Webequie Supply Road Project

Webequie First Nation

August 30, 2024

AtkinsRéalis Ref: 661910-4E-L01-PA or 00

APPENDIX I:

WEBEQUIE SUPPLY ROAD CLIMATE CHANGE RESILIENCE

AtkinsRéalis

Notice to Reader

This report has been prepared and the work referred to in this report has been undertaken by AtkinsRéalis Canada Inc., for the exclusive use of Webequie First Nation, who has been party to the development of the scope of work and understands its limitations. The methodology, findings, conclusions and recommendations in this report are based solely upon the scope of work and subject to the time and budgetary considerations described in the proposal and/or contract pursuant to which this report was issued. Any use, reliance on, or decision made by a third party based on this report is the sole responsibility of such third party. AtkinsRéalis accepts no liability or responsibility for any damages that may be suffered or incurred by any third party as a result of the use of, reliance on, or any decision made based on this report.

The findings, conclusions and recommendations in this report (i) have been developed in a manner consistent with the level of skill normally exercised by professionals currently practicing under similar conditions in the area, and (ii) reflect AtkinsRéalis, best judgment based on information available at the time of preparation of this report. No other warranties, either expressed or implied, are made with respect to the professional services provided to Webequie First Nation or the findings, conclusions and recommendations contained in this report. The findings and conclusions contained in this report are valid only as of the date of this report and may be based, in part, upon information provided by others. If any of the information is inaccurate, new information is discovered or project parameters change, modifications to this report may be necessary.

This report must be read as a whole, as sections taken out of context may be misleading. If discrepancies occur between the preliminary (draft) and final version of this report, it is the final version that takes precedence. Nothing in this report is intended to constitute or provide a legal opinion.

The contents of this report are confidential and proprietary. Other than by Webequie First Nation, copying or distribution of this report or use of or reliance on the information contained herein, in whole or in part, is not permitted without the express written permission of Webequie First Nation and AtkinsRéalis.

Signature Page

Project Team

AtkinsRéalis Canada Inc.

Simon Piché, P. Eng., Ph.D.                                                                          Air and Climate Change Project Manager Wing-Shun Wu, MCC, M. Env. Sc.                                                                     Climate Change Professional

Contents

1. Introduction………………………………………………………………………………………………………………………… 7
   1. Work Plan…………………………………………………………………………………………………………………. 7
   1. Study Area………………………………………………………………………………………………………………… 8
2. Project Description and Setting……………………………………………………………………………………………… 9
   1. Project Overview………………………………………………………………………………………………………… 9
   1. Geographic and Environmental Setting………………………………………………………………………….. 15
   1. Existing Built Environment…………………………………………………………………………………………… 15
3. Historical Climate Conditions………………………………………………………………………………………………. 17
   1. Average Climate Trends…………………………………………………………………………………………….. 17
   1. Extreme Weather Conditions……………………………………………………………………………………….. 19
   1. Local Environmental Conditions……………………………………………………………………………………. 21
      1. Hydrology and Hydrogeology…………………………………………………………………………. 21
      1. Terrain and Geotechnical Conditions……………………………………………………………….. 21
         1. Permafrost…………………………………………………………………………………. 22
         1. Erosion……………………………………………………………………………………… 22
         1. Geohazards……………………………………………………………………………….. 22
      1. Vegetation…………………………………………………………………………………………………. 22
4. Future Climate Projections………………………………………………………………………………………………….. 23
   1. Future Climate…………………………………………………………………………………………………………. 23
   1. Extreme Precipitations……………………………………………………………………………………………….. 26
   1. Freezing Rain………………………………………………………………………………………………………….. 27
   1. Wind……………………………………………………………………………………………………………………… 28
   1. Lightning………………………………………………………………………………………………………………… 28
5. Climate Risk Analysis………………………………………………………………………………………………………… 30
   1. Potential Vulnerabilities………………………………………………………………………………………………. 31
   1. Risk Level Assessment………………………………………………………………………………………………. 31
   1. Special Case – Wildfires…………………………………………………………………………………………….. 54
6. Conclusion……………………………………………………………………………………………………………………….. 55
7. References……………………………………………………………………………………………………………………….. 56

Contents (Cont’d)

Tables

Table 2-1:       Overview of Components Associated with the WSR Project…………………………………………………… 10

Table 3-1:       Past Climate Normals for Stations Nearest to Webequie (ECCC, 2024a)………………………………….. 17

Table 3-2:       Extreme Values at Meteorological Stations Nearest to Webequie (ECCC, 2024a)………………………. 20

Table 4-1:       Climate Projections for the WSR Region…………………………………………………………………………… 24

Table 4-2:       Historical and Future IDF Values for the Lansdowne House Station………………………………………… 27

Table 5-1:       Climate Hazards Selected for the Vulnerability Assessment…………………………………………………… 33

Table 5-2:       Potential Climate Vulnerabilities Identified for the Project………………………………………………………. 36

Table 5-3:       Climate Risks Classified as Low, Moderate or High……………………………………………………………… 41

Figures

Figure 2.1:     Project Location………………………………………………………………………………………………………….. 14

Figure 2.2:     WSR Project Layout and Environment Setting……………………………………………………………………. 16

Figure 3.1:     Climate Normals (1971-2000) at Lansdowne House Met Station (Source: ECCC, 2024a)…………….. 18

Figure 3.2:     Mean Annual Temperature and Total Annual Precipitations over Several Decades at the

Pickle Lake Meteorological Station (ECCC, 2024a)……………………………………………………………… 18

Figure 3.3:     Temperature and Daily Precipitation Extremes Observed at Landsdowne House Met Station

(ECCC, 2024a)…………………………………………………………………………………………………………… 20

Figure 4.1:     Future Climate Projections with the Moderate and High GHG emissions scenarios for

Select Temperature and Precipitation Indicators for the WSR Region………………………………………. 25

Figure 4-2:     Average Lightning Density (per km2 per year) in Eastern Canada (1999 to 2018)……………………….. 29

1.               Introduction

As climate changes over time especially in Ontario’s Far North, it is critical for infrastructure to be robust and be designed and constructed with potential future climate in mind. An assessment of climate change effects on the proposed Webequie Supply Road Project (WSR, the “Project”) is needed to assist in identifying unintended potential risks and impacts on the infrastructure longevity but also on the nearby ecosystems and the human health and safety. Such analysis can be carried out by figuring climate risk levels to or because of the road infrastructure during the construction and operation phases, in the context of increasing average temperatures and trending severe weather events.

Pursuant to requirements of the Ontario Environmental Assessment Act and the federal Impact Assessment Act, the assessment of climate change effects was carried out while considering the general guidelines provided in the draft “Technical guide related to the Strategic Assessment of Climate Change: Assessing climate change resilience” from Environment and Climate Change Canada (ECCC, 2022) and the guidance document entitled “Considering Climate Change in the Environmental Assessment Process” from the Ontario Ministry of Environment, Conservation and Parks (MECP, 2021). The following items were considered during this analysis:

• Project location and immediate environment.
• Current project design considerations.
• Historical and future climate projections at project location during its expected lifetime.
• Geotechnical, hydrogeological and hydro-geomorphological baseline conditions within the project’s immediate setting.
• Indigenous knowledge regarding historical climate events and trends.
• Identification of all potential climate change related impacts on various project components.
• Selection of control measures for components for which unacceptable potential risks could occur at one point during the project’s lifetime.
• Recommendations on a monitoring program assessing the performance of control measures.

