTING ROAD

CULVERT

0 05JUL'11 ISSUED WITH LETTER AS NSD VM SRM

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NOTES:

1. COORDINATE GRID IS UTM NAD83, ZONE 10 m.

2. PLAN BASED ON INFORMATION PROVIDED BY McELHANNEY, DATED DEC., 2009.

3. CONTOUR INTERVAL IS 1 METRES.

4. DIMENSIONS AND ELEVATIONS ARE IN METRES, UNLESS NOTED OTHERWISE.

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KITSAULT PROJECT

LAKE 493 DIVERSION TO LAKE 901 OPTIONS

OVERLAND PIPELINE

VA101-343/9 VA11-00935

0FIGURE 2

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6 144 200 N

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PIPE INLET

STRUCTURE

6 144 100 N

476 800

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BURIED

PIPELINE

CULVERT,

TYP.

LAKE 901

(W.L. 746)

LAKE 493

(W.L. 756)

EXISTING ACCESS

ROAD, TYP.

PIPE OUTLET

INTO LAKE 901

EXISTING ROAD

CULVERT


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KITSAULT PROJECT


BURIED PIPELINE

VA101-343/9 VA11-00935

0FIGURE 3

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A1-10 of 13

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LWD

TIE-IN EXISTING

STREAM AND POOL

RIFFLE/RUN/POOL

DEFLECTION LOG

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RIFFLE/RUN/POOL

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CHANNEL INLET

STRUCTURE

TIE IN EXISTING POOL

FIG

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DEFLECTION LOG

6 144 100 N

476 800

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BOULDER

CLUSTERS

FIG

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RIFFLE/RUN/POOL

FIG

2

A

BOULDER CLUSTERS

CONCRETE WEIR

LAKE 901

(W.L. 746)

LAKE 493

(W.L. 756)

BOULDER

CLUSTERS

EXISTING ROAD

CULVERT

OVERLAND HDPE

PIPELINE ROUTE

EXISTING ACCESS

ROAD, TYP.

LAKE 493 OUTLET

STRUCTURE

POOL DETAIL

FIG

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KITSAULT PROJECT


OPEN CHANNEL

VA101-343/9 VA11-00935

0FIGURE 5

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A1-12 of 13

A1-13 of 13

101-343/13-1 Rev 0 March 30, 2012

APPENDIX A2

FISH HABITAT COMPENSATION OF LAKE 901 OUTLET CHANNEL AND TRIBUTARY 886

(Pages A2-1 to A2-11)

Suite 1400 - 750 West Pender Street Vancouver, BC Canada V6C 2T8 File No.:VA101-343/9-A.01 Cont. No.:VA11-01068 Tel: 604.685.0543 Fax: 604.685.0147 www.knightpiesold.com

August 10, 2011 Mr. Craig Nelsen President & CEO Avanti Kitsault Mine Ltd 880 - 580 Hornby Street Vancouver, BC V6C 3B6 Dear Craig, Re: Kitsault Mine Project – Fish Habitat Compensation of Lake 901 Outlet Channel and

Tributary 886 Introduction Knight Piésold Ltd. (KPL) was retained by Avanti Kitsault Mine Ltd to outline the potential habitat enhancement opportunities within the Lake 901 outlet channel and Tributary 886. The locations of these channels are shown on Figure 1. This letter continues the discussions previously presented in the KPL letters “Kitsault Mine Project – Diversion Options between Lake 493 and Lake 901” (Knight Piésold, 2011a) and “Habitat Compensation Channel” (Knight Piésold, 2011b). This letter discusses the spawning habitat requirements for rainbow trout and the opportunities for incorporating these features within the Lake 901 outlet channel and Tributary 886. Habitat Enhancement Rainbow trout typically spawn in main river channels and their tributaries, and within the inlet and outlet channels of lakes. The preferred spawning location is within well-aerated gravels free of fine sediments at the head of riffles or at the tails of pools (Hunter, 1991). These locations deliver fresh oxygen and wash away waste products from the redds as water constantly flows through the substrate. The following physical habitat features are required in order to create suitable rainbow trout spawning areas: Ideal substrate size is 12 to 38 mm; however, rainbow trout will tolerate gravel as small as 2.5 mm

