wood environment & infrastructure solutions...wood environment & infrastructure solutions a...

Wood Environment & Infrastructure Solutions a Division of Wood Canada Limited

3456 Opie Crescent

Prince George, BC, Canada, V2N 2P9

Office : (250) 564-3243

‘Wood’ is a trading name for John Wood Group PLC and its subsidiaries Wood Environment & Infrastructure Solutions, a Division of Wood Canada Limited Registered office: 2020 Winston Park Drive, Suite 700, Oakville, Ontario L6H 6X7 Registered in Canada No. 1115271-8; GST: 899879050 RT0008; DUNS: 25-362-6642

Memo

To: R. F. Binnie & Associates Ltd. Gordon Wagner, P.Eng., Lynx East CPE

From: Eric Mohlmann, P.Eng. Reviewer: Nick Polysou, P.Eng.

cc: Wood File No.: KX052807.11

Date: 17 December 2019

Re: Highway No. 29, Lynx Creek East, Preliminary Stability Assessment of Farrell Creek Road Slide and In-Stream Reservoir Shoreline Stability Berm

Introduction

As part of BC Hydro’s proposed Site C Clean Energy Project, portions of the existing Highway 29 alignment between Hudson’s Hope and Charlie Lake will be flooded during normal reservoir operations. Before filling of the reservoir, the affected portions of the highway will be relocated away from the reservoir area. In support of the project, Wood Environmental & Infrastructure Solutions, a Division of Wood Canada Limited (Wood), was retained by R. F. Binnie & Associates Ltd. (Binnie) to provide geotechnical engineering services for design of the relocated segments of highway.

The currently proposed 2.57 km long Lynx Creek East highway realignment segment is referenced as the L1000A21-Line (Binnie plan dated 15 July 2019). The Lynx Creek East segment will comprise a 2-lane paved highway which begins at approximately Sta. 1004+700 and extends in a north easterly direction generally north (left) of and parallel to the existing Highway 29 alignment to approximately Sta. 1006+350, where it will cross Highway 29. East of approximately Sta. 1006+350, the new alignment follows the left bank of the Peace River until it merges back into the existing Highway 29 alignment at approximately Sta. 1007+272. The existing section of Highway 29 beyond the eastern limit of the proposed highway realignment is tightly constrained between a large landslide feature known as the Farrell Creek Road Slide, which is located above and to the left of the highway, and a steep erosional slope down into the Peace River on the right. An in-stream stability berm for reservoir shoreline stability considerations is contemplated on the steep erosional slope below the highway.

This memo outlines a preliminary stability assessment on:

1. The effect of the reservoir on the Farrell Creek Road Slide;

2. The effect of the in-stream reservoir shoreline stability berm on the Farrell Creek Road Slide; and

3. The effect of the in-stream reservoir shoreline stability berm on the steep erosional slope below the highway.

Highway No. 29, Lynx Creek East Preliminary Stability Assessment of Farrell Creek Road Slide and In-Stream Reservoir Shoreline Stability Berm

Wood File # KX052807.11 | 17 December 2019 Page 2

The locations of the Lynx Creek East highway realignment segment and the Farrell Creek Road Slide are shown in Figure 1, attached. The estimated extents of the Farrell Creek Road Slide and proposed location of the in-stream shoreline stability berm are shown in Figure 2, attached. Oblique view aerial photographs of the proposed location for the in-stream reservoir shoreline stability berm are included in Photo Plates 1 and 2, attached.

Background Information A review of background information was carried out, including previous work by Wood, published bedrock geology maps and reports, and available reports prepared for the Site C Clean Energy Project by BGC Engineering Inc. (BGC).

2.1 Previous Work by Wood AMEC, a predecessor company to Wood, carried out a preliminary geotechnical assessment of the site in 2012 to support definition design of the Lynx Creek highway realignment segment (AMEC, 2012). The assessment provided a general overview of site terrain, ground conditions and geotechnical constraints, and included initial recommendations for use in developing various geometric highway realignment options.

To support design of the highway realignment, Wood carried out geotechnical investigations in 2018 and 2019. The bulk of the geotechnical investigation work was carried out in 2018 for the original definition design alignment; however, in January 2019, a significant alignment shift away from the definition design was proposed and subsequently a supplemental geotechnical investigation specific to the new alignment was carried out in 2019. Information from the investigations is presented in a geotechnical data report (Wood, 2019).

2.2 Bedrock Geology The following description of bedrock geology is summarized from Geological Survey of Canada Bulletin 328 (Stott, 1982).

The Farrell Creek Road Slide and surrounding area is underlain by gently northeast-dipping sedimentary beds of Cretaceous age. Mapping identifies the site as being near a contact between the overlying Shaftesbury Formation and the underlying Boulder Creek, Hulcross and Gates formations. Bedrock exposed in a gully (colloquially known as the amphitheater) on the left bank of the river across from Gates Island is identified as the Hulcross Formation overlying Gates Formation, and the Boulder Creek Formation is noted to be possibly exposed near the top of the gully.

The Boulder Creek Formation is described as consisting of fine grained, laminated sandstone with interbedded mudstone, and the formation is described as laying gradationally on the underlying marine shales and siltstones of the Hulcross Formation.

The Hulcross Formation is described as consisting of rubbly, silty, dark grey to black shale or mudstone. The silt content is noted to increase upward through the member with thin beds of argillaceous siltstone and sandstone occurring in the uppermost part of the member.

In the vicinity of Gates Island, the Gates Formation is described as consisting of massive, thick bedded, fine-grained, well-sorted sandstone that often forms overhanging cliffs.



2.3 Quaternary Geology Based on an interpretation of valley evolution upstream of Halfway River by BGC (2012), the site may be underlain by the following quaternary units:

1. Glacial Lake Peace (Interbedded Sand, Silt and Clay), over

2. Laurentide Till, over

3. Interbedded layers of valley infill sediments including glaciolacustrine deposits (e.g. Glacial Lake Mathews) and granular fluvial deposits.

Glacial Lake Peace and Laurentide Till are located on the plain above the Peace River Valley, and valley infill sediments are located within the Peace River Valley. Due to down cutting of the modern Peace River Valley, there may only be remnants of the valley infill sediments remaining within the Peace River Valley.

