TERRAIN STABILITY ASSESSMENT SOIL EROSION ASSESSMENT. Proposed Perry Ridge North (PN) Forest Roads: Mainline Extension; 11000; 11030; and 11040

Transcription

1 TERRAIN STABILITY ASSESSMENT SOIL EROSION ASSESSMENT Proposed Perry Ridge North (PN) Forest Roads: Mainline Extension; 11000; 11030; and Selkirk Forest District Prepared for: British Columbia Timber Sales Arrow Field Unit Prepared by: Sitkum Consulting Ltd. Project No April 2013

2 Table of Contents 1.0 INTRODUCTION METHODOLOGY Office Review Field Review Limitations OBSERVATIONS and INTERPRETATIONS General Physiography Site Location - General Terrain Stability General PN Mainline Extension Down Slope Description PN Mainline Extension Landslide Partial Risk Analysis PN Mainline Extension PN PN 11000, Section 1: POC to Hub 105 ( ) Down Slope Description - PN Section 1: POC to Hub 105 ( ) Landslide Partial Risk Analysis PN Section 1: POC to Hub 105 ( ) PN 11000, Section 2: Hub 105 ( ) to Hub 214 (3+998) POT Down Slope Description - PN Section 2: Hub 105 ( ) to Hub 214 (3+998) POT Landslide Partial Risk Analysis PN Section 2: Hub 105 ( ) to Hub 214 (3+998) POT PN Down Slope Description PN Landslide Partial Risk Analysis PN PN Down Slope Description - PN Landslide Partial Risk Analysis PN Cumulative Effects of Forest Development Soil Erosion Considerations RECOMMENDATIONS General Recommendations Erosion and Sediment Control Recommendations Maintenance and Deactivation Recommendations Site Specific Recommendations FIELD REVIEWS CLOSURE REFERENCES List of Appendices A - Photos B - Construction Summary Tables C - Risk Analysis, Soil Erosion Hazard, and Soil Definitions D - Figures List of Figures 1 Location Map (1:100, 000 scale) 2 Overview Map (1:20,000 scale) 3 PN Mainline Extension, Hub 42 (POC) to Hub 130 (1:5000 scale) 4 PN Mainline Extension, Hub 130 to POT; PN 11000, Hub 1 (POC) to Hub 115 (1:5000 scale) 5 PN (Hub 115 to POT); PN 11030, PN (1:5000 scale) 6 Perry Ridge Road Traverse Map

3 April 8, 2013 Sitkum File No: British Columbia Timber Sales Arrow Field Unit 845 Columbia Ave. Castlegar, B.C., V1N 1H3 Attention: Cc: Subject: Mr. Todd Phillips, R.F.T. Engineering Technician Mr. Phil MacDonald, R.F.T. Engineering Specialist Terrain Stability Assessment and Soil Erosion Assessment Proposed Perry Ridge North (PN) Forest Roads Mainline Extension, 11000, 11030, Selkirk Forest District 1.0 INTRODUCTION At the request of Mr. Todd Phillips, R.F.T., of British Columbia Timber Sales, Arrow Field Unit (BCTS), Sitkum Consulting Ltd. (SCL) has carried out a Terrain Stability Assessment (TSA) and Soil Erosion Assessment (SEA) for the proposed construction of the Perry Ridge North (PN) forest roads PN Mainline extension, PN 11000, PN 11030, and PN The proposed road construction is situated on the northwest side of Perry Ridge in south eastern B.C., approximately 40 km north of Castlegar, B.C. (refer to Figure 1). Access is via the existing Perry Ridge North Forest Service Road (PN FSR). The TSA was requested by BCTS based on the BCTS Terrain Stability Management Model protocols for managing terrain stability in a gentle-over-steep (GoS) scenario. The scope of the work, as requested by BCTS, is: to identify potential terrain stability concerns associated with the proposed forest road construction; to evaluate the potential spatial impacts relating to slope stability on down slope resources including private land, the Little Slocan FSR, and fish habitat; to make recommendations for culvert sizing and placement as as construction methods intended to reduce the likelihood of landslides attributable to the proposed road construction; and to identify areas of concern with respect to soil erosion and sediment delivery associated with the proposed road construction, and to make recommendations for mitigation as appropriate. 2.0 METHODOLOGY This assessment has been carried out in a method consistent with the Guidelines for Terrain Stability Assessments in the Forest Sector (AFPBC/APEGBC, 2010). A partial risk analysis has been completed with specific definitions and an overview presented in Appendix C. Land Management Handbook 56, Landslide Risk Case Studies in Forest

4 SCL# April 2013 Development Planning and Operations (BCMoF 2004), can be referenced for additional background information on partial risk analysis. It is important to understand that the ratings present a partial risk as opposed to a specific risk; that is, they represent the likelihood of a specific landslide which will reach the site occupied by an element at risk. It does not take into account the vulnerability of the element, or the consequence of the event. It is the responsibility of the land manager to understand and accept the rating definitions used in the analysis as they are arbitrary and not set by any regional or provincial standards. It is also the responsibility of the land manager to determine the acceptable, tolerable, or unacceptable levels of risk for the development in order to complete the risk assessment, and decide whether or not to proceed with the development based on that decision. Down slope elements at risk which have been considered include unimproved private land, the Little Slocan Forest Service Road (including human safety), and fish habitat in the Little Slocan River. There are no licensed points of diversion (POD s) in any of the down slope streams, or in the Little Slocan River prior to the community of Passmore. Passmore is located approximately 12 km downstream of the south end of Lower Little Slocan Lake, and POD s at this location are not considered to be at risk from this proposed development. Other potential elements which have not specifically been addressed in this report include wildlife habitat, visual resources, timber value, and soil productivity. The likelihood of landslide initiation has been estimated in a qualitative manner based on generally accepted geotechnical interpretations and assumptions, the experience of SCL, comparative observations of both natural and forest development related landslides in the southern Columbia Mountains, and results from regional landslide attribute studies (refer to Section 3.3). The likelihood of landslide ratings presented are those attributable to the proposed road construction only, and are incremental to any other existing natural (or otherwise) hazards that may be present. The proposed roads are situated in a GoS scenario, and therefore a focus has been made on effective drainage control. Construction Summary Tables (refer to Appendix B) present culvert placement and sizing recommendations and refer to hubs as flagged in the field by Timberland Consultants (2001) Ltd. in August 2011 and Figures 2 through 6 in Appendix D present water features primarily based on Terrain Resource Information Management (TRIM). In addition, watercourses have been classified and mapped along the alignment as observed in the field by SCL, but have not been extrapolated beyond field observations when uncertain. Drainage divides have been presented on the figures based on a combination of air photo and map interpretation, supplemented with SCL field observations. The drainage divides in this report may not match those presented in other maps or reports commissioned for other purposes as they are subjective, approximate, and intended for the purpose of understanding drainage patterns along the assessed road alignments only. Approximate boundaries for the valley bottom fans have also been delineated on Figure 2. These polygons are intended for general reference only, and are based on air photo interpretation without field confirmation of the distal boundaries.

5 SCL# April 2013 A table that provides a list of descriptive terms relating to soil drainage, soil texture and consistency, surface expression, and bedrock characteristics, is presented in Appendix C. Mr. Bill Grainger, P.Geo., Eng.L., reviewed a draft of this report and provided numerous helpful comments which were taken into consideration during preparation of the final report; however, all analyses and conclusions are the sole responsibility of the authors. Worker and road user safety during and after construction relating to road layout and design considerations (grade, width, turn outs, etc.) is addressed by the forest development coordinating professional, along with work site safety standards and procedures. Worker and road user safety related to terrain stability is addressed in this assessment by means of identification of up slope hazards and recommendations for constructing a stable road prism. Such recommendations include appropriate cut and fill angles, the use of suitable fill material, and effective road drainage. 2.1 Office Review Prior to and/or following the field assessment, the following information was reviewed by SCL: 1:20,000 scale TRIM based topographic map with proposed and existing roads, preliminary planning shapes for cutblocks, and TSIL C terrain stability mapping; 1:25,000 Terrain and Channel Hazards Map with terrain stability mapping (TSIL C - Wehr, 1985; updated by Wehr in 1996, and further updated by Chatwin, S. in 1998), debris flow hazard ratings for select stream channels, domestic water points of diversion, residences, outbuildings, and elevation contours (10 m intervals on east half of ridge, 20 m intervals on west half of ridge) [BCTS compilation dated 99/02/16]; road survey notes (2011, 2012), Timberland Consultants (2001) Ltd.; draft geometric road design plan and profiles, SEL March 2013; 1:15,000 scale black and white air photos (September 1990 exposures) 30BCB90132 Nos ; ; ; 1:15,000 scale black and white air photos (1997 exposures) 30BCB97059 Nos , 30BCB97092 Nos , ; 1:10,000 scale colour air photos (September 1998 exposures) 30BCC98044 Nos , ; 1:20,000 scale colour air photos (2005 exposures) 30BCC05004 Nos , ; GoogleEarth and imapbc web applications, including 2009 orthomosaic imagery; Digital Geology Map of British Columbia: Tile NM11 Southeast B.C. A large number of reports relating to slope stability and hydrology on Perry Ridge have been completed to date. The majority of these relate to the east side of Perry Ridge, although some are relevant to the proposed development area on the north and west side. BCTS provided SCL with copies of available reports associated with Perry Ridge terrain and hydrology in 2007 as a part of the TSA relating to the now completed TSL A Background reports which have been reviewed by SCL are included in the references listed at the end of this report. In addition, a number of written correspondences between the Perry Ridge Water Users Association, local residents, Ministry of Forests, Valhalla Wilderness Society, Dr. June Ryder, P.Geo., Frank Bauman, P.Eng., and Allan Isaacson

6 SCL# April 2013 were reviewed as background information. 2.2 Field Review Mr. Tedd Robertson, P.Geo. Eng.L. of SCL carried out a field review of the proposed roads and down slope sections over five field days including November 1 st and 7 th, 2011, and June 28 th, July 31 st, and October 11 th, At the time of the November 1 st assessment there was up to a few centimetres of snow coverage on the ground and temperatures were near -3 C; this section required a snow free review for completion, and this review was completed on June 28 th During the November 7 th field review weather was overcast with flurries and there was snow coverage of less than 1 cm which did not hinder the assessment. At the time of the June 28 th and July 31 st field reviews the weather was mostly sunny with seasonal temperatures and the ground was snow free. The previous few days in June and July had seen generally similar weather conditions, with some precipitation on June 26 th. June 2012 was the wettest month on record since 1966 at the Castlegar weather station (227.7 mm total precipitation, compared to an average June rainfall of 65.7 mm). July also received more than twice the average precipitation for the month (117.1 mm compared to an average of 50.8 mm). The field traverses combined took approximately 35 hours to complete. Field positions were established based on p-line survey flagging, handheld GPS (Garmin GPSMap 60CSx) and recognizable land features (creeks, slope breaks, etc.). 2.3 Limitations Field assessments are a result of surface and near surface investigations of the surficial geology, soil drainage, and geomorphologic processes. Shallow soil pits, existing road cuts, and overturned root wads were examined; no deeper subsurface investigation was completed. Subsurface conditions are inferred from observations and interpretations of surface characteristics, and conditions encountered during excavation may vary. Interpretations of surface flow patterns were made by careful observations of the forest floor, vegetative indicators, and surface configuration, as is typical for geotechnical assessments. These interpretations took into account the experience of the author observing local conditions on adjacent sections of Perry Ridge to the northeast during periods of high runoff in the spring of The high runoff and stream flow during the June 28, 2011 transect of the stream #3 gully did obscure the channel bottom with turbulent flow in many locations; however, valuable observations to channel type and morphology were made throughout the length of the gully. This limitation is not believed to significantly reduce the validity of interpretations. 3.0 OBSERVATIONS and INTERPRETATIONS The following sections present observations and interpretations, as as the partial risk analysis and recommendations relating to the proposed road construction. 3.1 General Physiography The proposed development is situated in the Selkirk Mountains of the Columbia Mountain System. The general physiography of the region typically consists of serrated ridges and peaks above about 2000 m elevation and with rounded ridge crests and steep

7 SCL# April 2013 valley sides below 2000 m. Perry Ridge has a ridge top elevation ranging between approximately 1200 m and 1900 m elevation, and local relief of approximately 600 m to 1400 m is typical. 3.2 Site Location - General Perry Ridge forms a broad forested ridge between the Slocan River to the east and the Little Slocan River to the west, both of which are fish bearing rivers. The confluence of the Little Slocan River and the Slocan River is situated at the southern end of Perry Ridge. The Slocan River joins the Kootenay River approximately 15 km downstream of the south end of Perry Ridge, and 19 km upstream of the Kootenay River s confluence with the Columbia River at Castlegar. According to the referenced geology mapping, the bedrock in the area of the proposed development consists of primarily gneissic metamorphic rocks that are Carboniferous to Permian in age on the northwest side of the ridge, with younger granitic intrusive bedrock of the Sheppard, Tuzo Creek, and Shingle Creek Intrusions from the Paleocene to Eocene Epoch on the ridge top and southeastern side of the ridge. This rock type distribution is commonly associated with relatively coarse grained (gravelly silty sand, with typically minor clay) colluvium and till, and is generally consistent with field observations. According to the referenced Arrow Boundary Biogeoclimatic Ecosystem Classification (BEC) variant/subzone/zone map, Perry Ridge in this area below 900 m to 1000 m elevation is in the West Kootenay Dry Warm Interior Cedar - Hemlock (ICHdw) biogeoclimatic (BEC) sub-zone, and in the Columbia Shuswap Moist Warm Interior Cedar - Hemlock (ICHmw) BEC subzone between approximately 900 m m up to 1500 m elevation. Above approximately 1500 m lies the Wet Cold Englemann Spruce - Subalpine Fir (ESSFwc) subzone. Based on available climate data from the region, average annual precipitation in the mid elevation area of Perry Ridge where the proposed roads are located is estimated to be approximately 1000 mm, with an average winter snowpack on the order of 2 m deep (Summit, 2013). Runoff is generally greatest during the snow melt season in late spring (May and June most years). High amounts of runoff can also occur during fall rain on snow events, or with isolated extreme precipitation events that are possible during any month of the year. The proposed road construction begins at the southern end of the existing PN Mainline within the harvested area of TSL A80073 Block 4 (refer to Photo 1 and Photo 2), and extends to the southwest along the northwest side of the ridge top to gain access into a broad, gentle to moderately sloped, north draining basin. Drainage from the proposed alignment is divided between four primary down slope gully systems as indicated on Figure 2 (stream naming convention consistent with Summit, 2013). Down slope to the north northwest of the proposed development in the valley bottom there is unimproved private land, the LS FSR, and the fish bearing Little Slocan River (refer to Figure 2). A total of 8529 m of proposed road construction (long term permanent, 20 year term) is planned in five separate road sections as listed below: 1. PN Mainline Ext: 2548 m in length, POC at end of built PN Mainline within TSL A80073 Block 4 near 1430 m elevation, POT at POC of PN near 1600 m elevation in drainage area of stream #4; 2. PN 11000: 3989 m in length, POC at the POT of the PN Mainline Extension near

8 SCL# April m elevation, POT within north draining basin of stream #3 near 1565 m elevation; 3. PN 11030: 1304 m in length, POC at Hub 166 of PN near 1590 m elevation in basin of stream #3, POT near 1700 m elevation within basin of stream #3; and 4. PN 11040: 679 m in length, POC at Hub 178 of PN near 1590 m elevation within basin of stream #3, POT near 1660 m elevation within basin of stream #3. The referenced TSIL C terrain stability mapping shows the alignments are predominantly situated on terrain mapped as stable (class I, II, and III), with polygons mapped as potentially unstable (IV) and unstable (V) situated down slope to the northwest. At the northeast end of the development there is some overlap of the alignments with the upper portions of polygons mapped as class IV along the PN Mainline Extension and PN roads (approximately 400 m total road length). The down slope class IV and class V polygons are associated with moderately steep to very steep bedrock controlled slopes which are subject to naturally occurring periodic rock fall, snow avalanche, debris slide, and debris flow processes within some of the gullies. The primary slope stability concern for this proposed road construction is the potential for a down slope drainage-related landslide. There are few terrain stability concerns relating to a landslide initiating at the road prism, which is located on primarily gentle to moderate gradient slopes. Careful road drainage management is required in order to maintain down slope stability in this GoS scenario. 3.3 Terrain Stability General Landslides within the region occur both naturally and as a result of forest development. Landslide attribute studies completed in the region (Jordan, 2001, 2002) report an increase in landslide occurrence where forest development exists. Slope steepness, terrain type, and bedrock geology are identified in Jordan s studies as significant terrain variables when looking at development related landslides. In general, landslide frequency was found to increase with slope steepness to a maximum in the 35 to 40 degree category (70% to 84% gradient), with a decrease in the > 40 degree category (likely due to the presence of steep yet stable bedrock slopes in this category). Landslide frequency was found to be greater in gullied terrain in comparison with non-gullied. Glaciofluvial and kame deposits were found to have the greatest landslide frequency of all the surficial material types, with thick morainal materials being second. With respect to geology, the metasedimentary bedrock category was highest for landslide frequency (primarily attributable to weak bedrock such as phylite and mica schist, as as the commonly fine grained soils associated with these bedrock types); the granitic bedrock category was second. In the southern interior of B.C., roads have been shown to be a much more significant factor than harvesting for landslides attributable to forest development, with over 95% of development-related landslides attributable to roads and skid trails (Jordan 2001). Landslides caused by roads are primarily due to drainage diversions or unstable fill slopes, with cut slope failures being less common overall. As a result of improved road construction methods and standards, fill slope failures are much less common on newer roads, with drainage now being the most frequent cause (Jordan 2001). In some cases,

9 SCL# April 2013 harvesting can contribute to development related landslides by increasing local runoff that can be intercepted by roads and trails. With normal good construction practices and favourable surficial material properties (e.g. free draining, non-cohesive), road prism landslides following conventional balanced bench construction in the region are virtually non-existent on side slope gradients less than 45%, and uncommon on side slope gradients between 45% and 60%. Road prism landslides are more likely to occur on slopes exceeding 60% to 65%. It is important to understand that these estimates are approximate and critical slope angles vary depending on site specific conditions, including drainage and surficial material properties. In most cases, the likelihood of road prism landslides can be reduced through modified construction methods and drainage management appropriate to specific site conditions. GoS landslides are an important consideration in the region, with many road drainage related landslides initiating at some distance (several to several hundred metres) down slope of a road or trail (Jordan 2001, 2002; Grainger 2002). These drainage related landslides most commonly occur at a slope break to steeper terrain with slopes at the headscarp typically greater than 60%, but occasionally as low as 45% (Jordan 2001). They also more commonly occur on gullied terrain, and where weathered surficial materials are relatively thin overlying an impermeable layer such as bedrock or dense basal till, as opposed to where down slope materials are thicker and permeable (Grainger 2002). Drainage related landslides occur more frequently where there is greater potential for concentrated and redirected drainage along the road, and are most often preventable with a high level of effective drainage control including seasonal deactivation measures. Many of the landslides that occur in the region become channelized debris flows. Channelized debris flows in B.C. generally initiate either by a destabilizing impact to a gully channel from a smaller initial landslide, or from a critical high flow reached in a stream channel which causes localized destabilization of the stream banks and/or bedload (Geertsema et al., 2010). Either mode of initiation can result in progressive channel destabilization and entrainment of debris. The former is by far the most common cause of debris flow initiation within the region. The latter is generally associated with significantly increased stream flows due to widespread watershed disturbances such as wild fires. Other contributing factors to in-channel debris flow initiation can be significant runoff concentration or redirection from resource roads or trails which greatly increases effective drainage areas, redirected stream flows, or extreme runoff events. Most road prism landslides are less than 1000 m 3 in volume, and commonly remain small in size (50 m 3 to 500 m 3 ) unless they enter a gully and cause a channelized debris flow as described Drainage-related landslides are commonly larger, dependent on the length and steepness of slope, type and amount of material available for entrainment, and water discharge at the site. The concept of yield rate can be used to estimate potential event magnitude (Hungr et al., 2005), taking into account the likely area and depth of scour. Obviously, exceptions to these generalities exist, and there is a range of landslide size and runout distances possible for any given scenario (Jordan 2001).