This document provides a Statement on the Project’s resilience to climate change covering the aforementioned items in accordance with the following work plan.

1.1                   Work Plan

This report covers all essential objectives from a Climate Change Resilience Statement by first compiling the information allowing to provide an informed judgement on the climate for the region where the WSR will be located. This will then lead to the vulnerability assessment followed by the risk assessment of identified project components on a set of impact criteria that include WSR’s long-term sustainability; WSR users health and safety; and the natural environment and ecosystems. Overall, this report consists of seven sections including the current introduction:

• Project description and setting: This provides an overview of the WSRs structures for waterbody crossings, including the road itself and how climate change is being integrated into the design. A broad description of the nearby environmental context and setting along the WSR is also summarized, with the intent to support on the selection of project components and impact criteria to be analysed in terms of climate risks.
• Historical climate conditions: This section covers the baseline climate conditions based on existing meteorological data sets and studies specific to the region, including any Indigenous Knowledge or observed changing climatic conditions or trends observed by Indigenous communities. It also deals with past extreme

weather conditions. Baseline conditions with regard to hydrology and geotechnical conditions along the WSR are also examined.

• Future climate projections: This section presents the expected trends of different climate indicators based on temperature and precipitation that will be considered during the vulnerability assessment phase. This analysis will cover the period up to 2100 covering the operations and maintenance phase of the Project that is considered to be 75-years based on the expected timeframe when major refurbishment of the road components (e.g., bridges, culverts) are anticipated.
• Climate risk assessment: This section will first list the weather-related climate hazards (i.e., extreme precipitations) as well the climate hazards affected, at least in part, by climate change (i.e., landslides, droughts, freshets) that could potentially have an impact on at least one project components. In presence of a potential interaction, these sensitive components will be identified through the consideration of climate observations and projections related to the climate hazard, but also of the environmental setting. For each of these potential vulnerabilities, a proper risk assessment will be carried out determining the probability of occurrence and the related consequence for a given criterion. This assessment will result in a risk level (from very low to high) for the given vulnerability.
• Selection of control measures: Control measures (during the final design phase or the operation phase) to minimize or eliminate potential climate risk will be identified and applied for risks identified as « moderate » and « high ». The residual risk level when considering the control measure will also be established, with expectations to eliminate all unacceptable climate risks. Otherwise, compensation measures may need to be considered, where feasible.

1.2                   Study Area

The following study areas have been defined for the purposes of climate change effects assessment and are based on the geographic extent of available regional climate data and greenhouse gas (GHG) emissions.

• Local Study Area (LSA) extends 50 km from each side of the centreline of the preliminary recommended preferred route, and 500 m from the boundaries of temporary and permanent supportive infrastructure.
• Regional Study Area (RSA) includes the geographical area of northern Ontario.

2.               Project Description and Setting

This section reviews the main project components and describes the environment setting along the WSR. The information provided below are meant as an overview of elements that could potentially be relevant in terms of climate resiliency and were mainly excerpted from the WSR draft Environmental Assessment Report/Impact Statement (EAR/IS) in which more details are provided.

2.1                   Project Overview

The proposed WSR is a new two-lane all-season road within a cleared right-of-way (ROW) of approximately 35 metres

(m) in width and approximately 107 km in length. The preliminary recommended preferred route for the road consists of a northwest-southeast segment running 51 km from the Webequie First Nation Reserve to a 56 km segment running east-west before terminating near the McFaulds Lake within the mineralized deposit area known as the Ring of Fire. A total of 17 km of the WSR is within the Webequie First Nation Reserve lands, with the remainder of the road located on un-surveyed Ontario Crown lands.

The Project is located in north-western Ontario on un-surveyed Ontario Crown lands and WFN Reserve lands approximately 525 km northeast of the City of Thunder Bay in northwest Ontario as shown in Figure 2.1. The WSR is intended to facilitate the movement of materials, supplies and people from Webequie to the mineral exploration areas near McFaulds Lake area. It is expected to accommodate an annual average daily traffic of less than 500 vehicles consisting of light to medium personal vehicles, commercial vehicles and heavier trucks hauling industrial supplies and equipment.

The northwest-southeast segment of the road (51 km) rest mostly over mineral soil will be cleared of all vegetation across the 35 m ROW to accommodate the two-lane all-surface road. Shoulders, ditches, and berms of stripped organic materials on the outside will also be shaped along this segment.

The segment of the WSR running in an east-west direction is located within the Hudson Bay Lowlands Ecozone which includes the James Bay Ecoregion and is composed mostly of peatland (muskeg) having a depth of 2-4 m of waterlogged organic soil, which represents poor to very poor conditions for building a road. A floating road design is therefore considered by adding an underlying layer of aggregates (along with geotextile fabrics or geogrids) that will compress the peat resulting in settlement and consolidation. A surface layer of crushed stone will be added to complete the road that is expected to lay 1.2 m above the surrounding lowland areas.

For the west half of the WSR in stable soil conditions, the surface layer of the road that represents the driving surface for vehicles will be a chip seal treatment, which is similar to asphalt pavement, and consists of a tar slurry and gravel. For the east half of the road in the peatlands with poor soil conditions it is proposed the driving surface be initially gravel. During the operations phase, monitoring of the east half of the WSR in the peatlands will be conducted to assess performance/settlement, serviceability, and safety issues/concerns related to dust along the WSR. Depending on the outcome of this monitoring, the gravel driving surface may be replaced in a timeframe of approximately 3 to

5 years with a surface treatment such as chip seal treatment, or asphalt pavement.

The 35 m ROW where all vegetation will be cleared will accommodate a two-lane road, shoulders, ditches (for the western half only) as well as earth cut and fill sections when needed. It will require watercourse crossings over thirty-one waterbodies (Figure 2.2) using:

• Single-to-multi span bridges crossings of six major waterbodies, including the Muketei River, the Winiskisis Channel and the Winisk Lake; and
• A variety of culverts (e.g., corrugated steel pipe, concrete box culvert) to cross the minor watercourses.

The WSR will require regular maintenance and operation activities, so supportive infrastructure is proposed to facilitate that work. A permanent Maintenance and Storage Facility (MSF) will be erected at one location near the WSR with the purpose of storing the equipment and materials used for inspection, maintenance, and repair activities. An aggregate pit (ARA-4) will also be required during the operation and maintenance phase of the Project to provide processed aggregates, crushed stones and rocks needed maintain and repair the road and waterbody crossing structures.

Table 2-1 provides an overview of the components or group of components associated with the WSR and includes general details regarding their design and configuration at the current planning stage as described in Section 4 of the EAR/IS. It excludes what is considered minor components for which climate change is not expected to be a factor including:

• Road signage and fencing, where applicable.
• Road lighting/illumination as it is currently not considered in the design.

Table 2-1 also describes the construction and operation and maintenance activities as they are considered during the vulnerability and risk assessment, especially with regard to health, safety, and the environment (HSE).

Table 2-1:    Overview of Components Associated with the WSR Project

2.2                   Geographic and Environmental Setting

The proposed WSR is located in the northwestern region of Ontario. It traverses the Big Trout Lake and James Bay ecoregions as part of the Hudson Plains ecozone located in a cold and dry part of the province. The Big Trout Lake ecoregion (covering the western segment of the WSR) is mostly characterized by sparse, coniferous, and mixed forests covering 50% of the land along with about 20% of non-water wetlands while inversely the James Bay ecoregion (eastern segment of the WSR) consists primarily of wetlands (treed and open fens and bogs covering about 70% of land) along with some coniferous forests (12%). Considering this difference, the WSR will be built differently for both segments.