2.4 BGC Landslide Inventory As part of BGC’s reservoir impact study (BGC, 2012), BGC developed an inventory of landslides along the shores of the reservoir, including the Farrell Creek Road Slide. In the study BGC delineated the Farrell Creek Road Slide into six areas, and for each area provided information such as the basal failure surface elevation, basal failure surface material, and approximate age of the landslide.

The study identifies the Farrell Creek Road Slide area as having basal failure surfaces of between 605 and 645 m elevation (between 143 and 183 m above MNRL). Basal failure surface material is identified as either Glacial Lake Peace or Glacial Lake Mathews, and basal failure surfaces are not identified in bedrock.

BGC’s landslide inventory does not list any slides with basal failure surfaces in bedrock within a 2 km radius of the Farrell Creek Road Slide.

2.5 BGC Lidar Change Detection Analysis BGC carried out a topographic change detection analysis of LiDAR datasets collected in 2006 and 2015 (BGC, 2016). The analysis includes the Farrell Creek Road Slide and surrounding area. As described by BGC, the LiDAR change detection analysis involves comparing the 2006 and 2015 datasets to find regions of positive (deposition and bulging) and negative change (erosion and subsidence/slumping). BGC carried out a relatively coarse analysis of the reservoir area followed by a refined analysis of areas with potentially high consequences, including the Farrell Creek Road Slide and nearby area. As suggested by BGC’s drawings, the threshold for movement detection according to the refined analyses is on the order of 0.5 m. The refined change detection analysis indicated that localized ground movement has occurred within the Farrell Creek Road Slide, particularly along Farrell Creek Road where there is active localized land sliding; however, in general no large-scale trends of negative or positive change were detected within the overall Farrell Creek Road Slide area.

2018 and 2019 Site Investigations Geotechnical investigations to support design of the Lynx Creek East segment were carried out in 2018 and 2019. The investigations included boreholes and involved Cone Penetration Tests (CPT). The results of the investigations are presented in the geotechnical data report (Wood 2019). A summary of the investigations as they relate to the Farrell Creek Road Slide and in-stream reservoir shoreline stability berm is presented below.



3.1 Farrell Creek Road Slide At the Farrell Creek Road Slide, the investigation included:

1. 10 boreholes advanced in 2018;

2. Three CPTs advanced in 2018;

3. Four boreholes advanced in 2019;

4. Installation of 20 vibrating wire piezometers; and

5. Installation of 9 slope inclinometer casings.

3.2 In-Stream Reservoir Shoreline Stability Berm Along the edge of the Peace River and in the vicinity of the in-stream reservoir shoreline stability berm, the investigation included:

1. Three boreholes advanced in 2018.

Subsurface Conditions

4.1 Farrell Creek Road Slide

4.1.1 Quaternary Sediment and Bedrock Subsurface conditions encountered by boreholes advanced through the Farrell Creek Road Slide are variable, and a generalized description of soil conditions is provided below.

THS18-LX-002, which is located above the scarp of the slide and near the edge of the Peace River Valley, encountered a high plastic laminated clay and silt to 27.3 m depth (630.8 m elevation) over low plastic clay and silt with trace sand and trace gravel to 42.8 m depth (615.3 m elevation) over shale bedrock. The laminated clay and silt are interpreted to be a Glacial Lake Peace deposit, and the clay and silt with trace sand and trace gravel are interpreted to be a Laurentide Till deposit.

THS18-LX-001, 003, 004, 005, 008 and 009; CPT18-LX-025 to 027; and THS19-LX-301 to 304 were advanced through the slide mass. Soil conditions encountered at the boreholes were variable and generally consisted of fine-grained cohesive soil (low and high plasticity) with lenses of coarse-grained soils (particle sizes larger than 0.075 mm). Soil conditions are interpreted to be a landslide generated colluvium likely consisting of sediments from Glacial Lake Peace, Laurentide Till, and various valley infill deposits. A summary of the results of Atterberg Plasticity limits tests carried out on soil samples collected from the slide mass is included in Figure 4. The natural moisture content of the soil samples was typically above the plastic limit but below the liquid limit.

A steep slope with areas of exposed soil is located near the toe of the slide and above the highway; the slope is approximately 40 m high and 200 m long. An oblique view aerial photograph of the steep slope is included in Photo Plate 1. On 25 July 2019, personnel from Wood reviewed the slope and observed soil conditions in natural exposures and in shallow, hand-dug test pits. The upper part of the slope stood near vertical and generally consisted of a fine-grained soil with what appeared to be isolated coarse-grained particles (e.g. gravel and cobble-size particles). The deposit was on the order of 5 m thick and did not have observable structure. The deposit appeared to overlie another fine-grained soil deposit. The lower part of the slope was generally covered by a thin veneer of disturbed soil and bushes, and in some isolated areas soil exposures with sub-horizontal bedding were present. The individual exposures were variable in particle composition, dip and dip direction, and thickness of bed layers. At some exposures there were abrupt vertical contacts between different particle sizes



and structure. The variability and disjointed nature of the bedding in the lower part of the slope is consistent with a landslide-generated colluvium. The upper deposit of fine-grained soil is interpreted as being from a flow slide that occurred after the landslide.

TH18-LX-049, 052 and 055 were advanced along Highway 29. The boreholes encountered bedrock between 6.3 and 11.8 m depth (482.3 to 492.2 m elevation).

In general, bedrock encountered in all of the boreholes noted above consisted of shale interbedded with siltstone and mudstone (likely the Boulder Creek and Hulcross formations), and below approximately 450 m elevation bedrock was generally composed of sandstone (likely the Gates formation). Bedding observed in the bedrock drill core was typically near horizontal, consistent with bedrock geology for the area.

4.1.2 Groundwater Groundwater conditions in the slide area were observed using 20 vibrating wire piezometers. Four piezometers were installed within the quaternary sediment above bedrock, eight piezometers were installed at or up to 2 m above the bedrock surface, and eight piezometers were installed in bedrock.

Two of the four piezometers installed in the quaternary sediment encountered groundwater while the other two piezometers were dry. The phreatic surface measured by the piezometers in the sediment likely represents a localized perched groundwater table.

Of the eight piezometers installed at or near the bedrock surface, six were dry. The dry piezometers are located at higher elevations (piezometer tip between 537 and 617 m elevation), the piezometers that recorded groundwater pressure are located at lower elevations (piezometer tips at 498 and 503 m elevations).