10 SCL# April 2013 Factors that can increase the length of runout and/or decrease the angle of deposition include, but are not limited to, increased event volume 1,2,4, increased vertical relief 1,2, slope geometry 2, increased water supply 3, finer textured materials 3,4, confinement 1,2,3, and lack of obstructions or topographical constraints 1,2,3,4. Hungr et al. (2005) reports variable published deposition angles for relatively coarse grained debris flows in B.C. ranging from 12% to 25%, with lower angles for finer textured materials. Jordan et al. (2011) reports on three specific long runout events that recently occurred in the southern interior of B.C., and identifies fine textured materials, specifically those with substantial clay content, as an important contributing factor to the long runout. No detailed empirical-statistical analysis of runout distance specific to the region is available; however, consideration of the above factors combined with field observations of past landslide events in the area can provide context for the qualitative estimate of potential landslide runout distances. The above findings are generally consistent with comparative field observations of the author and reviewer over the past 15+ years assessing terrain stability in the region. These regional terrain stability considerations, along with professional judgment and the experience of SCL, provide the supporting rational for the conclusions and recommendations presented in this report. 3.4 PN Mainline Extension The PN Mainline Extension is generally situated on the gentle to moderate gradient ridge top slopes, approximately 50 m to 80 m distance up slope and to the southeast of the main slope break into steeper gully headwall areas associated with stream #4, #5, and #6. The alignment remains in the stream #6 drainage between the POC and approximately Hub 85, the stream # 5 drainage between approximately Hub 85 and Hub 135, and the stream # 4 drainage between approximately Hub 135 and the POT. A broad gentle to moderate slope gradient (20% to 50%) nose separates the upper portion of each of these three main down slope drainages, the most prominent of which is crossed by the alignment between Hub 75 and Hub 94 separating stream #5 and stream #6. The alignment is generally situated on slightly to bedrock controlled terrain, with typically 20% to 40% average gradient side slopes. Some short steeper slopes associated with bedrock outcrops (slope gradients to 75%) are intersected. The surficial material along the alignment is a till mantle of variable thickness, most commonly ranging from 0.5 m to 1.5 m in thickness, with occasional bedrock outcrops as as thicker material sections. The till texture generally ranges from silty sand with some gravel to gravelly silty sand with a trace cobbles, boulders, and clay. The typical coarse fragment content of the till ranges from approximately 25% to 35%. Soils are generally to moderately, with isolated areas of imperfectly soils associated with some swales and concave depressions (receiving sites). 1 Corominas Hunter and Fell VanDine Jordan et al. 2011

11 SCL# April 2013 Frequent shallow swales are crossed, with no significant gully crossings encountered along the alignment. In addition, four NCD s and one S6 stream are crossed. Some of the swales without NCDs or S6 streams also had some minor surface flow during the June 28, 2012 field review. All watercourses crossed likely experience intermittent (seasonal) flow, as opposed to perennial (permanent) flow. Runoff from the alignment flows north into the drainages of stream #4, #5, and #6, with seasonal surface flow connectivity to the main stem stream channels likely at the S6 stream and NCD crossings. The road grade remains favorable for approximately the first 770 m, and is generally rolling for the remainder due to a combination of the undulating bedrock controlled topography and certain alignment control points. No indication of slope instability was observed along the PN Mainline Extension alignment. As discussed in Section 3.3, landslides along forest roads within this region on similar predominantly gentle to moderate gradient bedrock controlled terrain are very uncommon, and where they have occurred they are generally associated with outdated road construction practices. Placed rock fills, keyed in rock fills, and some ¾ to full bench end haul construction has been recommended where warranted based on slope geometry. There is the potential for redirected runoff along the proposed road due to the initial section of continuous favorable grades, the four NCD and one S6 stream crossings, the seasonal surface flow within several other swales, and the numerous small drainage divides associated with the topography. In order to reduce the likelihood of significant redirected runoff and potential adverse effects on down slope stability, strategic culvert placement and conservative culvert sizing has been recommended in combination with effective seasonal deactivation measures during periods of nonindustrial use Down Slope Description PN Mainline Extension Down slope of the majority of the PN Mainline Extension alignment the terrain generally remains gentle to moderately sloped and (similar to at the alignment) for approximately 50 m to 80 m slope distance prior to a transition to steeper gradient slopes in the upper gully headwall areas of stream #4, stream #5, and stream #6. These steeper upper gully headwall slopes generally range from 50% to 85% gradient, and are commonly incised with shallow gullies and swales (2 m to 5 m in depth, 5 m to 20 m in width) that converge down slope into three prominent gully systems which extend to valley bottom colluvial fans. The surficial material on this down slope terrain is most commonly a colluvial veneer to blanket with occasional bedrock outcrops. The colluvium has a typical texture of sand and gravel with some cobbles and a trace of silt and boulders (50% to 70% angular to sub-angular coarse fragments). Soils are generally, with isolated areas of imperfect drainage associated with gullies, swales, and receiving sites. Occasional reforested dormant debris slides were noted on the main gully headwall areas; however, with the exception of minor rockfall, no indications of active instability was observed during the down slope traverse or helicopter overview. This adjacent down slope terrain would be sensitive to significant changes in runoff patterns. As discussed in Section 3.3, down slope landslides attributable to up slope

12 SCL# April 2013 forest road construction on similar terrain within the region have occurred. Where they have occurred, they are generally the result of ineffective road drainage control resulting in concentrated and redirected runoff, or as a result of cumulative impacts of up slope forest development (roads and harvesting combined), and rarely occur where there is a high level of effective drainage management in place. The prominent down slope gullies associated with stream #4, stream #5, and stream #6 were not traversed in the field. Interpretations can be made based on a combination of air photo interpretation, the helicopter overview flight, and field work on adjacent terrain. Examples of relevant field traverses completed by the author include the field traverse of adjacent stream #3 gully, field traverses of the valley bottom fans to the base of these gullies, and traverses across relatively similar gullies along the west side of Perry Ridge during TSIL C terrain stability mapping of a portion of TFL 3 for Springer Forest Products in Stream #6 Gully The main gully of stream #6 extends from approximately 1400 m elevation at the gully headwall to near 800 m elevation at the apex of the fan, with a channel distance of approximately 1250 m. The stream at both upper gully headwall and at the base of the gully was observed in the field as an intermittent (seasonal) S6 stream. The upper gully and gully headwall areas span approximately 600 m distance across, while the much more confined lower gully reach is on the order of 200 m across from the tops of the gully sidewalls. The gully ranges from approximately 40 m to 80 m deep. The average channel gradient along the length of the gully is 55%, and the main gully sidewall gradients generally range from approximately 70% to 100%. Bedrock generally controls the stream channel and most of the gully sidewalls. fall and small shallow debris slides are active processes further down slope within the gully system on the steep gradient gully sidewalls, as are snow avalanches up to size 3, likely with a return period on the order of five to ten years (more frequently for smaller size 2 events). These events input debris to the gully channel from gully sidewalls, and are likely the primary source of material in the channel as opposed to sediment loading from the stream banks. Periodic debris flows do occur in this down slope gully system, with an estimated return period on the order of a few decades to several centuries based on vegetation evidence on the fan below. Such debris flow events were likely much more prevalent during early post glacial times, but in the present climate regime may still occur periodically as a result of an impact to the channel from a smaller landslide, extreme weather events, or following major watershed disturbances such as forest fires. The valley bottom fan associated with stream # 6 shows an 8 m thick section of predominantly angular to sub angular, poorly sorted surficial material at the LS FSR. The majority of this material would have been deposited by a combination of debris flow (colluvial) and fluvial processes during early post glacial times when more water and sediment was available. An intermittent S6 stream exists on the fan without significant gully confinement, and is crossed by the LS FSR with a 600 mm culvert. The fan up slope of the FSR has a 25% to 30% gradient for approximately 240 m to the fan apex. Based on the vegetation growth on top of debris flow deposits, and the lack of old stumps Canadian Avalanche Size Classification (Refer to Weir, 2002)

13 SCL# April 2013 or burnt snags on the deposits, the most recent debris flow evidence on the fan appeared to be on the order of 50 to 100 years in age, and terminated approximately 25 m up slope of the FSR. Other defined debris flow lobes and levees observed terminated up slope of the FSR, with a general increase in lobes and levees towards the upper portion of the fan. Based on these past events, it is believed that most recent debris flow events in this gully system (as opposed to early post glacial) terminate prior to reaching the LS FSR location. However, based on the fan slope gradients and distance from the apex to the valley bottom flood plain, it is possible that a larger than average event would have the potential to reach the toe of the fan. Between the stream #6 and stream #5 fans there is gentle to moderate gradients slopes (25% to 35%) without any continuous gully confinement between the steeper up slope terrain and the LS FSR (approximately 200 m distance). A few intermittent S6 streams and NCD s are located on this toe slope, although not all of these watercourses reach the LS FSR location via surface flow. Some smaller up slope gully systems exist on this face unit. Medium sized debris flow events initiating from these gullies have resulted in deposits on the lower slope. Based on damage to mature trees and rotting wood debris within the deposits, the most recent appears to be approximately 30 to 50 years old. These more recent and some older debris flow deposits all terminate upslope of the LS FSR location. Stream # 5 Gully The main gully of stream #5 is similar to the stream #6 gully, below. The gully extends from approximately 1550 m elevation at the gully headwall to near 800 m elevation at the apex of the fan, with a channel distance of approximately 1300 m. The stream at both upper gully headwall and at the base of the gully was observed in the field as an intermittent (seasonal) S6 stream. The upper gully and gully headwall area spans approximately 620 m distance across, while the much more confined lower gully reach is on the order of 185 m across from the top of the gully sidewalls. The gully generally ranges from approximately 20 m to 60 m in depth. The average channel gradient over is 45%, and the main gully sidewall gradients generally range from approximately 60% to 100%. Bedrock generally controls the stream channel and most of the gully sidewalls. fall and small shallow debris slides are active processes within the gully system, as are snow avalanches up to size 3, likely with a return period on the order of five to ten years (more frequently for smaller size 2 events). These events input debris to the gully channel from gully sidewalls, and are likely the primary source of material in the channel as opposed to sediment loading from the stream banks. Periodic debris flows do occur in this down slope gully system, with an estimated return period on the order of a few decades to several centuries based on vegetation evidence on the fan below. Such debris flow events were likely much more prevalent during early post glacial times, but in the present climate regime may still occur periodically as a result of an impact to the channel from a smaller landslide, extreme weather events, or following major watershed disturbances such as forest fires. The valley bottom fan associated with stream # 5 has numerous past debris flow lobes and levees up slope of the LS FSR, all of which are reforested with no indications of recent deposits within the life of the mature forest. The mature forest on the fan is approximately 70 to 90 years based on Vegetation Resource Inventory (VRI) mapping

14 SCL# April 2013 accessed from imapbc, which is generally consistent with field estimations. The fan up slope of the LS FSR has a 25% to 35% gradient for a distance of approximately 460 m to the apex. Two intermittent S6 streams cross the fan from a natural point of avulsion approximately 60 m downstream of the apex. No culvert is located at the LS FSR along the length of the fan, and all flow from the S6 streams appear to drain subsurface beneath the road through the thick and permeable coarse textured materials. Based on vegetation growth and rotting large woody debris (LWD), the most recent debris flow evidence at the apex of the fan appeared to be from 30 to 90 years in age. This event terminated approximately 200 m upslope of the LS FSR. Some evidence of more recent small, nondestructive debris flow events or flood events with high cobble bedload movement and avulsion were observed near the fan apex in the form of angular to sub-angular gravel and cobble sediment wedges pushed up against trees without significant damage to the trunks. Similar to stream #6, all defined debris flow lobes and levees observed terminated prior to the LS FSR, with a general increase in lobes and levees towards the upper portion of the fan. As a result of this evidence of past events, it is believed that most recent debris flow events in this gully system (as opposed to early post glacial) terminate up slope of the LS FSR. However, based on the fan slope gradients and distance from the apex to the valley bottom flood plain, it is possible that a larger than average event would have the potential to reach the toe of the fan. Stream #4 Gully The main gully of stream #4 is similar to the stream #6 and stream # 5 gullies in many ways, but is generally larger and drains a bigger area with more tributary gullies, as described below. The main gully extends from approximately 1550 m elevation at the gully headwall to near 800 m elevation at the apex of the fan, with a channel distance of approximately 1750 m. The streams at the upper gully headwall location consist of NCD and S6 streams, while at the base of the gully there is a larger intermittent (seasonal) S5 stream, making this the largest stream down slope of the PN Mainline Extension. The upper gully and gully headwall areas span approximately 1000 m distance across, with an additional much smaller secondary tributary gully headwall to the northeast. The much more confined lower gully reach is on the order of 130 m to 400 m across from the top of the gully sidewalls. The gully ranges from approximately 20 m to 60 m deep. The average channel gradient is 47%, and the main gully sidewall gradients generally range from approximately 60% to 100%. The stream channel and most of the gully sidewalls are generally bedrock, although there is less exposed bedrock along the gully sidewalls than in the stream #5 and stream #6 gullies. fall and small shallow debris slides are active processes within the gully system, as are snow avalanches up to size 3, likely with a return period on the order of five to ten years (more frequently for smaller size 2 events, and size 3 events are generally less common than in stream #5 and stream #6 gullies). These events input debris to the gully channel from gully sidewalls, and are likely the primary source of material in the channel, as opposed to sediment loading from the stream banks. Periodic debris flows do occur in this down slope gully system, with an estimated return period on the order of a few decades to several centuries based on vegetation evidence on the fan below. Such debris flow events were likely much more prevalent during early post glacial times, but in the present climate regime may still occur periodically as a result of an impact to the channel from a smaller landslide, extreme weather events, or following major watershed disturbances such as forest fires.

15 SCL# April 2013 Stream # 4 reaches the LS FSR as an intermittent (seasonal) S5 stream channel, with a 1000 mm culvert at the LS FSR. This stream had evidence of active bedload movement with mobile cobbles and small boulders to approximately 0.3 m diameter. The valley bottom fan associated with stream # 4 has numerous past debris flow lobes and levees terminating approximately 190 m up slope of the FSR, all of which are reforested. There are no recent deposits within the life time of the mature forest. Numerous old burnt snags and stumps on the debris deposits and directly adjacent to the channel, suggests at least two forest rotations have established on these debris flow deposits. No evidence of debris flows or other destructive events younger than approximately 200 years was observed. The fan up slope of the FSR is approximately 20% gradient for a distance of approximately 200 m with an unconfined channel. The fan slope is 25% to 35% gradient for an additional 240 m between this and the bedrock controlled channel near the fan apex. Natural points of avulsion exist on the unconfined fan Landslide Partial Risk Analysis PN Mainline Extension Road Prism Hazards Based on the regional landslide process information presented in Section 3.3 and the site conditions described in Section 3.4, the likelihood of a road prism landslide is predominately very low where side slopes are less than approximately 45% gradient and low where side slopes are between approximately 45% and 60% gradient, assuming conventional sidecast fill construction. A low likelihood also applies to areas with more gentle side slopes but imperfectly soils. Where slopes exceed approximately 60% gradient, which is uncommon along the alignment, there is a moderate likelihood of a road prism landslide. Assuming all recommendations in this report are followed along with normal good construction and road maintenance practices, the residual likelihood of a road prism landslide will be reduced to very low to low. Refer to the attached construction summary tables for a more detailed spatial breakdown of hazard ratings. Based on the regional landslide process information presented in Section 3.3 and the site conditions described in Section 3.4, a road prism landslide would likely remain small in size (50 m 3 to 500 m 3 ) and terminate prior to the steeper down slope terrain. This estimate is based on the relatively coarse textured soils, the extent of bedrock anticipated during excavation that will be incorporated into the fill, and the down slope profile and distance to the steeper gully headwall areas. Road Prism Hazard Related Risks In the unlikely event of a road prism landslide impact to the S6 stream or one of the NCD s crossed by the alignment, it is possible that some fine suspended sediment could reach the valley bottom and the Little Slocan River via the main stem stream channels of stream #4, #5, or #6. Conservatively assuming some fine sediment would reach the Little Slocan River, and given the very low to moderate likelihood of landslide initiation, there is a very low to moderate partial risk relating to a temporarily elevated fine sediment load reaching fish habitat following conventional sidecast fill construction.

16 SCL# April 2013 Assuming all recommendations in this report are followed along with normal good construction and road maintenance practices, the residual likelihood of a road prism landslide will reduced to very low to low (see Road Prism Hazards section above), and thus there will be a very low to low residual partial risk relating to fine sediment reaching fish habitat. Elevated turbidity at the valley bottom would likely be limited in both severity and duration due to the limited connectivity of the road alignment to the main down slope streams, the separating distance between the proposed road and down slope fish habitat, and the seasonal nature of the tributary watercourses. There is the potential under adverse conditions for a landslide originating at the road prism to sufficiently influence down slope drainage patterns, or cause sufficient impact to a down slope watercourse, that a larger down slope landslide could result as a secondary event. This situation could then be considered comparable to a down slope landside as discussed below. GoS Hazards Based on the regional landslide process information presented in Section 3.3 and the site conditions described in Section 3.4.1, the considered hazardous down slope landslide is a medium sized (on the order of 500 m 3 to 1000 m 3 ) debris slide or debris flow initiating on the steeper gradient down slope terrain. This event would have the potential to enter one of the main down slope gullies and increase in magnitude to a channelized debris flow on the order of 2000 m 3 to 5000 m 3 in volume considering the gully length and estimated available material. This estimate assumes a relatively low yield rate based on the expected limits of erosion from a frequently bedrock controlled channel with coarse textured colluvial banks. Based on the regional landslide process information presented in Section 3.3 and the site conditions described in Section 3.4 and 3.4.1, and considering the uncertainty about how severe redirected drainage could be if no special precautions are taken, there is a moderate to high likelihood of a drainage related down slope debris flow, assuming no special precautions are taken to manage drainage. Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a drainage related down slope debris flow will be reduced to low. Based on the evidence of the most recent past events, in the event of a down slope debris flow it would most likely terminate on the mid to upper colluvial fan surfaces up slope of the LS FSR. Considering the average slopes on the fans it could be possible for a larger than expected debris flow to reach the LS FSR and extend to the toe of the fan, but it is unlikely considering the coarse textured nature of material available for entrainment within the gully which would facilitate relatively steep angles of deposition (refer to Section 3.3 for general discussion on landslide runout). GoS Hazard Related Risks - Little Slocan River Fish Habitat The Little Slocan River is an ly sinuous fish bearing river situated approximately 350 m distance to the north northwest of the LS FSR, and separate from it by flat to gentle gradient slopes.