The western half of the road crossing forest covers will need to be cleared. The majority of the vegetation is coniferous forests with Black Spruce as the dominating species with Jack Pine, White Birch, and Poplar species as associates while the ground cover consists primarily of mosses and lichens, shrubs, and herbs. This segment is mainly composed of glacial mineral terrains composed of till with discontinuous lacustrine clay veneer, glaciofluvial ice-contact, esker ridges, and alluvial floodplains. This segment is also characterized by the presence of large waterbodies. The WSR will avoid these waterbodies, except for the Winisk Lake at one location that will require construction of a long 6-span bridge. Otherwise, around fourteen (14) smaller water crossings (culverts and smaller bridges) will be required along the way.

The eastern half of the WSR will pass through large stretches of water-logged areas/marshes with organic surface layer typically from 1 to 2 m in thickness within a vast network of waterbodies, including streams, rivers, lakes, and ponds. In fact, there are several larger river systems in the area, most notably the Attawapiskat, Ekwan and Muketai watersheds. The wetlands are composed of diverse ecosystem types associated with swamps, bogs, fens and scattered marches characterized by organic deposits including peat, muck, and marl. At the Muketei River near the eastern terminal, glaciofluvial in-contact deposits of gravel and sand are present. With the presence of water, the WSR will need to cross over fifteen (15) waterbodies using culverts or small bridges. Small portion of the ROW will also need to be cleared of trees although not to the same extent as the western segment of the road.

The topography along the proposed ROW is generally flat with some localized relief, especially in the western segment of the WSR which is also defined as the upland area since it is elevated at 200 meters or more above sea level while the eastern section, in the lowlands, has elevations of less than 200 meters above sea level.

2.3                   Existing Built Environment

The proposed WSR is located mostly in an untouched environment. There are currently few existing structures or infrastructures in the LSA, with the exception of the local airport located south of Webequie and which acts as the starting point for the WSR. Otherwise, the closest dwelling is located over 1 km from the western terminus of the WSR and in the south part of Webequie community, infrastructure includes sanitary sewers and sewage treatment plant, and a diesel fuel power plant. The community is proposing to eventually build new dwellings along the road, mostly on the eastern part of Winisk Lake and near the Webequie airport. This part of the study area is currently composed of forest.

The area east of Webequie is limited to a few sparse informal trails while a formal seasonal winter road is located to the west, connecting Webequie to Pickle Lake. There are tourist lodges, fly-in hunting and fishing camps and other

tourist-related activities in the broader study area, but no operators are located in proximity to the proposed ROW. The road will however pass near multiple natural areas known to provide country foods (e.g., wild berries) and used for hunting and fishing. The proposed ROW also intersects traplines legally registered to Webequie First Nation, Neskantaga First Nation and Marten Falls First Nation members.

3.               Historical Climate Conditions

Historical climate conditions and trends are presented in this section based on existing meteorological data and studies in the RSA. Two aspects are addressed: the average trends and extreme weather which are the basis of climate change concerns since they can lead to dangerous situations for people, the environment and/or the sustainability of built systems. It is therefore important to gather all available data on past extreme weather conditions in order to establish a starting point with regard to future events. This section also includes a broad review of local environmental conditions with regard to hydrology, geology and vegetation that could potentially interact with climate hazards presently or in the future.

3.1                   Average Climate Trends

The proposed WSR is located within the Hudson Bay Lowlands characterized by a sub arctic climate with cool short summer, with only three months with a mean temperature above 10 °C. It is subjected to cold and extended winters with relatively low precipitations (compared to southern Canada) due to low temperature and related evapotranspiration. The majority will occur during summertime while winter precipitations are generally associated with cyclonic storms. The relatively flat area provides a few barriers to the weather system sweeping down from the north. As a result, the area can experience a variety of weather events.

In absence of specific monitoring station in the LSA, the numbers presented below come from observations at the meteorological stations located in Landsdowne House and Pickle Lake (ECCC, 2024a) which are located respectively 100 km and 250 km from Webequie (Table 3-1 and Figure 3.1). Annual mean temperatures along the WSR are estimated at about -2 °C considering that Pickle Lake and Landsdowne House communities are located to the south. During summer months, mean temperatures reach 13 to 17 °C with a maximum daily average temperature slightly above 20 °C at Landsdowne House (but most likely slightly lower in Webequie). During winter, the average temperature oscillates between -18 and -22 °C, with a minimum daily temperature of -28 °C in January as measured at Landsdowne House station. Temperatures in Webequie have the potential to be much lower as described in Section 3.2.

Precipitation levels in the area can range between 550 and 650 mm per year, considering that dryer conditions are typically observed when going northward (compared to Pickle Lake and Landsdowne House stations). In fact, precipitations in the Hudson Bay Lowlands Ecozone are said to range between 500 and 700 mm, with the latter being predominant in the James Bay area. A large portion of precipitations falls as rain during summertime (40% of total annual precipitations) while precipitations during wintertime represent low levels for a typical year (13% of total annual precipitations). Hence, about 30% of total precipitations fall as snow. Most precipitation falls as rain from May to September and as snow from November to March, with April and October as transition months.

Table 3-1:    Past Climate Normals for Stations Nearest to Webequie (ECCC, 2024a)

(1)  Both stations are located to the south-west relative to the WSR.

Figure 3.1:     Climate Normals (1971-2000) at Lansdowne House Met Station (Source: ECCC, 2024a)

Figure 3.2 illustrates the historical trend for the last decades in terms of mean temperature and total precipitations observed in Pickle Lake. Like many other regions in Canada, the average temperature has been slowly increasing at an apparent rate of +0.030 °C per year, meaning that over the last 50 years the average temperature has increased by

1.5 °C or so. The impact of climate change on temperature is most noticeable during wintertime although the interannual variation is more significant compared to summertime. Although Pickle Lake is located 250 km away from Webequie, similar conclusions are more than likely for the WSR area.

Total precipitations monitored over a 35-years period (1975 – 2010) also appear to have slightly increased, but it is less definite due to the large annual variations. The annual increase in precipitations from Figure 3.2 is equivalent to less than 1 % of total annual precipitations seemingly showing that it does not and is not expected to increase by much in the near future. Extreme precipitations are however expected to increase at a greater rate, as explained in Section 3.2.

