Webequie Supply Road Project

May 1, 2025

AtkinsRéalis Ref: 661910

Draft Environmental Assessment Report / Impact Statement

SECTION 7: ASSESSMENT OF EFFECTS ON SURFACE WATER RESOURCES

Contents

• Assessment of Effects on Surface Water Resources………………………………………………………………. 7-5
  • Scope of the Assessment………………………………………………………………………………………….. 7-5
    • Regulatory and Policy Setting………………………………………………………………………… 7-5
    • Consideration of Input from Engagement and Consultation Activities………………………. 7-9
    • Incorporation of Indigenous Knowledge and Land and Resource Use Information…….. 7-17
    • Valued Component and Indicators………………………………………………………………… 7-21
    • Spatial and Temporal Boundaries…………………………………………………………………. 7-23
      • Spatial Boundaries………………………………………………………………………. 7-23
      • Temporal Boundaries……………………………………………………………………. 7-23
    • Identification of Project Interactions with Surface Water Resources………………………. 7-25
  • Existing Conditions…………………………………………………………………………………………………. 7-27
    • Methods…………………………………………………………………………………………………. 7-27
      • Desktop Review of Background Information……………………………………….. 7-29
      • Surface Water Quantity…………………………………………………………………. 7-29
        • Peak Discharge…………………………………………………………… 7-29
        • Waterbody Crossing Hydraulics and High-Water Level…………. 7-31
      • Surface Water Quality…………………………………………………………………… 7-31
        • Sampling Locations……………………………………………………… 7-31
        • Sampling Parameters…………………………………………………… 7-32
      • Sediment Quality…………………………………………………………………………. 7-33
        • Sampling Locations……………………………………………………… 7-33
        • Sampling Parameters…………………………………………………… 7-33
    • Results…………………………………………………………………………………………………… 7-34
      • Surface Water Quantity…………………………………………………………………. 7-34
        • Peak Discharge…………………………………………………………… 7-34
        • Waterbody Crossing Hydraulics and High-Water Level…………. 7-35
      • Surface Water Quality…………………………………………………………………… 7-35
      • Sediment Quality…………………………………………………………………………. 7-44
  • Identification of Potential Effects, Pathways, and Indicators……………………………………………… 7-44
    • Change in Surface Water Quantity………………………………………………………………… 7-45
    • Change in Surface Water Quality………………………………………………………………….. 7-46
    • Change in Sediment Quality………………………………………………………………………… 7-47
  • Mitigation Measures………………………………………………………………………………………………… 7-51
    • Dewatering, Water Takings, and Discharges……………………………………………………. 7-51
    • Vegetation Clearing and Grubbing………………………………………………………………… 7-52
    • Installation of Culverts and Bridges……………………………………………………………….. 7-52
    • Permanent Waterbody Crossings…………………………………………………………………. 7-53
    • Roadway Drainage Design………………………………………………………………………….. 7-53

Contents (Cont’d)

• Accidental Spills and Leaks………………………………………………………………………… 7-53
  • Blasting of Rock………………………………………………………………………………………. 7-54
  • Construction and Maintenance Activities………………………………………………………… 7-54
  • Disposal of Waste…………………………………………………………………………………….. 7-54
  • Summary………………………………………………………………………………………………… 7-55
  • Characterization of Net Effects…………………………………………………………………………………. 7-67
    • Potential Effect Pathways Not Carried Through for Further Assessment………………… 7-69
    • Predicted Net Effects………………………………………………………………………………… 7-69
      • Change in Surface Water Quantity………………………………………………….. 7-70
        • Short-term water takings………………………………………………. 7-70
        • Short-term discharges of construction water, wastewater, or

wash water………………………………………………………………… 7-70

• Land cover changes resulting in changes to infiltration and

runoff rates and volumes………………………………………………. 7-70

• Installation of waterbody crossing structures leading to temporary changes to discharge rates upstream or

downstream of waterbody crossings……………………………….. 7-71

• Permanent waterbody crossings leading to changes in localhydraulics (flow depth/water level and velocity)………………….. 7-71
  • Road maintenance resulting in changes to overland runoffdrainage patterns………………………………………………………… 7-71
    • Change in Surface Water Quality……………………………………………………. 7-72
      • Short-term discharges of construction water, wastewater,

or wash water…………………………………………………………….. 7-72

• Blasting activities releasing chemical constituents into nearbywaterbodies……………………………………………………… 7-72
  • Road maintenance activities leading to the deposition of

sediment into waterbodies…………………………………………….. 7-72

• Change in Sediment Quality…………………………………………………………… 7-73
  • Short-term discharges of construction water, wastewater,

or wash water runoff……………………………………………………. 7-73

• Blasting activities releasing chemical constituents into nearbywaterbodies……………………………………………………… 7-73
  • Road maintenance activities leading to the deposition of

sediment into waterbodies…………………………………………….. 7-73

• Summary………………………………………………………………………………………………… 7-73
  • Determination of Significance…………………………………………………………………………………… 7-77
    • Surface Water Quantity……………………………………………………………………………… 7-78
    • Surface Water Quality……………………………………………………………………………….. 7-78
    • Sediment Quality………………………………………………………………………………………. 7-78

Contents (Cont’d)

• Cumulative Effects…………………………………………………………………………………………………. 7-78
  • Prediction Confidence in the Assessment……………………………………………………………………. 7-79
  • Predicted Future Condition of the Environment if the Project Does Not Proceed…………………… 7-80
  • Follow-Up and Monitoring………………………………………………………………………………………… 7-80
  • References…………………………………………………………………………………………………………… 7-81

In-Text Figures

Figure 7.1:    Surface Water Resources Study Areas…………………………………………………………………………… 7-24

Figure 7.2:    Surface Water and Sediment Sampling Locations……………………………………………………………… 7-28

Figure 7.3:    Waterbody Crossings and their Watersheds…………………………………………………………………….. 7-30

In-Text Tables

Table 7-1:     Key Regulation, Legislation, Policy Relevant to Surface Water Resources Assessment for

the Project…………………………………………………………………………………………………………………. 7-6

Table 7-2:     Surface Water Resources VC – Summary of Inputs Received During Engagement and Consultation………………………………………………………………………………………………………………. 7-9

Table 7-3:     Surface Water Resources VC – Summary of Indigenous Knowledge and Land and Resource

Use Information…………………………………………………………………………………………………………. 7-17

Table 7-4:     Surface Water Resources VC – Subcomponents, Indicators, and Rationale…………………………….. 7-22

Table 7-5:     Project Interactions with Surface Water Resources VC and Potential Effects…………………………… 7-25

Table 7.6:     Water Quality Sampling Sites……………………………………………………………………………………….. 7-32

Table 7-7:     Surface Water Quality – Summary of Field Measuring and Laboratory Analytical Parameters

Collected in 2019, 2020, 2021, and 2023…………………………………………………………………………. 7-32

Table 7-8:     Sediment Quality Sampling Sites…………………………………………………………………………………… 7-33

Table 7-9:     Sediment Quality – Summary of Field Measuring and Laboratory Analytical Parameters

Collected in 2020……………………………………………………………………………………………………….. 7-34

Table 7-10: Summary of Analytical Results for Water Quality in the Winisk River Watershed……………………….. 7-36

Table 7-11: Summary of Analytical Results for Water Quality in the Ekwan River Watershed……………………….. 7-38

Table 7-12: Summary of Analytical Results for Water Quality in the Attawapiskat River Watershed……………….. 7-41

Table 7-13: Potential Effects, Pathways, and Indicators for Surface Water Resources VC…………………………… 7-49

Table 7-14: Summary of Potential Effects, Mitigation Measures, and Predicted Net Effects for Surface Water Resources VC…………………………………………………………………………………………………………… 7-57

Table 7-15: Criteria for Characterization of Predicted Net Effects on Surface Water Resources VC……………….. 7-67

Table 7-16: Summary of Predicted Net Effects on Surface Water Resources VC………………………………………. 7-74

7.               Assessment of Effects on Surface Water Resources

Surface water resources were identified as one of the valued components (VC) during the VC scoping and selection as part of the Environmental Assessment / Impact Assessment (EA/IA) process. This section describes and assesses the potential effects that the Project may have on the Surface Water Resources VC.