17 SCL# April 2013 There are two types of spatial effects to fish habitat possible: a) a direct impact by the run out of a debris flow, with a significant input of coarse bedload sized material as as large amounts of fine sediment and woody debris; and b) fine sediment delivery from turbid flow which extends beyond the main deposit at the time of event, and from subsequent surface erosion of the debris flow deposit. In either case, elevated turbidity in the Little Slocan River could last for a period of days to months, depending on the event characteristics and timing. It could also reoccur during times of high runoff for a few years following the event as a result of erosion of the landslide surface and reworking of sediment in the stream channel. There is a low likelihood of a debris flow directly impacting fish habitat due to the extent of flat to gentle gradient slopes at and beyond the toe of the fan onto the Little Slocan River floodplain, and since ground evidence suggest for the last several hundred years debris flows terminated up slope of the Little Slocan River. The likelihood of some temporarily elevated suspended sediment loads reaching the Little Slocan River is assumed to be equivalent to the likelihood of the debris flow occurring in the first place (moderate to high). Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk to fish habitat will be reduced to very low for a direct impact from a debris flow, and low for a temporarily increased fine sediment load. GoS Hazard Related Risks - Little Slocan FSR The LS FSR crosses the lower to mid elevation portion of the colluvial fans down slope of stream #4, #5, and #6. The likelihood of a debris flow impacting the LS FSR is considered moderate as ground evidence suggest most past debris flow events terminate on the gentle gradient up slope fan surface to the south, prior to reaching the LS FSR elevation. In the event of an impact to the LS FSR, debris would likely be deposited on the road surface, but significant structural damage to the road is not expected. Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk relating to a debris flow impacting the LS FSR will be reduced to low. Human Safety has been considered for users of the LS FSR. Unlike the other considered elements at risk, human safety must consider a temporal likelihood of impact since users are not always present. To strictly define the temporal likelihood would include taking into account traffic volume in addition to average driving speeds, likely stopping distances of drivers, reaction time of drivers, and site visibility. For example, Nicol (2004) estimates the probability of an impact to highway users to be approximately 14% that of the impact to the highway itself in a risk analysis concerning Highway 6 near Summit Lake, B.C., where traffic volumes and exposure rates would be significantly higher. Taking the low temporal probability into account, the partial risk relating to human safety at the LS FSR is considered to be orders of magnitude less than the likelihood of an event reaching the LS FSR, and is reduced to low. Following the recommendations presented in Section 4 and in the construction summary tables,

18 SCL# April 2013 along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk relating to human safety at the LS FSR will be reduced to very low. GoS Hazard Related Risks - Private Land There is no private land located down slope of stream #5 or stream #6. Unimproved private land does exist along the Little Slocan River to the north of the LS FSR and down slope of stream #4 (refer to Figure 2). The partial risk relating to a direct impact of a debris flow with the private land is considered low to moderate, as ground evidence suggests the more recent past debris flow events in Stream #4 terminated approximately 300 m to the south, with gentle gradient separating terrain. In the event of a debris flow reaching the private land, it would most likely be in the depositional stage of spreading debris and sediment laden afterflow. Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk relating to private land will be reduced to very low. 3.5 PN The PN alignment is situated within the stream #4 drainage between the POC and approximately Hub 75 ( ), after which it transitions into the stream # 3 drainage for the remainder of its length. For the purpose of this report the alignment has been divided into two sections: POC to Hub 105 ( ); and Hub 105 to POT. The first section remains within the catchment area of stream #4 and an eastern tributary gully to stream #3. The second section remains in the main upper basin catchment area of stream # PN 11000, Section 1: POC to Hub 105 ( ) Initially the alignment remains on the broadly concave upper gully headwall portion of the stream #4 drainage, with moderate to moderately steep slope gradients (35% to 65%) at the alignment location. After approximately 350 m distance (near Hub 16) side slope gradients become more commonly gentle to moderate (15% to 40%) with occasional short moderately steep (50% to 60%) slopes associated with bedrock controlled terrain as the road alignment moves south, away from the steeper down slope terrain. The transition out of the stream #4 drainage area occurs near Hub 75 ( ), with drainage into stream #3 by approximately Hub 84 ( ). Between Hub 75 and Hub 84 drainage appears to be directed onto a smaller gully system on the face unit separating stream #3 and #4 (refer to Figure 4). The surficial material along this portion of the alignment is predominantly a till veneer to blanket, most commonly ranging from 0.5 m to 1.0 m in thickness, with occasional bedrock outcrops as as thicker material sections. The till texture generally ranges from silty sand with some gravel to gravelly silty sand with a trace cobbles, boulders, and clay. The typical coarse fragment content of the till ranges from approximately 25% to 35%. Soils are generally to moderately, with isolated areas of imperfectly soils associated with some swales and receiving sites.

19 SCL# April 2013 Frequent shallow swales are crossed, with no significant gully crossings encountered along the alignment. In addition, seven NCD s and two S6 streams are crossed. All watercourses crossed likely experience intermittent (seasonal) flow, as opposed to perennial (permanent) flow. Seasonal surface flow connectivity to the main stem stream # 3 and stream # 4 channels is likely at the S6 stream and NCD crossings. The road grade generally remains rolling throughout this section with high and low points in the grade due to a combination of the undulating bedrock controlled topography and alignment control points. No indication of slope instability was observed along this first section of the PN alignment. As discussed in Section 3.3, landslides along forest roads on similar terrain within the region are uncommon, and where they have occurred they are generally associated with outdated road construction practices. Placed rock fills, keyed in rock fills, and some ¾ to full bench end haul construction has been recommended where side slopes warrant special construction methods as opposed to conventional half bench construction. The potential for redirected runoff does exist in some areas due to the several small drainage divides crossed and frequency of seasonal water courses (NCD s and S6 streams). However, the overall potential for significant redirected runoff is limited along the proposed road due to the rolling road grade. Strategic culvert placement and conservative culvert sizing has been recommended in combination with effective seasonal deactivation measures during periods of non-industrial use in order to reduce the likelihood of significant redirected runoff, and potential adverse effects on down slope stability Down Slope Description - PN Section 1: POC to Hub 105 ( ) The down slope terrain to the north of this section has been assessed based on a combination of air photo and map interpretation, comparison with ground traverses on adjacent similar terrain, and a helicopter overview flight. The down slope terrain generally becomes progressively steeper within the gully headwall area of stream #4 or the east tributary gully of stream #3. The separating distance to the steeper gradient slopes is greatest between approximately Hub 64 ( ) and Hub 84 ( ) where there is approximately 200 m to 350 m of moderate gradient (30% to 50%) terrain between the alignment and the slope break. The steeper down slope terrain generally ranges from 60% to 85% slope gradient, and is commonly incised with shallow gullies and swales. The surficial material is most likely a colluvial veneer to blanket with occasional bedrock outcrops on the moderately steep to steep gradient slopes, with a till veneer remaining on the upper moderate gradient slopes approaching the alignment. The till and colluvium are likely to have textures typical for the local area in sections Soils appear to be generally moderately to, with isolated areas of imperfect drainage associated with gullies, swales, and receiving sites. No evidence of recent or active instability except for minor rock fall was observed on the helicopter overview or identified by air photo interpretation. Refer to report Section for additional description of the down slope stream #4 gully.

20 SCL# April 2013 The eastern tributary gully to stream # 3 joins the main stem channel of stream # 3 near 1100 m elevation. Snow avalanches to size 3 impact the main gully channel from the eastern tributary gully (as as from at least two other locations along the eastern main gully sidewall, one upstream and one downstream of 1100 m elevation). Refer to Section for additional descriptions of the stream # 3 gully system. This down slope terrain would be sensitive to significant changes in runoff patterns. As discussed in Section 3.3, landslides attributable to up slope forest road construction on similar terrain within the region have occurred; however, they are generally the result of ineffective drainage control resulting in significantly concentrated and redirected runoff Landslide Partial Risk Analysis PN Section 1: POC to Hub 105 ( ) Road Prism Hazards Based on the regional landslide process information presented in Section 3.3 and the site conditions described in Section 3.5.1, the likelihood of a road prism landslide is predominately very low where side slopes are less than approximately 45% gradient, and low where side slopes are between approximately 45% and 60% gradient assuming conventional sidecast fill construction. A low likelihood also applies to areas with more gentle side slopes but imperfectly soils. There is a moderate likelihood of a road prism landslide at some shallow gully crossings and short sections with slopes exceeding 60%, with a residual likelihood of low achieved through increased benching and the use of placed or keyed rock support in fill slopes as recommended in the construction summary tables. Refer to the attached construction summary tables for a more detailed spatial breakdown of hazard ratings. Based on the regional landslide process information presented in Section 3.3 and the site conditions described in Section and 3.5.2, a road prism landslide would likely remain small in size (50 m 3 to 500 m 3 ) and terminate prior to entering one of the main down slope gullies. This estimate takes into account the relatively coarse textured soils, extent of bedrock anticipated during excavation that will be incorporated into the fill. Road Prism Hazard Related Risks In the event of a landslide impact to one of the seasonal watercourses crossed by the alignment, it is possible that some suspended sediment could reach the valley bottom and the Little Slocan River via the main stem stream channels of stream #3 or #4. Conservatively assuming some fine sediment would reach the Little Slocan River, there is a very low to moderate partial risk relating to fine sediment following conventional sidecast fill construction (partial risk assumed equivalent to likelihood of road prism landslide initiation). Assuming all recommendations in this report are followed along with normal good construction and road maintenance practices,, the residual likelihood of a road prism landslide will reduced to very low to low (see Road Prism Hazards section above), and thus the residual partial risk relating to fine sediment reaching fish habitat will be reduced to very low to low. Elevated turbidity at the valley bottom would likely be limited in both severity and duration due to the limited connectivity of the road alignment to the down slope streams, separating distance between the proposed

21 SCL# April 2013 road and down slope fish habitat, and intermittent (seasonal) nature of the tributary watercourses. There is the potential under adverse conditions that a landslide originating at the road prism could sufficiently influence down slope drainage patterns, or could cause sufficient impact to a down slope watercourse, that a larger down slope debris flow could result as a secondary event. This situation could then be considered comparable to a down slope landside as discussed below. GoS Hazards Based on the regional landslide process information presented in Section 3.3 and the site conditions described in Section 3.5.2, the considered hazardous down slope landslide is a medium sized (on the order of 500 m 3 to 1000 m 3 ) debris slide or debris flow initiating on the steeper gradient down slope terrain. This event would have the potential to enter one of the main down slope gullies and increase in magnitude to a channelized debris flow on the order of 2000 m 3 to 5000 m 3 in volume considering the gully length and estimated available material. This estimate assumes a relatively low yield rate based on the expected limits of erosion from a frequently bedrock controlled channel with coarse textured colluvial banks. Based on the regional landslide process information presented in Section 3.3 and the site conditions described in Section and 3.5.2, and taking into account the uncertainty about how severe redirected drainage could be if no special precautions are taken, there is a moderate to high likelihood of a drainage related down slope debris flow, assuming no special precautions are taken to manage drainage. Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a drainage related down slope debris flow will be reduced to low. Based on the evidence of the most recent past events, in the event of a debris flow it would most likely terminate on the mid to upper colluvial fan surfaces up slope of the LS FSR. Considering the average slopes on the fans it could be possible for a larger than expected debris flow to reach the LS FSR and extend to the toe of the fan, but it is unlikely considering the coarse textured nature of material available for entrainment within the gully which would facilitate relatively steep angles of deposition (refer to Section 3.3 for general discussion on landslide runout). GoS Hazard Related Risks - Little Slocan River Fish Habitat The Little Slocan River is an ly sinuous fish bearing river situated approximately 350 m distance to the north northwest of the LS FSR, and separate from it by flat to gentle gradient slopes. There are two types of spatial effects to fish habitat possible: a) a direct impact by the run out of a debris flow, with a significant input of coarse bedload sized material as as large amounts of fine sediment and woody debris; and b) fine sediment delivery from turbid flow which extends beyond the main deposit at the time of event, and from subsequent surface erosion of the debris flow deposit. In either case, elevated turbidity in the Little Slocan River could last for a period of days to months, depending on the event

22 SCL# April 2013 characteristics and timing. It could also reoccur during times of high runoff for a few years following the event as a result of erosion of the landslide surface and reworking of sediment in the stream channel. There is a low likelihood of a debris flow directly impacting fish habitat due to the extent of flat to gentle gradient at and beyond the toe of the fan onto the Little Slocan River floodplain, and since ground evidence suggest for the last several hundred years debris flows terminated up slope of the Little Slocan River. The likelihood of some temporarily elevated suspended sediment loads reaching the Little Slocan River is assumed to be equivalent to the likelihood of the debris flow occurring in the first place (moderate to high). Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk to fish habitat will be reduced to very low for a direct impact from a debris flow, and low for temporarily increased fine sediment load. GoS Hazard Related Risks - Little Slocan FSR The LS FSR is crosses the lower to mid elevation portion of the colluvial fans down slope of stream #3 and #4. There is a moderate partial risk relating to a direct impact of a debris flow to the LS FSR, as ground evidence suggest most past debris flow events terminate on the gentle gradient up slope fan surface to the south. In the event of an impact to the LS FSR, debris would likely be deposited on the road surface with the potential for plugged and damaged culverts, but significant structural damage to the road is not expected. Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk relating to a debris flow impacting the LS FSR will be reduced to low. Human Safety has been considered for users of the LS FSR. Unlike the other considered elements at risk, human safety must consider a temporal likelihood of impact since users are not always present. To strictly define the temporal likelihood would include taking into account traffic volume in addition to average driving speeds, likely stopping distances of drivers, reaction time of drivers, and site visibility. For example, Nicol (2004) estimates the probability of an impact to highway users to be approximately 14% that of the impact to the highway itself in a risk analysis concerning Highway 6 near Summit Lake, B.C., where traffic volumes and exposure rates would be significantly higher. Taking the low temporal probability into account, there is a low partial risk relating to human safety at the LS FSR, as it is considered to be orders of magnitude less than the likelihood of a debris flow reaching the LS FSR. Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk relating to human safety at the LS FSR will be reduced to very low.

23 SCL# April 2013 GoS Hazard Related Risks - Private Land Essentially the entire valley bottom colluvial fan associated with stream #3 is located on unimproved private land. Unimproved private land is also located down slope of stream #4 along the Little Slocan River to the north of the LS FSR (refer to Figure 2). The partial risk relating to a debris flow reaching private land down slope of stream #3 is considered equivalent to the likelihood of the debris flow occurring in the first place (moderate to high). The partial risk relating to debris flow reaching private land down slope of stream #4 is considered low to moderate, as ground evidence suggest most past debris flow events terminate approximately 300 m to the south, with gentle gradient separating terrain. In the event of a debris flow reaching the private land, at stream #4 it would most likely be in the depositional stage of spreading debris and sediment laden afterflow, with more significant debris lobes and levees as as channel scour and/or avulsion probable on the upper portions of the stream #3 fan. Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk is reduced to low for the private land down slope of stream #3, and very low for the private land down slope of stream # PN 11000, Section 2: Hub 105 ( ) to Hub 214 (3+998) POT This section of the alignment remains within the lower elevations of the stream #3 drainage basin, essentially contouring near 1600 m elevation from east aspect slopes through north aspect slopes to the POT on west aspect slopes. Slope gradients along the alignment generally remain gentle to moderate (10% to 45%). All drainages crossing this section of the alignment join the main stem stream #3 channel prior to the abrupt transition to the down slope gully system below approximately 1485 m elevation. In general, the surficial material along this portion of the alignment is thicker than the sections to the east. The till materials commonly form a blanket on the order of 1.0 m to 2.0 m in thickness, with occasional bedrock outcrops as as thinner and thicker material sections. The till texture generally ranges from silty sand with some gravel to gravelly silty sand with a trace cobbles, boulders, and clay. The typical coarse fragment content of the till ranges from approximately 25% to 35%. Soils are generally moderately, with common areas of imperfectly soils associated with some swales and receiving sites. Frequent shallow swales are crossed, with no significant gully crossings encountered along the alignment. In addition, eleven NCD s, three S6 streams, and the main S5 stream channel draining this upper basin are crossed by the alignment (refer to Photo 3). Most watercourses crossed likely experience intermittent (seasonal) flow, as opposed to perennial (permanent) flow. A low level of perennial flow is likely within the S5 stream channel, and permanent seepage can be expected at the most defined receiving sites. Seasonal surface flow connectivity to the main stem S5 stream channel is likely at all S6 stream and NCD crossings. An 1800 mm culvert is prescribed for the S5 stream crossing at Hub 174. This sizing is based on a combination of stream channel and drainage area measurements taking into

24 SCL# April 2013 account regional precipitation and runoff regimes. Sizing for this culvert was reviewed and confirmed by SNT Engineering Ltd. based on information provided by SCL. The road grade remains rolling throughout this section with numerous high and low points in the grade as a result of the road layout and undulating terrain. No indication of slope instability was observed along this second section of the PN alignment. As discussed in Section 3.3, landslides along forest roads on similar terrain within the region are uncommon, and where they have occurred they are generally associated with outdated road construction practices. Placed rock fills, keyed in rock fills, and some ¾ to full bench end haul construction has been recommended where side slopes warrant special construction methods, as opposed to conventional half bench construction. Gentle slope gradients with imperfectly soils and areas of seepage are encountered in some locations. These sites are not necessarily a concern with respect to long term road prism slope stability, but can pose challenges to construction and can also contribute to subsurface runoff interception. Overland construction and subsurface soil separation using geotextile fabric have been recommended in some of these wet areas in order to achieve a functional road grade as as to reduce excavation and shallow subsurface runoff interception. Refer to the attached construction summary tables for applicable sections. In general, the potential for significant redirected runoff is limited along the proposed road due to a combination of the rolling road grade and the broad basin which contains all drainage into the main stream channel prior to the steeper down slope terrain. The potential for concentrated and accelerated runoff does exist due to the areas of imperfectly soils where intercepting seepage can be expected during excavation. Frequent culvert placements and some areas of overland construction to reduce excavations has been recommended in combination with effective seasonal deactivation measures during periods of non-industrial use in order to reduce the extent of intercepted, concentrated, and accelerated runoff, and the related potential adverse effects on down slope stability Down Slope Description - PN Section 2: Hub 105 ( ) to Hub 214 (3+998) POT The down slope terrain to the north of this section includes the steep gully system of stream #3. This gully was traversed from top to bottom on June 28 th, 2012, by Mr. Robertson and Mr. Deschenes in order to characterize its current state of stability and the nature of landslide events within the gully system, and to consider its sensitivity to potential changes in flow regime. No indication of debris flow or debris flood events was noted within the main stem channel or any tributary channels within the stream #3 basin upstream of the gully headwall near 1485 m elevation (refer to Photo 4). The main gully below 1485 m elevation has a relief of approximately 680 m over a channel distance of approximately 1500 m to the apex of the valley bottom colluvial fan at approximately 805 m elevation. Stream #3 flows into the Little Slocan River at approximately 680 m elevation after

25 SCL# April 2013 approximately 500 m to 600 m distance crossing the fan. The main gully is ranges from approximately 200 m to 400 m in width between the top of the gully sidewalls, and is ranges from approximately 160 m deep in the upper reaches to 60 m deep in the lower reaches. Based on a combination of stream channel measurements and a regional area analysis, the average annual peak flow (Q2) over the top of the gully headwall is likely on the order of 2.5 m 3 /s, with 100 year return period floods (Q100) in excess of 6 m 3 /s. Annual peak flows are anticipated to occur between mid May and mid June in most years, as is typical for watersheds of similar elevations within the region. Stream #3 Gully Upper Reach Between approximately 1500 m and 1200 m elevation the main stream is steep and tightly confined to a single, steep-sided gully channel bounded by bedrock cliffs and coarse textured colluvial slopes (refer to Photo 5). Some waterfall and canyon sections of this upper reach were unsafe to traverse, and where possible were viewed from the steep side slopes above the gully bottom. In general, the channel in this reach has a predominantly bedrock and boulder cascade channel morphology that is typically on the order of 3 m wide (2 m to 4 m) and 0.5 m to 1.5 m deep (refer to Photo 6). Channel gradients are commonly and typically range from 45% to 65%, with several short steeper waterfall sections (refer to photo 7) as as short, less steep bedrock controlled benches. Common angular boulders, 0.5 m diameter and larger, are in and adjacent to the channel derived from local rock fall of the bedrock gully sidewalls (refer to Photo 8 and Photo 9). The channel bed load, where present, is predominantly cobbles and boulders, typically ranging from 0.1 m to 1 m diameter (refer to photo 9). There are very few fine sediment deposits within or adjacent to the channel. Snow avalanches, ranging from size 1 to size 3, impact the stream channel on an annual basis (in general, reduced frequency for larger events). These snow avalanche events introduce some woody debris as as some rock and soil into the stream when they occur during the winter and early spring months, typically before the onset of high seasonal flows (refer to Photo 10). Most debris flow events that initiate within this reach appear to be the result of direct impacts to the channel by large rock fall or small to medium sized debris slide events which impact the channel and continue downstream as channelized debris flows. Progressive bulking from stream bank erosion is generally not a cause for in-stream debris flow initiation in this reach due to the typically non-erosive bank materials. In general, due to the robust bedrock and coarse textured colluvial nature of the stream bed and banks and lower gully sidewalls, this reach appears to be supplylimited with a finite amount of material available for entrainment along and directly adjacent to the channel. As a result of the above observations and interpretations, this upper reach would have a low sensitivity to changes in peak flow. Stream #3 Gully Lower Reach Between approximately 1200 m and 800 m elevation the channel gradient is somewhat less steep, typically ranging from 30% to 45%. Some steeper bedrock controlled channel sections as as gentle bedrock controlled benches also exist within this reach. The channel bed load is predominantly cobbles and boulders, typically ranging from 0.1 m to 1 m diameter. Some functional large woody debris (LWD) exists, and there are occasional over-bank deposits of bed load sized material and woody debris located in the