3.2                   Extreme Weather Conditions

Table 3-2 provides a list of extreme conditions that were measured at Lansdowne House and Pickle Lake meteorological stations in the past (ECCC, 2024a). The following observations can be inferred:

• Maximum temperatures historically reached 36.7°C in Lansdowne House while the temperature exceeded 30 °C for a total of 2.1 days per year in average from May to August (Figure 3.3). However, when considering data from Pickle Lake, it is likely that past extreme temperatures in the Webequie area are lower by probably 1 to 2 °C since it is located northward of the meteorological stations.
• Minimum temperatures historically reached -47.8°C in Lansdowne House while the temperature went below -30°C for a total of 34 days per year on average. In fact, temperatures have dropped below -40°C during the month of December to March in the past (Figure 3.3). Similarly, Webequie has likely seen lower minimum temperatures in the past and a higher frequency of days with temperatures below -30°C and -40°C.
• Extreme rainfall has reached 108 mm per day in Lansdowne House but only 78 mm per day in Pickle Lake even though higher precipitation events are to be expected in more southern localities like Pickle Lake. However, the number of days with substantial (>10 mm/d) and heavy (>25 mmm/d) precipitations is more significant in Pickle Lake meaning that Lansdowne House has probably seen a 1:100-year event or so in 1974 while the frequency of high daily precipitations remain lower. Again, Webequie has likely less frequent extreme rainfall events compared to Lansdowne House and especially Pickle Lake, although such events are also conditional to local topography. High rainfall events occur during summertime including September (Figure 3.3).
• The maximum hourly wind speed reached 80 km/h in Landsdowne House but given that wind is highly specific to location, it is likely not entirely relevant to the LSA. In fact, different wind regimes are to be expected along the proposed ROW depending on terrain, the presence of lakes, vegetation and so forth. As it is the case for most of northern Ontario, the maximum hourly wind speed should be expected to range between 50 and 60 km/h

(Tang, 2016) and wind gusts can be expected to exceed 100 km/h along the WSR. Other notes of importance include:

• Winter winds are typically from the west to northwest, with the summer winds usually from the west to southwest. Lakes typically begin to freeze in mid-October, with spring thaws typically initiating in mid-May.
• Fog is common, with extended periods typically expected in the transition months of ice ‘freeze-up’ in the Fall months and ice ‘break-up’ or freshet in the Spring. It is also not unusual to have fog occurring during the summer months.
• Annual ice formation in the Hudson Bay Lowlands Ecozone is caused by air temperatures consistently falling below freezing and the subsequent lowering of surface water temperatures starting in September / October. Thawing begins in spring, even before the mean daily air temperatures rise above freezing. Hudson Bay exerts a cooling effect on the Hudson Bay Lowlands Ecozone extending a substantial distance inland well into the summer.
• Snow coverage in the Hudson Bay Lowlands Ecozone often remains until June, reflecting much of the arriving radiant energy back into the atmosphere. In recent years, spring thaw has been observed at early dates.

Table 3-2:    Extreme Values at Meteorological Stations Nearest to Webequie (ECCC, 2024a)

(1)  Both stations are located to the south-west relative to the WSR.

Figure 3.3:     Temperature and Daily Precipitation Extremes Observed at Landsdowne House Met Station (ECCC, 2024a)

3.3                   Local Environmental Conditions

This section provides a broad overview of currently observed conditions with regard to hydrology, geology, and vegetation that could potentially be impacted by climate change in presence of the Project or that could have an impact on the Project itself. The descriptions provided in the following subsections come mostly from the Natural Environment Existing Condition (NEEC) Report (AtkinsRéalis, 2024) for the WSR EA/IA for the respective field. As described in the NEEC report, the study area for characterizing local environment conditions extends approximately 1 km to 6 km from the centreline of the ROW for the proposed WSR, and 500 m to 5 km from the boundaries of temporary and permanent supportive infrastructure. For the purpose of describing local environmental conditions in the following subsections, this study area is referred to as the general project area.

3.3.1             Hydrology and Hydrogeology

Streams in the region have low velocity flow throughout most of the year. Stream flow peaks in the spring and early summer (May to June) as a result of snowmelt runoff and rainfall runoff from saturated soils. Flows recede through the summer and increase in the fall due to an increase in rainfall and a decrease in evaporation. Flows are normally lowest in the winter, and some small streams freeze completely to the stream channel bed. Through much of the area, surface waters move as diffuse flow through broad, densely vegetated fens, with occasional consolidation in defined channels. The stream banks are typical of low gradient and are well defined by earth, boulders, bedrock outcrops and natural levees.

The primary source for groundwater recharge is precipitation including rain and snowfall (melting) which flows in shallow water bearing zones (overburden or shallow bedrock zones) towards nearby water bodies. However, during major storm events, surface water levels within the water bodies may rise quickly and recharge groundwater for a short period of time. The groundwater contribution rates to the stream flows along the proposed WSR are estimated to be ranging typically from 20% to 30% at major streams and tributaries. The groundwater contribution tends to be smaller at small tributaries compared to major streams and tributaries, and greater during dry seasons compared to wet seasons.

Localized eskers are scattered along the north-south section and towards the east end of the WSR. These eskers are comprised predominantly of sand and gravel and so, the charge rates are expected to be higher than the remaining sections of the WSR.

Thirty-one (31) waterbody crossings have been identified for the proposed WSR. Twenty-seven (27) have a defined channel/flow path and do not include wetlands or areas that may experience ephemeral flow. The estimated highwater levels (water depth above the stream bed) at the water crossings based on field observations and measurements range from 0.4 m to 4.1 m.

3.3.2             Terrain and Geotechnical Conditions

The WSR will cross extensive organic terrains along the east-west section and glacial terrains with mineral soils (sand to silty sand till, silt to silty clay till) on the roughly north-south section leading to the community of Webequie. The organic deposits include peat, muck, and marl from a vast network of bogs (open and treed), fens (open, treed and shore) and swamps with glaciofluvial in-contact deposits of gravel and sand as the eastern terminus. The road will pass through layers of peat and organic clays from 0.5 to 2 m in thickness with some locations greater than 3 m. The organic layer is underlain by a clay/silt till layer of up to 2 m thick, and a Quaternary till layer of up to 5 m thick. Depth to bedrock ranges from 5 to 12 m below the surface.

The terrain and topography along the proposed WSR are relatively flat with two distinct sections: the north-south trending section consisting of a high relief plateau; and the east-west trending section which is an area of low relief. The region has a very low level of seismic activity with the LSA being classified generally as having a “very dense soil and soft and soft rock profile”.

3.3.2.1             Permafrost

The proposed WSR is located within a band of sporadic permafrost where areas have permafrost beneath the land surface while other areas are free of permafrost. Based on this classification, it is estimated that 10-50% of the land area is underlain by permafrost of a few meters thickness with the upper 10-20 m of the ground containing less than 10% of ice. That said, no observed areas of permafrost were documented along the WSR during soil and terrain field investigations. In fact, dense/hard till and bedrock have no challenges with thaw consolidation while the overburden thickness along the WSR is generally small; therefore, thaw strain is not expected to be substantial. Taliks, supra- permafrost, sub-permafrost and/or intra-permafrost groundwater are not expected either.

3.3.2.2             Erosion

Erosion is the physical dislodgement of soil particles from the Earth surface by the action of wind, rain, or other weather processes. This occurs naturally over time, but human interference can cause it to accelerate. The degree of erosion risk at a given site is a function of its regional climate, the erodibility of the soil, and the terrain. For example, erosion risk is increased in regions with heavy rainfall and high winds. Based on prevalent soils along the WSR (silty clay, sandy silt, and organic material), their erodibility is classified as medium. That said, the primary connection between terrain and erosion is the way in which terrain affects hydrology. Higher flow velocities cause increased erosion. The flat and heavily vegetated terrain along the WSR slows overland water flow velocities substantially, resulting in low erosion risk in general.

3.3.2.3             Geohazards

There are no major hazardous slopes within 1 km of the proposed ROW. No landslide hazards were identified, nor were sinkholes or major geological depressions or geological anomalies observed along the proposed ROW.