and as large as 76 mm. Preferred spawning depths range between 0.15 to 0.61 m. Preferred spawning velocities range between 0.2 to 1.0 m/s. During egg development, water depths and velocities may vary as long as the submergence of redds

is maintained. Other features, which are important for rainbow trout rearing habitat, include: Suitable cover provided from overhanging riparian vegetation, in-stream wood and boulders, and

bank structures (e.g. undercut banks). Deep pools and cobble substrate with interstitial spaces for overwintering habitat. Lake 901 Outlet Channel An existing channel profile, cross sections and photographs of the Lake 901 outlet channel are shown on Figure 2 and 3 as provided by Brad Horne of AMEC Earth and Environment Ltd (AMEC). The outlet channel is approximately 318 m long from the outlet of Lake 901 to the culvert crossing located at the existing road downstream. The average channel slope is 3% with predominant step-pool morphology.

A2-1 of 11

2 of 4 VA11-01068 August 10, 2011

The photographs show that habitat complexity is already present within the stream with riparian vegetation, small riffles and large woody debris (LWD) distributed throughout the system. The proposed habitat enhancement of the Lake 901 outlet channel outlined below aims to complement the existing habitat in the channel and is focused on providing additional spawning and rearing habitat for young-of-the-year (YOY) rainbow trout. The upper section of the Lake 901 outlet channel is too narrow and confined by bedrock to allow for channel alignment manipulation (an example of a bedrock outcrop is shown on Photo 4, Figure 2). Therefore, in order to provide spawning habitat through this reach, rock riffles with spawning platforms will be introduced. Rock riffles with “V” shaped crests act as small in-stream weirs that promote backwatering upstream of the riffle and a section of faster velocities over the elongated rock weir, therefore creating a pool-riffle-run sequence. The pools created upstream of the rock riffles provide deeper, slower moving water suitable for rearing habitat. Localized excavation may be incorporated to create pools with suitable depths for YOY overwintering habitat. The extended tail of the rock riffle creates a run section providing faster velocities, and when stocked with appropriately sized gravels, creates a spawning platform. The proposed placement and details for the rock riffles with spawning platforms are shown on Figure 4 and Figure 5 respectively. Typically, these structures are placed approximately 6 to 7 channel widths apart; however, it is recommended for this system that the rock riffles are placed in a manner that compliments the existing topography and habitat already present within the outlet channel (approximately 3.5 channel widths on average). Through the lower reach of the Lake 901 outlet channel there is more flexibility to incorporate spawning and rearing habitat features. Where possible, rock riffles with spawning platforms, in-stream and off-stream alcove ponds, LWD, boulder clusters and deflector logs will be incorporated. These features will be used to provide spawning habitat, low velocity zones and areas of refuge and cover. Figure 4 shows the potential locations of these features, while Figure 5 shows typical details. Any existing or created pools with a depth greater than 2 m will have LWD incorporated and a double layer of cobble substrate to provide interstitial spaces for overwintering rainbow trout. Depending on the sediment transport potential of the stream, possibility exists for spawning gravels to migrate downstream. To minimize this effect, gravel-retaining structures (e.g. log deflectors, or boulder clusters) will be placed along the channel that will promote sediment accumulation. Additional spawning gravel will also be stockpiled in the upper reaches of the outlet channel, as well as downstream of the bedrock section, as shown on Figure 4. These stockpiles will be placed along the stream banks and will keep contributing new gravel at higher flow events (e.g. 2-10 year flood events), providing for a self-maintained system. They will also serve as reserves for additional spawning sediments when more replenishment is required after floods with even higher return periods. The confluence of Lake 493 and Lake 901 outlet channels is located a small distance downstream of a hanging culvert crossing that is currently impassable for fish to move back upstream. By replacing the culvert with a single span bridge and improving the access, Lake 493 and Lake 901 will be reconnected, therefore providing access to Lake 901 for the fish from Lake 493. The culvert replacement will increase the stream length available to rainbow trout and therefore increase the amount of available habitat. Flows expected in the Lake 901 outlet channel prior to, during the construction and operation phases, and post-operations of the Kitsault Mine Project were estimated in KPL letter “Kitsault Mine Project – Surface Water Hydrology Flow Changes” (Knight Piésold, 2011c). The monthly mean annual hydrographs for the Lake 901 outlet channel are summarized in Table 1 and shown on Figure 6. The outflows of Lake 901