26 SCL# April 2013 lower reach (refer to Photo 14). These lateral deposits form lobes and levees where the channel is not overly confined and are indicative of past debris flow events. Some mature timber along the channel does play a minor role in stream bank stability, but understorey vegetation is not a significant factor due to its sparse existence along the channel as as the generally coarse textured materials forming the stream banks (typical bank material consists of coarse gravel, cobbles, and boulders, 0.05 m to 3 m diameter; refer to Photo 11). Some recent gully sidewall failures have impacted the channel (refer to Photo 12), and based on landslide headscarps and tracks on the gully sidewalls with varying ages of revegetation, this is an ongoing process. Occasional coarse textured sediment wedges exist within the channel, as as partially decomposed log jams (refer to Photo 13). These debris accumulations are likely the result periodic debris inputs to the channel from gully sidewall failures. Most debris flow events within this reach appear to initiate either upstream above, or from rock fall or debris slide events directly impacting the channel from up slope on the steep gully sidewalls, continuing downstream entraining available bedload material. Evidence of recent debris flow events (10 to 30 years old) was noted including trunk damage and cobbles embedded in tree trunks adjacent to the channel; however, these events did not appear to result in significant bank erosion or tree mortality (refer to Photo 15 and Photo 16). Colluvial inputs from the gully sidewalls also continues to be an active process in this reach, along with impacts from size 2 and size 3 snow avalanches (refer to Photo 17). In general, due to the robust bedrock and coarse textured colluvial nature of the stream bed and banks and lower gully sidewalls, this reach appears to be supply-limited, with a limited amount of material available for entrainment along and directly adjacent to the channel. Progressive bulking from stream bank erosion is generally not a cause for instream debris flow initiation in this reach due to the typically non-erosive bank materials. Based on the above observations and interpretations, this channel section would have a low sensitivity to changes in peak flow. While somewhat more sensitive than the upper reach due to some decrease in bedrock control, channel changing events are generally a result of periodic destructive debris flows rather than high peak flows, and these larger debris flow events do not appear to be initiated within the channel as a result of high peak flows. Stream #3 Gully Valley Bottom Fan The apex of the fan is situated at approximately 805 m elevation. Evidence of debris flow and debris flood events of various magnitudes and age are apparent along the channel on the fan (refer to photo 18), which is typically 20% gradient. The smaller and most recent events are apparent from remnant sediment wedges, small log jams, and minor damage to trees adjacent to the channel (refer to Photo 19). Debris levees with frequent large boulders were also noted along the active channel on the fan and appear to be a result of larger debris flow events which likely occur at a frequency of several decades to centuries based on vegetation evidence on the deposits, and rotting wood within the deposits (the most recent large destructive event appears to be over 100 years old). Flood, debris flood, and smaller less destructive debris flow events likely occur more commonly based on vegetation evidence on the deposits and wood within the deposits (frequency on the order of five to 50 years, most recent event approximately 10 to 30 years ago). Channel shifting events also occur periodically resulting in avulsions both near the apex and at lower elevations on the fan. The majority of the fan is situated on unimproved private land, most of which has been previously harvested to the stream

27 SCL# April 2013 banks. In general, this channel section would have a moderate sensitivity to changes in peak flow due to the potential for avulsion, bedload movement, and bank erosion in some sections. The sensitivity is moderated by the coarse textured nature of the bed and bank material, with channel changing events generally caused by debris flows or debris floods as opposed to floods alone. The LS FSR crosses the lower portion of the fan near 700 m elevation with three metal culverts (1200 mm, 800 mm, and 600 mm; refer to photo 20) at the stream crossing. There is evidence of active bedload movement to 0.5 m diameter within the channel (0.1 m to 0.3 m typical), and ongoing road maintenance has been required to clear material from the culvert inlets, which have sustained some damage over time. These culverts are likely near maximum capacity on an annual basis during spring runoff, with combined capacity on the order of 2.8 m 3 /s based on the Armtec Design Handbook. Debris flows attributable to up slope forest development in down slope gullies similar to stream #3 have occurred within the region when a gully sidewall failure or open slope landslide attributable to the up slope forest development directly impacts the channel. They have also occurred when there have been significant increases to peak flows as a result of drainage diversions or widespread watershed disturbances such as forest fires, but rarely initiate within the channel itself as a result of incremental changes to peak flow due to harvesting Landslide Partial Risk Analysis PN Section 2: Hub 105 ( ) to Hub 214 (3+998) POT The primary concern with respect to slope stability relating to the PN road between the Hub 105 and Hub 214 (3+998) POT is the potential for causing accelerated runoff into the down slope gully of stream #3 by means of a combination of interception, concentration, and/or redirection along the proposed road. Other geotechnical concerns include construction through wet soils on gentle slopes, and the potential for erosion and sediment delivery to streams. Careful road drainage management which considers the potential for cumulative effects of the proposed PN 11000, PN 11030, and PN roads as as planned harvest areas has been prescribed in order to reduce the potential for changes to down slope flow regimes. Road Prism Hazards Based on the regional landslide process information presented in Section 3.3 and the site conditions as presented in section 3.5.4, the likelihood of a road prism landslide is predominately very low were side slopes are less than approximately 45% gradient, and low where side slopes are between approximately 45% and 60% gradient assuming conventional sidecast fill construction. A low likelihood also applies to areas with more gentle side slopes but imperfectly soils. Based on the regional landslide process information presented in Section 3.3 and the gentle gradient down slope terrain prior to the gully headwall, a road prism landslide would likely remain small in size (50 m 3 to 500 m 3 ) and terminate prior to entering the main down slope gully. Sediment delivery or a direct impact to the S5 stream within the upper basin would be possible from a road prism landslide; however, major changes to stream channel morphology are unlikely.

28 SCL# April 2013 Road Prism Hazard Related Risks In the event of an impact by a landslide to one of the seasonal watercourses crossed by the alignment, it is possible that some suspended sediment could reach the valley bottom and the Little Slocan River via stream #3. Elevated turbidity at the valley bottom would likely be limited in both severity and duration due to the separating distance, seasonal nature of the tributary watercourses, and effects of dilution in the larger streams. Conservatively assuming some sediment delivery to fish habitat in the event of a road prism landslide, given the very low to low likelihood of landslide initiation there is a very low to low partial risk relating to temporarily elevated turbidity reaching fish habitat following conventional sidecast fill construction (partial risk assumed equivalent to likelihood of road prism landslide initiation). GoS Hazards A debris flow in the stream #3 gully that is attributable to the proposed road construction would likely be on the order of 2000 m3 to 5000 m3, based on the gully length and available material. This estimate assumes a relatively low yield rate based on the expected limits of erosion from a frequently bedrock controlled channel with coarse textured colluvial banks. All drainage from the road reaches the main S5 creek prior to the steep down slope terrain, therefore there is virtually no opportunity for drainage from this road section to be directed onto the steeper down slope terrain outside of the main creek channel. As a result, a debris flow event attributable to the proposed road would have to initiate in-channel as a result of increased peak flows. Based on the regional landslide process information presented in Section 3.3, the site conditions and low gully channel sensitivity as presented in Section and 3.5.5, and taking into account the uncertainty of the extent of accelerated runoff possible assuming no special precautions to manage drainage are taken, there is a low to moderate likelihood of a debris flow in the stream # 3 gully that is attributable to the proposed road construction. Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a debris flow in the stream # 3 gully that is attributable to the proposed road construction will be reduced to low. Based on the evidence of the more recent past events, in the event of a debris flow (natural or development related) the majority of debris would most likely terminate on the mid to upper colluvial fan surface. Some debris and sediment laden flow would likely reach or approach the toe of the fan in the stream, and turbid flow would reach the Little Slocan River. Based on the fan gradients, it could also be possible for a larger than expected debris flow to reach the toe of the fan with greater impacts, but it is unlikely considering the coarse textured nature of material available for entrainment within the gully which would facilitate relatively steep angles of deposition (refer to Section 3.3 for general discussion on landslide runout). The following paragraphs summarize the down slope landslide partial risk analysis. GoS Hazard Related Risks - Little Slocan River Fish Habitat The Little Slocan River is an ly sinuous fish bearing river situated near 680 m elevation approximately 125 m to 300 m distance across flat to gentle gradient slopes to the north northwest of the LS FSR.

29 SCL# April 2013 There are two types of spatial effects to fish habitat possible: a) a direct impact by the run out of a debris flow, with a significant input of coarse bedload sized material as as large amounts of fine sediment and woody debris; and b) fine sediment delivery from turbid flow which extends beyond the main deposit at the time of event, and from subsequent surface erosion of the debris flow deposit. In either case, elevated turbidity in the Little Slocan River could last for a period of days to months, depending on the event characteristics and timing. It could also reoccur during times of high runoff for a few years following the event as a result of erosion of the landslide surface and reworking of sediment in the stream channel. In the event of a debris flow in the stream #3 gully, it is unlikely to directly impact the Little Slocan River, as ground evidence suggests most past debris flow events terminated up slope of the Little Slocan River, and there is sufficient flat to gentle gradient separating terrain for a debris flow to terminate (see GoS Hazards section above). As a result, the partial risk relating to a direct impact to fish habitat from a debris flow is considered very low to low. A temporarily elevated suspended sediment load would likely reach the Little Slocan River in the GoS hazards section As a result, the partial risk relating to fine sediment delivery to fish habitat from a debris flow is considered low to moderate (equivalent to the likelihood of the debris flow occurring). Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk to fish habitat is reduced to very low for a direct impact from a debris flow, and low for temporarily elevated fine sediment loads. GoS Hazard Related Risks - Little Slocan FSR The likelihood of a direct impact to the LS FSR from a debris flow is somewhat reduced from the low to moderate likelihood of the debris flow initiating, as ground evidence suggest the majority of debris from past events is deposited on the gentle gradient up slope fan surface to the south. The present stream #3 crossing of the LS FSR appears to be undersized and vulnerable to blockage in the case of high bedload movement. Even if there is not a direct impact, there is likely to be a high degree of bedload and woody debris movement, as as a surge of highly turbid stream flow at the crossing location. These present culverts are likely to be overwhelmed resulting in some debris deposition on the road surface as as possible road surface scour or washout from the stream flow over the road. As a result, the partial risk relating to some damage and debris deposition on LS FSR is considered low to moderate. Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk relating to some damage and debris deposition on LS FSR will be reduced to low. Human Safety has been considered for users of the LS FSR. Unlike the other considered elements at risk, human safety must consider a temporal likelihood of impact since users are not always present. To strictly define the temporal likelihood would include taking

30 SCL# April 2013 into account traffic volume in addition to average driving speeds, likely stopping distances of drivers, reaction time of drivers, and site visibility. For example, Nicol (2004) estimates the probability of an impact to highway users to be approximately 14% that of the impact to the highway itself in a risk analysis concerning Highway 6 near Summit Lake, B.C., where traffic volumes and exposure rates would be significantly higher. Taking the low temporal probability into account, there is a low partial risk relating to human safety at the LS FSR, as it is considered to substantially less than the likelihood of a debris flow reaching the LS FSR. Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk relating to human safety at the LS FSR will be further reduced to very low. GoS Hazard Related Risks - Private Land Essentially the entire valley bottom colluvial fan associated with stream #3 is located on unimproved private land. In the event of a debris flow in the stream #3 gully, it would likely reach the private land. As a result, the partial risk relating to a direct impact of a debris flow with the private land is considered low to moderate (equivalent to the likelihood of the debris flow occurring). The debris flow would be in the depositional stage once reaching the private land on the colluvial fan, and effects would be similar to what has happened during natural events in the past, including possible channel avulsion, levee and lobe debris deposits, and bedload movement. Following the recommendations presented in Section 4 and in the construction summary tables, along with normal good construction and road maintenance practices, the residual likelihood of a GoS landslide occurring is reduced to low (see GoS hazards section above), and thus the residual partial risk will be reduced to low. 3.6 PN The PN alignment remains within the mid elevation range of the stream #3 drainage basin with a continuous favourable grade on the southeast side of the S5 stream channel. Slope gradients along the alignment generally remain gentle to moderate (5% to 30%). All drainage crossing this section of the alignment joins the main stem stream #3 channel prior to the abrupt transition to the down slope gully system below approximately 1485 m elevation. In general, the surficial material along this portion of the alignment is a till blanket on the order of 1.0 m to 2.0 m in thickness, with occasional thinner and thicker material sections. The till texture generally ranges from silty sand with some gravel to gravelly silty sand with a trace cobbles, boulders, and clay. The typical coarse fragment content of the till ranges from approximately 25% to 35%. Soils are generally moderately, with common areas of imperfectly soils associated with some swales and receiving sites. Frequent shallow swales are crossed, with no significant gully crossings encountered along the alignment. In addition, five NCD s and two S6 streams are crossed by the alignment. Most watercourses crossed likely experience intermittent (seasonal) flow, as opposed to perennial (permanent) flow. Permanent seepage can be expected at the most

31 SCL# April 2013 defined receiving sites. Seasonal surface flow connectivity to the main stem S5 stream channel is likely at all S6 stream and NCD crossings. No indication of slope instability was observed along the PN alignment. As discussed in Section 3.3, landslides along forest roads on similar terrain within the region are very uncommon, and where they have occurred they are generally associated with outdated road construction practices. Gentle slope gradients with imperfectly soils and areas of seepage are encountered in some locations. While not necessarily a concern with respect to road prism slope stability, these types of sites often pose challenges to construction and can also contribute to subsurface runoff interception. Some wet areas may warrant special construction methods such as importing suitable free draining sub-base material or using a suitable permeable geotextile underlay for subsurface soil separation. Refer to the attached construction summary tables for applicable sections. There is the potential for redirected runoff along the proposed road due to a combination of the continuous favourable grade and frequency of wet sites and seasonal watercourses. Significant redirection capable of affecting down slope stability is unlikely on the gully headwall, as all drainage reaches the S5 stream channel prior to the steeper down slope terrain. However, there is potential for concentrated and accelerated runoff which could affect stream flow. Frequent culvert placements are recommended in combination with effective seasonal deactivation measures during periods of non-industrial use in order to reduce the potential for concentrated and accelerated runoff, and the related potential changes to stream flow Down Slope Description PN In general, terrain down slope of the alignment remains gentle gradient (<25%) approaching the S5 stream channel of stream #3 situated approximately 90 m to 430 m to the north or northwest. The stream #3 gully headwall at the top of the steep down slope gully system is located over 850 m downstream to the north from the PN alignment, with the separating stream channel gradients averaging between 8% and 17%. Refer to report Section for a description of this down slope gully system Landslide Partial Risk Analysis PN The primary slope stability concern relating to the PN road is the potential for causing accelerated runoff into the down slope gully of stream #3 by means of a combination of interception, concentration, and/or redirection. Other geotechnical concerns include construction through wet soils on gentle slopes and the potential for erosion and sediment delivery. Careful road drainage management which considers the potential for cumulative effects of the proposed PN 11000, PN 11030, and PN roads as as planned harvest areas has been prescribed in order to reduce the potential for changes to down slope flow regimes. Road Prism Hazards Based on the regional landslide process information presented in Section 3.3 and the site conditions described in Section 3.6, there is predominantly a very low likelihood of a

32 SCL# April 2013 road prism landslide following conventional sidecast fill construction on the gentle gradient terrain. A low likelihood applies to some areas with gentle side slopes but imperfectly soils. Based on the regional landslide process information presented in Section 3.3 and the gentle gradient down slope terrain prior to the S5 stream and downstream gully headwall, a road prism landslide would likely remain small in size (50 m 3 to 500 m 3 ) and terminate prior to impacting the S5 stream. Road Prism Hazard Related Risks In the event of an impact by a landslide to one of the seasonal watercourses crossed by the alignment, it is possible that some suspended sediment could reach the valley bottom and the Little Slocan River via stream #3. Elevated turbidity at the valley bottom would likely be limited in both severity and duration due to the separating distance and effects of dilution in the larger stream. Conservatively assuming some limited sediment delivery to fish habitat in the event of a road prism landslide, there is a very low to low partial risk relating to limited temporarily elevated turbidity reaching fish habitat (partial risk equivalent to the likelihood of a road prism landside). GoS Hazards and Related Risks The down slope GoS Hazards and Related Risks for this road section are essentially the same as for the PN Section 2, so have not been repeated here. Refer to report Section for a partial risk analysis relating to the down slope stream # 3 gully as it applies to PN Section 2, which is also applicable to PN PN The PN alignment remains within the mid elevation range of the stream #3 drainage basin on the east aspect slopes above the S5 stream channel. It ascends with a continuous favourable grade and one switchback. Slope gradients along the alignment generally remain gentle to moderate (10% to 45%). All drainage crossing this section of the alignment joins the main stem stream #3 channel prior to the abrupt transition to the down slope gully system below approximately 1485 m elevation. In general, the surficial material along this portion of the alignment is a till blanket on the order of 1.0 m to 1.5 m in thickness from the POC to approximately Hub 25, with predominantly thinner materials on the order of 0.5 m thick between Hub 25 and the POT. The till texture generally ranges from silty sand with some gravel to gravelly silty sand with a trace to some cobbles, and a trace boulders and clay. The typical coarse fragment content of the till ranges from approximately 25% to 35%. Soils are generally moderately, with common areas of imperfectly soils between Hub 7 and Hub 20 associated with swales and receiving sites. Frequent shallow swales are crossed, with no significant gully crossings encountered along the alignment. In addition, one NCD is crossed by the alignment. Permanent seepage can be expected at the most defined receiving sites. Seasonal surface flow connectivity to the main stem S5 stream channel is possible at the NCD crossing, as as from the cross drain culverts located near the switchback.

33 SCL# April 2013 No indication of slope instability was observed along the PN alignment. As discussed in Section 3.3, road prism landslides along forest roads on similar terrain within the region are very uncommon, and where they have occurred they are generally associated with outdated road construction practices. There is the potential for redirected runoff along the proposed road due to a combination of the continuous favourable grade, frequency of wet sites, and the switchback. Significant redirection capable of affecting down slope stability on the gully headwall is unlikely as all drainage reaches the S5 stream channel prior to the steeper down slope terrain. However, there is some potential for concentrated and accelerated runoff which could affect stream flow in stream #3. Frequent culvert placements which have been aligned through the switchback are recommended in combination with effective seasonal deactivation measures during periods of non-industrial use in order to reduce the extent of concentrated and accelerated runoff, and the related potential changes to stream flow Down Slope Description - PN In general, terrain down slope of the alignment remains gentle to moderate gradient (<45%) approaching the S5 stream channel of stream #3 situated down slope to the east. The stream #3 gully headwall at the top of the steep down slope gully system is located over 500 m downstream to the north from the PN alignment, with the separating stream channel gradients averaging between 8% and 17%. Refer to report Section for a description of this down slope gully system Landslide Partial Risk Analysis PN The primary concern with respect to slope stability relating to the PN road is the potential for causing accelerated runoff into the down slope gully of stream #3 by means of a combination of interception, concentration, or redirection. Other concerns include construction through wet soils on gentle to moderate gradient slopes, and erosion and sediment delivery. Careful road drainage management has been prescribed which considers the potential for cumulative effects of the proposed PN 11000, PN 11030, and PN roads, as as planned harvest areas in order to reduce the potential for changes to down slope flow regimes. Road Prism Hazards Based on the regional landslide process information presented in Section 3.3 and the site conditions described in Section 3.7, there is predominantly a very low likelihood of a road prism landslide following conventional sidecast fill construction on the gentle to moderate gradient terrain. A low likelihood applies to some areas with imperfectly soils. Based on the regional landslide process information presented in Section 3.3 and the gentle to moderate gradient down slope terrain prior to the S5 stream and downstream gully headwall without significant gully confinement, a road prism landslide would likely remain small in size (50 m 3 to 500 m 3 ) and mostly terminate prior to reaching the S5 stream #3 channel. Some debris and fine sediment may reach the S5 stream channel, but a major change to channel morphology is unlikely.