Two piezometers were installed in bedrock in each of boreholes THS19-LX-301 to -304. The eight piezometers installed in the bedrock recorded groundwater pressures corresponding to a phreatic surface that generally parallels the buried bedrock surface. The phreatic surface is between 1.7 and 40.6 m below the bedrock surface.

4.1.3 Slope Inclinometer Readings Nine slope inclinometers were installed in the Farrell Creek Road slide area. The slope inclinometers were initialized shortly after installation, approximately 3 subsequent reading were taken. The current readings show slight movement (typically between 0 and 5 mm) in the quaternary sediments. No discernable movement has been observed within bedrock. The inclinometer reading are included in the geotechnical data report (Wood, 2019), and attached to this memo.

4.2 In-Stream Reservoir Shoreline Stability Berm

4.2.1 Sediment and Bedrock Due to access and environmental constraints, limited subsurface investigation was carried out in the vicinity of the proposed in-stream reservoir shoreline stability berm and on the adjacent steep erosional slope below Highway 29. TH18-LX-045, 047, and 050 located on the river shore and at the toe of the steep erosional slope encountered between 1.2 to 2.6 m of sediment over bedrock. Sediment was variable and included clay and silt to gravelly sand. Bedrock consisted of interbedded sandstone, siltstone and shale.

Oblique view aerial photographs were taken of the river shoreline and valley slope during spring 2019, and are included in Photo Plates 1 and 2. The photos show dark grey bedrock east of Sta. 1007+550 as being prominently exposed along the steep erosional slope and a relatively thin layer of soil present at the crest of the slope with a small apron of colluvium at the toe. West of Sta. 1007+550, the slope appears to consist of a thicker



layer of colluvium obscuring the underlying bedrock, and the thickness of colluvium appears to gradually increase to the west. During construction of the highway, excess cut material was likely dumped over the slope crest, over-steepening the colluvium slope. Significant depths of fill were also likely placed across an old drainage gully in the vicinity of Sta. 1007+300, as the highway was incrementally realigned at this location over the years. Areas of existing instability are present within these old fill and colluvium sections along the steep erosional slope adjacent the Peace River.

4.2.2 Groundwater Vibrating wire piezometers installed in boreholes TH18-LX-101 to -104 encountered phreatic pressures that appear to be consistent to the river elevation. It is anticipated that groundwater conditions at the in-stream reservoir shoreline stability berm will also be consistent with river or reservoir elevations.

To evaluate groundwater conditions along the steep erosion slope, oblique view aerial photographs were reviewed for surface expression of groundwater. The photos show a relatively uniform slope surface incised by shallow, linear, regularly spaced rills that extend from slope crest to toe. The rills are likely the result of surface flow, possibly from seasonal snow melt. An incised gulley is located below the outfall of a culvert near Sta. 1007+280. Surface expressions of groundwater were not observed on the photographs.

Stability Analyses To assess how the reservoir may impact the Farrell Creek Road Slide and the effectiveness of the in-stream reservoir shoreline stability berm, two-dimensional limit equilibrium slope stability analyses were carried out using the Slope/W by GeoStudio computer program (Geo-Slope, 2016). The analyses were carried out by maintaining consistent material shear strength parameters and assessing the relative changes in factors of safety under the influence of the reservoir and under rapid drawdown conditions. As such, the modelled factors of safety do not necessarily represent actual conditions but do provide a reasonable basis for comparing changes in stability conditions for different scenarios.

5.1 Geological Models Three geological models were developed for the preliminary analyses.

1. The Farrell Creek Road Slide model was developed to assess how the reservoir and in-stream reservoir shoreline stability berm may impact the slide. The model is based on a cross-section located at Sta. 1007+490 that extends from Peace River up to the top of the Peace River Valley. Ground surface geometry is based on LiDAR data collected in 2015. Subsurface stratigraphy and groundwater conditions are based on information collected from: THS-18-LX-002 to 004 and 009; TH18-LX-052; and THS19-LX-301 to 304.

2. The in-stream reservoir shoreline stability berm at Sta. 1007+490 model was developed to assess how the reservoir could impact the steep erosional slope (and consequently the toe of the Farrell Creek Road Slide) and the mitigating effect of the in-stream reservoir shoreline stability berm on the steep erosional slope. The model uses the same ground surface geometry, subsurface stratigraphy and groundwater conditions as those used in the Farrell Creek Road Slide model. Stability of the steep erosional slope is bedrock controlled.

3. The in-stream reservoir shoreline stability berm at Sta. 1007+316 model was developed to assess how the reservoir could impact the steep erosional slope in an area where the slope is not bedrock-controlled but consists of a thick layer of old fill and/or colluvium. The model also assesses the mitigating effect of the in-stream reservoir shoreline stability berm. Ground surface geometry is based on the 2015 LiDAR data, and subsurface stratigraphy is based on information collected from DH11-38.



The in-stream stability berm was modelled with a top elevation of approximately 466.8 m, a top width of 5 m, and a 2.5H:1.0V slope into the reservoir. Note that the top width of the berm varies by location but is never narrower than 5 m. The berm is located on a fill platform with a top elevation of approximately 446.8 m, the outside edge of the platform corresponds to a slope drawn down at 3H:1V from the top outside edge of the stability berm.

5.1.1 Material Parameters Material parameters used in the analyses were determined based on:

1. Observations made during the subsurface investigations;

2. Laboratory testing;

3. Correlations between soil index properties and soil strengths presented in published literature;

4. Slope stability model back analyses.

Bedrock strength was modelled by a Mohr-Coulomb failure envelope using friction angles and cohesive strengths that are equivalent to Hoek-Brown failure criteria using the Roclab computer program developed by Rocscience Inc. (Rocscience, 2007). Bedrock materials in the Peace region can be governed by near horizontal weak bedding planes and near vertical stress relief joints, and to account for these potential zones of weakness, zero cohesion was used +/- 10˚ from horizontal and +/- 20˚ from vertical.

Material strength parameters used in the models are summarized in Table 5-1 below.