Other potential geohazards include isostatic rise or subsidence, or more commonly referred to as isostatic rebound associated ice sheet retreat. In the general project area, uplift rates are in the order of 8 to 10 millimetres (mm) per year. Generally, the potential risks from isostatic rebound to inland (i.e., non-marine) infrastructure and infrastructure projects are perceived to be negligible. However, the potential effects of isostatic rebound in the project area will be evaluated, and its implications to the design and/or operation of the Project will be considered and documented (e.g., effects of rebound on seismic conditions, structure design, etc.).

3.3.3             Vegetation

In the Big Trout Lake Ecoregion, sparse forest covers approximately 21% of the ecosystem in the general project area. Coniferous and mixed forests grow on 19.4% and 8.4% of the area, respectively, and small pockets of deciduous forest grow along river valleys. Burns occupy 8.1% of the ecoregion, the highest percentage in Ontario. This ecoregion is therefore susceptible to fire; however, they are generally smaller than those in more southerly ecosystems in northwestern Ontario. Throughout the western and central portions of the ecoregion, fires are fairly evenly distributed across the landscape, with the exception of the extreme northern fringe. However, in the eastern, wetter part of the ecoregion, burned patches are smaller and further apart (MNR, 2022).

4.               Future Climate Projections

This section initiates the vulnerability analysis by consolidating future climate projections for the region until the end of this century since the road’s lifespan is indetermined and expected to remain operational for a very long time.

4.1                   Future Climate

Projections of the future climate in the WSR region, which is represented by a variety of indicators, are compiled for both annual and seasonal scales. These projections are derived from the results of the WCRP CMIP6 general circulation model (GCM) ensemble, downscaled and bias-corrected using the BCCAQv2 method (a statistical scaling approach for GCM model outputs developed by the Pacific Climate Impacts Consortium).

Table 4-1 shows the projected values representative of current conditions (Horizon 2020), medium-term future conditions (Horizon 2050) and future conditions towards the end of the century (Horizon 2080), calculated for the moderate greenhouse gas (GHG) emission scenario (SPP-2; previously RCP4.5, known as stabilization) and the pessimistic scenario (SPP-5; previously RCP8.5, with high and continuous GHG emissions; refer to Appendix A for more details). The SPP-2 scenario is the sought target at present, but following the precautionary principle in the resilience approach, the worst-case scenario (SPP-5) must also be considered, since there is no guarantee that GHG emission reduction measures will enable the SSP-2 scenario targets to be achieved on the long run.

The median projections of the 35 models from the CMIP6 ensemble are shown in Table 4-1 for each emission scenario. These values represent rolling averages over 30 consecutive years to smooth out the modelling results which tend to fluctuate from year to year. Figure 4.1 illustrates the temporal evolution of selected temperature and precipitation indicators, showing the upward or downward trend, as well as the range of projections when considering all models (excluding outliers). Appendix A provides similar figures for other climate indicators for reference. The following findings can be extracted from Table 4-1 and the various figures:

• The mean annual temperature will rise by 1.4°C (SPP-2) to 2.4°C (SPP-5) in the medium term (Horizon 2050) and by 2.6°C to 5.4°C at the end of the century (Horizon 2080) compared to today (Horizon 2020). This rise would be roughly equivalent for all seasons except for winter under the SPP-2 scenario (+3.9°C during Horizon 2080 instead of +2.2–2.3°C for other seasons), whereas the RCP8.5 scenario shows slightly more variance, with a more significant rise for winter (+7.2°C by 2080).
• Extreme maximum summer temperatures are expected to increase by +3–4°C for Horizon 2050 and +3–6.4°C for Horizon 2080 compared to today. According to projections, the extreme maximum temperature will not exceed 40°C by 2080 (albeit by not much considering the SPP-5 scenario). The number of days with temperatures reaching 30°C or more would rise in parallel, from under 4 days per year in average presently to 12 days per year by the end of the century under the SPP-2 scenario (31 days for the SPP-5 scenario).
• A significant increase in the extreme minimum temperature is also expected for the medium (+2.7 to 3.4°C) and long term (+4.8 to 8.0°C). The coldest temperature should therefore gradually rise from around -39.7°C today

to -34.9°C by the end of the century, according to the moderate SPP-2 scenario (-31.7 °C for the SPP-5 scenario).

• Total annual precipitations are expected to rise relatively steadily, reaching a +4–5% increase (+19 to 27 mm) for Horizon 2050 and +6–13% (+32–72 mm) for Horizon 2080 compared to today (549 mm per year). This increase would be evenly distributed across winter and the shoulder seasons (+22 to +25 mm by 2080 for the SPP-5 scenario), while total summer precipitations are projected to decrease by 5% (-11 mm).

• The models do not project significant increases in maximum daily precipitations (maximum of 38 to 39 mm/d by 2080). That said, model results suggest a slight increase in daily precipitation levels overall. For example, the frequency of daily precipitation greater than 10 mm would rise from the current average of 11 days per year to 13 days per year during Horizon 2080.
• The standardized precipitation evapotranspiration index (Table 4-1) currently indicates a slight water deficit (-0.12) on an annual basis due to higher water loss from soils and vegetation by evapotranspiration than water input from precipitations. For the SPP-2 scenario, this trend would reduce to water surpluses according to model results. For the SPP-5 scenario, conditions would however become more drier given the larger increase in temperatures.

Table 4-1:    Climate Projections for the WSR Region

• Since this is a comparison with future projections, the values of the modelled historical data from Climate Data Canada were considered (as opposed to measured data at a monitoring station for example).
• Horizon 2050: 2041-2070; Horizon 2080: 2071-2100
• Standardized precipitation evapotranspiration index (SPEI) is a drought index based on the difference between precipitation and potential evapotranspiration. Negative values indicate water deficit and positive values, water surplus.

Figure 4.1:     Future Climate Projections with the Moderate and High GHG emissions scenarios for Select Temperature and Precipitation Indicators for the WSR Region

4.2                   Extreme Precipitations

Climate models do not project a significant increase in maximum daily precipitations by the end of the century

(40 mm/d; Figure 4.1). It must be noted that past daily maximums at Lansdowne House and Pickle Lake meteorological stations were much higher (up to 108 mm/d; Table 3-2) and that this level of precipitation can certainly occur again.

This observation is not inconsistent since it is recognized that statistical scaling of GCMs tends to underestimate precipitation extremes relative to historical data and that further processing is required to obtain more consistent projections (Mailhot et al., 2015). That said, model results still suggest a small increase of daily precipitation levels in general.

To offset this gap, a scale-up approach on Intensity-Duration-Frequency (IDF) curves is often used to establish extreme precipitation values for a given region. These curves, developed according to a dataset from a meteorological station, define the intensity of extreme precipitation events in function of probability (return periods). Some specific IDF values for the Lansdowne House station are presented in Table 4-2. For example, a daily maximum of 113 mm is obtained for the 100-year return period based on historical observations. The probability of this occurrence will occur by the end of the century (75 years) is 53%, which assumes that “historical IDF curves remain representative of reality over time”.

Environment and Climate Change Canada (ECCC) recommends using the approach developed by the CSA group (2019) for scaling the IDF values applicable for the future. In short, this method assumes that the increase in extreme precipitation is correlated with the rise in global atmospheric humidity, which in turn increases with global warming.