34 SCL# April 2013 Road Prism Hazard Related Risks In the event of a landslide impact to one of the adjacent seasonal watercourses crossed by the alignment or the S5 stream channel down slope, it is possible that some suspended sediment could reach the Little Slocan River via stream #3. Elevated turbidity at the Little Slocan River would likely be limited in both severity and duration due to the separating distance, seasonal nature of the tributary watercourses, and effects of dilution in the larger streams. Conservatively assuming some sediment delivery to fish habitat in the event of a road prism landslide, there is a very low to low partial risk relating to temporarily elevated turbidity reaching fish habitat (partial risk equivalent to the likelihood of the road prism landslide). GoS Hazards and Related Risks The down slope GoS Hazards and Related Risks for this road section are essentially the same as for the PN Section 2, so have not been repeated here. Refer to report Section for a partial risk analysis relating to the down slope stream # 3 gully as it applies to PN Section 2, which is also applicable to PN Cumulative Effects of Forest Development An important consideration in forest development planning and operations is the potential cumulative effects that multiple contributing factors can have on down slope stability. Some landslides attributable to up slope forest developments may be unlikely to result from only one or a few development related factors, but can result from the cumulative effects of several factors. In general, this report has focused on terrain stability concerns relating to the proposed road construction, with descriptions and partial risk ratings provided above for individual road sections with similar characteristics. A separately commissioned hydrologic assessment has been completed by Summit Environmental Consultants Ltd. (Summit 2013) to consider the potential cumulative effects of the proposed forest development on stream flow. In order to fully consider the partial risk relating to down slope stability in this particular GoS scenario, consideration is also given within each of the main drainage areas to the potential for cumulative effects (including the likelihood for redirected runoff, the likelihood of a hazardous landslide attributable to the proposed road construction, the likelihood for an increase in peak flows, down slope sensitivity, and stream channel sensitivity). The Summit report indicates a low likelihood of increased peak flows in all of the affected drainage areas as a result of the proposed forest development including timber harvesting and road construction. Combining the Summit results with the site specific TSA results along the proposed road alignments, it can be concluded that assuming normal good development practices are followed along with all recommendations in this TSA report and the Summit report, there is a low residual incremental increase in the likelihood for a down slope debris flow in each of the affected drainages attributable to the proposed road construction of PN Mainline Extension, PN 11000, PN 11030, and PN Debris flow events in these gully systems have occurred in the past and will occur again in the future; however, the magnitude and frequency of events is unlikely to be significantly affected by the proposed road construction.

35 SCL# April Soil Erosion Considerations It has been documented that the majority of soil erosion resulting from forest development is caused by roads and trails as opposed to timber harvesting. In general, the till soils along the majority of the road alignment can be susceptible to erosion based on the material properties. Using the criteria of Jordan (2000) and assuming a moist climate regime, the soil erosion hazard is rated as predominantly high, with areas of very high where thick materials and imperfectly soils are present, and areas of moderate where the surface configuration is and surficial materials are thin. Refer to Appendix C for Soil Erosion Hazard criteria and management implications. Erosion and sediment control measures should be focused where the potential for sediment delivery to watercourses is greatest, such as at and adjacent to watercourse crossings. In the event of erosion and subsequent sediment delivery to a watercourse, the likelihood of significantly elevated suspended sediment loads reaching fish habitat is reduced due to a combination of factors. These factors include the frequency of natural sediment traps within the upland watercourses, the relatively small flow rates of the NCD and S6 streams at the crossing locations in comparison with the larger water volumes of the main stem tributaries and the Little Slocan River, the downstream distance in excess of 2 km between the road alignment and fish habitat, and the seasonal nature of the streams which likely only have surface flow connectivity for a portion of the year. In addition, the relative proportion of silt and clay within the soil matrix is not high. The silt and clay fraction is generally capable of significantly further downstream transport than the sand fraction due to decreased settling rates. Efforts should be made to control erosion at the source as opposed to controlling sediment once erosion has occurred; in practice the latter is generally more costly and less effective. Where thicker materials with imperfect or poor soil drainage are encountered in close proximity to seasonal watercourses, over-landing with a coarse rock sub-grade has been recommended to reduce the potential for shallow subsurface water interception as as erosion and sediment delivery. The potential for erosion also increases where road grades are steeper than approximately 12%. A portion of the PN road has grades in excess of 12%, and road surface erosion should be controlled with frequent waterbars during periods of non industrial use (as recommended in Section 4). If no erosion and sediment control measures are implemented during construction, there is a high likelihood that erosion and subsequent sediment delivery to watercourses crossed by the alignment would result, and a moderate likelihood that significantly elevated suspended sediment loads would reach fish habitat in the Little Slocan River. This effect would likely be limited to periods of high runoff during the first few years following construction. Based on comparison with similar roads in the region, assuming preventative erosion and sediment control measures are installed at the time of construction based on the recommendations presented in this report, including normal good construction practices and ongoing assessment of required works by a qualified construction supervisor in consultation with a qualified registered professional, the likelihood of significant soil erosion will be reduced to

36 SCL# April 2013 low. The resulting residual partial risk of significant sediment delivery to fish habitat will be reduced to low. 4.0 RECOMMENDATIONS Refer to the attached construction summary tables for station by station recommendations of construction methods as as culvert sizing and placement. Recommended cut and fill slope angles presented in the construction summary tables are based the experience of SCL, taking into account the specific material properties and slope configurations in comparison with existing cut and fill slope angle performance in the local and regional area. In addition, the following general recommendations apply to all road segments to reinforce or supplement normal good construction practices General Recommendations 1. Refer to Figure 7 for a typical section of a placed rock fill, Figure 8 for a typical section of a keyed in rock fill, and Figure 9 for typical section of a dumped rock fill. 2. Culvert inlets and outlets should be armoured with coarse rock (>300 mm diameter) to reduce the likelihood of blocked culverts from cutslope sloughing and erosion from culvert discharge. 3. Some culvert discharge take-off ditches will be required for culvert outlets on gentle slopes with little fill. These lateral ditches should be constructed to allow for unimpeded flow from the culvert outlet. 4. Construction should be modified or suspended when there is abundant hill slope runoff occurring at the site, which is likely to occur during times such as spring break-up or periods of high runoff from prolonged heavy precipitation. This is intended to reduce the likelihood of concentrated or redirected drainage as as unstable excavations and fill placements due to saturated soil conditions. 5. requirements for construction can be sourced from the cutslope where bedrock is encountered, and from additional optional quarry sites adjacent to the alignment. Some suitable quarry sites have been identified in the construction summary tables, and additional sites can be identified during construction if required. 6. The road grade should be swaled at stream culverts and culverts draining seepages sites wherever practical. Low points in the road grade are not always achievable in the geometric road design; however, can often be accommodated during construction, and provide a functional and fail safe limit to the potential for redirected runoff. 7. If late fall or winter road construction is carried out, a plan should be in place for the effective installation of drainage control measures prior to any necessary shut downs (e.g. spring break up or other). Proper culvert placement or cross ditch installations in hard frozen ground can be difficult to achieve, but effective drainage management as prescribed is required at all times for the presented risk analysis to apply.

37 SCL# April Erosion and Sediment Control Recommendations 1. The road surface should be frequently crowned, in-sloped, or out-sloped to shed runoff and limit the potential for road surface runoff to continue down grade for extended distances. This recommendation applies to the entire length of all assessed roads and is intended to reduce the potential for runoff to be redirected for significant distances on the road running surface. 2. Where seepage is encountered and materials are highly erodible, or where sediment delivery to a watercourse is possible, cut slopes should be armoured using >200 mm rock and a suitable permeable geotextile underlay. This recommendation is intended to improve cut slope stability and reduce erosion and sediment delivery. An option to use rolled erosion control products, such as coconut matting, on cut slopes adjacent to watercourses may be appropriate instead of armouring in some locations where erosion may be a concern but cut slope stability is not. Final determination of appropriate erosion control or cut slope stabilization works is to be determined at the time of construction by a qualified road construction supervisor in consultation with a qualified registered professional. 3. If significant or unexpected seepage is encountered then a field review by a qualified registered professional is required to confirm appropriate drainage management. 4. Check dams made of rock (>150 mm diameter) with a geotextile filter fabric and/or anchored straw bales wrapped with filter fabric should be installed in the ditch line approaching watercourse crossings as as at nearby contributing culverts. The extent and configuration of these control structures should be confirmed at the time of construction by the construction supervisor and a qualified registered professional. This recommendation is intended to reduce the likelihood of sediment delivery to watercourses which may have seasonal connectivity with down slope elements at risk. 5. S6 and S5 stream culverts should be installed using appropriate in the dry methods. In the dry methods use a non-erosive diversion of flow (e.g. flexible diversion pipe) around a work site to install a culvert into a dry channel prior to returning flow to the original channel with culvert in place. This is intended to reduce the amount of sediment production and delivery to watercourses during construction. Appropriate methods for NCD crossing installations should be confirmed by the BCTS road foreman at the time of construction based on conditions encountered (e.g. material properties, flow rate, connectivity to S6 or S5 streams). 6. Cut slopes and fill slopes should be seeded with an appropriate seed mix as soon as practicable after construction. 7. A suitable road base of non-erodible material should be installed where the road is located on thick soils with imperfect or wetter drainage, or embankment material is fine textured and over-landing is not recommended or beneficial. Suitable materials would include small blast rock or rippable rock, with a nominal base thickness of 200 mm. Approximately 2 km to 4 km of suitable road base installation is likely to be required to reduce seasonal use restrictions, as as reduce erosion and maintenance requirements. Most of this requirement is anticipated within the stream # 3 basin, with final requirements to

38 SCL# April 2013 be determined by the BCTS road foreman at the time of construction based on conditions encountered Maintenance and Deactivation Recommendations The following general maintenance activities are recommended to reduce the likelihood for redirected runoff: 1. seasonal deactivation measures during periods of non-industrial use (back up cross ditches for all watercourse culvert locations, and intermediate back up cross ditches and waterbars as appropriate based on ground conditions and location of drainage divides and seepage areas); 2. regular road inspections for additional required maintenance/work (possible ditch cleaning, culvert cleaning, additional water bar or cross ditch placements, or cross ditch improvement). Road inspections should take place semi-annually, once in the fall and once during the spring freshet, for the first two years following road construction. Subsequent inspections should be based on BCTS road maintenance inspection protocols, and carried out at least annually as as following industrial use, taking into account the results of previous inspections. Timing the inspection during the freshet is especially important during the first two years to ensure the road drainage structures are functioning as intended and that small cut slope sloughing does not result in blocked ditch lines. Seasonal deactivation measures during extended periods of non-industrial use should include additional drainage control measures, such as more frequent waterbars and cross ditches Site Specific Recommendations The following site specific maintenance recommendation is intended to reduce the likelihood of road surface runoff and erosion: 1. Seasonal deactivation methods should include frequent (20 m spacing) waterbars on continuous roads sections greater than 12% gradient, such as on sections of the PN and PN roads. 4.2 FIELD REVIEWS If site conditions encountered vary significantly from those described in this report (e.g. unexpected and significant seepage, unexpected material textures encountered in excavations, etc.), or if any stability or erosional concerns become apparent during construction, then an immediate field review by a qualified registered professional is recommended. Timely mitigation of problem sites can significantly reduce potential adverse effects. Construction supervision must be carried out by a qualified person (BCTS road foreman) with knowledge of the local terrain and down slope elements at risk. Field reviews by a qualified registered professional during and at completion of construction are required to confirm final culvert placement, the subsurface conditions encountered, and that the intent of the recommendations are being met. An additional field review of the road systems by a qualified registered professional

39 SCL# April 2013 is required during the first spring runoff following construction to confirm functional drainage control.

40 SCL# April CLOSURE The discussions and recommendations presented above are based on a visual field assessment and additional information, which was reviewed at the time of the assessment. This report has been prepared for the use by BCTS, which includes distribution as required for purposes for which the assessment was commissioned. The assessment has been carried out in accordance with generally accepted geotechnical practice. Geotechnical judgment has been applied in developing the recommendations in this report. No other warranty is made, either expressed or implied. SCL trusts that the information presented above meets your current requirements. If you have any questions, or require further information, please do not hesitate to contact the undersigned. Respectfully submitted, Sitkum Consulting Ltd. Prepared by: Reviewed by: Tedd Robertson, P.Geo. Eng.L. Geoscientist - Principal Wayne Miller, P.Geo. Eng.L. Engineering Geologist - Principal

41 SCL# April REFERENCES AFPBC/APEGBC, Guidelines for terrain stability assessments in the forest sector. Association of Professional Engineers & Geoscientists of British Columbia (APEGBC), Burnaby B.C. Apex Geoscience Consultants Ltd Geological Hazards Mapping of the Slocan Valley, Phase 1, In the Arrow Forest District. Report for the Arrow Forest District. Apex Geoscience Consultants Ltd Hydrological Assessment of Drainage Areas A and B, Perry Ridge North. Report for the Arrow Forest District. B.C. Ministry of Forests, Soil Erosion Hazard Criteria for Watershed Assessments in the Southern Interior-final report. B. C. Ministry of Forests, Forest road engineering guidebook. For. Prac. Br., B.C. Min. For., Victoria, B.C. Forest practices Code of British Columbia Guidebook. B. C. Ministry of Forests, Biogeoclimatic Ecosystem Classification Subzone/Variant Map for the Kootenay Lake Forest District, Nelson Forest Region, 1:250,000 scale. Boyer et al Perry Ridge Risk Assessment for the Perry Ridge Local Resource Use Plan (LRUP) Table. Chatwin, S Perry Ridge Road Right of Way: Assessment of Stability and Soil Erosion Hazard. Report for the Arrow Forest District. Corominas, J The angle of reach as a mobility index for small and large landslides. Can. Geotech. J. 33: NRC Research Press (1996). D.J. Grant Engineering Ltd., Perry Ridge Forest Service Road (km ) Stability Assessment and Engineering Prescriptions, report for the Arrow Forest District. Geertsema et al., Hillslope Processes. Chapter 8 in Compendium of forest hydrology and geomorphology in British Columbia. Pike et al. (eds.) B.C. Min. For Range., For. Sci. Prog., Victoria, B.C. and FORREX Forum for Research and Extension in Natural Resources, Kamloops B.C. Land Manag. Handb. No. 66. Grainger, B Terrain stability assessments in gentle-over-steep terrain of the southern interior of British Columbia. in Terrain stability and forest management in the Interior of British Columbia workshop proceedings, May 23-25, 2001 Nelson, BC. Jordan, P. and J. Orban (eds.) Res. Br., B.C. Min. For., Victoria, B.C. Tech Rep Hungr et al Entrainment of material by debris flows; in Debris Flow Hazards and Related Phenomena. pp Jacob, M. and Hungr, O. (eds). Praxis. Springer Berlin Heidelberg Hunter, G. and Fell, R Travel distance angle for rapid landslides in constructed and natural soil slopes. Can. Geotech. J. 40: NRC Research Press (2003). Isaacson, A Hydrology Report for Perry Ridge Jordan, P. and Nicol, D., Geotechnical Review and Risk Analysis of a proposed Forest Development Plan on Woodlot License 1702, Perry Ridge, Arrow Forest District. Report for the Arrow Forest District.

42 SCL# April 2013 Jordan, P Regional Incidence of Landslides; in Watershed Assessment in the Southern Interior of British Columbia: Workshop Proceedings, March 9-10, 2000 Penticton, B.C. Toews, D.A.A. and Stephen Chatwin (eds.) Res. Br., B.C. Min. For., Victoria, B.C. Work Pap. 57/ Jordan, P Landslide Frequencies and Terrain Attributes in Arrow and Kootenay Lake Forest Districts. in Terrain stability and forest management in the Interior of British Columbia workshop proceedings, May 23-25, 2001 Nelson, BC. Jordan, P. and J. Orban (eds.) Res. Br., B.C. Min. For., Victoria, B.C. Tech Rep Jordan et al Debris flow hazards in the southern interior of British Columbia: the problem of events with unusually long runout. GeoHazPaper124. Proceedings of the 5 th Canadian Conference on Geotechnique and Natural Hazards; Kelowna, May 15 to 17, McIntyre Woods Geotechnical Engineers, Detailed Terrain Stability Report (TSIL B) Woodlot 1702, Perry Ridge, B.C. Report for West Kootenay Woodlot Association, Woodlot Massey, N.W.D, D.G. MacIntyre, P.J. Desjardins, and Cooney, R.T., Digital Geology Map of British Columbia: Tile NM11 Southeast B.C., B.C. Ministry of Energy and Mines, Geofile Salway Perry Ridge Hazard Assessment. Report for the Valhalla Wilderness Society. Skaha Consultants, 2002 (N. Skermer). Review Slocan Valley Hazard Mapping. Report for the Regional District of Central Kootenay. Summit Environmental Consultants Ltd Hydrologic Assessment Perry Ridge T.S.L. A80073; Proposed Blocks 1, 2, and 3. Report for BCTS, Kootenay Business Area. Summit Environmental Consultants Ltd (January). DRAFT Hydrologic Assessment of areas of interest, Perry Ridge. Report for BC Timber Sales, Kootenay Business Area. VanDine, D. F Debris flow control structures for forest engineering. Res. Br., B.C., Min. For. Victoria, B.C., Work. Pap. 22 VanDine et al Perry Ridge, an Example of a Risk Assessment for Forestry Planning (Published in: Confronting Uncertainty: Managing Change in Water Resources and the Environment, Canadian Water Resources Association, British Columbia Branch, Conference Proceedings, Oct , 1999, Richmond, B.C., p ) Wise et al Landslide risk case studies in forest development planning and operations. B.C. Min. For., Res. Br., Victoria, B.C. Land Manage. Handb. No

43 Appendix A Photos

44 SCL# i April 2013 Photo 1: POT of existing PN Mainline as seen from the POC of new construction PN Mainline Extension (TR photo, June 9 th, 2012). Photo 2: POC of PN Mainline Extension (Hub 42 painted orange in centre of image) as seen from the POT of existing PN Mainline (TR photo, June 9 th, 2012).

45 SCL# ii April 2013 Photo 3: S5 stream crossing at Hub 174 on PN (July 31, 2012 photo).

46 SCL# iii April 2013 Photo 4: Confluence of large S6 tributary stream channel (R) and main stem S5 stream channel (L) at approximately 1485 m elevation, immediately prior to the steep gradient stream #3 gully down slope (June 28, 2012 photo).

47 SCL# iv April 2013 Photo 5: Upper reach of the stream #3 gully headwall showing steep forested side slopes, bedrock cliffs and tributary gullies.

48 SCL# v April 2013 Photo 6: Upper reach of the stream # 3 channel in main gully showing bedrock along the channel and high energy flow.

49 SCL# vi April 2013 Photo 7: Upper reach of the stream #3 channel showing waterfall through a bedrock canyon section.

50 SCL# vii April 2013 Photo 8: Upper reach of the stream #3 channel showing bedrock cliff and active rock fall.

51 SCL# viii April 2013 Photo 9: Steep channel gradient in the upper reach of stream #3 showing coarse bed load material including large boulders, angular blocks and some large woody debris.

52 SCL# ix April 2013 Photo 10: Snow and woody debris indicative of impacts to the stream #3 channel from winter 2012 snow avalanches.

53 SCL# x April 2013 Photo 11: Bouldery debris levee containing some coarse material, including boulders up to 3 m 3 indicative of periodic large debris flow events within the stream #3 gully. The most recent large channel forming event is estimated at 100+ years in age.