A2-2 of 11

3 of 4 VA11-01068 August 10, 2011

are estimated assuming that Lake 901 inflow losses are mitigated by diverting flows from the neighboring Lake 493. Tributary 886 Tributary 886 is an inlet channel to Lake 901 as shown on Figure 1. It was considered for spawning habitat enhancement opportunities since the Kitsault Mine Project will not affect its drainage area. Investigation of Tributary 886 revealed that the lower section of the stream is a small, very low gradient channel that does not appear to receive sufficient flows or velocities to provide adequate spawning habitat. The lowermost section of the tributary is influenced by lake fluctuations, followed by a small narrow channel and then a wider channel flowing through a “bog” type plateau (personal comm. with Brad Horne, AMEC). The combined length of these sections is about 150 m. The upstream sections of this tributary incised in a V-shaped bedrock channel may be impassable for fish and offer very limited options for habitat improvement. To increase the flows within Tributary 886, diversion options from Lake 493 were explored; however, these options where deemed unfeasible primarily due to inadequate elevation differences and inability to divert water without pumping. The low gradient of Tributary 886 makes it unsuitable for creating spawning platforms, while the low flows do not provide adequate depths for creating rearing habitat. Habitat enhancement within Tributary 886 is not considered viable at this time; however, additional fieldwork is necessary to fully investigate this option. Recommendations Before a detailed design of the habitat enhancement of the Lake 901 outlet channel is undertaken, the following recommendations are made regarding detailed site investigation and field data collection: Perform detailed topographic survey (0.5 m contours) to enable optimizing the design of the channel

enhancement options. Collect at least one year of continuous stage record at the outlet of Lake 901 (station installed in May

2011), as well as 10 unique stage-discharge measurements in order to develop a rating curve and determine the in-situ outflows for the lake.

Perform site investigations during the rainbow trout spawning season in late May to mid-June to establish the current utilization of the Lake 901 inlet and outlet channels. Collect information on substrate size, water depth and water velocity in those areas that have the highest utilization by spawners.

Undertake additional design and modelling work to confirm that the habitat enhancement works will meet the velocity and depth requirements for spawning rainbow trout.

References Hunter, C. J. Better Trout Habitat: A guide to stream restoration and management. Washington: Island

Press, 1991. Knight Piésold (2011a). Kitsault Mine Project – Diversion Options between Lake 493 and Lake 901. Ref

no.VA11-00935, July 2011. Knight Piésold (2011b). Fish Habitat Compensation Channel. Ref no. VA11-00966. July 2011. Knight Piésold (2011c). Kitsault Mine Project – Surface Water Hydrology Flow Changes. Ref no.VA11-

00964, July 2011.

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KITSAULT PROJECT

LAKE 901 OUTLET CHANNEL AND TRIBUTARY 886

PROJECT LOCATION

VA101-343/9 VA11-01068

0FIGURE 1


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PHOTO #6

LAKE 901 OUTLET LOOKING U/S

PHOTO #5

SECTION 5 LOOKING U/S

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5. PHOTOGRAPHS #1-6 PROVIDED BY BRAD HORNE, AMEC EARTH AND

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KITSAULT PROJECT

LAKE 901 OUTLET CHANNEL

PLAN

VA101-343/9 VA11-01068

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APPROX. CREEK INVERT

PROFILE ALONG LAKE 901 OUTLET CHANNEL


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NOTES:

1. PROFILE BASED ON INFORMATION PROVIDED BY McELHANNEY,

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2. DIMENSIONS AND ELEVATIONS ARE IN METRES, UNLESS NOTED

OTHERWISE.