Existing conditions for the surface water resources have been established through the field work programs, desktop studies and engagement and consultation activities completed by the Project Team. This includes, but not limited to, background information review, internet research, surface water and sediment sampling, hydrologic and hydraulic analysis, engagement with Indigenous communities and stakeholders, and expert opinion. The existing conditions are being used as baseline conditions to assess and determine the potential effects of the Project. The results of the baseline studies are provided in Appendix F – Natural Environment Existing Conditions (NEEC) Report.

The assessment of potential effects for the Surface Water Resources VC is presented in the following manner:

• Scope of the Assessment;
• Existing Conditions Summary;
• Potential Effects, Pathways and Indicators;
• Mitigation Measures;
• Characterization of Net Effects;
• Determination of Significance;
• Cumulative Effects;
• Prediction of Confidence in the Assessment;
• Predicted future Condition of the Environment if the Project Does Not Proceed;
• Follow-up and Monitoring Programs; and
• References.

7.1                   Scope of the Assessment

7.1.1             Regulatory and Policy Setting

The Surface Water Resources VC is assessed in accordance with the requirements of the Impact Assessment Act, the Ontario Environmental Assessment Act, the Tailored Impact Statement Guidelines (TISG) for the Project (Appendix A-1), the provincial approved EA Terms of Reference (ToR) (Appendix A-2), and EA/IA guidance documents.

Table 7-1 outlines the key regulations, legislation, and policies relevant to the assessment of the Surface Water Resources VC for construction and operations of the Project.

Table 7-1:      Key Regulation, Legislation, Policy Relevant to Surface Water Resources

7.1.2             Consideration of Input from Engagement and Consultation Activities

Table 7-2 summarizes input related to Surface Water Resources received during the engagement and consultation for the EA/IA and how inputs are addressed in the EAR/IS. This input includes concerns raised by Indigenous communities and groups, the public, government agencies, and stakeholders prior to the formal commencement of the federal IA and provincial EA, during the Planning Phase of the IA and ToR phase of the EA.

Table 7-2:      Surface Water Resources VC – Summary of Inputs Received During Engagement and Consultation

7.1.3             Incorporation of Indigenous Knowledge and Land and Resource Use Information

To date, the following First Nations have provided Indigenous Knowledge and Land and Resource Use (IKLRU) information to the Project Team:

• Webequie First Nation;
• Marten Falls First Nation; and
• Weenusk First Nation.

Table 7-3 summarizes IKLRU information relating to Surface Water Resources VC and indicates where the information is incorporated in the EAR/IS.

Table 7-3:      Surface Water Resources VC – Summary of Indigenous Knowledge and Land and Resource Use Information

Notes: Names of First Nations and associated location-specific description in some instances are not presented in this table due to potential sensitivity and confidentiality of IKLRU information.

7.1.4             Valued Component and Indicators

Valued components, including surface water resources, have been identified in the TISG and by the Project Team and are, in part, based on what Indigenous communities and groups, the public, government agencies, and stakeholders have identified as valuable to them in the EA/IA process to date. Subcomponents (or criteria) of the Surface Water Resources VC are further identified to help inform the report structure and better assess and present the data and assessment results. The assessment of these subcomponents is being conducted using the methodology as outlined in

Section 5 (Environmental Assessment / Impact Assessment Approach and Methods). The identified subcomponents for the Surface Water Resources VC are:

• Surface water quantity;
• Surface water quality; and
• Sediment quality at waterbodies.

“Indicators”, are used to assess potential effects to a VC. In general, indicators represent a resource, feature or issue related to a VC that if changed from the existing conditions may demonstrate a positive or negative effect.

Table 7-4 shows the subcomponents and indicators identified for the Surface Water Resources VC.

Table 7-4:      Surface Water Resources VC – Subcomponents, Indicators, and Rationale

7.1.5             Spatial and Temporal Boundaries

The following assessment boundaries have been defined for the Surface Water Resources VC.

7.1.5.1             Spatial Boundaries

The spatial boundaries for the Surface Water Resources VC are shown on Figure 7.1 and include the following:

• Project Footprint – the area of direct disturbance (i.e., the physical area required for project construction and operations). The Project Footprint is defined as the 35 m wide right-of-way (ROW) of the WSR; and temporary or permanent areas needed to support the Project that include access roads, construction camps, laydown and storage yards, aggregate pits/quarries, and a Maintenance and Storage Facility.
• Local Study Area (LSA) – the area where potential largely direct, and indirect effects of the Project are likely to occur and can be predicted or measured for assessment. The LSA extends approximately 1 km from the centreline of the preliminary recommended preferred route and 500 m from the boundary of the temporary and permanent supportive infrastructure.
• Regional Study Area (RSA) – the area where potential largely indirect and cumulative effects of the Project in the broader, regional context may occur. The RSA includes the LSA and further extends on each side of the LSA boundaries to include quaternary watersheds crossed by the recommended preferred route.

7.1.5.2             Temporal Boundaries

Temporal boundaries for the assessment address the potential effects of the Project over relevant timescales. The temporal boundaries for the Project consist of two main phases:

• Construction Phase: All activities associated with the initial development of the road and supportive infrastructure from the start of construction to the start of operation and maintenance of the Project and is estimated to be approximately 5 to 6 years in duration; and
• Operations Phase: All activities associated with operation and maintenance of the road and permanent supportive infrastructure (e.g., operations and maintenance yard, aggregate extraction and processing areas) that will start after construction activities are complete, including site restoration and decommissioning of temporary infrastructure (e.g., construction camps). The Operations Phase of the Project is anticipated to be 75 years based on the expected timeline for when major refurbishment of road components (e.g., bridges) is deemed necessary.

The Project is proposed to be operated for an indeterminate period; therefore, future suspension, decommissioning, and eventual abandonment is not evaluated in the EA/IA (refer to Project Description, Section 4.4).

7.1.6             Identification of Project Interactions with Surface Water Resources

Table 7-5 identifies the project activities that may interact with the Surface Water Resources VC to result in a potential effect. The identification of project interactions with surface water resources provides a basis for the subsequent assessment of the potential effects of the Project. The potential effects are described separately for subcomponents of Surface Water Resources VC including surface water quantity, surface water quality, and sediment quality.

Table 7-5:      Project Interactions with Surface Water Resources VC and Potential Effects

Notes:

✓ = Potential interaction – = No interaction

¹ Emissions, Discharges, and Wastes (e.g., air, noise, light, solid wastes, and liquid effluents) are generated by many project activities. Rather than acknowledging this by placing a checkmark against each of these activities, “Wastes and Emissions” is an additional component under each project phase.

² Accidents and Malfunctions including spills, vehicle collisions, flooding, forest fire and vandalism may occur at any time during construction and operations of the Project. Rather than acknowledging this by placing a checkmark against each of these activities, “Potential for Accidents and Malfunctions” is an additional component under each project phase. The potential effects of accidental spills are assessed in Section 23 – Accidents and Malfunctions.

³ Project employment and expenditures are generated by most project activities and components and are the main drivers of many socio-economic effects. Rather than acknowledging this by placing a checkmark against each of these activities, “Employment and Expenditures” is an additional component under each project phase.

7.2                   Existing Conditions

This section summarizes the existing conditions of surface water and sediment based on desktop review and field investigations conducted for the Project. Limited existing surface water and sediment quality data were available in RSA for the Project due to the remote location and limited development. Relevant environmental studies in the region have been completed by the Ontario Ministry of the Environment and Climate Change, resource development companies, and other governmental and non-governmental organizations. However, these studies were not completed near the project location and do not provide sufficient data to establish baseline surface water quality conditions in the RSA. As such, it was necessary to collect project-specific surface water and sediment quality data.

Baseline surface water and sediment quality sampling was conducted to establish existing surface water and sediment quality conditions at waterbody and watercourse crossings within the LSA and along the route of the proposed WSR. The waterbody crossing locations along the route of the proposed WSR are shown in Figure 7.2. A hydrology and hydraulic analysis were conducted to establish peak discharge estimates (e.g., design flow) and hydraulic characteristics of peak discharges under existing conditions. Detailed description of existing surface water and sediment conditions is provided in Appendix F – NEEC Report.