54 SCL# xi April 2013 Photo 12: Recent debris slide (<2 years) along west gully sidewall directly adjacent to the stream #3 channel. Re-vegetated features on adjacent slopes indicate repeated events over time. Photo 13: Vegetated sediment wedge with deteriorating log jam from older events within stream #3.

55 SCL# xii April 2013 Photo 14: Reforested lateral deposit with partially buried and decomposing woody debris located on the east side of the stream #3 channel resulting from a past significant debris flow event. Photo 15: Mature trees showing impact scarring and embedded cobbles in lower trunk from past debris flow events within stream #3.

56 SCL# xiii April 2013 Photo 16: Close up of embedded cobble adjacent to stream #3 as seen in Photo 14. Photo 17: Open, blocky talus slope at the base of cliffs on the west side of the stream #3 channel, which is also the runout zone of a snow avalanche path (size 3) on the east side of the channel. Note lack of weathering on the rock surfaces along the lower right of the talus slope indicating relatively recent movement.

57 SCL# xiv April 2013 Photo 18: Debris flow levee located near the top of the stream #3 fan. Photo 19: Debris flow levees located near the top of the stream #3 fan. Note the impact scarring on the mature cottonwood indicating smaller, less destructive debris flow events on the order of 15 to 30 years in age.

58 SCL# xv April 2013 Photo 20: Little Slocan FSR crossing of stream #3 (November 7, 2011 photo).

59 Appendix B Construction Summary Tables

60 Perry Ridge North PN Mainline Extension Construction Summary Tables

61 Perry Ridge North Mainline Extension TSA 1 April 8, 2013 Station/Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS Station/Survey Hub naming convention: 42 hubs as flagged in the field by Timberland Consultants (2001) Ltd. in 2011, and referenced in design by SEL in SEL Design Reference Stationing (fish) CUT FILL ( ) Timberland Consultants (2001) field chainage WP 1 SCL GPS waypoints ( ) WP 1 59/8 20/.. -37/7 Silty sand with some gravel to gravelly silty sand with trace cobbles, boulders, and clay; 30% coarse fragments (1m) Well II L VL END OF BUILT ROAD START OF PERRY RIDGE NORTH (PN) MAINLINE EXTENSION TERRAIN STABILITY ASSESSMENT (TSA); Note: First assessment from Hub 42 to Hub 146 completed in November 2011; second assessment (Hubs 42 to POT) in snow-free conditions, June 2012 Coincides with Hub on 2008 survey for PN Mainline (now existing) Bedrock (gneiss) exposed ~5m above p-line ( ) WP 2 21/4 52/.. -14/13-26/.. As described (1.5m) II L VL Conventional sidecast fill construction INSTALL 450mm CULVERT At broad swale, NVC

62 Perry Ridge North Mainline Extension TSA 2 April 8, 2013 Station/Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( ) WP 3 32/.. -23/8-31/.. As described (1.5m) II VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT At shallow swale, NVC ( ) WP 4 10/.. -7/11-20 As described (1m) Imperfectly at swale, to moderately on adjacent slopes II L VL Conventional sidecast fill construction INSTALL 450mm CULVERT At moist swale, NVC ( ) WP 5 11/ -15/ As described (1.5m) Imperfectly IV L VL Conventional sidecast fill construction INSTALL 600mm CULVERT At NCD in shallow swale NCD is located ~3m on town side of hub Locate culvert to capture all drainage from swale ( ) WP6 30/10 38/ -20/ As described (1.5m) IV VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT At broad concave slope to disperse seasonal ditch flow (1+520) 26/ -34/ As described (1.5m) IV VL VL Conventional sidecast fill construction POSSIBLE INSTALL 450mm CULVERT if seepage is encountered between here and Hub 64

63 Perry Ridge North Mainline Extension TSA 3 April 8, 2013 Station/Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( ) WP 7 35/ -35/ As described (1.5m) II VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT To capture seasonal cutslope seepage at broad swale (moist NVC) and direct into down slope gully, approximately 5m on town side of hub ( ) WP 8 35/6 26/ -35/ As described (1m) II VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT Above down slope gully, dry NVC Down slope gully remains separate from 64 gully for at least 50 m ( ) WP 9 32/4 43/ -43/9-36/ As described (1.5m) II L L Conventional sidecast fill construction INSTALL 450mm CULVERT Above broad down slope swale, NVC ( ) WP 10 46/ -18/4-5/8 5/ As described (1.5m) I L L Conventional sidecast fill construction INSTALL 450mm CULVERT Above swale, NVC

64 Perry Ridge North Mainline Extension TSA 4 April 8, 2013 Station/Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL ~0+752 (~1+749) As described (1.5m) I VL VL Conventional sidecast fill construction At this high point in the road grade, it is favourable on town side and adverse on woods side Maintain high point in design/construction ( ) WP 11 16/ -9/15-20/ As described (1.5m) Imperfectly III L VL Overland construction INSTALL 600mm CULVERT At NCD in wet swale Wet swale with Devil s Club, and channel contains organics with no visible gravel/alluvial bedload Construct an overland crossing (about 15m overlanding required) and maintain low point in grade ( ) WP 12 23/ -11/ As described (1.5m) to imperfectly III VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT At moist swale, NVC This drains into a moist depression prior to micro drainage divide down slope ( ) WP 13 30/ -13/ As described (1.5m) Imperfectly II L L Conventional sidecast fill construction INSTALL 450mm CULVERT At moist swale, NVC, prior to small drainage divide

65 Perry Ridge North Mainline Extension TSA 5 April 8, 2013 Station/Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( ) WP 14 35/5 28/ -15/ As described (2.0m) Imperfectly II L VL Conventional sidecast fill construction INSTALL 450mm CULVERT At wet swale prior to small down slope drainage divide, minor flow in June (2+086) WP 15 53/6 24/10 55/ -44/8 0/3 32/ at surface 0 m II L VL Conventional sidecast fill construction INSTALL 450mm CULVERT Above dry swale, NVC, which is draining to W-NW To maintain drainage to natural pattern ( ) WP 16 40/7 21/ -18/7-13/ As described Veneer (< 0.3m) on town side; (1m) on woods side. Well II L VL Conventional sidecast fill construction INSTALL 600mm CULVERT At -defined dry swale, NVC, ~2m deep; surface flow in June ( ) WP 17 28/ -10/5-23/13-15/ As described (1 m) to imperfectly II L VL Conventional sidecast fill construction INSTALL 600mm CULVERT At NCD in -defined swale; flow in June 2012 Construct as low point in road grade if reasonably possible ( ) 61/9 20/ -45/10-36/10-15/ As described Veneer (0.3 m ) Well II L VL End conventional sidecast fill construction; Start ¾ bench to full bench construction with endhaul through nose in slope Use rock for keyed-in fills & armouring 1H:1V Keyed Fill 1.1H:1V

66 Perry Ridge North Mainline Extension TSA 6 April 8, 2013 Station/Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( ) WP 18 50/ -50/18-43/ As described Veneer (0.5 m) Well II L VL End ¾ bench, start keyed in rock fill across swale. INSTALL 450mm CULVERT In shallow swale prior to small drainage divide Keyed in Fill 1.1H:1V (2+433) 39/5 46/ -34/9-50/ As described (1.5 m) II L VL End keyed in rock fill, Start conventional sidecast fill construction ( ) WP 19 28/9 55/9 20/ -12/10-46/ As described (1m) II L VL Conventional sidecast fill construction INSTALL 600mm CULVERT At -defined swale; signs of seasonal surface flow. Conservative culvert size recommended due to size of fill at defined swale ( ) WP 20 29/8 18/ -21/ As described Veneer (0.5m) Well III VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT To disperse ditch water prior to small drainage divide; no -defined drainage feature here. A transition to 70% gradient slopes is within 50 m down slope

67 Perry Ridge North Mainline Extension TSA 7 April 8, 2013 Station/Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL (2+617) WP 21 24/5 12/8 23/ -30/3-15/8-31/ As described Veneer (0.5m) Well II VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT To disperse seasonal ditch water prior to drainage divide on town side of 111 Culvert placement intended to avoid concentrating water onto slope break approximately 50m down slope ( ) WP 22 20/ -10/3-31/5-2/ As described Veneer (<0.5m) Well II L VL Conventional sidecast fill construction INSTALL 800mm CULVERT At S6, bedrock exposed in channel Alignment will maintain FAV grade through crossing ( ) 45/15 20/ 10/5 0/5-28/ As described Veneer (<0.5m) Well II VL VL Conventional sidecast fill construction Drainage divide and high point; switch from FAV to ADV ( ) WP 23 24/7-35/8 0/ -8/2 18/8-20/ As described Veneer (0.5m) II VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT At swale, NVC Top of NCD, flow begins 5 m down slope in June 2012

68 Perry Ridge North Mainline Extension TSA 8 April 8, 2013 Station/Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( ) WP 24 20/7 28/ -15/6-25/ As described (1m) to imperfectly II L VL Conventional sidecast fill construction INSTALL 450mm CULVERT At broad swale and likely low point in road grade. Expect seasonal seepage; surface water in June ( ) 33/5 10/ -25/8-50/ As described (1m) Well II VL VL Conventional sidecast fill construction High point in road grade ( ) WP 25 40/4 25/5 5/ -24/10-31/ As described (1m) II L VL Conventional sidecast fill construction INSTALL 600mm CULVERT At shallow swale, NCD; wet depression up slope Expect seasonal seepage and surface flow ( ) WP 26 22/11 31/ 0/2-19/14-42/ As described (1.5m) II VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT Down slope of -defined swale Expect seasonal seepage ~ (~3+124) WP 27 As described (1.5m) II L VL Conventional sidecast fill construction INSTALL 450mm CULVERT To maintain natural drainage; no defined drainage feature

69 Perry Ridge North Mainline Extension TSA 9 April 8, 2013 Station/Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( ) WP 28 31/ -35/ As described Veneer (0.5m) II VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT Down slope of -defined swale, NVC Signs of seasonal surface flow; minor flow in June ( ) WP 29 48/12 70/2 27/ -17/8-25/5-47/ As described Veneer (1m) Well to moderately III L VL Conventional sidecast fill construction INSTALL 450mm CULVERT Prior to small drainage divide ( ) WP 30 30/5 43/ -14/ As described Veneer (1m) Well III VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT At -defined swale, NVC 140 to 146 Construction field review to confirm if additional culverts are required (3+479) WP 31 80/2 46/ -45/5-22/10-49/ As described Veneer (0.5m) Well III L VL Conventional sidecast fill construction INSTALL 450mm CULVERT Above broad swale, NVC (3+553) WP 1000 POT 35/2 0/3 26/10 48/ -25/6-50/10-58/ As described (1m) Well III L VL END OF PN MAINLINE EX TENSION TSA; START OF PN TSA End conventional sidecast fill construction

70 Perry Ridge North Mainline Extension TSA 10 April 8, 2013 * Risk analysis is based on definitions provided in Appendix C: Risk Analysis Definitions and Overview and is consistent with Land Management Handbook 56, Landslide Risk Case Studies in Forest Development Planning and Operations (BCMoF 2004). P(H) refers to the likelihood of a hazardous landslide at the road prism as a result of conventional ½ bench cut, side cast fill construction. P(HA) refers to the likelihood of a hazardous and affecting landslide (partial risk) at the road prism as a result of conventional ½ bench cut, side cast fill construction, with the considered element shown in brackets. The residual likelihoods are based on following all recommendations as presented in these tables and the accompanying report, along with normal good construction practices. Refer to attached report for additional information concerning the likelihood of a down slope landslide as a result of redirected drainage. Refer to the attached report for discussion with respect to all considered elements. NVC = No visible channel NCD = Non-classified drainage

71 Perry Ridge North PN Construction Summary Tables

72 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP 1000 POC 25/5 38/ -25/6-45/7-51/ Till: Gravelly silty sand with some cobbles and trace boulders, and clay; 25% to 35 % coarse fragments 1.0 m Well III L VL START OF Perry Ridge North (PN) TERRAIN STABILITY ASSESSMENT (TSA); Junction with PN Mainline Start conventional sidecast fill construction Road high point; start of adverse grade No WP 74/2 55/6 26/ -62/ Bedrock at surface 0.0 m Well III M/L M/L End conventional sidecast fill construction; Start ¾ bench construction with placed rock fill or full bench construction for short section approaching Hub 5 swale crossing Placed Fill 1H:1V WP 1 51/5 30/ -56/ Swale Veneer 0.5 m Well III M/L M/L Placed rock fill construction at crossing, then return to conventional sidecast fill construction INSTALL 450 mm CULVERT At dry swale, NVC Placed Fill 1H:1V WP 2 51/20 32/ -48/ Swale Veneer 0.5 m I M/L M/L Placed rock fill construction at crossing INSTALL 450 mm CULVERT At dry -defined swale, NVC; Swale becomes a gully 30 m down slope of alignment; Expect seasonal surface flow Placed Fill 1H:1V WP 3 53/4 15/3 40/5 17/ -55/7-37/ Veneer 0.5 m Well I L L Conventional sidecast fill construction INSTALL 450 mm CULVERT prior to small drainage divide At wood side of concave basin, NVC; Will drain into gully down slope of Hub 9;

73 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL No WP 31/4 50/13 16/ -20/4-65/2-45/ 1.0 m to imperfectly II L L Conventional sidecast fill construction Soil drainage changes WP 99 51/5 30/ -56/ Swale 1.0 m to imperfectly II M/L M/L Placed rock fill construction at crossing INSTALL 450 mm CULVERT At moist swale, NVC, expect seasonal seepage Construct as low point in road grade during construction if reasonably possible. Placed Fill 1H:1V 15.1 ~ No WP 48/3 35/ -18/7-30/10-47/ Veneer 0.5 m Well II L L Conventional sidecast fill construction No WP 50/3 32/4 18/ -32/3-65/2-45/6-37/ Veneer 0.5 m II L L Conventional sidecast fill construction Additional 450 mm CULVERT may be required near 17 to disperse seepage depending on as-built conditions WP / -18/3-32/5-11/ Swale 1.0 m to imperfectly II L L Conventional sidecast fill construction INSTALL 600 mm CULVERT; armour sides of fill adjacent to crossing At broad wet swale, NCD, flow directly below alignment disappears <50 m downslope

74 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP / -18/3-32/5-11/ Swale 1.0 m Imperfectly II L L Conventional sidecast fill construction INSTALL 600 mm CULVERT; armour sides of fill adjacent to crossing, install appropriate erosion and sediment control measures based on conditions encountered during construction At broad wet swale, NCD Construct as low point in road grade during construction if reasonably possible WP /3 30/ -30/ Swale 1.0 m to imperfectly II L L Conventional sidecast fill construction INSTALL 450 mm CULVERT At moist swale, NVC; Joins 20 NCD 20 m downslope 22.1 ~ No WP 36/6 16/ -36/ 1.0 m Well II VL VL Conventional sidecast fill construction Construct high point in road grade between 22 and 23 if reasonably possible during construction WP /7 20/ 0/2-35/10-21/ Bedrock at surface 0.0 m Well II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT At broad swale, NVC

75 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP / -20/ Swale Veneer 0.5 m to imperfectly II L L Conventional sidecast fill construction INSTALL 800 mm CULVERT; armour sides of fill adjacent to crossing, install appropriate erosion and sediment control measures based on conditions encountered during construction At -defined swale, S6 creek Bedload movement of ~ 15 cm diameter gravel and cobbles Construct as low point in road grade during construction if reasonably possible WP / -10/5-35/ Swale 1.0 m to imperfectly II L L Conventional sidecast fill construction INSTALL 600 mm CULVERT; armour sides of fill adjacent to crossing, install appropriate erosion and sediment control measures based on conditions encountered during construction At shallow swale, S6 creek; Joins 26 stream ~ 50 m down slope 30.1 ~ No WP 52/10 25/ -15/2-55/5-18/9-48/ Veneer 0.5 m Well II L L Conventional sidecast fill construction WP / -13/4-36/ Swale Veneer 0.5 m II L L Conventional sidecast fill construction INSTALL 450 mm CULVERT At -defined dry swale, NVC; Expect seasonal flow

76 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP /10 120/5 40/ -3/7-25/10-36/ Concave Veneer 0.5 m to imperfectly II L L Conventional sidecast fill construction INSTALL 450 mm CULVERT; construct as low point in road grade At broad moist depression, NVC No WP 31/10 50/10 55/ -38/ Swale Veneer 0.5 m II L L Conventional sidecast fill construction INSTALL 450 mm CULVERT At dry swale, NVC; Evidence of seasonal surface flow WP /15 58/7 25/ -39/ Swale 1.0 m II L L Conventional sidecast fill construction INSTALL 600 mm CULVERT; armour sides of fill adjacent to crossing, install appropriate erosion and sediment control measures based on conditions encountered during construction At broad swale, NCD WP /10 39/ -37/4-22/ Swale Veneer 0.5 m to imperfectly III L L Conventional sidecast fill construction INSTALL 600 mm CULVERT; armour sides of fill adjacent to crossing, install appropriate erosion and sediment control measures based on conditions encountered during construction At broad swale, NCD Discontinuous alluvial channel

77 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP /10 55/5 36/ -20/8-15/ Concave 1.0 m to imperfectly III L L Conventional sidecast fill construction INSTALL 600 mm CULVERT; armour sides of fill adjacent to crossing, install appropriate erosion and sediment control measures based on conditions encountered during construction At catchment area, NCD Construct as low point in road grade WP /7 30/9 50/ -23/16 0/ Concave Veneer 0.5 m III L L Conventional sidecast fill construction INSTALL 450 mm CULVERT Align with wet depression below road No WP 10/5 46/ -5/5-35/ Veneer 0.5 m Well III VL VL Conventional sidecast fill construction Construct as high point in road grade WP /3 18/ -35/4-40/10-15/ Swale Veneer 0.5 m III VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT At dry swale, NVC WP / -21/10-36/ Swale Veneer 0.5 m III VL VL Conventional sidecast fill construction INSTALL 600 mm CULVERT; armour sides of fill adjacent to crossing, install appropriate erosion and sediment control measures based on conditions encountered during construction At swale, NCD

78 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP / -37/17-55/ Swale Veneer 0.5 m Well to moderately III VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT At dry subtle swale, NVC; Discontinuous swale down slope WP /10 25/ -25/6-35/11-55/ Swale Veneer 0.5 m Well to moderately III L L Conventional sidecast fill construction INSTALL 450 mm CULVERT At dry broad swale, NVC Construct as low point in road grade. Next high point is between Hub 59 and Hub /10 150/2 20/ -45/10-70 Veneer 0.5 m Well to moderately III M/L M/L Placed rock fill construction to limit fill slope length above steeper slope below Placed 1H:1V No WP 54/15 20/ -60/13-80/ Bedrock at surface 0.0 m Well III M/L M/L End placed rock fill; Start full bench construction Bench approximately 70 m down slope No WP 63/ -70/10-63/ Bedrock at surface 0.0 m Well III M/L M/L Full bench construction Bench approximately 70 m down slope

79 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL No WP 65/5 130/3 100/3 60/ -61/18-50/ Bedrock at surface 0.0 m Well III M/L M/L End full bench construction; Start conventional sidecast fill construction Bench approximately 70 m down slope WP /5 40/2 50/ -48/20-30/ Bedrock at surface 0.0 m Well to moderately III L L Conventional sidecast fill construction INSTALL 450 mm CULVERT At dry broad swale, NVC WP /10 50/10 40/ -26/ Swale Veneer 0.5 m to imperfectly III L L Conventional sidecast fill construction INSTALL 600 mm CULVERT; construct as low point in road grade; armour sides of fill adjacent to crossing, install appropriate erosion and sediment control measures based on conditions encountered during construction At subtle swale, NCD; No alluvial bed, but evidence of strong seasonal flow Low point in road grade No WP 0/20 55/2 15/3 48/ -55/3-25/3-20/ Veneer 0.5 m Well III L L Conventional sidecast fill construction Junction with PN Some surface boulders to 1 m diameter near hub WP / -29/6-50/ Veneer 0.5 m Well III L L Conventional sidecast fill construction INSTALL 450 mm CULVERT For ditch relief