Table 5-1: Material Strength Parameters used in Stability Analyses

Unit Name Unit Weight Shear Strength Model Parameters Colluvium

(Farrell Creek Road Slide) 17 kN/m3 Mohr-Coulomb

Φ = 11.7˚ (from back analysis)

Colluvium/Fill (Steep Erosional Slope)

17 kN/m3 Mohr-Coulomb Φ = 36.2˚

(from back analysis) Fluvial

(Peace River) 20 kN/m3 Mohr-Coulomb Φ = 29˚

Glacial Lake Peace 19 kN/m3 Mohr-Coulomb Φ = 25˚

c = 20 kPa

Laurentide Till 23 kN/m3 Mohr-Coulomb Φ = 35˚

c = 20 kPa Stability Berm 23 kN/m3 Mohr-Coulomb Φ = 38˚

Shale Bedrock 25 kN/m3 Mohr-Coulomb

(based on Hoek-Brown Criterion)

Φ = 36.1˚ c = 288 kPa (GSI = 58) (mi = 6) (D = 0.7)

c = 0 (+/- 10˚ horizontal) c = 0 (+/- 20˚ vertical)

Sandstone Bedrock 25 kN/m3 Mohr-Coulomb

(based on Hoek-Brown Criterion)

Φ = 56.5˚ c = 1,048 kPa

(GSI = 71) (mi = 17) (D = 0.7)

c = 0 (+/- 10˚ horizontal) c = 0 (+/- 20˚ vertical)



The strength parameters noted in Table 5-1 may be refined for future analyses. The strength parameters for Colluvium (Farrell Creek Road Slide) and Colluvium/Fill (Steep Erosional Slope) are based on model back analyses to a factor of safety of 1.1, and as such the modelled factors of safety do not necessarily represent actual conditions but do provide a reasonable basis for comparing changes in stability conditions for different scenarios.

5.1.2 Groundwater Conditions Groundwater conditions were modelled as a static groundwater surface based on phreatic pressures observed by the piezometers. Where piezometer data was not available, the groundwater surface was modelled approximately parallel to the valley slope.

The water level in the Peace River was assumed to be 445 m. The MNRL of 461.8 m results in a water level increase of 16.8 m. To simulate the influence of the reservoir impoundment, groundwater levels are assumed to increase to at least the MNRL and then slope upwards approximately parallel to the ground surface. However, as part of BGC’s reservoir impact study (BGC, 2012), BGC modeled groundwater flow and the influence of the reservoir impoundment and noted that “groundwater elevations currently greater than approximately 475 meters are generally not predicted to increase due to reservoir impoundment”, suggesting that the above noted methodology may be conservative for changes to the groundwater table above 475 m elevation.

Groundwater elevations used in the stability model to simulate the influence of the reservoir impoundment are summarized in Table 5-2 below. Note that groundwater elevations are maximum levels assumed under the influence of the reservoir impoundment at MNRL. Individual piezometers located in the boreholes may be located above the maximum groundwater elevations noted in Table 5-2.

Table 5-2: Maximum Groundwater Elevations Assumed at MNRL

Location Boreholes Corresponding Maximum Groundwater Elevation (m) THS18-LX-002 595.5 m THS19-LX-301 582.5 m THS18-LX-003 564.0 m THS19-LX-302 555.0 m THS18-LX-009 548.5 m THS19-LX-303 518.5 m THS18-LX-004 497.5 m THS19-LX-304 487.5 m TH18-LX-052 473.5 m

A rapid drawdown scenario was modelled assuming that the groundwater table within the slope remains consistent with reservoir impoundment conditions; however, the water level within the reservoir is modelled at 445 m elevation. It is assumed that the in-stream shoreline reservoir stability berm is free draining and that the groundwater table within the berm will drop with the water level in the reservoir. It is assumed that the bedrock (Shale and Sandstone) and both colluvium units would remain undrained during a rapid drawdown scenario.



5.1.3 Farrell Creek Road Slide The Farrell Creek Road Slide was modelled as a continuous slide mass that extends across the majority of the length of the Peace Valley slope; however, the slide likely consists of at least two individual but overlapping masses that are likely delineated by the approximate location of the current Farrell Creek Road. The results of the analyses of the Farrell Creek Road Slide are presented in Figures 5 to 9 and summarized in Table 5-3 below.

Table 5-3: Summary of Stability Results for the Farrell Creek Road Slide Scenario Factor of Safety

Current Conditions (Back Analysis) 1.10 Reservoir Inundation (MNRL) 1.09

MNRL Rapid Drawdown 1.09 MNRL with In-Stream Reservoir Shoreline Stability Berm 1.09

MNRL Rapid Drawdown with In-Stream Reservoir Shoreline Stability Berm 1.09

The stability analyses indicate:

1. The Farrell Creek Road Slide slip surface is likely located within quaternary sediments above the bedrock contact;

2. If groundwater levels at the toe of the slide were to increase on the order of 4 m, the factor of safety would decrease by approximately 1%; however, the likely slip surface is at an elevation where groundwater levels are unlikely to change due to reservoir impoundment;

3. Rapid drawdown of the reservoir does not have a significant direct impact on the stability of the slide;

4. The in-stream reservoir shoreline stability berm does not have a direct mitigating effect on the stability of the slide during MNRL or during rapid drawdown of the reservoir.

5.1.4 In-Stream Reservoir Shoreline Stability Berm (Sta. 1007+490) The in-stream reservoir shoreline stability berm was modelled at the toe of the Farrell Creek Road Slide. The model was used to assess how the reservoir and in-stream reservoir shoreline stability berm may impact the stability of the bedrock-controlled steep erosional slope below the existing Highway 29 location and toe of the Farrell Creek Road Slide, which left unmitigated could indirectly reduce the stability of the Farrell Creek Road Slide. The results of the analyses are presented in Figures 10 to 15 and summarized in Table 5-4 below.