7.2.1             Methods

This section summarizes methods used to characterize the existing surface water and sediment conditions. The methods included a desktop review of background information sources, field surveys to establish approximate channel bathymetry, surface water quality and sediment quality, and hydrological analysis, with the objective of addressing the requirements in Sections 8.6 and 14.2 of the TISG and meeting the requirements of the MECP and other provincial ministries as identified in the ToR for the Project. The NEEC Report prepared for the Project (Appendix F) includes a detailed description of the methods and results of the desktop review, field surveys, and hydrological analysis.

Indigenous community members raised concerns about heavy metals including chromium, being introduced to the project area during construction and operations. To address this, strict regulatory guidelines were followed during the groundwater baseline investigation program concerning heavy metals including chromium, mercury and methylmercury. The study also included total metal and dissolved metal concent

7.2.1.1             Desktop Review of Background Information

The following background information sources were reviewed to characterize existing surface water conditions for the Project.

• Regional hydrology data obtained from the historic Ontario Flow Assessment Tool (MNR, 2019), re-launched in 2022 as Ontario Watershed Information Tool Ministry of Natural Resources (MNR);
• Google Earth Satellite Imagery;
• Field notes from site geotechnical and biological investigations reconnaissance;
• Light detection and ranging (LiDAR) data collected for the Project;
• Environment Canada, Water Survey of Canada Monitoring Stations; and
• Ring of Fire Baseline Environmental Monitoring Program (Preliminary Report; MECP, 2019).

Existing surface water yield and surface water quality conditions were determined by review and analysis of information extracted from the Ontario Watershed Information Tool (OWIT; previously Ontario Flow Assessment Tool [OFAT]) and atlases, as well data available from the Water Survey of Canada and Provincial Water Quality Monitoring Network.

7.2.1.2             Surface Water Quantity

• Peak Discharge

Twenty-six potential waterbody crossings (watercourse/waterbody) were initially identified prior to the field studies from 2019 through 2021. In 2023, an additional large waterbody crossing (WC-27) was added along the access road to an aggregate source area (ARA-4). Four additional small waterbody crossings, with catchment areas less than 1.5 km2, were also identified along the proposed WSR route. These small crossings were labelled with the number of the waterbody crossing to the west with an additional sequential letter (WC-1A, WC-1B, WC-2A, and WC-6A). A field study was conducted in 2023 to collect data at the additional five waterbody crossings. Data collected relevant to surface water quantity included:

• Waterbody type;
  • Flow estimates;
    • Mean wetted depth;
    • Mean wetted width;
    • Mean bankfull width;
    • Substrate;
    • Beaver dam presence;
    • Riparian vegetation;
    • Floodplain characteristics; and
    • Ground photography.

The waterbody crossings are described in detail in Section 5 of the NEEC Report (Appendix F). These crossings were noted as having a defined channel/flow path and do not include wetlands or areas that may experience ephemeral flow for a short duration after a precipitation event in a given year. The OWIT, developed by the Ontario MNRF (now MNR) was utilized to calculate watershed characteristics. The waterbody crossing locations of the proposed WSR route are shown in Figure 7.3.

The method of establishing the peak discharge for each waterbody crossing depends on several factors such as available data, crossing location, and watershed catchment size. Section 5.2.4 in the NEEC Report (Appendix F) and Section 3.1 and Figure 2.1 in the Hydrologic and Hydraulic Analysis for the Webequie First Nation Supply Road Memo (Appendix 5-A of the NEEC Report) outline the general approach to identifying the methods to follow when developing a design flow for roads. It should be noted that the proposed crossings are on waterbodies that are not gauged

(i.e., no flow records).

The methods considered to establish peak discharges at proposed watercourse crossing with larger catchments were the Index Flood Method (from OFAT), Modified Index Flood Method, the Transposition of Flood Discharge Method (using single station), the Transposition of Flood Discharge Method (using Regional Flow Frequency Analysis), Northern Ontario Hydrology Method, and Unified Ontario Flood Method. Rational Method was used to establish peak discharges for smaller catchments. Note that the discharge estimate feature in OFAT is no longer available in OWIT.

• Waterbody Crossing Hydraulics and High-Water Level

The existing hydraulics (flow depth/water level and average velocity) and High-Water Level for each of the waterbody crossings were subsequently estimated using 1-dimensional hydraulic models. The 1-dimensional model uses known values or estimates of waterbody geometry and channel roughness (Manning’s ‘n’) to predict flow depth and velocity for a range of discharge conditions. Geometry was generated from LiDAR data (where available) or Canadian Digital Elevation Model data and field estimates for channel size (depth/width). A high degree of estimation was required to model each waterbody crossing due to data availability. For instance, Manning’s ‘n’ values and channel side slopes were estimated from photographs of the water crossings. Channel slope and overbank topography was estimated from LiDAR data and channel shape was estimated from field observations. Further details for these methods are described in detail in Section 5.2.4 in the NEEC Report (Appendix F).

7.2.1.3             Surface Water Quality

The water quality sampling was conducted during the baseline aquatic field work program in August 2019,

October 2020, May 2021, and August 2023. Sampling collection methods, QA/QC protocols, and application of relevant water quality guidelines are described in detail in Section 5 of the NEEC Report (Appendix F).

Indigenous community members raised concerns about potential contamination of the headwaters and rivers by heavy metals including chromium. Methylmercury and other water quality concerns (parameters) have been included in the surface water baseline investigation program. Surface water quality was monitored for seasonal and annual changes during the EA/IA process. A Surface Water and Storm Water Management and Monitoring Plan will be developed during detail design as part of the Construction Environmental Management Plan (CEMP) and the Operation Environmental Management Plan (OEMP) for implementation in the construction and operation phases. The Project Team continues to seek guidance from regulatory agencies throughout the EA/IA process on project design requirements and submission requirements for applicable permits, approvals and/or authorizations needed to construct the WSR.

• Sampling Locations

Field measurements of pH, and temperature were recorded during the sampling event using a multi-parameter probe YSI Proplus meter. Turbidity water samples were collected and put into a Lamotte 2020WE turbidity meter. The probe and meter were calibrated prior to each sampling and re-calibrated daily or as required according to the operating manual for the instrument. Water quality data were collected from 24 sampling stations along the proposed WSR route. The locations of these stations were the same as aquatic assessment locations/stations (refer to Section 8 of the NEEC Report [Appendix F]) and are listed by watershed in Table 7-6 and shown in Figure 7.2.

Table 7-6:  Water Quality Sampling Sites

• Sampling Parameters

Standard surface water quality parameters were measured in all samples collected. The samples were analyzed for the parameters listed in Table 7-7 during the years indicated with a checkmark. Detailed analysis results are provided in the NEEC Report (Appendix F).

Table 7-7:      Surface Water Quality – Summary of Field Measuring and Laboratory Analytical Parameters Collected in 2019, 2020, 2021, and 2023

Notes:

✓ = Parameters included in sampling and testing

– = Parameters not measured in samples

7.2.1.4             Sediment Quality

The sediment quality sampling was conducted during the baseline aquatic field work program in October 2020. Sampling collection methods, QA/QC protocols, and application of relevant sediment quality guidelines are described in detail in the NEEC Report (Appendix F).

• Sampling Locations

Sediment samples were acquired during the benthic invertebrate surveys from October 14 – 25, 2020. Due to poor weather and access conditions, samples were only collected at the five sampling locations listed in Table 7-8 and shown in Figure 7.2.

Table 7-8:      Sediment Quality Sampling Sites

• Sampling Parameters

Standard sediment quality parameters were measured in all samples collected in 2020, which are summarized in

Table 7-9. Detailed analysis results are provided in the NEEC Report (Appendix F).