𝑅𝑅𝑃𝑃,𝑌𝑌 = 𝑅𝑅𝐶𝐶 × 1,07^(𝑇𝑇𝑌𝑌−𝑇𝑇𝑋𝑋)                                                                                                                                                                                                                                                               (1)

RP,Y:     IDF value for horizon Y (mm)

RC:       historical IDF value based on data from period X (mm)

TY:        mean annual temperature (excluding winter period) projected for horizon Y (°C)

TX:        mean annual temperature (excluding winter period) calculated for the historical period X (°C)

The historical IDF values in Table 4-2 are based on precipitation data from 1971 to 2021, so the difference in projected mean annual temperature for the horizon 2080 (2071-2100) is 4.3°C for the SPP-2 scenario and 7.2°C for the SPP-5 scenario. This results in a 34% to 66% scaling of the historical IDF curves to represent expected conditions at the end of the century. However, the historical data and model projections for the IDF curves are based on results from the Lansdowne House station, which is the closest station to WSR region with available data and located approximately 100-150 km southwest of the WSR region. Since Lansdowne House is projected with an annual temperature of 0.8°C comparing to 0.2°C for the WSR region for Horizon 2020, actual precipitation in the WSR region is expected to be less and the results from the IDF curves used in this analysis are likely overestimated.

The projections in Table 4-2 should be treated with caution since they remain estimates based on the simple assumption that the rise in extreme precipitation levels is correlated with the average rise in temperature. For example, despite its own uncertainties, another calculation tool (IDF_CC Tool 5.0) developed by a team of Canadian researchers (University of Western Ontario, 2023) projects a lower and more narrow scaling ranging (+28-32%) for the year 2100 at the Lansdowne House station. In reality, scaling factors can vary according to location, type of precipitation event, topography, and natural variability.

Table 4-2:    Historical and Future IDF Values for the Lansdowne House Station

• Represents the probability (P = 1 – exp(-75/T)) according to the return period (T) that the extreme precipitation event (IDF value) will occur at least once in the next 75 years.
• Historical values were calculated according to a precipitation’s dataset from 1971 to 2021 at Lansdowne House station. The values were rounded to the closest mm.
• Calculated according to equation (1) knowing that the temperature differential between horizon 2080 and the 1971-2021 period is 4.3 and 7.2 °C for SPP-2 and SPP-5 scenarios, respectively. The values were rounded to the closest mm.

4.3                   Freezing Rain

Freezing rain occurs over several hours and even several days when the ground-level temperature is below the freezing point when cold droplets solidify in contact of surfaces forming ice. Being a meteorological event of specific nature (often mixed with other types of precipitations likes rain, snow, and sleet), the frequency and intensity of freezing rain events are not only linked to the climate but also on the meteorological conditions of the moment.

According to ECCC (2020), the annual frequency of freezing rain is increasing in Canada since last century and this trend will most likely continue for a major part of Canada. However, climate models cannot precisely forecast the extent of this increase at the local scale. Some models seem to indicate a gradual shift of freezing rain events towards higher latitudes because of global warming and the movement of the 0°C isotherm to the north. According to the Ontario Provincial Climate Change Impact Assessment Technical Report (CRI, 2023), the northern regions are expected to see an increase in snowfalls initially but will be followed by declines and more precipitation falling as rain. With the increase of precipitations projected during fall and winter, the rise of maximum daily temperatures in winter, and an increase of frost-free days annually, it suffices to say that freezing rain events will be more frequent in the future which includes the Far North.

The Far North of Ontario currently sees few rains during winter with a rain-to-snow ratio of 1.3% but according to

Cheng et al. (2011), Northern Canada (over the 50th parallel) still receives very short-duration freezing rain (< 4 h) about

2.8 days per year. Longer freezing rain events (>4 h) occur an average of 0.8 days per year. For comparison, it represents about 50% of very-short duration freezing rain days observed in the Ontario-Montreal region annually but only, 25% for longer duration events. Cheng et al. (2011) estimates that these “long duration freezing rain events” will double by the end of century for northern Canada regions. However, based on already low occurrences, major freezing rain events are not to be expected to increase a lot in number, at least on the short to medium term.

4.4                   Wind

Current modelling of storm intensity, frequency and wind pressure does not allow establishing a reliable trend for the WSR region. Wind is greatly influenced by very local processes, and measurements from a weather station are not necessarily representative of the immediate surroundings, making interpolation for mapping and analysis complex (Charron, 2015).

In a warmer future, earlier ice melt and higher summer temperatures should generate more heat in water bodies, which may lead to more atmospheric instability, theoretically favoring the formation of storms and gusty winds. ECCC (2020) suggests, albeit with considerable uncertainty, that wind speeds and wind-driven rain could increase in Canada with an even higher level of global warming, but at a rate of less than 10% compared with today. For example, ECCC projects an increase in hourly wind pressures for 25-, 50- and 100-year return periods of approximately +5% for the Lansdowne House station for a 2°C rise in mean temperature, and approximately +6% for a 3°C rise. Another study (Cheng et al., 2015) also reports a possible increase in the frequency of wind gusts above 70 km/h towards the end of the century for most Canadian regions, and specifically in summer (+10 to >50%) and winter (+30 to >50%) for regions comprising Northern Ontario. The extent of regional variations is subject to considerable uncertainty, due in part to the lack of consensus between the various models.Apart from gusty winds, the formation of tornadoes, downbursts, or derechos (violent rectilinear winds) is another issue for elevated structures. Although no tornadoes were recorded within 100 km of Webequie from 1980 to 2009, one was recorded at Landsdowne House at F0 level in 1980. Also, nine tornadoes ranging between F0-F2 levels were recorded in Ontario at latitudes of 50° or higher between 1980 and 2009 (Webequie latitude is 52.9°).

4.5                   Lightning

Lightning strikes have been monitored by the Canadian Lightning Detection Network since 1998, specifically total cloud-to-ground lightning flashes calculated within a 25 km radius of the center of cities or towns (ECCC, 2023c). The closest station with these measurements is in Big Trout Lake, which is approximately 200 km northwest of Webequie.

The cloud-to-ground lightning flashes from 1999-2018 amounted to 11,369, representing approximately 0.5 flash per square kilometer per year which is a low frequency value. In fact, Northern Canada usually see few lightning strikes due to the colder climate, as demonstrated in Figure 4-2. For comparison, the lightning density in Toronto according to the network is 2.9 flashes/km2/yr.

Knowledge of the relationship between climate and atmospheric electricity has improved in the past decade. In a recent study (Pérez-Invernón et al., 2023), climate models simulated an increase of global total lightning of 6.4 x 108 flashes per year by the 2090s under RCP6.0 scenario with an average global surface temperature increase of 4°C. Polar region total lightning is projected to increase by 56% comparing to 2009-2011 (at 14% per °C of temperature increase), while polar region cloud-to-ground lightning is projected to increase by 28% (at 7% per °C of temperature increase). Given that temperatures are projected to increase by 2.6 to 5.4 °C in the region by 2100, cloud-to-ground lightning may increase accordingly by 18–38% leading to a total of 13,400 to 15,700 flashes per year (or 0.6 to 0.7 flashes/km2/yr) which all things considered will remain low.

Figure 4-2:     Average Lightning Density (per km2 per year) in Eastern Canada (1999 to 2018)

5.               Climate Risk Analysis

Climate risk analysis on the project components listed in Table 2-1 was carried out following a systematic approach to:

• Ensure a complete and exhaustive analysis of factors to consider when proposing a resilience strategy.
• Reduce the subjectivity of analysts using a differentiated analysis based on impact likelihood and their consequence.
• Offer a quantitative basis on which to identify the most significative climate risks for the Project.