Table 5-4: Summary of Stability Results for In-Stream Reservoir Shoreline Stability Berm (Sta. 1007+490) Scenario Factor of Safety

Current Conditions 1.78 MNRL 1.70

MNRL Rapid Drawdown 1.64 MNRL with In-Stream Reservoir Shoreline Stability Berm 1.78

MNRL Rapid Drawdown with In-Stream Reservoir Shoreline Stability Berm 1.75 MNRL Rapid Drawdown with 3H:1V In-Stream Reservoir Shoreline Stability Berm 1.82

The stability analyses indicate:

1. Reservoir impoundment will reduce stability of the steep erosional bedrock slope below the Farrell Creek Road slide by approximately 4% from current conditions;

2. The in-stream reservoir shoreline stability berm (at its current proposed configuration) will generally counteract the destabilizing effect of the reservoir;

3. Rapid drawdown of the reservoir could reduce the factor of safety of the bedrock slope by 8% without the in-stream reservoir shoreline stability berm and by 2% with the berm;



4. An additional analysis was carried out for the rapid drawdown scenario using a stability berm configuration with a top width of 5 m and a 3H:1.0V slope into the reservoir (Figure 15), the results indicate that this berm configuration will result in a factor of safety that exceeds the factor of safety of current conditions by approximately 2%.

5.1.5 In-Stream Reservoir Shoreline Stability Berm (Sta. 1007+316) The in-stream reservoir shoreline stability berm was modelled in an area where the steep erosion slope consists of a thick layer of old fill and/or colluvium. These slope materials will be more sensitive to reservoir inundation and rapid drawdown than the bedrock noted in Section 5.1.4. The results of the analyses are presented in Figures 16 to 22 and summarized in Table 5-5 below.

Table 5-5: Summary of Stability Results for In-Stream Reservoir Shoreline Stability Berm (Sta. 1007+316) Scenario Factor of Safety

Current Conditions (Back Analysis) 1.10 MNRL 1.04

MNRL Rapid Drawdown <1.00 (affects road prism) MNRL with In-Stream Shoreline Stability Berm

(upper/shallow portion of slope not influenced by reservoir) 1.17

MNRL with In-Stream Shoreline Stability Berm (Global) 1.48 MNRL with In-Stream Shoreline Stability Berm Rapid Drawdown

(upper/shallow portion of slope not influenced by reservoir) 1.17

MNRL with In-Stream Shoreline Stability Berm Rapid Drawdown (Global) 1.58

The stability analyses indicated:

1. The existing fill/colluvium slope is currently unstable to marginally stable, depending on location;

2. Reservoir impoundment will have a destabilizing effect on the slope;

3. Rapid drawdown of the reservoir will result in a calculated factor of safety of less than 1.0 for the slope below the highway;

4. The in-stream shoreline stability berm will mitigate the destabilizing effects of a rapid drawdown event, providing a stability condition (factor of safety) for a global failure scenario that is greater than exists currently;

5. Note that stability of the upper/shallow portion of the slope not influenced by the reservoir will remain the same and will not be mitigated by the in-stream shoreline stability berm.

Discussion

6.1 Farrell Creek Road Slide The slip surface for the Farrell Creek Road Slide is likely limited to within the quaternary sediments above the underlying bedrock surface. This is supported by the lack of existing slides with bedrock slip surfaces in the surrounding area, the undisturbed nature of the bedrock bedding observed in the drill core, and a lack of movement observed in slope inclinometer casings where the casing is located in bedrock. The bedrock surface could be considered the lower-bound limit of the slip surface. The lowest elevation of the bedrock surface encountered during the 2018 and 2019 subsurface investigations is 481 m elevation, at least 19 m above the MNRL. In BGC’s reservoir impact study (BGC, 2012), BGC noted that “groundwater elevations currently greater than approximately 475 meters are generally not predicted to increase due to the reservoir impoundment”, suggesting that the reservoir impoundment is unlikely to affect groundwater conditions at a potential slip surface at 481 m elevation. The stability analyses described in this memo account for an approximately 4 m



increase in groundwater elevation at the toe of the slide due to reservoir impoundment, and the corresponding decrease in factor of safety is approximately 1%. Considering the information contained in BGC’s reservoir impact study and the stability analyses of the Farrell Creek Road Slide included in this memo, it is unlikely that reservoir impoundment will adversely impact the stability of the Farrell Creek Road Slide.

The in-steam shoreline stability berm located below the slip surface of the Farrell Creek Road Slide will have little direct mitigating influence on the stability of the slide; however, the in-stream shoreline stability berm will benefit the stability of the slope below the toe of the slide as discussed below.

6.2 In-Stream Shoreline Stability Berm (Sta. 1007+490) The in-stream shoreline stability berm will have little if any direct mitigating effect on the stability of the Farrell Creek Road Slide. However, the berm will have a direct beneficial effect on the stability of the steep erosional slope below the existing Highway 29 location, which if left unprotected could result in eventual failure and retrogressive loss of support for the highway and the adjacent toe of the Farrell Creek Road Slide. The analyses for the erosional slope below the slide assume that the slope is bedrock-controlled (e.g. stability of the slope is largely dependent on the shear strength of the underlying bedrock). During reservoir inundation and reservoir rapid drawdown, stability of the steep erosional bedrock slope will be reduced. The analyses indicate that the effect of the current configuration of the in-stream shoreline stability berm is insufficient to result in no net reduction in stability between the current conditions (FoS = 1.78) and the controlling post-reservoir rapid drawdown scenario (FoS = 1.75). Given the relatively high post-reservoir rapid drawdown factor of safety achieved it is considered that at this location the in-stream shoreline stability berm in its current configuration provides sufficient global stability, and the berm will protect the slope from retrogressive erosion, rather than achieve a no net reduction in stability between current conditions and the rapid drawdown scenario. To achieve a no net reduction in stability between current conditions and the rapid drawdown scenario, the slope of the berm would need to be flatter and on the order of 3H:1V and would fall within the footprint of the currently planned platform.

6.3 In-Stream Shoreline Stability Berm (Sta. 1007+316) The in-stream shoreline stability berm was also modelled where the steep erosional slope consists of a thick layer of old fill and/or colluvium. The slope is currently marginally stable, and in some areas there is existing instability. The preliminary analyses described in this memo indicate that the calculated factor of safety of the existing slope will be less than 1.0 during rapid drawdown. The in-stream shoreline stability berm, as currently modeled, provides a buttressing effect to the lower portion of the slope and mitigates the destabilizing effect of the reservoir. However, the in-stream shoreline stability berm does not mitigate instability of the upper/shallow portion of the slope not influenced by the reservoir.