Table 7-9:      Sediment Quality – Summary of Field Measuring and Laboratory Analytical Parameters Collected in 2020

7.2.2             Results

7.2.2.1             Surface Water Quantity

Baseline surface water quantity conditions were characterized at water crossings to support the design of water crossing structures. The objectives of the water crossings structures include minimizing erosion and flooding, protecting water quality, and maintaining aquatic diversity and are described in further detail in Section 4.3.2 (Drainage and Stormwater Management in the Project Description).

• Peak Discharge

The estimated peak discharges for larger catchments were determined by considering the following methods:

• Index Flood Method (using OFAT);
  • Modified Index Flood Method (MIFM);
    • Transposition of Flood Discharge Method (using single station);
    • Transposition of Flood Discharge Method (using Regional Flow Frequency Analysis [RFFA]);
    • Northern Ontario Hydrology Method (NOHM); and
    • Unified Ontario Flood Method (UOFM).

The peak discharges are summarized in Appendix 5-A of the NEEC Report (Appendix F).

For catchment areas greater than 100 km2, the OFAT, MIFM, Transposition of Single Station, and RFFA yielded the best results. MIFM was about 15% higher for catchments from 100 – 1000 km2, but over 40% for catchments greater than 1000 km2. Transposition of Single Station was generally about 15% higher than OFAT and RFFA was generally 10% lower than OFAT. For catchment areas less than 100 km2 (MIFM not applicable), the Transposition of Single Station was generally about 20% lower than OFAT results and RFFA were generally about 30% higher than OFAT results. The OFAT results (Index Flood Method) were selected as the most representative of the watercourse peaks, as they typically fell in the middle of all the results.

The NOHM (only from <100 km2) and the UOFM results were more than 90% less than all other methods. NOHM and UOFM rely on the total area of lakes and wetlands within the catchment. However, the wetland areas for the project are quite large (47% to 95%), resulting in an overly reduced discharge, as the peak is effectively damped by the wetland area, and these methods were not adopted.

The estimated peak discharges for smaller catchments were determined using Rational Method.

Table 3.1 in Appendix 5-A of the NEEC Report (Appendix 6) provides a summary of the waterbody crossing characteristics and the estimated peak discharge for the 1:50 year and 1:100 year storm events.

• Waterbody Crossing Hydraulics and High-Water Level

The flow, depth, and width data are summarized in Appendix 5-A of the NEEC Report (Appendix 6). It should be noted that, due to access constraints, several of the road waterbody crossings were not visited and therefore physical parameters/measurements were taken from either upstream or downstream of the actual proposed crossing location or from an aerial view.

The estimated high-water levels for the crossings are shown in Table 5-10 of the NEEC Report (Appendix 6). It should be noted that the hydraulic model geometries of the crossings are based on currently available field data collected for this project, LiDAR data, and orthophotos and further surveys of the crossings’ bathymetry will be taken during the next design stage to confirm the assumptions on flow, depth, and width data.

7.2.2.2             Surface Water Quality

There are three main watersheds within the project study areas, including Winisk, Upper Ekwan, and Attawapiskat watersheds. Surface water quality results for each of the three main watersheds are summarized in the following subsections. Detailed analytical results are presented in Appendix 5-B of the NEEC Report (Appendix 6). Statistical results are presented in Table 5-13 in the NEEC Report (Appendix 6). Exceedances of the Canadian Environmental Quality Guidelines (CEQG), Water Quality Guidelines for the Protection of Aquatic Life, Freshwater (CCME, 2023), the Provincial Water Quality Objectives (PWQO, Ministry of Environment [MOE] 1994), or Guidelines for Canadian Drinking Water Quality (GCDWQ, 2022) were not common, considering the large number of samples and parameters analyzed. However, some exceedances were observed. The greatest number of exceedances were observed in 2019, and exceedances of field pH, aluminum, and iron occurred in all four sampling years. Given the low degree of development in the LSA and RSA, the exceedances were likely naturally occurring from sources such as natural sediment deposition from weathering of rocks and potential atmospheric sources from distant emissions but could originate from a distant upstream source.

Analytical results for water quality in the Winisk River, Ekwan River, and Attawapiskat River watersheds are summarized in Table 7-10, Table 7-11, and Table 7-12, respectively.

Table 7-10: Summary of Analytical Results for Water Quality in the Winisk River Watershed

Notes:

¹ Values shown depicte the statistical values of all samples collected in the watershed: mean (minimum – maximum).

² The number of exceedances represent samples that exceed at least one guideline. The total number of samples collected was 26, including two duplicate samples.

³ Canadian Environmental Quality Guidelines (CEQG). Water Quality Guidelines for the Protection of Aquatic Life, Freshwater (CCME, 1999, as updated).

⁴ Provincial Water Quality Objectives (MOEE, 1994, reprinted 1999 version).

⁵ Guidelines for Canadian Drinking Water Quality (GCDWQ) Summary Table (Health Canada, September 2020).

⁶ Guideline varies with pH. Where pH is measured, the pH-specific guideline has been applied.

⁷ Select PAHs include anthracene, benzo(a)anthracene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, fluoranthene, and perylene.

Table 7-11: Summary of Analytical Results for Water Quality in the Ekwan River Watershed

Notes:

¹ Values shown depicte the statistical values of all samples collected in the watershed: mean (minimum – maximum).

² The number of exceedances represent samples that exceed at least one guideline. The total number of samples collected was 18, including two duplicate samples.

³ Canadian Environmental Quality Guidelines (CEQG). Water Quality Guidelines for the Protection of Aquatic Life, Freshwater (CCME, 1999, as updated).

⁴ Provincial Water Quality Objectives (MOEE, 1994, reprinted 1999 version).

⁵ Guidelines for Canadian Drinking Water Quality (GCDWQ) Summary Table (Health Canada, September 2020).

⁶ Guideline varies with pH. Where pH is measured, the pH-specific guideline has been applied.

⁷ Select PAHs include anthracene, benzo(a)anthracene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, fluoranthene, and perylene.

⁸ Guideline varies with hardness. Where hardness is measured, the hardness-specific guideline has been applied. If hardness is not analyzed, the most stringent guideline has been applied.

Table 7-12: Summary of Analytical Results for Water Quality in the Attawapiskat River Watershed

Notes:

¹ Values shown depicte the statistical values of all samples collected in the watershed: mean (minimum – maximum).

² The number of exceedances represent samples that exceed at least one guideline. The total number of samples collected was 19, including one duplicate sample.

³ Canadian Environmental Quality Guidelines (CEQG). Water Quality Guidelines for the Protection of Aquatic Life, Freshwater (CCME, 1999, as updated).

⁴ Provincial Water Quality Objectives (MOEE, 1994, reprinted 1999 version).

⁵ Guidelines for Canadian Drinking Water Quality (GCDWQ) Summary Table (Health Canada, September 2020).

⁶ Guideline varies with pH. Where pH is measured, the pH-specific guideline has been applied.

⁷ Select PAHs include anthracene, benzo(a)anthracene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, fluoranthene, and perylene.

7.2.2.3             Sediment Quality

Sediment samples collected at waterbodies within Winisk, Upper Ekwan, and Attawapiskat watersheds in the LSA for the Project were generally fine-textured and appeared to contain considerable organic and decaying matter. Ekman grabs frequently grabbed small woody debris in most samples and multiple grabs were required to obtain sufficient sediment, especially as the fine-textured sediment tended to run out of the Ekman sampler. Small gravels were occasionally found in sediment samples collected within WC3-SD (Winiskisis Channel), but these gravels were subsequently removed from the substrate samples before analysis. The 2020 sample sites are summarized by watershed in Table 7-8.

Results from the parameters analyzed in the sediment samples were generally below the regulatory guidelines and standards, with the exception of the following parameters:

• Concentrations of Arsenic at WC-3 and WC-15, exceeded ISQG and MOE LEL. The concentration of arsenic of 12 µg/g in sample WC-20 equals the CCME PEHH criteria (12 µg/g).
• Concentration of total Chromium at WC-20 exceeds the MOE LEL only.
• RDL values for Chromium VI at WC-3 and WC-15 exceeds the CCME PEHH, whereas RDL values at WC-20 and WC-24 equals the CCME PEHH criteria (0.4 µg/g).
• Concentration of Iron at WC-3 and WC-20 exceeds the MOE LEL.
• Concentrations of Manganese at WC-3, WC-15, WC-20, and WC-24 MOE LEL.
• Exceedances of Fraction of Organic Carbon, Total Organic Carbon, and Total Kjeldahl Nitrogen were recorded above the MOE LEL standards at WC-3, WC-15, W-C16, WC-20, and WC-24.