The analysis is loosely based on the Public Infrastructure Engineering Vulnerability Committee (PIEVC) Protocol from Engineers Canada and Natural Resources Canada, version 2009, now the ownership of a new partnership. It respects the requirements from the Strategic Assessment for Climate Change (SACC) and Ontario’s guidelines within the framework of environmental impact assessments. The risk assessment is carried out in five (5) steps resulting in the calculation of risk levels that act as a climate risk rating. Details on the approach are provided in Appendix B and the steps are as follows.

1. Selection of climate hazards and their probability of occurrence ratings (Table 5-1 in Section 5.1).
2. Determining the “potential” vulnerabilities of the components towards each climatic hazard (Table 5-2 in Section 5.1).
3. Determining the net probability of an impact over the component’s lifetime (Table 5-3 in Section 5.2).
4. Determining the consequence of the impact on the component (Table 5-3 in Section 5.2).
5. Calculating risk levels and prioritizing control measures (Table 5-3 in Section 5.2).

The vulnerability and risk assessment on the project components were carried out considering the climate hazards listed in Table 5-1 that were selected based on the potential to impact on one or more of the components. The hazards can be discerned between meteorological events, whether intermittent (i.e., tornado, freezing rain) or progressive

(i.e., increase in average temperatures) and socio-natural features that can be a result of climate change (e.g. landslides, droughts, wildfires, freshets, permafrost degradation). Selection of the climate hazards therefore depends on the site and/or type of structures and infrastructure.

The following hazards were excluded from analysis mainly due to an absence of an interactions or potentially significant interactions with any project components.

• Heatwaves and extreme temperatures: Although temperatures should significantly increase in northern Ontario, hotter temperatures in the future, while remaining infrequent and below 40 °C, do not have any particular impact on the road infrastructure like the road base, culverts, and bridges.
• Hail of large dimensions: The impact of hail on the road and bridges do not cause damages (other than cosmetic). No impact is also expected from the interaction of hail with a project component on health and safety, natural and built environments covered in this study.
• Lightning storms: The infrastructures are not impacted by lightning and are not expected to add to the danger for the road users. Note that wind gusts, heavy precipitations, and wildfires that can be associated with lightning are already covered as individual climate hazards.
• Extreme cold spell: While extreme cold temperatures can impact some materials and cause cracking for example, such conditions are already well taken into consideration in Canada and are expected to significantly decrease in frequency and intensity.

• Topsoil droughts, hydrological droughts, and sinkhole formation from droughts: With cooler conditions in the Far North, severe droughts that would remove groundwater at places enough to cause the land surface to collapse is deemed impossible. Topsoil and hydrological droughts are also not considered to be an issue with regard to the road integrity.
• Freezing depth: This hazard is relevant to buried infrastructures like water or gas lines. Hazard not to be confounded with freeze-thaw cycles or permafrost degradation in this case.
• Tornado / downburst / derecho: The region is not known for such events and should still be the case in the future. No control measures other than the ones already covered in the “wind gusts” hazard would be available, so a risk analysis specific to tornados is excluded.
• Ice breakup season: This hazard applies to the change on the time and extent of ice breakup on large waterbodies. Although the road traverses some large watercourses, this potential change will not have any direct impact on culverts and bridges. Hazard not to be confounded with spring freshets.
• Landslide / rockslide: The topography along the road is relatively flat and there are no hazardous slopes or geological anomalies nearby.

5.1                   Potential Vulnerabilities

This step consists of establishing whether a component can potentially be affected by a climate hazard for any of the following criteria. If so, an actual risk analysis is performed on the “component / hazard / criterion” combination.

Otherwise, the analysis stops at this stage.

• Sustainability and operation (P): Can the climate hazard cause damages requiring repairs (P1); affect the integrity or performance of the component (P2); and/or add significant operating costs (P3)?
  • Health and safety (S): Can the interaction between the climate hazard and the component cause dangerous conditions for the drivers (S1); and/or employees related to the WSR (S2)?
  • Natural environment (E): Can the interaction between the climate hazard and the component cause adverse impacts to the soil (E1); air (E2); surface water (E3); and/or vegetation/country food (E4).
  • Built environment (B): Can the interaction between the climate hazard and the component cause damage to the Webequie air strip (B1); and/or future dwellings that will be built near the road (B2). Current residences are not included as a criterion considering that the main features of the WSR are out of the range of influence.

Table 5-2 provides the list of components identified as potentially vulnerable based on available data and observations from previous sections. Explanations on reasons why a component is not deemed vulnerable towards a climate hazard are provided in Appendix C.

Given that there is no road infrastructure, beyond the community of Webequie, it is important to note that this assessment was carried out based on the expected impact of climate change over time and not according to the climate strictly speaking. It is therefore acknowledged that the road designers already consider current climate conditions in their decisions.

5.2                   Risk Level Assessment

For each identified vulnerability, the risk level is quantified according to the approach described in Appendix B, by selecting a correction factor (CI) for the impact probability allowing to integrate the adaptation capacity (CI < 0) or amplified sensitivity of the component (CI > 0) towards the climate hazard. No correction (CI = 0) implies an absence of mitigating factors.

The consequence rating (GB = 1 to 5) is attributed based on the expected sensitivity of the component related to the assessed criteria. Like for the probability rating, the selection of the consequence rating has its own uncertainties since the level of damage or tolerance can vary depending on the event. Those uncertainties are integrated into the analysis by multiplying GB with a correction factor (GC).

From these ratings, « very low », « low », « moderate » or « high » risk levels can be obtained. Risk levels and their associated color coding are presented below.

Table 5-3 presents the results on risks for which a low level is achieved minimally. The risks established as very low are available in Appendix C.

• Probability rating going from 1 « extremely improbable » to 5 « highly probable » that the climate hazard increase in frequency and/or intensity in the future according to models and studies on climate for the region.
• Confidence rating on the selected PA rating going from 1 « highly confident » to 5 « low confidence » selected mainly based on the number of proofs and concurring studies about the future evolution of the climate hazard for the region.

• Probability rating going from 1 « extremely improbable » to 5 « highly probable » that the climate hazard increase in frequency and/or intensity in the future according to models and studies on climate for the region.
• Confidence rating on the selected PA rating going from 1 « highly confident » to 5 « low confidence » selected mainly based on the number of proofs and concurring studies about the future evolution of the climate hazard for the region.

• Probability rating going from 1 « extremely improbable » to 5 « highly probable » that the climate hazard increase in frequency and/or intensity in the future according to models and studies on climate for the region.
• Confidence rating on the selected PA rating going from 1 « highly confident » to 5 « low confidence » selected mainly based on the number of proofs and concurring studies about the future evolution of the climate hazard for the region.

Criteria

P: Sustainability of the component (damages requiring repairs or maintenance « P1 »; integrity or performance « P2 »; operation cost « P3 ») S: Health and safety (dangerous conditions for the drivers « S1 »; employees related to the WSR « S2 »)

E: Natural environment (environmental damage to the vicinity including soils « E1 »; air « E2 »; waterbodies « E3 »; vegetation/country food « E4 ») B: Build environment (damage to existing structure and infrastructures including the air strip « B1 »; future buildings along the road « B2 »)

• CI = correction factor on impact probability; GB = impact consequence rating; GC = uncertainty correction on GB rating.
• Risk level: R = (PA – CI) x (1+ 0,2 x PC) x GB x (1+ 0,2 x GC); PA and PC ratings are specified inTable 5-1.