3. SECTION GEOMETRY WAS SURVEYED IN JULY 2010 AND PROVIDED

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PROFILE AND SECTIONS

VA101-343/9 VA11-01068

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HABITAT ENHANCEMENT PLAN

VA101-343/9 VA11-01068

0FIGURE 4

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FLOW

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LOG(S)

PINS

BACKWATER AREA

(VELOCITY REFUGE) COBBLES OR BOULDERS

FOR GRAVEL RETENTION

ANCHOR BOULDERS

ANCHOR PINS AND

CABLES (REBAR)

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BASE EMBEDDED

IN BANK

ARMOUR OPPOSING

BANK BOULDERS)

4

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NTS

BOULDER

CLUSTER

3

-

3

-

FLOW

BACKWATER AREA

(VELOCITY REFUGE)

BOULDERS

FIG

TYPICAL SECTION3

-

BOULDER CLUSTERS

NTS

FIG

TYPICAL DETAILC

4

BOULDER CLUSTERS

NTS

FLOW

FLOW

BACKWATER AREA

(VELOCITY REFUGE)

BACKWATER AREA

(VELOCITY REFUGE)

2

-

2

-

FIG

TYPICAL DETAILB

4

LWD/BOULDER COMPLEX

NTS

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W

COBBLES

LWD PLACEMENT DESIGNED TO COVER 20%

OF POOL SURFACE AREA

BOULDERS FOR ANCHORING LWD

COBBLES

F

L

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WEIR BOULDER GROUP

COBBLES

COBBLES AND

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SP

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FLOW

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BOULDERS ALONG PERIMETER

OF SPAWNING GRAVELS

WEIR BOULDER GROUP

(KEYED IN APPROPRIATELY)

1

-

1

-

LWL

FIG

TYPICAL SECTION5

-


NTS

5

-

5

-

FIG

TYPICAL DETAILE

4


NTS

LWD PLACEMENT DESIGNED TO COVER 20%

OF POOL SURFACE AREA

BOULDERS FOR ANCHORING LWD

COBBLES

MAIN

CHANNEL

MAIN

CHANNEL

FIG

TYPICAL SECTION1

-

ROCK RIFFLE / SPAWNING PLATFORM

NTS

6

-

6

-

FIG

TYPICAL CROSS-SECTION6

-

RIFFLE CREST

NTS

"V" SHAPED CREST

1

2

1

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AVANTI KITSAULT MINE LTD

KITSAULT PROJECT


HABITAT ENHANCEMENT DETAILS

VA101-343/9 VA11-01068

0FIGURE 5

NOTES:

1. LWD (LARGE WOODY DEBRIS) SHOULD RETAIN ROOTWADS AND LIMBS IF

POSSIBLE.

2. CABLING OF LWD MAY NOT BE REQUIRED IF THE STEMS CAN BE PINNED UNDER

BOULDER COMPLEXES.

3. ALL ON-SITE SWD (SMALL WOODY DEBRIS) IS TO BE INCORPORATED INTO THE

POOL OR CHANNEL MARGINS WHERE APPLICABLE. OVERSIZED OR UNDERSIZED

BOULDERS MAY ALSO BE INCORPORATED INTO THE CHANNEL DESIGN.

0 08JUL'11 ISSUED WITH LETTER AS NSD VM SRM A2-10 of 11

M:\1\01\00343\09\A\Data\Task 600 (Kitsault River Fish Comp)\Lake 901 Outlet Channel Habitat Enhancement\[Outlet Channel Flows.xls]901 Out hydrograph Print 10/08/2011 10:55 AM

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

January February March April May June July August September October November December

Dis

char

ge (m

3 /s)

Month

Baseline and Construction Phase 1 & 2

Construction Phase 3

Operations

Closure and Post-closure

NOTES:1. OUTFLOW VALUES FOR EACH PHASE OF THE MINE LIFE WERE BASED ON THE KP WATERSHED MODEL.2. OUTFLOWS ARE ESTIMATED ASSUMING THAT LAKE 901 INFLOW LOSSES ARE MITIGATED BY DIVERTING

FLOWS FROM NEIGHBOURING LAKE 493.