The exceedances could occur from sources such as natural sediment deposition from weathering of rocks and potential atmospheric sources from distant emissions, given that there have been relatively limited resource development activities in the general project area.

7.3                   Identification of Potential Effects, Pathways, and Indicators

As indicated in Table 7-5, some project activities may interact with and impose potential effects on the Surface Water Resources VC during the project construction and operations. This section describes the nature of the potential effects, the pathways that link the project activities and the effects, and the indicators that can be used to assess and measure the effects. Table 7-13 summarizes the potential effect pathways and effect indicators for the Surface Water Resources VC. The primary potential effects include alteration of surface water drainage pattern and flows and changes to surface water quality and sediment quality.

The descriptions of effect pathways are grouped by their potential effect to avoid repetition since many of the same effect pathways may occur during different phases of the project. The potential effects of accidental spills on surface water resources are assessed in Section 23 – Accidents and Malfunctions.

Indigenous community members raised concerns about how potential changes in surface water quality/patterns due to project activities may affect soils, vegetation and wildlife. A pathway of effects approach is applied to identify and address related VCs (and related indicators of change) additional to those identified in Appendix B of the ToR as they are identified and further ecological linkages become more evident. Pathways describe how project activities could result in a potential effect (e.g., dewatering may reduce in-stream discharge resulting in reduced streamflow or water levels in nearby waterbodies) during each project phase (i.e., construction and operations). For an example on a linkage to other VCs, hydrology

(e.g., changes to water availability) is a major evaluation criterion during the evaluation of wetland function which forms part of the vegetation effects analysis.

7.3.1             Change in Surface Water Quantity

There could be a change in surface water quantity as a result from changes to the surface water drainage patterns and flows during construction and throughout operations. The pathways in which such changes may occur are described below and the predicted net effects, including magnitude, likelihood, and duration, as a result of these changes are assessed in Section 7.5.

Dewatering, water takings → Decrease in-stream discharge → Reduced streamflow or water levels in nearby waterbodies

Dewatering of surface water at waterbodies and groundwater dewatering is likely required during construction to keep the work area dry for the construction of the structure foundations (e.g., bridges and culverts, etc.). Groundwater dewatering may also be required when extracting aggregate materials at quarry and borrowing sites if the extraction is advanced below the groundwater table. Water takings may also be required for other purposes including water use for camps, concrete production, dust control, and site restoration – seeding, etc. Dewatering and short-term water takings for construction and operations may result in temporarily reduced baseflow contributions from groundwater sources and streamflow or water levels in nearby waterbodies.

Indigenous community members raised concerns about the potential ecological consequences if peatlands were drained during the construction of the WSR. Recognizing the importance of peatlands to First Nations due to their ability to store carbon in their soils and hold a lot of freshwater, a “floating” road design – the proposed road will be constructed on top of the peat (no peat is removed) – will be used for the section of the WSR that crosses peatlands as described in Section 4.3.1.3.1 Road Design in Peatlands.

Water discharge → Changes to runoff rates and volumes, infiltration rates, and overland flow paths → Change to surface water drainage patterns and flows → Increased streamflow or water levels in nearby waterbodies

Short-term discharges of construction water, wastewater, or wash water from project activities may result in temporary increased streamflow or water levels in nearby waterbodies.

Vegetation clearing and grubbing → Alteration of vegetation coverage → Changes to runoff rates and volumes, infiltration rates, and overland flow paths → Change to surface water drainage patterns and flows

Alterations to land cover may result in changes to runoff rates and volumes, infiltration rates, and overland flow paths. These changes would include permanent alterations (operations phase) such as roadway construction as well as temporary alterations (construction phase) such as vegetation clearing outside of permanent structure footprints, stockpiles, and laydown preparation. Changes to runoff rates and runoff volumes due to changes in land cover in the Project Footprint would result in decreased infiltration and increased streamflow or water levels during construction and operations.

Construction of permanent or temporary structures (culverts and bridges) at waterbody crossings → Change in-stream discharge, channel flow depth/water level and velocity → Change to surface water drainage patterns and flows

Construction of culverts and bridges will temporarily alter discharge rates and flow paths at waterbody crossings. Changes to local hydraulics (flow depth/water level and velocity) at and around constructed waterbody crossings could result in an increase or reduction of local shear stress, erosion, water levels, and sedimentation upstream or downstream of the crossings during the operations phase. For example, the short-term flow diversion will involve the

use of a temporary dam and pump bypass system (active in-stream diversion) or temporary diversion channels and/or dams (passive in-stream diversion). The implementation of short-term water diversions, in combination with the construction and removal of temporary waterbody crossing structures, may result in changes to surface water quantity.

Operations, maintenance, and repair of road → Changes to runoff rates and volumes, infiltration rates, and overland flow paths → Change to surface water drainage patterns and flows

Changes in overland flow paths due to road drainage system maintenance, winter snow clearing, localize road surface repairs, and vegetation control may result in an increased or decreased streamflow or water levels in the local receiving bodies.

The effects of project activities outlined in the effect pathways above on surface water drainage patterns and flows can be indicated through observable erosion in areas that were previously stable, water levels exceeding channel banks on a continual basis, and changes to annual water levels within waterbodies upstream or downstream.

Surface water and groundwater conditions are strongly associated and as runoff rates increase, rates of infiltration and recharge to groundwater decrease. The vitality of fish and their habitats, vegetation, and wetlands is contingent upon the combined impacts to surface water discharge and its dynamic connection to groundwater.

7.3.2             Change in Surface Water Quality

The surface water quality can be affected by alterations to drainage pattern and flows in addition to potential spills or releases of chemicals and pollutants. The pathways or activities which may result in changes to surface water quality include the following:

Dewatering and discharging → Disturbance of subsurface soils → Elevated sediment levels in discharge water

→ Reduction in surface water quality

When the extracted water from dewatering activities is discharged to the natural environment and reaches nearby surface water bodies, it may impair the surface water quality by introducing the extra sediment (e.g., total suspended solids) to the surface water.

Short-term discharges of construction water, wastewater, or wash water could result in temporary increases to chemical constituents and exceedances of water quality guidelines in nearby waterbodies.

Indigenous community members raised concerns about how dewatering activities during the project construction may affect levels of methylmercury and other environmental effects. Methylmercury and other water quality concerns (parameters) have been included in the surface water baseline investigation program. Surface water quality was monitored for seasonal and annual changes during the EA/IA process. A Surface Water and Storm Water Management and Monitoring Plan will be developed during detail design as part of the Construction Environmental Management Plan (CEMP) and the Operation Environmental Management Plan (OEMP) for implementation in the construction and operation phases.

Accidental spills or leaks → Leaching and infiltration, overland flow with surface runoff → Reduction in surface water quality

Accidental spills or leaks originating from construction machinery and road traffic have the potential to reach surface water through runoff during precipitation events, either flowing along surfaces or entering road stormwater drainage systems. These spills, carrying heavy pollutants, can lead to the contamination of surface water, influencing its quality and depositing the sediment in the bed of waterbodies. Potential effects of accidental spills are assessed in Section 23 – Accidents and Malfunctions.

Construction and maintenance activities → Generation of airborne particulate matter → Reduction in surface water quality

Construction and maintenance activities can produce airborne particulate matter (e.g., dust) that has the potential to settle directly onto the water surface or be transported by the wind into nearby waterbodies. This introduction of contaminants may adversely influence water quality by raising concentrations of deleterious substances.

Fugitive dust concerns expressed by an Indigenous community will be addressed by the use of the industry best management practices. Water trucks and the use of erosion and sediment control measures will be used along the road right-of-way to eliminate or reduce potential effects of fugitive dust on the water quality.