Based on the current level of analyses, the current configuration of the in-stream shoreline stability berm is sufficient to maintain a factor of safety greater than exists currently, with the global factor of safety of the slope during rapid drawdown on the order of 1.58. Although the calculated factor of safety is approximate, it is supported by parameters derived from back analyses of current conditions, field investigation, lab testing and instrumentation. The factor of safety is also reliant on the in-stream shoreline stability berm that is assumed to be constructed on high shear strength material (e.g. bedrock or gravel and sand), which will have to be confirmed during future phases of assessment once the lower platform portion of the berm is constructed.



References AMEC Environment & Infrastructure (05 March 2012). Report Preliminary Geotechnical Assessment, Proposed Lynx Creek Segment, Highway 29 Definition Design, Site C Clean Energy Project. Submitted to R.F. Binnie & Associates Ltd.

BGC Engineering Inc. (30 November 2012). Report Site C Clean Energy Project, Preliminary Reservoir Impact Lines. Submitted to BC Hydro.

BGC Engineering Inc. (15 August 2016). Project Memorandum Site C Airborne LiDAR Scanning Detection Analysis – FINAL. Submitted to BC Hydro.

GEO-SLOPE International Ltd., Computer Program, GeoStudio 2016, version 8.16.5.15361

Rocscience Inc., Computer Program, RocLab (2007), version 1.031

Stott, D.F. (1982). Lower Cretaceous Fort St. John Group and Upper Cretaceous Dunvegan Formation of the Foothills and Plains of Alberta, British Columbia, District of Mackenzie and Yukon Territory. Geological Survey of Canada, Bulletin 328.

Wood Environment and Infrastructure Solutions (15 August 2019). Geotechnical Data Report, Lynx Creek East Segment. Submitted to R.F. Binnie & Associates Ltd.

Aerial Photography

BC Government Crown Registry and Geographic Base Branch

1945 A8149: 17-19

1953 BC1769: 109-111

1955 BC2143: 34-36

1964 BC5116: 246-247, BC5117: 054-055

1970 BC7277: 158-159, 243-247

1975 BC7783: 027-028

1976 BC7873: 066-067

1981 BC81011: 177-179, 241-242

1989 BC89061: 28-31

1996 BCB96024: 141-142

2006 BCC06070: 107-109

L1000A21Design

Alignment

Hwy 29

P e a c eR i v e r

L y n x

C r e e k

D r yC r e e k

F a r r e l l

Cre

ek

LynxCreekWest

LynxCreekEast

Farrell CreekRoad Slide

Extents

Notes:1. L1000A21 centreline alignment provided by R.F. Binnie & Associates CAD file 'Lynx Creek L1000A21.dwg', received 15 July 2019.2. Image provided by Bing Maps Road - © 2019 Microsoft Corporation © 2018 HERE

LegendL1000A21 Centreline Alignment

Farrell Creek Road Slide Extents

Borrow Investigation Area

!(

!(

!(

!(

!(

_̂

VancouverKamloops

ChetwyndFort St John

PrinceGeorge

ProjectLocation

This drawing was originally produced in colour.

CLIENT:

\\Prg-fs1\cad\Internal\KX052807-GIS\1-LynxCreek\LCE-PrelimStabAssess-Fig1-SiteLocPlan.mxd

SCALE:

PROJECTION:

DATUM:

CHK'D BY:

DWN BY: TITLE:

PROJECT:REV NO.:

PROJECT NO.:

DATE:

HIGHWAY NO. 29LYNX CREEK EAST

PRELIMINARY STABILITY ASSESSMENTOF FARRELL CREEK ROAD SLIDE AND

IN-STREAM STABILITY BERMUTM Zone 10

NAD 83

EM

BBSITE LOCATION PLAN

A

FIGURE 1

KX052807.11

OCTOBER 2019

$

1:150,000

0 2 4 6 81km

3456 Opie CrescentPrince George, BC, CANADA V2N 2P9Tel. (250) 564-3243 Fax (250) 562-7045

WoodEnvironment & Infrastructure Solutions

a Division of Wood Canada Limited (Wood)

BC HYDRO c/o R.F. BINNIE &ASSOCIATES LTD.

DRAFT


a Division of Wood Canada Limited (Wood)Wood Environment & Infrastructure Solutions

1007+000

1007+200

1007+4001007+600

F

F

!A

!A

!A

!A

!A

!A

!A !A!A

!A

!A!A

!A

!A

!A

!A!A

!A

!A

!A

!A!A

!A

!A

!A

!A!A

!A!A

!A

!A

!A

!A

!A

!A

!A

#*

#*

#*

")

!A!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

!A

")

!A

!A!A

!A

!A

!A

!A

")

Farrell Creek Road

Highway 29

P e a c e R i v e r

CrossSectionLocation

1007+490

CrossSectionLocation

1007+490 Approximate Locationof In-StreamStability Berm

Farrell CreekRoad Slide

Extents

TP19-LX-229

THS19-LX-301

THS19-LX-302

THS19-LX-303

THS19-LX-304

59598

80257

DH-56

TP05-01

TP05-02

TP05-03 BH06-01

BH06-01ABH06-02

BH06-03BH06-04

BH06-05

BH06-06

BH06-07

TP06-01TP06-02

TP06-03

TH03-01

PV05-01

TH96-01

TH96-02TP96-01

TP96-03

TH81-24

TH80-02TH80-03

TH80-04 TH80-05

DH11-36

DH11-38

DH11-40

DH11-49

TH18-LX-041

TH18-LX-044

TH18-LX-045

TH18-LX-047

TH18-LX-049

TH18-LX-050

TH18-LX-052

TH18-LX-055TH18-LX-056

TH18-LX-105

THS18-LX-001

THS18-LX-002

THS18-LX-003

THS18-LX-004

THS18-LX-005

THS18-LX-008

THS18-LX-009

TPH18-LX-052

TPH18-LX-053 TPH18-LX-054

CPT18-LX-025

CPT18-LX-026

CPT18-LX-027

TP18-LX-055 PV18-LX-037

PROJECTION:

DATUM:

CHK'D BY:

DWN BY:


CLIENT: DATE:

KX052807.11

OCTOBER 2019

A

SITE PLAN WITH LIDAR HILLSHADE

HIGHWAY NO. 29LYNX CREEK EAST

PRELIMINARY STABILITY ASSESSMENTOF FARRELL CREEK ROAD SLIDE AND

IN-STREAM STABILITY BERM FIGURE 2

TITLE:

PROJECT:

UTM Zone 10

NAD 83

EM

BBPROJECT NO.:

REV NO.:

1:5,000\\Prg-fs1\cad\Internal\KX052807-GIS\1-LynxCreek\LCE-PrelimStabAssess-Fig2-SitePlan-LIDAR-HS.mxd

SCALE:

0 100 200 300 40050m

Notes:1. L1000A21 centreline alignment and slope stake lines provided by R.F. Binnie & Associates CAD file 'Lynx Creek L1000A21.dwg', received 15 July 2019.2. Maximum Normal Reservoir Level (461.8 m) downloaded from BC Hydro SharePoint 11 April 2018.3. Hillshade imagery processed from LIDAR provided by BC Hydro 9 January 2018.