0 08JUL'11 ISSUED WITH LETTER AS VM SRMDATE DESCRIPTION PREP'D CHK'D APP'DREV

LAKE 901 OUTLET CHANNELMONTHLY HYDROGRAPH

FIGURE 6


KITSAULT PROJECT

REV0

P/A NO. VA101-343/09

REF. NO.VA11-01068

A2-11 of 11

101-343/13-1 Rev 0 March 30, 2012

APPENDIX A3

KITSUALT MINE PROJECT – KITSAULT RIVER SIDE CHANNELS

(Pages A3-1 to A3-11)

Suite 1400 - 750 West Pender Street Vancouver, BC Canada V6C 2T8 File No.:VA101-343/9-A.01 Cont. No.:VA11-00936 Tel: 604.685.0543 Fax: 604.685.0147 www.knightpiesold.com

July 5, 2011 Mr. Craig Nelsen President & CEO Avanti Kitsault Mine Ltd 880 - 580 Hornby Street Vancouver, BC V6C 3B6 Dear Craig, Re: Kitsault Mine Project – Kitsault River Side Channels Knight Piésold Ltd. (KPL) was tasked to further investigate the development of side channel options recommended by LGL Limited in 2007 (LGL, 2007). This letter presents the summary of considerations for fish compensation options for the Kitsault Mine on the Kitsault River. It discusses side channel enhancement opportunities for wild chum salmon stocks on the Kitsault River. Introduction Fisheries inventory data and chum salmon escapement trends illustrate that fall chum salmon stocks in the streams of Statistical Area 3 (including the Kitsault River) have remained depressed for many years. Marc Gaboury and Robert Bocking of LGL Limited undertook a preliminary site investigation on the Lower Kitsault River during the chum salmon spawning season of August 2006. To improve productivity, they proposed habitat enhancement and restoration of side channels to advance stable spawning habitat on the Kitsault River. In their report (LGL, 2007), they identified four possible locations for side channel improvement (Figure 1). Two of the proposed side channels, Channels 1 and 4, are located on the right river bank and are accessible by an existing road. Channels 2 and 3 are located on the left river bank and have no road access. A recent site reconnaissance visit (June 13-14, 2011) was undertaken by Marc Gaboury (LGL Limited), Brad Horne (AMEC), Shawn Ducharme (Nisga’ Fisheries), Craig Nistor (KPL), Sam Mottram (KPL) and Violeta Martin (KPL). The flow conditions on the Kitasult River were reasonably low with the spring freshet conditions already passed. Channels 2 and 3 were investigated from the air, while Channels 1 and 4 were investigated on foot. Channels 1, 2 and 3 were flowing at the time of the visit, while Channel 4 was dry, and based on vegetation it appeared that flows through this channel are infrequent and may have not occurred in several years. It was concluded that side channel restoration is viable for Channels 1 and 4, and not for Channels 2 and 3 due to the lack of road access (Figure 2). Road access to the side channels is necessary both during the construction phase and later for periodic inspections and maintenance. Side Channel Enhancement Proposed side channels 1 and 4 have potential to provide habitat diversity to accommodate the requirements of several fish species and life stages (Figures 3 and 4). The primary focus of restoration works at these two locations is spawning habitat improvement for chum salmon. However, it is also possible to incorporate restoration works on existing ponds and improve rearing and overwintering habitat for juvenile coho salmon as well. Based on the observations during the site reconnaissance visit in June 2011, it appeared that the flows and velocities in Channel 1 might be too low (Photos 1 and 2), while