The potential impact of runoff from bridges will be addressed through stormwater management designs. Conduits to direct stormwater runoff for treatment, such as stormwater management ponds, will be incorporated into the road design if deemed necessary to minimize the potential impacts to surface water quality.

Blasting of rocks → Introduction of deleterious substances → Reduction in surface water quality

Blasting activities can release contaminants into the air that may settle into nearby waterbodies or reach surface water through runoff. Chemical constituents from blasting can change surface water quality by introducing compounds not naturally present in surface water.

Road maintenance activities → Deposition and transportation of sediment into waterbodies → Reduction in surface water quality

Road drainage system maintenance, winter snow clearing, localize road surface repairs, and vegetation control could result in deposition of sediment into nearby waterways and changes to water chemistry.

The effects of project construction and operation activities on surface water can be monitored through the comparison of suspended sediment and chemical constituent concentrations with baseline characterization of surface water quality derived from samples from waterbody crossings and naturally occurring rates of erosion and sedimentation.

Changes to infiltrating water quality may have a lasting effect on groundwater quality due to the dynamic interaction. The vitality of fish, fish habitat, vegetation, and wetlands relies on specific criteria related to water quality, making them directly vulnerable to changes in surface water quality.

7.3.3             Change in Sediment Quality

The sediment quality in waterbodies can be affected by erosion of stockpiles and the road from changes to drainage pattern and flows in addition to potential spills or releases of chemicals and pollutants. The pathways or activities which may result in changes to sediment quality include the following:

Dewatering and discharging → Disturbance of subsurface soils → Elevated sediment levels in discharge water

→ Reduction in sediment quality

Short -term discharges, carrying diverse chemical constituents, may directly enter surface waterbodies via drainage systems or nearby water channels. This flow has the potential to modify the chemical composition, thereby affecting sediment quality as dissolved substances settle within the sediment.

Construction and maintenance activities → Generation of airborne particulate matter → Reduction in sediment quality

Airborne particulate matter from construction and maintenance activities has the potential to settle directly onto the water surface or be transported by the wind into nearby waterbodies. This introduction of contaminants influences water quality and may have a lasting effect on sediment as the particles gradually settle over time.

Blasting of rocks → Introduction of deleterious substances → Reduction in sediment quality

Contaminants released into the air during blasting activities may settle onto nearby waterbodies or reach surface water through runoff. Chemical constituents from blasting can change surface water quality, and potentially settle in the sediment, and thereby, influencing its overall sediment quality.

Construction and maintenance activities → Deposition and transportation of sediment into waterbodies →Reduction in sediment quality

Runoff, erosion, and sedimentation processes associated with construction activities may lead to the transportation of suspended solids and particulate matter into waterbodies. The introduction of suspended solids can affect water quality, with the potential for these particles to settle in sediment and modify its composition.

Road drainage system maintenance, winter snow clearing, localize road surface repairs, and vegetation control could result in deposition of sediment into nearby waterways.

Accidental spills or leaks → Leaching and infiltration, overland flow with surface runoff → Reduction in sediment quality

Accidental spills, arising from construction machinery and road traffic, may reach surface water through diverse mechanisms, potentially affecting both water and sediment. These spills, laden with substance pollutants, have the potential to contaminate surface water through runoff during precipitation events, either by flowing along surfaces or entering the road stormwater drainage system that ultimately outlets to a waterbody. Consequently, they contribute to the degradation of water quality and settle within the sediment in the bed of waterbodies. The potential effects of spills on water quality and sediment quality are assessed in Section 23 – Accidents and Malfunctions.

The assessment of potential effects of project construction and operations on surface water and sediment quality involves evaluating changes in concentrations of suspended sediment and chemical constituents in water quality at waterbody crossings. This assessment takes specific activities into consideration as indicators of change such as increased sediment dislodgment from vehicle activities, sedimentation downstream of stockpile areas, and sediment discharge during the loading and unloading of construction materials.

Table 7-13:    Potential Effects, Pathways, and Indicators for Surface Water Resources VC

7.4                   Mitigation Measures

This section describes the proposed mitigation measures to eliminate, reduce, control, or offset potential adverse effects to water quantity, water quality and sediment quality during construction and operations of the Project as detailed in Section 7.3. Mitigation measures are described for each key project activity that may result in potential adverse effects to water quantity, water quality and/or sediment quality. Further measures will be provided in the CEMP and the Operation Environmental Management Plan (OEMP) that will be developed for the Project. Refer to Section 4.6 for details of the proposed framework for the development of the CEMP and the OEMP.

In addition to the mitigation measures described below, the preliminary recommended preferred route was selected to minimize watercourse crossing spans and hydrology issues at watercourse crossings. The full route optimization criteria are presented in Appendix D-1 – Preliminary Engineering Design Report.

7.4.1             Dewatering, Water Takings, and Discharges

Indigenous community members raised concerns about the potential ecological consequences if peatlands were drained during the construction of the WSR. Recognizing the importance of peatlands to First Nations due to their ability to store carbon in their soils and hold a lot of freshwater, a “floating” road design – the proposed road will be constructed on top of the peat (no peat is removed) – will be used for the section of the WSR that crosses peatlands as described in Section 4.3.1.3.1 Road Design in Peatlands.

Regulated by MECP Permits

All short-term water takings from surface water and/or groundwater sources for construction purposes will be carried out in accordance with O. Reg. 387/04, as amended by O. Reg. 64/16 under the Ontario Water Resources Act, and industry best standards. Based on the dewatering assessment results described in Section 8.3.5, the maximum

(worst-case) daily water taking volumes are estimated to be more than 400,000 L/day. Therefore, a permit to take water (PTTW) will be required for the Project. At some locations, the dewatering volumes may be more than 50,000 L/day, but less than 400,000 L/day. In this situation, an Environmental Activity and Sector Registry (EASR) registration (for Water Taking) will be used to permit the activity. Several dewatering sources/locations can be combined and included in the same EASR registration or PTTW application.

As part of the supporting documents for the PTTW or EASR applications, hydrogeological studies are required to detail the dewatering and impact assessments, discharge plans, mitigation measures and monitoring plans. Discharge water quality should be tested and meet Ontario PWQO as water will likely be discharged to the natural environment. Detailed discharge monitoring plans including discharge water quality testing, and contingency measures recommended in the hydrogeological studies as supporting documents for the PTTW application or EASR registration should be followed. In

general, the applicants and contractors are required to comply with terms and conditions of the approved PTTW or EASR, including monitoring and reporting to verify compliance.

Other Related Mitigation Measures

Dewatering activities should, at a minimum, follow Ontario Provincial Standard Specification (OPSS) 517 Dewatering of Pipeline, Utility, and Associated Structure Excavation and OPSS 518 Construction Specification for Control of Water from Dewatering Operations.

Erosion and Sediment Control measures (e.g., OPSS 805, Construction Specification for Temporary Erosion and Sediment Control Measures) should be incorporated into the detail design and implemented during construction to prevent erosion and migration of soils from the work site during rainfall events. Geotextile filter bag(s) or equivalent sediment trap should also be used at a minimum during dewatering activities to capture and treat dewatering effluent that may have elevated level of sediment (suspended solids). Discharge locations should be at least 30 m away from waterbodies.

Use industry best management practices (BMP) to minimize dewatering/pumping volumes:

• Temporary supporting systems can be used, where feasible, to help reduce the amount of groundwater inflow into the excavations.
• Surface water runoff will be directed away from the open excavations to reduce rain and surface water contribution to the total dewatering volumes.

For more detailed descriptions of proposed mitigation measures, refer to Section 5.20 (Quarry Site Selection and Development Requirements) in Appendix E – Mitigation Measures.

7.4.2             Vegetation Clearing and Grubbing

Alterations to land cover may result in changes to runoff rates and volumes, infiltration rates, and overland flow paths. To minimize the effects on runoff rates and increases to surface water quantities due to vegetation clearing and grubbing, the disturbed areas (for temporary supporting infrastructure) can be restored through decompaction of soil and placement of similar native soils (removed or excavated from the same area) or materials that are more permeable than the native soils, where practical. This along with planting of vegetation as part of the site rehabilitation will restore or increase infiltration rates and prevent or reduce soil erosion.