80 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP /8 18/ -38/5-62/9-30/ Swale Bedrock at surface. 0.0 m Well III L L Conventional sidecast fill construction INSTALL 450 mm CULVERT prior to small drainage divide At dry swale, NVC WP / -4/19-20/ Swale 1.0 m III VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT At dry broad swale, NVC WP /7 30/ -23/10-17/10-10/ Swale 1.0 m III VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT At dry swale, NVC WP /6 37/ -43/6-29/ Swale Veneer 0.5 m to imperfectly IV L L Conventional sidecast fill construction INSTALL 450 mm CULVERT At moist swale, NVC; Joins west-trending gully down slope; Evidence of seasonal surface flow No WP 39/ -50/5-20/2-50/15-60/ Bedrock at surface Veneer 0.0 m Well IV L L Conventional sidecast fill construction High point in road grade

81 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP /3 27/7 39/ -40/9-60/6-100/ Bedrock at surface Veneer 0.0 m Well IV M/L M/L Placed Fill at crossing INSTALL 600 mm CULVERT to reduce risk of blockage in Gentle Over Steep (GOS) terrain; Swale up slope, bedrock cliffs down slope, dry NCD; No alluvial bed, but evidence of small seasonal channel on forest floor at alignment Placed Fill 1H:1V No WP 47/12 30/ -45/9-30/10-80/ Veneer 0.5 m Well IV L L Conventional sidecast fill construction INSTALL 450 mm CULVERT, construct as low point in road grade For ditch relief No WP 31/7 45/ -25/15-35/ Veneer 0.5 m Well III VL VL Conventional sidecast fill construction Junction with PN Abrupt transition to -80% slope gradients not far down slope WP / -8/14-17/ Veneer 0.5 m Well III VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT Down slope of dry swale, NVC Abrupt transition to -80% slope gradients not far down slope No WP 15/8 120/2 0/ -15/2-40/9-20/ Bedrock at surface 0.0 m Well III VL VL Conventional sidecast fill construction High point in road grade

82 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL No WP 15/15 45/ 0/2-22/ Swale Veneer 0.3 m Well III VL VL Conventional sidecast fill construction INSTALL 600 mm CULVERT to reduce risk of blockage at dry swale, NCD, with evidence of significant seasonal flow on forest floor WP /10 180/5 20/ -38/5-18/ Veneer 0.5 m Well III L L Conventional sidecast fill construction INSTALL 450 mm CULVERT Align with large down slope swale trending south, NVC, dry No WP 46/6 58/ -35/ 1.0 m III L L Conventional sidecast fill construction Soil drainage changes WP /4 10/5 35/ -22/10-15/ Swale 1.0 m III VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT Align with -defined swale draining into S6 stream approximately 35 m down slope Low point in road grade No WP 28/8 45/ -5/ 1.5 m to imperfectly II L L Conventional sidecast fill construction Soil drainage changes

83 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL No WP 20/4 170/1 30/ -20/20 0/ 0.5 m Well to moderately II L L Conventional sidecast fill construction Soil drainage changes No WP 36/10 20/ -24/8-18/ 1.5 m to imperfectly II L L Conventional sidecast fill construction Soil drainage changes No WP 22/10 30/ -9/ Gully 1.5 m Imperfectly II L L Placed rock fill or dumped rock fill construction at crossing INSTALL 1000 mm CULVERT; install appropriate erosion and sediment control measures based on conditions encountered during construction Placed Fill 1H:1V S6 stream; gravel and cobble bedload 2 cm to 5 cm typical, mobile bedload up to 10 cm dia. Lots of functional woody debris in channel maintaining step pool morphology. Construct as low point in road grade during construction if reasonably possible (note: was not practical at design stage).

84 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL No WP WP No WP WP / -25/4-18/ 50/6 20/ 25/3 35/8 15/ -20/4-12/ -3/7-12/ 1.0 m Veneer 0.5 m Veneer 0.5 m to imperfectly II L L Conventional sidecast fill construction Soil drainage changes II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT For ditch relief onto gentle slopes prior to stream crossing II VL VL Start overland fill construction with suitable geotextile and imported free-draining material; End conventional sidecast fill construction Intent is to minimize cut as practical and provide free draining fill separated from the wet soil conditions with suitable geotextile fabric Install appropriate erosion and sediment control measures based on conditions encountered during construction Soil drainage changes Overland fill construction with suitable geotextile and imported free-draining material from Hub 123, to Hub 128, Minimize excavation as practical. If majority of close suitable material only available on woods side, minimize machine disturbance to overland section during access. 50/6 20/ -20/4-12/ 1.0 m Imperfectly to poorly II L L Overland fill construction with suitable geotextile and imported free-draining material INSTALL 450 mm CULVERT Expect seepage Install appropriate erosion and sediment control measures based on conditions encountered during construction

85 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP /4 40/ -17/ 1.5 m Imperfectly to poorly II L L Overland fill construction with suitable geotextile and imported free-draining material INSTALL 450 mm CULVERT At permanent seepage site, wet site conditions Install appropriate erosion and sediment control measures based on conditions encountered during construction WP / -23/4-14/ 1.0 m Imperfectly II L L Start conventional sidecast fill construction; End overland fill construction. INSTALL 600 mm CULVERT At NCD, no swale. Install appropriate erosion and sediment control measures based on conditions encountered during construction No WP 38/ -19/15-10/ 1.0 m II VL VL Conventional sidecast fill construction Soil drainage changes WP / -20/ Veneer 0.5 m Well II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT For ditch relief at low side of wet site Install appropriate erosion and sediment control measures based on conditions encountered during construction

86 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL No WP WP WP / -21/ 28/ -28/ 33/4 39/ -12/4-20/ Veneer 0.5 m to imperfectly Veneer 0.5 m to imperfectly Veneer 1.0 m Imperfectly II VL VL Conventional sidecast fill construction Soil drainage changes II L L Conventional sidecast fill construction INSTALL 600 mm CULVERT At small unconfined NCD Discharge ditch required based on design. Install appropriate erosion and sediment control measures based on conditions encountered during construction II L L Conventional sidecast fill construction INSTALL 450 mm CULVERT At moist swale, NVC; Discharge ditch required based on design. Perry Ridge North (PN) starts at the POT of Perry Ridge North Mainline Extension, Hub 154, and merges with Hub 60, of the original PRN Alignment at PN Hub 137, Original PN hubs are shown in (brackets and italics) below the new PN design/tsa hubs for field cross reference.

87 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP 152 ( WP 71 old PRN 13000) 25/ -25/ Swale 1.5 m to imperfectly II L L PRN October 2012 TSA joins original PRN July 2012 TSA Conventional sidecast fill construction INSTALL 600 mm CULVERT At moist swale, NCD; Evidence of strong seasonal flow Install appropriate erosion and sediment control measures based on conditions encountered during construction ( WP 73) 30/30-25/10-35/20 Swale 2.0 m to imperfectly II L L Conventional sidecast fill construction INSTALL 600mm CULVERT At NCD in broad swale Install appropriate erosion and sediment control measures based on conditions encountered during construction ( WP 74) 30/30-30/20-10/10 Swale 2.0 m to imperfectly II L L Conventional sidecast fill construction INSTALL 600mm CULVERT At NCD in shallow swale; culvert will also drain surface flow that meets the alignment approximately 10m on the town side; both drain into the same swale 15m down slope Install appropriate erosion and sediment control measures based on conditions encountered during construction

88 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( WP 75) 35/7 20/ -15/5-30/ Swale 2.0 m to imperfectly II L L Conventional sidecast fill construction INSTALL 600mm CULVERT At NCD in shallow swale Install appropriate erosion and sediment control measures based on conditions encountered during construction ( WP 76) 37/ -30/20-15/10 Concave 2.0 m to imperfectly II L L Conventional sidecast fill construction INSTALL 450mm CULVERT At imperfectly concave slope; Construct as low point in road grade during construction if reasonably possible ( ) 35-30/10-15/ m Imperfectly II L L Conventional sidecast fill construction Junction with spur (previously named PN13010) ( WP 77) 37/30-25/10-20/ Swale 2.0 m Imperfectly II L L Conventional sidecast fill construction INSTALL 600mm CULVERT At NCD in swale Install appropriate erosion and sediment control measures based on conditions encountered during construction ( WP 78) 45/15 30/ -35/5-20/ 1.0 m to imperfectly II L L Conventional sidecast fill construction INSTALL 450mm CULVERT For ditch relief

89 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( WP 79) 25/ -15/20-10/ Gully 1.0 m to imperfectly II L L INSTALL 1400mm CULVERT At S6 stream in gully; bedrock observed in gully sidewalls; active bedload to approximately 15 cm diameter; lots of functional woody debris in channel. Construct fill with suitable free draining material (<5% fines), compacted in lifts during construction; armour both sides of fill with coarse rock (>400 mm); key toe of fills in with larger diameter rock (>600 mm), and ensure functional seepage wall construction. Option to construct dumped rock or placed rock fill if materials are readily available. Install appropriate erosion and sediment control measures based on conditions encountered during construction. Anticipated measures include sediment catchment basins at ditch prior to stream, and cutslope/ditch armouring on approach to crossing. Construct as low point in road grade during construction if reasonably possible (note: was not practical at design stage) ( WP 153) 35/10 15/ -10/5-45/5-10/ 1.5 m to imperfectly II L L Conventional sidecast fill construction Junction with PN Optional rock source up slope of p-line between Hub 166 and Hub 167; approximately 500m 3 available.

90 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( WP 80) ( WP 81) ( No WP) 45/8 20/ -10/10-5/ Concave 0.5 m to imperfectly II L L Conventional sidecast fill construction INSTALL 450mm CULVERT At imperfectly depression Subsurface soil separation with suitable geotextile likely required. Intent is to provide greater road subbase strength over wet soils. Optional rock source up slope of p-line between Hub 166 and Hub 167; could quarry approximately 500m3 Subsurface soil separation with suitable geotextile fabric likely required Hub 167 (original 90), to Hub 174 (original 97), due to gentle slopes and wet till soils. 15/7 30/ 25/5 60/5 20/ -5/ Swale -5/ 1.0 m Imperfectly 1.0 m Imperfectly II L L Conventional sidecast fill construction Subsurface soil separation with suitable geotextile likely required. Intent is to provide greater road subbase strength over wet soils. INSTALL 600mm CULVERT At NCD in broad, wet swale Install appropriate erosion and sediment control measures based on conditions encountered during construction Construct as low point in road grade. II VL VL Conventional sidecast fill construction Subsurface soil separation with suitable geotextile likely required. Intent is to provide greater road subbase strength over wet soils. Optional rock source directly up slope of p-line; could quarry approximately 500m3 Optional rock source up slope of p-line near Hub 170; approximately 500m 3 available.

91 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( WP 82) 10/ 0/30 Uniform to slightly 2.0 m Imperfectly II VL VL Conventional sidecast fill construction Subsurface soil separation with suitable geotextile likely required. Intent is to provide greater road subbase strength over wet soils. INSTALL 450mm CULVERT At imperfectly site with seasonal surface flow Install appropriate erosion and sediment control measures based on conditions encountered during construction 10/ -5/ Gully 2.0 m II L L INSTALL 1800mm CULVERT At S5 stream; lots of natural log jams and functional woody debris in place; mobile bedload to typically 4 cm to 15 cm, some mobile boulders up to 35 cm. Mobile coarse woody debris to 1.5 m length noted ( WP 83) Construct fill with suitable free draining material (<5% fines), compacted in lifts during construction; armour both sides of fill with coarse rock (>400 mm); key toe of fills in with larger diameter rock (>600 mm), and ensure functional seepage wall construction. Option to construct dumped rock or placed rock fill if materials are readily available. Install appropriate erosion and sediment control measures based on conditions encountered during construction. Anticipated measures include sediment catchment basins at ditch prior to stream, and cutslope/ditch armouring on approach to crossing.

92 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( WP 84) 20/ -15/20-25/ m III VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT At imperfectly site, for ditch relief prior to S5 stream crossing Install appropriate erosion and sediment control measures based on conditions encountered during construction ( No WP) 15/10 45/10 20/ -15/ 1.5 m III VL VL Conventional sidecast fill construction Junction with PN ( WP 85) 38/ -10/ 2.0 m II VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT At imperfectly site, for ditch relief ( WP 86) 15/5 25/ -15/ Swale 2.0 m II VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT At moist swale, NVC ( WP 87) 15/ -20/ Broad swale 2.0 m II VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT At broad swale, NVC, imperfectly, for ditch relief

93 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( WP 88) 20/ -15/ Swale 2.0 m II VL VL Conventional sidecast fill construction INSTALL 600mm CULVERT At NCD in swale Install appropriate erosion and sediment control measures based on conditions encountered during construction ( No WP) 15/ -15/ 2.0 m II VL VL Conventional sidecast fill construction Direct ditch flow to culvert at hub ( No WP) 10/ -15/ 2.0 m II VL VL Conventional sidecast fill construction ( WP 89) 25/ -25/15-40/ Swale 2.0 m II VL VL Conventional sidecast fill construction INSTALL 450mm CULVERT At moist swale, NVC ( WP 90) 30/10 40/ -20/ Swale 1.5 m II VL VL Conventional sidecast fill construction INSTALL 1000mm CULVERT At S6 stream in imperfectly swale Install appropriate erosion and sediment control measures based on conditions encountered during construction

94 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL ( WP 91) ( No WP) 15/ -10/ 30/ -30/ 2.0 m Veneer 0.5 m II VL VL Conventional sidecast fill construction II VL VL INSTALL 600mm CULVERT At NCD, poorly confined Install appropriate erosion and sediment control measures based on conditions encountered during construction Conventional sidecast fill construction Start of rock source above road cut Optional blast rock source above road cut from Hub 201 (original 124), to Hub 204 (original 127), 3+802; approximately 700 m ( WP 92) 35/5 40/5 60/ -25/ Veneer 0.5 m II VL VL Conventional sidecast fill construction End of rock source above road cut INSTALL 450mm CULVERT At low point in road grade, for ditch relief ( WP 93) 25/ -15/ Swale 1.0 m, imperfectly in swale II L L Conventional sidecast fill construction INSTALL 600mm CULVERT At broad swale, imperfectly with an NCD up slope on the woods side; Make sure culvert catches flow from NCD Install appropriate erosion and sediment control measures based on conditions encountered during construction

95 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] DESIGN CONSTRUCTION/ COMMENTS CUT FILL POT ( WP 94) 0/5 20/10 10/ 0/5-10/ 1.0 m II VL VL END OF PN Bedrock outcrop located 6 m up slope. End conventional sidecast fill construction * Risk analysis is based on definitions provided in Appendix C: Risk Analysis Definitions and Overview and is consistent with Land Management Handbook 56, Landslide Risk Case Studies in Forest Development Planning and Operations (BCMoF 2004). P(H) refers to the likelihood of a hazardous landslide at the road prism as a result of conventional ½ bench cut, side cast fill construction. P(HA) refers to the likelihood of a hazardous affecting landslide (partial risk) at the road prism as a result of conventional ½ bench cut, side cast fill construction, with the considered element shown in brackets. The residual likelihoods are based on following all recommendations as presented in these tables and the accompanying report, along with normal good construction practices. Refer to attached report for additional information concerning the likelihood of a down slope landslide as a result of redirected drainage. Refer to the attached report for discussion with respect to all considered elements. NVC = No visible channel NCD = Non-classified drainage

96 Perry Ridge North PN Construction Summary Tables

97 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL Perry Ridge North (PN) starts at Hub 166, of PN 11000, originally Hub 89, of PN as noted in the field No WP POC 28/3 45/6 15/ -4/4-50/4-10/ Till: Gravelly silty sand with some cobbles and trace boulders, and clay; 25% to 35 % coarse fragments 1.5 m II L VL START OF PRN TERRAIN STABILITY ASSESSMENT (TSA) October 2012; Junction with PN Start conventional sidecast fill construction WP / -19/10-25/ Swale Till: As described 1.5 m Imperfectly II VL VL Conventional sidecast fill construction INSTALL 600 mm CULVERT At broad swale, NCD Install appropriate erosion and sediment control measures based on conditions encountered during construction WP /8 25/ -15/20-25/ Till: As described 1.5 m Imperfectly II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT At seasonal seepage site No WP 10/5 60/6 12/ 0/15-20/ Till: As described 1.0 m Imperfectly II VL VL Conventional sidecast fill construction Soil depth change WP / -14/ Till: As described 1.0 m II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT Align with swale up slope, NVC

98 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL No WP 30/4 20/ -20/9-25/ Till: As described Veneer 0.5 m Well to moderately II VL VL Conventional sidecast fill construction Soil drainage change WP /5 35/ -15/ Swale Till: As described 1.0 m Imperfectly II VL VL Conventional sidecast fill construction INSTALL 600 mm CULVERT At swale, NCD Install appropriate erosion and sediment control measures based on conditions encountered during construction No WP 36/15 20/ -33/14-8/ Till: As described Veneer 0.5 m Well to moderately II VL VL Conventional sidecast fill construction Soil drainage change WP / -25/ Till: As described 1.0 m II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT prior to drainage divide; may need to locate closer to Hub 14 during construction based on conditions encountered For ditch relief No WP 28/ -28/ Till: As described 1.0 m Well to moderately II VL VL Conventional sidecast fill construction Soil depth and drainage change

99 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP / -25/ Till: As described 1.5 m II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT For ditch relief WP /8 21/ -20/ Till: As described 1.5 m to imperfectly II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT For ditch relief WP / -5/6-13/ Swale Till: As described 1.5 m II VL VL Conventional sidecast fill construction INSTALL 600 mm CULVERT At shallow swale, NCD Install appropriate erosion and sediment control measures based on conditions encountered during construction WP / -12/ Swale Till: As described 1.5 m II VL VL Conventional sidecast fill construction INSTALL 1000 mm CULVERT; larger size warranted for mobility of bedload (up to ~15 cm) and woody debris At shallow swale, S6 steam with lots of channel diversions within swale; mobile bedload to 15 cm diameter, and lots of woody debris movement. Install appropriate erosion and sediment control measures based on conditions encountered during construction No WP 24/8 35/ -8/ Till: As described 1.5 m to imperfectly II VL VL Conventional sidecast fill construction Soil depth and drainage change applies through to 32

100 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP / -5/8-12/ Swale Till: As described 1.5 m to imperfectly II VL VL Conventional sidecast fill construction INSTALL 600 mm CULVERT At shallow swale, S6 stream Install appropriate erosion and sediment control measures based on conditions encountered during construction WP / -15/ Till: As described 1.5 m to imperfectly II VL VL Conventional sidecast fill construction INSTALL 600 mm CULVERT At seepage site, NCD Install appropriate erosion and sediment control measures based on conditions encountered during construction ~ No WP 23/13 28/ -14/ Till: As described 1.5 m to imperfectly II VL VL Conventional sidecast fill construction ADDITIONAL INSTALL 450 mm CULVERT near 30 may be required due to wet site; to be determined during construction Imperfectly site, expect seasonal seepage WP / -9/ Till: As described 1.5 m to imperfectly II VL VL Conventional sidecast fill construction INSTALL 600 mm CULVERT At small NCD Install appropriate erosion and sediment control measures based on conditions encountered during construction

101 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP /10 10/ -10/ Swale Till: As described 2.0 m II VL VL Conventional sidecast fill construction INSTALL 800 mm CULVERT At S6 steam in swale Install appropriate erosion and sediment control measures based on conditions encountered during construction WP /6 10/ -8/ Swale Till: As described 2.0 m to imperfectly II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT At broad swale, NVC Hub 36 though Hub 40: Ensure fill does not block swale down slope, and apply appropriate sediment and erosion control measures to avoid sediment delivery to surface flow in swale down slope No WP WP 179 0/ 29/7-10/ 7/15 0/ 8/15-10/ Same soils 1.0 m Swale Same soils 1.5 m to imperfectly II VL VL Conventional sidecast fill construction Soil depth and drainage change applies through to 38 II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT At broad swale, expect seasonal surface flow; Connects through 36 culvert; ensure that fill erosion does not impede seasonal surface flow in swale No WP 13/ -5/7 0/ Same soils 1.5 m Imperfectly II VL VL Likely to require imported free-draining material for road base/surfacing from Hub 40 through to 41; actual requirements to be determined at time of construction.