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2 of 4 VA11-00936 July 5, 2011

flows were non-existent in Channel 4 (Photo 3). Flows in these channels can be increased by excavating deeper channels and promoting additional ground water inflow, while chum salmon spawning habitat can be improved by placing adequate gravel substrate. The existing rearing habitat for juvenile coho salmon (Photo 4) can be enhanced by providing good connectivity to side channels 1 and 4, culvert replacement where necessary and placement of large woody debris (LWD) for cover. The Lower Kitsault River is geomorphologically very active with braided sections and gravel bars shifting the thalweg position on an annual basis. For this reason, surface intake structures are not recommended. The bedload and suspended sediment load in the river are very high, and maintenance and operation of surface intakes and side channels fed by these intakes would require ongoing attention. Surface intake structures must be inspected and maintained regularly to remove accumulated debris (Slaney and Zaldokas, 1997). The ongoing maintenance is a challenging task in remote areas if stewardship groups or local contractors cannot be employed. This appears to be the case for the Lower Kitsault River, primarily due to the remoteness of this area and lack of connection by land transportation routes. Side channels located on the river floodplain, fed by groundwater and protected by berms from the river mainstem represent a much more practical option for the Lower Kitsault River. To ensure adequate flows in a groundwater fed channel, the invert of these channels needs to be excavated below the elevation of the river mainstem (typically 0.9 to 1.2 m below the lowest water table in the summer and approximately 1.5 m below the bed of the main river channel). Low longitudinal berms are constructed from the excavated material, which run parallel to the side channel, between the side channel and the river mainstem. The top berms that are located at the upstream end of side channels and run along the river mainstem have the highest exposure to direct flooding by the Kitsault River. The top berms are recommended to be protected by riprap and constructed to a higher elevation than the longitudinal berms. The top berms should be constructed of well graded material to prevent scour or clogging by fines, with construction materials sized to promote the passage of inflows from the river into the side channels through the berms. The side channel protection berms are designed for overtopping by moderate flood events (e.g. a flood with a 30 year return period or higher). This safe-fail philosophy for berm design is an approach that reduces floodplain impacts and flood protection costs, while minimizing the impacts on the river regime (Slaney and Zaldokas, 1997). Minor maintenance and repairs are usually required only after major flood events. The total channel lengths considered for restoration works are 1200 m and 750 m for side channel 1 and 4, respectively. The cross-section of a groundwater fed channel is typically trapezoidal with bank slopes of 1.5 horizontal to 1 vertical. The bottom width (typically 2 m to 5 m) and low channel slope (up to 1%) are selected such that a water depth of 0.25 m to 0.5 m (up to about 1 m) is achieved. In areas where spawning is expected, the banks should be protected by 0.2 m to 0.5 m sized riprap to prevent bank erosion. The gravel substrate for spawning should contain grain sizes between 1 and 10 cm with less than 10% fines (< 6 mm diameter). The area of spawning gravel patches should be at least 2.5 m2 in size. Existing off-channel ponds can be excavated deeper as necessary and connected to side channels to provide rearing and overwintering habitat for juveniles.

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4 of 4 VA11-00936 July 5, 2011

Attachments: Figure 1 Rev 0 Map 1 – Lower Kitsault River (from LGL 2007 report) Figure 2 Rev 0 Kitsault River – Channel Morphology Overview Figure 3 Rev 0 Kitsault River – Side Channel 1 Figure 4 Rev 0 Kitsault River – Side Channel 4 Figure 5 Rev 0 Side Channel and Berm Details Photo 1 Existing Side Channel 1 – upstream section Photo 2 Existing Side Channel 1 – middle section Photo 3 Side Channel 4 - not active Photo 4 Existing pond near Side Channel 4 for coho salmon rearing habitat Copy To: Shane Uren (Greenwood Environmental Inc.) and Brad Horne (AMEC Earth &

Environmental Limited) /vm

A3-4 of 11

rev date description designed drawn chk'd app'd figure … · 2012-05-10 · knight piésold ltd....

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