For more detailed descriptions of proposed mitigation measures, refer to Section 5.1 (Clearing and Grubbing) and Section 5.21 (Site Decommissioning and Rehabilitation) in Appendix E – Mitigation Measures.

7.4.3             Installation of Culverts and Bridges

Construction of permanent and temporary waterbody crossing structures will be timed for low-flow conditions to minimize the effect of temporary diversions on stream discharge. Erosion and sediment control measures, including temporary flow diversions or bypass pumping to isolate the work zone will be implemented throughout the construction phase by the Contractor to prevent or reduce environmental effects. These erosion and sediment control management practices include, but are not limited to sediment fences, sedimentation ponds, check dams, and erosion control fabric. Water quality will be directly mitigated through the implementation of spill response and storage and handling procedures for materials that have the potential for adverse interaction with surface water quality and indirectly mitigated through erosion control and water quantity mitigation measures. Water quality monitoring will be implemented during construction to identify exceedances of water quality guidelines and information. Construction operators’ work may need to be temporarily halted or additional mitigation methods be applied.

As discussed in Section 10 – Fish and Fish Habitat, the majority of activities with the potential to affect fish and fish habitat will be conducted within the appropriate timing windows for in water or near water work, as determined by the, MNR and DFO in consultation with Webequie First Nation and other First Nations. This will include clustering the construction of waterbody crossings outside of these windows to reduce overall time in waterbodies and potential effects to surface water. Based on the fish species present in the project study area, the restricted activity timing window is April 1 to June 20, except for the restricted activity timing window for Winisk Lake (September 1 to June 15). If in water work is required during the restricted activity timing window, DFO and MNR will be consulted well in advance to request and seek permission for an extension to the fisheries timing window.

For more detailed descriptions of proposed mitigation measures, refer to Section 5.11 (Bridge and Culvert Installation) in Appendix E – Mitigation Measures.

7.4.4             Permanent Waterbody Crossings

To mitigate potential changes to water quantity (flow/discharge, water levels), waterbody crossings will be designed with single-span elements (bridges or culverts), where possible, to limit the encroachment of structures into stream channels and thereby minimize the effect on discharge under variable flow conditions. As a result, three waterbody crossings require multiple spans (WB-1, WC-3, and WC-27), and 28 crossings were designed with single-span elements.

Hydrology estimates used to size waterbody crossing structures were based on 100-year return period peak flood events and included an increase adjustment, or up-sizing, to account for climate change. The adjustment for climate change incorporates potential increases to peak precipitation events and rises in annual temperatures and varies depending on the peak discharge method. The structures from a hydraulic perspective have been designed to pass frequent floods or precipitation events (2-year return period) with minimal effect on stream discharge, accommodate fish passage requirements (MTO, Department of Fisheries and Oceans Canada [DFO]) and where navigable waterways were identified the design of culverts and bridges has made allowance for a minimum navigational clearance, or opening, for small motorized and unmotorized watercraft passage.

7.4.5             Roadway Drainage Design

To mitigate potential changes to water quality, the roadway and swales were designed with consideration of low impact development procedures for linear infrastructure. These features include permanent enhanced swales that are designed to convey, treat, and attenuate stormwater runoff from the road. Enhanced grass swales incorporate design features such as modified geometry and rock check dams that improve the contaminant removal and runoff reduction functions of simple grass channel roadside ditch designs. The topography along the length of the road, particularly the east half of the WSR, is very flat with shallow relief. Drainage cross-culverts (900 mm diameter) are designed to be installed at regular intervals in lowland areas to prevent water from ponding on either side of the roadway and allow overland flow to follow existing hydrological flow paths. Additionally, the road cross-fall is designed to continue draining water after deterioration of the loose gravel road surface until seasonal maintenance operations crews return to reshape the roadway.

7.4.6             Accidental Spills and Leaks

Fuel spills, leaks and releases present a hazard to human health and safety, and can be a threat to soil, groundwater and aquifers, surface water, vegetation, wetlands, and wildlife habitats. Besides the potential impacts on health and the environment, there may be significant costs associated with wasted fuel, treatment of oily wastewater, and remediation of fuel-impacted sites.

General mitigation measures to prevent accidental spills and leaks include proper handling and storage of petroleum and other hazardous materials. Emergency response plans will be in place for any spills of hazardous material including thorough documentation of the incident and clean-up response.

For more detailed descriptions of proposed mitigation measures, refer to Section 5.2 (Petroleum Handling and Storage), Section 5.3 (Spill Prevention and Emergency Response), and Section 5.5 (Materials Handling and Storage) in

Appendix E – Mitigation Measures.

7.4.7             Blasting of Rock

The blasting with explosives will be limited to the places where other options are not feasible. Wherever practical, alternatives including bedrock ripping, typical or standard drilling, hammering, and non-explosive agent (e.g., expanding grout) can be considered. A Construction Blasting Management Plan for the Project will be prepared and submitted by applicable contractor(s) after contract award prior to initiation of blasting activities (refer to Section 2.1.3 in Appendix E – Mitigation Measures.

If blasting is required, it should be conducted in accordance with Ontario Provincial Standard Specification (OPSS) 120 General Specification for the Use of Explosive. A pre-blasting survey will be conducted to identify water supply wells and other environmentally sensitive features within 250 m from the blasting location. Mitigation measures will be modified or enhanced, if needed, based on the survey results. Blasting will not be conducted within 50 m of water supply wells (if any) and should be avoided in shallow groundwater table areas, where possible.

For more detailed descriptions of proposed mitigation measures, refer to Section 5.12 (Blasting near a watercourse) and Section 5.20 (Quarry Site Selection and Development Requirements) in Appendix E – Mitigation Measures.

7.4.8             Construction and Maintenance Activities

Construction and maintenance activities can produce airborne particulate matter (e.g., dust) that has the potential to settle directly onto the water surface or be transported by the wind into nearby waterbodies. Water will be used to control the dispersion of dust. When deemed necessary, exposed excavations, disturbed ground surfaces and traffic areas will be sprayed with water. If chemical dust suppressants are proposed, they will not be applied within 100 m of a water crossing.

For more detailed descriptions of proposed mitigation measures, refer to Section 5.18 (Dust Control Practices) in Appendix E – Mitigation Measures.

7.4.9             Disposal of Waste

A construction waste management plan will be developed to minimize the amount of the waste to be generated, and the portion going to landfills, by applying industry BMP including collection, recycling and disposal. All the solid and sewage wastes collected will be disposed and treated at designated facilities.

Domestic wastewater and sewage in the form of liquid effluent generated from portable sewage treatment facilities at construction camps and the Maintenance and Storage Facility may be treated on site using portable facilities (e.g., septic tank) or transported offsite by tanker truck for treatment at approved disposal facilities, depending on available facilities.

For more detailed descriptions of proposed mitigation measures, refer to Section 5.5 (Materials Handling and Storage) and Section 5.22 (Water Quality Monitoring) in Appendix E – Mitigation Measures.

7.4.10       Summary

Table 7-14 identifies key mitigation measures outlined in Appendix E of the EAR/IS to eliminate or reduce potential adverse effects of the Project. These mitigation measures reflect environmental protection guidelines to protect “Environmentally Sensitive Areas” as described in the Webequie First Nation On-Reserve Land Use Plan (Webequie First Nation, 2019a). Further measures will be provided in the CEMP and the OEMP that will be developed for the Project. Refer to Section 4.6 for details of the proposed framework for the development of the CEMP and the OEMP.

The following sections in Appendix E (Mitigation Measures) describe mitigation measures to prevent or limit the effect of construction and operations on water quantity:

• Section 5.1 – Clearing and Grubbing;
• Section 5.5 – Materials Handling and Storage;
• Section 5.6 – Working Within or Near Fish Bearing Watercourses;
• Section 5.7 – Temporary Watercourse Crossings;
• Section 5.8 – Temporary Watercourse Diversions;
• Section 5.9 – Fish Passage;
• Section 5.10 – Fish Salvage;
• Section 5.11 – Bridge and Culvert Installation;
• Section 5.18 – Dust Control Practices;
• Section 5.19 – Aggregate Pit Decommissioning;
• Section 5.20 – Quarry Site Selection and Development Requirements; and
• Section 5.21 – Site Decommissioning and Rehabilitation.