BC HYDRO c/o R.F. BINNIE & ASSOCIATES LTD.Legend

!A 2019 Alignment Test Hole Location

") 2019 Alignment Test Pit Location

#* 2019 Alignment CPT Location

!A 2018 Alignment Test Hole Location") 2018 Alignment Test Pit Location#* 2018 CPT Location") 2018 Pavement Core Location!A Historical Drillhole Location

L1000A21 Centreline AlignmentL1000A21 Slope Stake LineMaximum Normal Reservoir Level(461.8 m)Farrell Creek Road Slide ExtentsApproximate Location of In-StreamStability Berm

IN-PROGRESS

$

500

600

100

Ele

va

tio

n (m

)

Offset (m)

0-100-200-300-400-500-600-700-800

500

600

Ele

va

tio

n (m

)

700 700

400 400

Highway

29

Farrell

Creek

Road

P e a c e R i v e r

MNRL

Glacial Lake Peace

Laurentide Till

Colluvium

Colluvium

Shale Bedrock

Sandstone Bedrock

Colluvium

Colluvium/Fill

Fluvial

Proposed Stability Berm

(7/8/2019)

(7/8/2019)

(7/8/2019)(7/8/2019)

(7/12/2019)

(7/12/2019)

(7/8/2019)

(7/8/2019)(7/8/2019)

(7/8/2019)

(7/8/2019)

VWP

VWP

VWP

VWP

VWP

VWP

VWP

VWP

VWP

VWP

VWP

CL

CLGP-GM

BR

END

THS19-LX-301

TSCL CH

GP

BR

END

THS19-LX-302

CLCH

CL

CLML

BR

END

THS19-LX-303

CL

MLCL

ML

BR

BR

END

THS19-LX-304

ASPHFI

ML

BR

END

TH18-LX-052

CHCL

CH

CL

BR

ENDCH

CL

BR

END

THS18-LX-003

TSML

CL

CHCL

BR

END

THS18-LX-004TSCLCH

BR

END

THS18-LX-009

THS18-LX-002

SM2

GC1GM1

SM2-MHGM3

SM3SM2

SM3

SM3

SM4

GM3

N/A

PROJECTION:

N/A

DATUM:

CROSS SECTION

1007+490

PROJECT:

TITLE:

REV. NO.:

PROJECT NO.:

KX052807.11

A

CLIENT:

DWN BY:

CHK'D BY:

OCTOBER 2019

DATE:

SCALE:

EM

1:3 000

BB

HIGHWAY NO. 29

LYNX CREEK EAST

PRELIMINARY STABILITY ASSESSMENT OF FARRELL CREEK ROAD

SLIDE AND IN-STREAM STABILITY BERM


FIGURE 3

Wood Environment & Infrastructure Solutions

a Division of Wood Canada Limited (Wood)


BC HYDRO c/o R.F. BINNIE & ASSOCIATES LTD.

IN-PROGRESS

0m 30 60 90 120

Notes:

1. SPT N values and associated laboratory testing data provided with the Sticklogs may not be presented

at representative elevations. Please refer to Appendix B – Investigation Logs for additional details.

2. L1000A21 centreline alignment and existing ground surface provided by R.F. Binnie & Associates Ltd.

CAD file 'ACAD-20190720-Lynx Creek East L1000A21 Sections.dwg', received 22 July 2019.

3. Not all instrumentation, groundwater levels, and slope inclinometer movement levels shown.

4. Additional existing surface (approximate) processed from LIDAR provided by BC Hydro 9 January 2018.

Legend

Typical Cross Section Based on

L1000A21 Centreline Alignment

Existing Ground Surface

1 : 3000

Phreatic Surface

Maximum Normal Reservoir Level

(461.8 m)

EM October 2019

NP KX052807.11

N/A A

N/A

AS SHOWN

SUMMARY OF ATTERBERG PLASTICITY RESULTS

HIGHWAY NO. 29, LYNX CREEK EAST

PRELIMINARY STABILITY ASSESSMENT OF FARRELL

CREEK ROAD SLIDE AND IN-STREAM STABILITY

BERMFIGURE 4

B.C. Ministry of Transportation and Infrastructure

Wood Environment & Infrastructure Solutionsa Division of Wood Canada Limited (Wood)

3456 Opie Crescent

Prince George, BC, Canada V2N 2P9

0

5

10

15

20

25

30

35

40

45

50

0 10 20 30 40 50 60 70 80

Pla

stic

ity

Ind

ex (

%)

Liquid Limit (%)

THS19-LX-301 THS18-LX-003 THS19-LX-302 THS18-LX-009 THS19-LX-303 THS18-LX-004 THS19-LX-304

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

TITLE

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

CH or OH

MH or OH

CL or OL

CL-MLML or OL

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN

SLOPE STABILITY ANALYSES

FARRELL CREEK ROAD SLIDE

CURRENT CONDITIONS (BACK ANALYSIS)

HIGHAY No. 29, LYNX CREEK EAST


CREEK ROAD SLIDE AND IN-STREAM STABILITY BERM FIGURE 5

BC MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE


3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



RESERVOIR INUNDATION (MNRL)






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



MNRL RAPID DRAWDOWN






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



MNRL WITH IN-STREAM STABILITY BERM






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



MNRL RAPID DRAWDOWN WITH IN-STREAM BERM



CREEK ROAD SLIDE AND IN-STREM STABILITY BERM FIGURE 9



3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN


IN-STREAM STABILITY BERM (STA. 1007+490)