102 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP 180 6/7 12/ -9/ Concave Same soils 1.5 m Imperfectly II VL VL Likely to require imported free-draining material for road base/surfacing; actual requirements to be determined at time of construction. INSTALL 450 mm CULVERT At depression, imperfectly site, moist No WP 15/14 0/ -5/10-12/ Same soils 1.5 m I VL VL Conventional sidecast fill construction Soil drainage change WP / -6/5-18/ Same soils 1.5 m I VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT For ditch relief END OF PN TSA October 2012 Remainder of road to be reviewed by QRP at time of construction. END OF PN TSA October 2012 Remainder of road to be reviewed by QRP at time of construction No WP 20/ -12/ Same soils 1.5 m III VL VL Conventional sidecast fill construction *INSTALL 450 mm CULVERT *Based on TCL traverse No WP 9/ -6/ Same soils 1.5 m III VL VL Conventional sidecast fill construction *INSTALL 450 mm CULVERT *Based on TCL traverse

103 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL POT 17/ -5/10-9/ Same soils 1.5 m III VL VL END OF PN End conventional sidecast fill construction * Risk analysis is based on definitions provided in Appendix C: Risk Analysis Definitions and Overview and is consistent with Land Management Handbook 56, Landslide Risk Case Studies in Forest Development Planning and Operations (BCMoF 2004). P(H) refers to the likelihood of a hazardous landslide at the road prism as a result of conventional ½ bench cut, side cast fill construction. P(HA) refers to the likelihood of a hazardous and affecting landslide (partial risk) at the road prism as a result of conventional ½ bench cut, side cast fill construction, with the considered element shown in brackets. The residual likelihoods are based on following all recommendations as presented in these tables and the accompanying report, along with normal good construction practices. Refer to attached report for additional information concerning the likelihood of a down slope landslide as a result of redirected drainage. Refer to the attached report for discussion with respect to all considered elements. NVC = No visible channel NCD = Non-classified drainage

104 Perry Ridge North PN Construction Summary Tables

105 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL Perry Ridge North (PN) starts at Hub 178, of PN 11000, originally Hub 101, of PN as flagged in the field WP 153 POC 15/15 45/10 32/ -15/18-12/ Till: Gravelly silty sand with some cobbles and trace boulders and clay; 25% to 35 % coarse fragments 1.5 m III VL VL START OF PN TERRAIN STABILITY ASSESSMENT (TSA); Junction with PN Start conventional sidecast fill construction No WP 20/17 42/ -19/ Till: As described 2.0 m III VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT at road low point and junction with PRN For ditch relief WP /2 39/ -22/18-10/ Till: As described 1.5 m II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT For ditch relief into down slope swale; Connects to WP 86 below WP /15 44/ -30/5-18/ Till: As described 1.5 m Imperfectly II L L Conventional sidecast fill construction INSTALL 450 mm CULVERT Align with imperfectly depression up slope WP /10 38/ -17/3-21/ Swale Till: As described 1.0 m Imperfectly II L L Conventional sidecast fill construction INSTALL 450 mm CULVERT At broad swale, NVC, moist

106 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL WP /8 36/ -35/15-21/ Till: As described 1.0 m Imperfectly II L VL Conventional sidecast fill construction INSTALL 450 mm CULVERT To disperse ditch water into down slope swale, NVC, moist No WP 33/ -6/ Swale Till: As described 2.0 m Imperfectly II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT At gentle swale, NVC, moist WP / 34/10 38/ Swale Till: As described 1.5 m Imperfectly II L L Conventional sidecast fill construction INSTALL 450 mm CULVERT At swale, NVC, moist; Evidence of seasonal flow; Connects to culvert below switchback WP /17-30/ 59/11 36/ Swale Till: As described 1.0 m II L L Conventional sidecast fill construction INSTALL 450 mm CULVERT At swale, NVC, dry; Expect seasonal seepage; Connects to Hub 10 below switchback

107 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL No WP -41/ 35/ Till: As described Veneer 0.5 m Well II VL VL Conventional sidecast fill construction Soil depth change applies to 29 Soils are for the remainder of the assessed road except where noted WP /14-50/ 26/5 33/ Swale Till: As described Veneer 0.5 m to imperfectly II L L Conventional sidecast fill construction INSTALL 450 mm CULVERT At shallow swale, NVC Expect seasonal seepage No WP -35/4-45/ 44/3 20/11 30/ Swale Till: As described Veneer 0.3 m Well II VL VL Conventional sidecast fill construction Soil depth change WP /9-41/ 35/4 20/11 37/ Swale Till: As described Veneer 0.5 m Well II L L Conventional sidecast fill construction INSTALL 600 mm CULVERT At NCD in shallow swale Evidence of strong seasonal surface flow Install appropriate erosion and sediment control measures based on conditions encountered during construction WP /3-40/ 35/5 15/ Swale Till: As described Veneer 0.5 m to imperfectly II VL VL Conventional sidecast fill construction INSTALL 450 mm CULVERT At swale, NVC, dry

108 Perry Ridge North PN April 8, 2013 Station/ Survey Hub Left SLOPE Right SOIL CHARACTERISTICS Config. Type Thickness (approx.) & Drainage Terrain Stability Class (TSIL C) *PARTIAL RISK ANALYSIS P(H) / P(H) [Hazard] P(HA)/ P(HA) [Partial Risk] (fish) DESIGN CONSTRUCTION/ COMMENTS CUT FILL No WP -4/7-63/10-25/ 35/ Bedrock at surface 0.0 m Well II L L END OF PN TSA Junction with Spur End conventional sidecast fill construction * Risk analysis is based on definitions provided in Appendix C: Risk Analysis Definitions and Overview and is consistent with Land Management Handbook 56, Landslide Risk Case Studies in Forest Development Planning and Operations (BCMoF 2004). P(H) refers to the likelihood of a hazardous landslide at the road prism as a result of conventional ½ bench cut, side cast fill construction. P(HA) refers to the likelihood of a hazardous affecting landslide (partial risk) at the road prism as a result of conventional ½ bench cut, side cast fill construction, with the considered element shown in brackets. The residual likelihoods are based on following all recommendations as presented in these tables and the accompanying report, along with normal good construction practices. Refer to attached report for additional information concerning the likelihood of a down slope landslide as a result of redirected drainage. Refer to the attached report for discussion with respect to all considered elements. NVC = No visible channel NCD = Non-classified drainage

109 Appendix C Risk Analysis, Soil Erosion Assessment & Soil, Slope, and Classification Definitions and Overview

110 Risk Analysis Definitions and Overview The following sections provides important definitions for terminology used in this report, and are based on definitions presented in Land Management Handbook 56 - Landslide Risk Case Studies in Forest Development Planning and Operations (Wise et al. 2004) (LMH-56). Hazard: a source of potential harm, or a situation with the potential for causing harm, to a specified element at risk. With respect to landslide risk analysis, the landslide itself is the hazard. Likelihood of occurrence: the qualitative estimate of probability (P), or the chance for an event to occur. Elements at risk (elements): a thing of value that is put at risk. Elements at risk may include human life, public and private property, transportation system/corridor, utility and utility corridor, domestic or community water quality and supply, fish habitat, wildlife habitat and migration, visual resource in a scenic area, timber value, and soil productivity (adapted from B.C. MoF, 2002). Hazard analysis, P(H): an estimation of the probability of a specific hazardous event. With respect to landslide hazard analysis, it refers to the probability or likelihood of occurrence for a specific hazardous landslide. Spatial probability, P(S:H): relates to the potential for an event to reach or have a spatial effect on the location of a considered element, and mathematically can range from a value of 0 (certain not to reach the element) to 1 (certain to reach the element). Temporal probability, P(T:S): relates to the potential for a mobile element to be at the affected location, if the considered event occurs. If the element is of a fixed location and is always present (such as permanent infrastructure) then the temporal probability is numerically equal to 1, with a value of less than 1 applicable for mobile elements depending on the proportion of time exposed. Consequence, C: the effect on a specified element at risk. With respect to landslide risk analysis, the consequence is the change, loss, or damage to the considered element caused by the landslide. Consequence takes into account the vulnerability as as spatial and temporal probabilities of an event affecting an element. Vulnerability, V: a measure of the robustness of an element at risk and its relative exposure to a hazard. Partial risk analysis, P(HA): the product of the probability of occurrence and the probability of a spatial effect, taking into account both spatial and temporal probabilities. With respect to landslide risk analysis, it is the product of the probability for a specific hazardous landslide and the probability of that landslide reaching or otherwise affecting a considered element. It can also be referred to as the probability of a specific hazardous affecting landslide. Partial risk does not take into account the potential consequence of the event. Specific risk analysis, R(S): the risk of loss or damage to an element. With respect to landslide risk analysis, it is the risk of loss or damage to a specific element resulting from a specific hazardous affecting landslide. It takes into consideration the consequence rating of the considered element at risk. Specific Value of Risk, R(SV): the worth of loss, or damage to a specific element, excluding human life, resulting from a specific hazardous affecting event. In general terms, risk is defined as the product of probability of occurrence and consequence (R=PXC). In the consideration of consequence to a specific element at risk, the vulnerability or robustness of the specific element must be understood. The vulnerability of specific elements is

111 generally best assessed by specialists (e.g. biologists, foresters, utility engineers) with a greater knowledge of the element than the terrain stability professional may have. As a result, it is generally appropriate for a terrain stability professional to carry out a partial risk analysis, in which the likelihood of a specific hazardous landslide is determined, and whether or not a specific element at risk could be spatially affected by the hazardous landslide; however, the vulnerability of the specific element, including an estimation of consequence, is not considered (Wise et al. 2004; LMH 56). The following tables further outline the terms and ratings presented in this report. Table 1 provides the qualitative descriptions for the relative likelihood of occurrence ratings for a considered event, and the related approximate quantitative probability ranges. While there is an inherent degree of uncertainty in estimating the probability of a specific landslide, and it is a subjective interpretation that is dependent on numerous factors, these relationships can give some physical meaning to the qualitative terms applied. Table 1: Qualitative description of the likelihood of occurrence, and related quantitative probability ranges 1 Likelihood of Occurrence Very High (VH) High (H) Moderate (M) Low (L) Very Low (VL) Qualitative Description An event is imminent or likely to occur frequently; within the lifetime of a typical forest road 2 or soon after logging 3. An event can happen or is probable within the lifetime of a typical forest road 2 or soon after logging 3. An event is not likely, but possible within the lifetime of a typical forest road 2 or soon after logging 3. An event is unlikely to occur (remote possibility) within the lifetime of a typical forest road 2 or soon after logging 3. The likelihood of an event occurring is extremely remote to nil within the lifetime of a typical forest road 2 or soon after logging 3. Annual probability of occurrence 4 >0.05 (>1/20) (1/100-1/20) (1/500-1/100) (1/2500 1/500) < (<1/2500) Probability of occurrence over a 20 year term > ) Modified from Wise et al (2004), Table 2, pg 14; and B.C. MoF (2002), Appendix 10.2., and refers to a 1 km segment of road or a specified area of development. 2) Assumes a 20 year+ design life. 3) Time period between logging and establishment of a new-growth forest (generally on the order of 20 to 30 years). 4) Annual probability of occurrence does not consider the design life of the road. <0.01 These rating definitions are used for a considered event, and can apply to the likelihood of a specific hazardous landslide occurring [P(H)] as as to the likelihood of a specific hazardous affecting landslide [P(HA)], or partial risk. This rating system can also be used to describe the likelihood for other events such as stream channel avulsion, soil erosion, or redirected runoff.

112 As partial risk, P(HA), is defined as the probability of a specific hazardous affecting landslide, it is derived from the product of the probability of a specific hazardous landslide [P(H)], the probability of that landslide reaching an element [P(S:H)], and the probability of the element being present at the time of event [P(T:S)]. This can be expressed mathematically as: Partial Risk, P(HA) = P(H) X P(S:H) X P(T:S) In the case where there is assumed certainty that the landslide would reach the element, and that the element would always be present, then P(S:H) and P(T:S) would both be numerically equal to 1 and the partial risk would be equal to the probability of the specific hazardous landslide occurring [P(HA) = P(H)]. Alternatively, if an element is always present [P(T:S) = 1], but it is not certain that the landslide would reach or otherwise affect the site of the element, [P(S:H) <1], then the partial risk rating may be reduced from the probability of the hazardous landslide occurring depending on the situation and level of certainty. With this methodology the partial risk rating can be equal to or less than the likelihood of the hazardous landslide occurring in the first place, but will not be increased as can result from some qualitative matrix multiplication. Understanding how risk ratings are derived is important when management decisions may be based on the outcome, or when ratings may be compared between different developments or assessments. In some cases, land managers may choose to complete a specific risk or specific value of risk analysis by incorporating additional vulnerability [V(L:T)], consequence [C], or worth [E] information with input from the appropriate specialists as required (refer to LMH 56 for additional information on specific risk). Note: It is the responsibility of the land manager to understand and accept the rating definitions used in the analysis as they are arbitrary and not set by any regional or provincial standards. It is also the responsibility of the land manager to determine the acceptable, tolerable, or unacceptable levels of risk (partial, specific, or specific value of risk) for the development in question. References B.C. Ministry of Forests Forest road engineering guidebook. For. Prac. Br., B.C. Min. For., Victoria, B.C. Forest Practices Code of British Columbia Guidebook. Wise et al Landslide risk case studies in forest development planning and operations. B.C. Min. For., Res. Br., Victoria, B.C. Land Manage. Handb. No. 56. <

113 Soil Erosion Hazard Definition and Criteria Tables Soil Erosion Hazard Criteria* 1 Soil Drainage Class Imperfect or Wetter or evidence of seepage Well or Drier; seepage absent Soil Depth Hillslope Gradient Texture and Consolidation 1 m All All Road Grade Coarse Fragment Content and Bedrock <20% >80% or 50% 80% Bedrock < 12% VH H M L > 12% VH H H L > 1 m All All all VH VH VH M 2 m All All > 2 m <50% All 50% Si, S, LS/ Loose Other < 12% VH H M L > 12% VH H H L < 12% VH H M L > 12% VH H H L All VH H H L < 12% VH H M L > 12% VH H H L * adapted from Soil Erosion Hazard Criteria for Watershed Assessments in the Southern Interior, Final Report. Jordan, P and Assessing Surface Erosion Hazard on Forest Roads (DRAFT). Thompson, S based on the site being situated within a moist climate regime as defined in Assessing Surface Erosion Hazard on Forest Roads (DRAFT). Thompson, S Soil Erosion Hazard Generalized Management Implications* Hazard Class Symbol Interpretation Low L Low levels of erosion expected. No special measures are required. Moderate High Very High M H VH Low levels of erosion are expected and can usually be controlled with standard road construction and maintenance practices. Significant problems may develop on a site specific basis. Evaluate critical locations where sediment delivery potential is high following road construction. Moderate levels of erosion are expected but can usually be controlled with standard road construction practices and high maintenance standards. Significant problems may develop on a site specific basis. A review of the entire road immediately following construction is recommended. High levels of erosion are expected. Special measures will be required to control erosion from the road surface, cut slope and ditch. Mitigation strategies should be incorporated into the road design and revised following construction. Continuous monitoring immediately following construction is recommended. Higher standards of road maintenance and deactivation will be required to control erosion from the road surface. Erosion of the road surface may impair operational use of the road. *from Soil Erosion Hazard Criteria for Watershed Assessments in the Southern Interior, Final Report. Jordan, P Hazard ratings may be bumped up one category where polygon specific conditions warrant (e.g. concave slope configurations or severely gullied terrain). Hazard ratings may be bumped down one category where polygon specific conditions warrant (e.g. bedrock controlled terrain, convex ridge top slope positions).

114 Soil, Slope, and Classification Course Grained Soils ¹ (Cohesionless): Density Very Loose Loose Compact Dense Very Dense Field Test Easily excavated with a spade Some resistance to spade Considerable resistance to space Requires pick for excavation High resistance to pick Fine Grained Soils ¹ (Cohesive): Consistency Very Soft Soft Firm Stiff Very Stiff Hard Strength ¹: Strength Extremely Weak Very Weak Weak Medium Strong Strong Very Strong Extremely Strong Field Test Easily excavated with a spade Easily penetrated by thumb Readily penetrated by thumb Readily indented by thumb Penetrated by thumbnail Difficult to indent with thumb Field Identification Indented by thumbnail Crumbles under firm blow of hammer; can be peeled with a pocket knife Can be peeled by pocket knife (difficult): shallow indents from firm blow of hammer point Cannot be scraped or peeled with knife; fractures with single blow of hammer. Requires more than one blow of hammer to fracture Requires many blows of hammer to fracture Can only be chipped by hammer Spacing of Discontinuities in ¹: Spacing Spacing Width (m) Extremely Close <0.02 Very Close Close Close Wide Very Wide Extremely Wide >6.0 Soil Description 1,4 : Noun Gravel, sand, silt, clay > 50% and Silt and gravel, etc > 35% Adjective Gravely, sandy, silty, etc % Some Some sand, some silt, etc % Trace Trace sand, trace silt, etc 1-10% Soil Thickness 2,3 : Thickness Veneer > 1.0 m <1.0 m Soil Drainage 5 (adapted): Rapidly Well Well Imperfectly Poorly Very Poorly Slope Gradient: Slope Gradient Percent (%) Range Degree Range Flat <5 <3 Gently Moderate Steep Steep Very Steep 90 >42 Surface Configuration ² (modified): Surface Configuration Uniform <1.0 Relief (metres) Irregular Irregular Very Irregular >4.0 : Slope Shape ³ (modified) and Features::: Based on the overall shape of the slope between distinct slope breaks; includes concave, convex and straight and benched shapes. Gullies 6 (modified): sidewalls >3m high (measured along the fall line); sidewall gradients >50%; channel gradients typically >20% (may be less for some sections); may or may not contain an active stream channel. Swales: any linear depressions in the landscape that do not meet the gully criteria above; generally shallower with lower channel and sidewall gradients; may or may not contain an active stream channel. Qualitative landslide magnitude ratings 7 Magnitude Rating Water is removed from the soil rapidly in relation to supply. Water is removed from the soil readily but not rapidly. Water is removed from the soil somewhat slowly in relation to supply. Water is removed from the soil sufficiently slowly in relation to supply to keep the soil wet for a significant part of the growing season. Some mottling is common. Water is removed so slowly in relation to supply that the soil remains wet for a comparatively large part of the time the soil is not frozen. Soils are generally mottled and/or gleyed. Water is removed from the soil so slowly that the water table remains at or on the surface for the greater part of the time the soil is not frozen. Typically associated with wetlands. Typical Area affected (ha) Typical Volume Involved (m 3 ) Very Large >5 50,000 Large ,000 50,000 Medium ,000 Small Very Small <0.005 <50 REFERENCES: 1. Canadian Geotechnical Society, Canadian Foundation Engineering Manual, 3 rd Edition, Identification and Classification of Soil and, Ministry of Forests, A Guide for Management of Landslide Prone Terrain in the Pacific Northwest, 2 nd Edition, Land Management Handbook #18, Ministry of Environment, Terrain Classification for British Columbia, Revised Edition, Manual # 10, Ministry of Forests, Forest Road Engineering Guidebook, 2 nd Ed., Ministry of Environment Lands and Parks and Ministry of Forests, Field Manual for Describing Terrestrial Ecosystems, LMH#25, Ministry of Forests, Gully Assessment Procedures Guidebook Ministry of Forests, Landslide Risk Case Studies in Forest Development Planning and Operations, LMH#56, 2004.

115 Appendix D Figures

116 Approximate Site Location Project Perry Ridge North Roads Title Location Map Client British Columbia Timber Sales Scale Approx. 1:250,000 Base Map Source Toporama web mapping application " Her Majesty the Queen in Right of Canada, Department of Natural Resources. All rights reserved." Project Number Date Figure SCL February 2013 Figure 1