5.3                   Special Case – Wildfires

Dryer conditions due to warmer temperatures may intensify in northern Ontario, especially when considering the SPP-5 scenario, increasing the probability of wildfires in the project area. Although they are destructive events that cause extensive damages to wide geographic areas, the interaction between the Project and wildfires is expected to be limited to the sustainability of its components since health and safety hazards and damages to the environment (natural and built) would be directly impacted by wildfires and not due to the presence of the road.

With the exception of oil stains on the road, the road surface is generally not flammable and direct damages to the road due to fire should remain limited. Wildfire risks on the eastern part of the WSR is anticipated to be low as the peatlands is saturated and not very flammable. For the western part of the WSR, the 35 m ROW on either side of the road should provide sufficient clearance from potential burning trees that fall on the road surface. As such, damage to the road due to a wildfire is expected to be limited to cracks and potholes due to heating. Other components that are made with metal such as road signs, guardrails and culverts are more susceptible to damages from heat and may require repairs following a wildfire event. The same applies to bridges composed of concrete and steel that would also be impacted by heat if it comes near them.

6.               Conclusion

According to the climate risk analysis, there are no « moderate » and « high » risks associated with this Project. The interactions for which the risk level is « very low » or « low » represent in general situations where the component is recognized to be sensible, but the impact is considered marginal or sufficiently low considering all available information (final design criteria, construction standards, hydrological/geotechnical attributes, etc.) to not have tangible repercussion on the road integrity. Extra control measures are not considered necessary.

This conclusion is based on the Project adopting, and in some cases exceeding provincial standards, guidelines and codes for the design and operation and maintenance of provincial highways. These standards were developed by the Ministry of Transportation in consultation with other regulatory agencies to ensure that provincial highway standards address environmental and engineering concerns. These standards ensure that the safety and integrity of the highway itself, its users and the surrounding environment is protected today and in the future during the road’s lifecycle.

Standards for all aspects of the highways planning, design, construction, operation and maintenance have been developed and are updated on a regular basis. Key standards and guidelines include, but are not limited to, the following:

• Design Supplement for Transportation Association of Canada Geometric Design Guide for Canadian Roads, Ontario Ministry of Transportation, April 2020;
  • Preliminary Design Report Guideline, Ontario Ministry of Transportation, September 2016;
  • Roadside Design Manual, Ontario Ministry of Transportation, May 2020;
  • Highway Drainage Design Standards, Ontario Ministry of Transportation, January 2008;
  • Pavement Design and Rehabilitation Manual, Ontario Ministry of Transportation, May 2013;
  • Road Safety Audit Guidelines, University of New Brunswick, 1999;
  • Structural Manual, Ontario Ministry of Transportation, August 2021;
  • Canadian Highway Bridge Design Code CSA S6:19, CSA Group, 2019; and
  • Maintenance Manual, Ontario Ministry of Transportation, August 2003.

7.               References

AtkinsRéalis Canada Inc. (AtkinsRéalis). 2024. Webequie Supply Road Project – Natural Environment Existing Conditions Report. Draft. 2024.

Charron, I., 2015. Élaboration du portrait climatique régional du Nunavik, Ouranos, Montréal, [Online]. https://mffp.gouv.qc.ca/documents/forets/inventaire/Portrait_climatique_regional_Nunavik.pdf

Cheng, C.S., Li, G., Auld, H., 2011. Possible impacts of climate change on freezing rain using downscaled future climate scenarios: Updated for eastern Canada, Atmosphere-Ocean Journal, 49 (1), p. 8-21.

Cheng, C.S., Lopes, E., Fu. C., Huang, Z., 2015. Possible impacts of climate change on wind gusts under downscaled future climate conditions: updated for Canada, Journal of Climate, 27 (3), p. 1255-1270.

Climate Risk Institute (CRI), 2023. Ontario Provincial Climate Change Impact Assessment Technical Report. Report prepared by the Climate Risk Institute, Dillon Consulting, ESSA Technologies Ltd., Kennedy Consulting and Seton Stiebert for the Ontario Ministry of Environment, Conservation and Parks [Online]. www.ontario.ca/page/ontario-provincial-climate-change-impact-assessment

CSA Group, 2019. CSA Plus 4013: F19 – Technical guide: Development, interpretation, and use of rainfall intensity- duration-frequency (IDF) information: Guideline to Canadian water resources practitioners [Online].

Environment and Climate Change Canada (ECCC), 2020. Climate-Resilient Buildings and Core Public Infrastructure: an assessment of the impact of climate change on climatic design data in Canada [Online]. https://climate- scenarios.canada.ca/index.php?page=buildings-report

Environment and Climate Change Canada (ECCC), 2022. Technical guide related to the Strategic Assessment of Climate Change of Climate Change: Assessing climate change resilience, draft version [Online]. www.strategicassessmentclimatechange.ca/

Environment and Climate Change Canada (ECCC), 2024a. Canadian Climate Normals, https://climat.meteo.gc.ca/climate_normals/index_f.html

Environment and Climate Change Canada (ECCC), 2024b. Climate Data, https://donneesclimatiques.ca/

Mailhot, A., Talbot, G., Aubin, P., Bolduc, S., 2015. Tome 1: Évaluation du potentiel des réanalyses pour l’estimation des intensités des précipitations extrêmes dans le nord québécois (version préliminaire), Rapport No R1629, Centre Terre Eau environnement de l’INRS à l’Université du Québec, 78 p.

Mastrandrea, M.D., Field, C.B., Stocker, T.F., Edenhofer, O., Ebi, K.L., Frame, D.J., Held, H., Kriegler, E., Mach, K.J., Matschoss, P.R. Plattner, G.K., Yohe, G.W., Zwiers, F.W., 2010. Guidance Note for Lead Authors of the

IPCC Fifth Assessment Report on Consistent Treatment of Uncertainties. Intergovernmental Panel on Climate Change (IPCC), [Online]. www.ipcc.ch/site/assets/uploads/2018/05/uncertainty-guidance-note.pdf

Ontario Ministry of Environment, Conservation and Parks (MECP), 2021. Considering Climate Change in the Environmental Assessment Process [Online]. www.ontario.ca/page/considering-climate-change-environmental- assessment-process

Ontario Ministry of Natural Resources (MNR), 2022. The ecosystems of Ontario – Part 1: ecozones and ecoregions [Online]. https://www.ontario.ca/page/ecosystems-ontario-part-1-ecozones-and-ecoregions

Pérez-Invernón. F.J., Gordillo-Vázquez, F.J., Huntrieser, H., and Jöckel, P., 2023. Variation of lightning-ignited wildfire patterns under climate change. Nature Communications, 14, 739.

Tang, Q., 2016. Estimation of Wind Hazard over Canada and Reliability-based Assignment of Design Wind Load [Online]. https://ir.lib.uwo.ca/cgi/viewcontent.cgi?article=5762&context=etd

Western University, 2023. IDF_CCTool 6.0, Computerized tool for the Development of Intensity-Duration-Frequency curves under climate change [Online]. www.idf-cc-uwo.ca/home