CURRENT CONDITIONS






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN









3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



MNRL RAPID DRAWDOWN






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



MNRL WITH IN-STREAM STABILITY BERM






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN









3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



MNRL RAPID DRAWDOWN WITH 3H:1V IN-STREAM

BERM






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



CURRENT CONDITIONS (BACK ANALYSIS)






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN









3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



MNRL RAPID DRAWDOWN






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



MNRL WITH IN-STREAM STABILITY BERM (UPPER)






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



MNRL WITH INSTREAM STABILITY BERM (GLOBAL)






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN









3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM November 2019

NP KX052807.11

N/A A

N/A

AS SHOWN



MNRL RAPID DRAWDOWN WITH BERM (GLOBAL)






3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

FIGURE NO:

CHK'D BY:

TITLE

EM October 2019

NP KX052807.11

N/A A

N/A

AS SHOWN

OLIQUE VIEW AERIAL PHOTOGRAPH




CREEK ROAD SLIDE AND IN-STREAM STABILITY BERM Photo 1



3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

Photo Plate:

CHK'D BY:

TITLE

EM October 2019

NP KX052807.11

N/A A

N/A

AS SHOWN

OLIQUE VIEW AERIAL PHOTOGRAPH




CREEK ROAD SLIDE AND IN-STREAM STABILITY BERM Photo 2



3456 Opie Crescent


Tel. (250) 564-3243 Fax (250) 562-7045

CLIENT DWN BY:

CHK'D BY:

PROJECTION:

DATUM:

SCALE:

PROJECT

DATE:

PROJECT NO:

REV. NO.:

Photo Plate:

CHK'D BY:

TITLE

Profile Change

Initial Reading: 9/1/2018

Correction Bias

TH18-LX-049Highway No.29 Lynx Creek East

A-Axis

11/7/2018 4/5/2019 5/22/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

mm

-10 0 10

AB-Axis

11/7/2018 4/5/2019 5/22/2019 Fill

CL-ML SM2 ML Shale

Depth

in M

ete

rs

440

445

450

455

460

465

470

475

480

485

490

mm

-10 0 10

B-Axis

11/7/2018 4/5/2019 5/22/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

mm

-10 0 10

Profile Change


Correction Bias

TH18-LX-052Highway No.29 Lynx Creek East

A-Axis

11/7/2018 4/5/2019 5/22/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

mm

-10 0 10

AB-Axis

11/7/2018 4/5/2019 5/22/2019 Asphault

Fill ML Shale

Depth

in M

ete

rs

440

445

450

455

460

465

470

475

480

485

490

495

mm

-10 0 10

B-Axis

11/7/2018 4/5/2019 5/22/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

mm

-10 0 10

Profile Change


Correction Bias

THS18-LX-001Highway No.29 Lynx Creek East

A-Axis

11/8/2018 4/6/2019 5/22/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

mm

-10 0 10

AB-Axis

11/8/2018 4/6/2019 5/22/2019

ML CL Shale

Depth

in M

ete

rs

565

570

575

580

585

590

595

600

605

610

615

mm

-10 0 10

B-Axis

11/8/2018 4/6/2019 5/22/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

mm

-10 0 10

Profile Change


Stick up: -0.6 m with 1.37 m extension

Correction Bias


A-Axis

9/29/2018 11/6/2018

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

mm

-10 0 10

AB-Axis

9/29/2018 11/6/2018 CH CL

CH CL Shale

Depth

in M

ete

rs

595

600

605

610

615

620

625

630

635

640

645

650

655

mm

-10 0 10

B-Axis

9/29/2018 11/6/2018

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

mm

-10 0 10

Profile Change


Stick up: -0.6 m with 1.0 m extension

Correction Bias


A-Axis

4/25/2019 5/13/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

mm

-10 0 10

AB-Axis

4/25/2019 5/13/2019 CH CL

CH CL Shale

Depth

in M

ete

rs

595

600

605

610

615

620

625

630

635

640

645

650

655

mm

-10 0 10

B-Axis

4/25/2019 5/13/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

mm

-10 0 10

Profile Change


Correction Bias


A-Axis

11/7/2018 4/6/2019 5/13/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

mm

-10 0 10

AB-Axis

11/7/2018 4/6/2019 5/13/2019

CH ML Shale

Depth

in M

ete

rs

515

520

525

530

535

540

545

550

555

560

565

570

575

580

585

mm

-10 0 10

B-Axis

11/7/2018 4/6/2019 5/13/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

mm

-10 0 10

Profile Change


Correction Bias


A-Axis

9/29/2018 11/7/2018 4/6/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

mm

-10 0 10

AB-Axis

9/29/2018 11/7/2018 4/6/2019 TS ML-SM2

CL CH CL Shale

Depth

in M

ete

rs

465

470

475

480

485

490

495

500

505

510

515

520

525

530

535

mm

-10 0 10

B-Axis

9/29/2018 11/7/2018 4/6/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

mm

-10 0 10

Profile Change


Correction Bias


A-Axis

4/25/2019 5/14/2019 7/11/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

mm

-10 0 10

AB-Axis

4/25/2019 5/14/2019 7/11/2019 Fill

ML/SM2 CL ML-CL SM3

CL-ML SM4-SM3 GW Shale

Depth

in M

ete

rs

485

490

495

500

505

510

515

520

525

530

535

540

545

550

mm

-10 0 10

B-Axis

4/25/2019 5/14/2019 7/11/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

mm

-10 0 10

Profile Change


Correction Bias


A-Axis

11/8/2018 4/5/2019 5/22/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

mm

-10 0 10

AB-Axis

11/8/2018 4/5/2019 5/22/2019 TS CH

CL SC3 GC1 CL Shale

Depth

in M

ete

rs

470

475

480

485

490

495

500

505

510

515

mm

-10 0 10

B-Axis

11/8/2018 4/5/2019 5/22/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

mm

-10 0 10

Profile Change


Correction Bias


A-Axis

4/25/2019 5/15/2019 7/11/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

mm

-10 0 10

AB-Axis

4/25/2019 5/15/2019 7/11/2019 CL

CH ML GM3 Shale

Depth

in M

ete

rs

495

500

505

510

515

520

525

530

535

540

545

550

555

560

mm

-10 0 10

B-Axis

4/25/2019 5/15/2019 7/11/2019

Depth

in M

ete

rs

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

mm

-10 0 10

wood environment & infrastructure solutions...wood environment & infrastructure solutions a...

Documents