The following sections in Appendix E (Mitigation Measures) describe mitigations measures to prevent or limit the effect of construction and operations on water quality:

• Section 5.1 – Clearing and Grubbing;
• Section 5.2 – Petroleum Handling and Storage;
• Section 5.3 – Spill Prevention and Emergency Response;
• Section 5.5 – Materials Handling and Storage;
• Section 5.6 – Working Within or Near Fish Bearing Watercourses;
• Section 5.7 – Temporary Watercourse Crossings;
• Section 5.8 – Temporary Watercourse Diversions;
• Section 5.11 – Bridge and Culvert Installation;
• Section 5.12 – Blasting Near a Watercourse;
• Section 5.16 – Erosion and Sediment Control;
• Section 5.17 – Concrete Washout Management Practices;
• Section 5.18 – Dust Control Practices; and
• Section 5.22 – Water Quality Monitoring.

The following sections in Appendix E (Mitigation Measures) describe mitigations measures to prevent or limit the effect of construction and operations on sediment quality:

• Section 5.1 – Clearing and Grubbing;
• Section 5.2 – Petroleum Handling and Storage;
• Section 5.3 – Spill Prevention and Emergency Response;
• Section 5.5 – Materials Handling and Storage;
• Section 5.6 – Working Within or Near Fish Bearing Watercourses;
• Section 5.7 – Watercourse Crossings;
• Section 5.8 – Temporary Watercourse Diversions;
• Section 5.11 – Culvert Maintenance and Installation;
• Section 5.12 – Blasting Near a Watercourse;
• Section 5.16 – Erosion and Sediment Control;
• Section 5.17 – Concrete Washout Management Practices;
• Section 5.18 – Dust Control Practices;
• Section 5.20 – Quarry Site Selection and Development Requirements;
• Section 5.21 – Site Decommissioning and Rehabilitation; and
• Section 5.22 – Water Quality Monitoring.

Table 7-14:    Summary of Potential Effects, Mitigation Measures, and Predicted Net Effects for Surface Water Resources VC

7.5                   Characterization of Net Effects

Net effects are defined as the effects of the Project that remain after application of proposed mitigation measures. Table 7-15 presents definitions for net effects criteria, developed with specific reference to Surface Water Resources VC. These criteria are considered together in the assessment, along with context derived from existing conditions and proposed mitigation measures, to characterize predicted net effects from the Project on Surface Water Resources VC.

Table 7-15:    Criteria for Characterization of Predicted Net Effects on Surface Water Resources VC

7.5.1             Potential Effect Pathways Not Carried Through for Further Assessment

Potential effect pathways that are expected to be eliminated through the implementation of mitigation measures include the following:

• Introduction of airborne particulate matter from construction and maintenance activities
• Erosion and sedimentation associated with construction activities

The construction phase is anticipated to include activities that could disburse airborne particulate matter into nearby waterbodies. These activities are expected to be localized, temporary, and short in duration and affect a small spatial extent within the LSA. Airborne particulate matter is not anticipated to affect surface water quality during the operations phase. With implementation of mitigation measures such as dust control measures (refer to Section 5.18 – Dust Control Practices in Appendix E – Mitigation Measures), the net effect of airborne particulate matter on surface water quality is anticipated to be negligible (refer to Section 9 – Assessment of Effects on Atmospheric Environment) and is therefore not carried forward for further assessment.

The construction phase is anticipated to included activities that could result in increased erosion and sedimentation that subsequently lead to increased suspended solids and particulate matter entering waterbodies. Construction activities will be controlled with the implementation of mitigation measures (refer to Section 5.16 – Erosion and Sediment Control in Appendix E – Mitigation Measures) to limit the extent of erosion and prevent sediment from reaching waterbodies.

The net effect of erosion and sedimentation is anticipated to be negligible and is therefore not carried forward for further assessment.

Potential net effects that remain following the implementation of mitigation measures are carried forward for further assessment (Section 7.5.2).

7.5.2             Predicted Net Effects

An effect on the Surface Water Resources VC may remain after the implementation of mitigation measures. The determination of whether a net effect is considered significant is described in Section 7.6. The predicted net effects include:

• Change in surface water quantity due to:
  • Short-term water takings for construction and operations such as dust suppression, water use for camps, and dewatering;
  • Short-term discharges of construction water, wastewater, or wash water into surface waterbodies;
  • Alterations to land cover resulting in changes to runoff rates, runoff volumes, infiltration rates, and overland flow paths;
  • Installation of culverts and bridges resulting in alteration of discharge rates and flow paths at waterbody crossings;
  • Permanent waterbody crossings leading to changes in local hydraulics (flow depth/water level and velocity); and
  • Road maintenance resulting in changes to overland runoff drainage patterns.
• Changes in surface water quality due to:
  • Short-term discharges of construction water, wastewater, or wash water that have different quantities of chemical constituents or suspended solids from the receiving waterbody;

• Blasting activities releasing chemical constituents into nearby waterbodies; and
  • Road maintenance activities leading to the deposition of sediment into waterbodies.
• Changes in sediment quality due to:
  • Short-term discharges of construction water, wastewater, or wash water that have different quantities of chemical constituents or suspended solids from the receiving waterbody;
  • Blasting activities releasing chemical constituents into nearby waterbodies; and
  • Road maintenance activities leading to the deposition of sediment into waterbodies.

7.5.2.1             Change in Surface Water Quantity

• Short-term water takings

Short-term water takings for construction and operations are predicted to result in reduced streamflow or water levels in nearby waterbodies. The spatial extents of the change in water quantity would be limited to the waterbody and watershed from which the water is taken. This would be more noticeable within the LSA and downstream of the ROW. The direction of the effect is negative because there would be a change from normal conditions by reducing water in streams and waterbodies. The magnitude of the change is expected to be low because limitations and restrictions will be applied to where, when, and how much water can be used for construction and operations to avoid adverse effects to water levels. The timing of the effects may be within or outside the restricted activity timing window during construction to protect fish/fish habitat (refer to Section 7.4) and in the summer for operations when dust suppression is required. The duration of the effects will be short-term and limited to within the periods that water takings occur. The effect is expected to occur frequently during construction and infrequently during operations. The waterbodies have high resilience to this effect because of the mitigation measures and limitations applied to water takings. The likelihood of occurrence is certain because short-term water takings will be required for construction. However, the net effect is reversible and water levels and stream flows would return to pre-construction levels shortly after the termination of water takings, depending on weather and the change of seasons.

• Short-term discharges of construction water, wastewater, or wash water

Short-term discharges of construction water, wastewater, or wash water would result in increased streamflow or water levels in nearby waterbodies. The spatial extents of the change in water quantity would be limited to the receiving watershed. This would be more noticeable within the LSA and downstream of the ROW. The direction of the effect is negative because there would be a change to normal conditions by increasing water in streams and waterbodies. The magnitude of the change is expected to be low because limitations and restrictions will be applied to where, when, and how much water can be discharged. The timing of the effects would primarily be outside the restricted activity timing window during construction to protect fish/fish habitat (refer to Section 7.4). The duration of the effects will be

short-term and limited to within the periods that water is discharged. The effect is expected to occur frequently during construction. The waterbodies have high resilience to this effect because of the mitigation measures and limitations applied to discharges. The likelihood of occurrence is certain because short-term discharges will be required for construction. However, the net effect is reversible and water quantity should return to pre-construction levels within a year or less, depending on weather and the change of seasons.

• Land cover changes resulting in changes to infiltration and runoff rates and volumes

Changes to runoff rates and runoff volumes due to changes in land cover in the Project Footprint would result in reduced infiltration and increased streamflow or water levels during construction and operations. The spatial extents of changes to infiltration would be limited to the Project Footprint and changes to runoff rates and volumes would be limited to the LSA. The direction of the effect is negative because there would be a change to normal conditions by increasing water in streams and waterbodies and reducing groundwater recharge rates. The frequency and magnitude of flooding in the LSA could increase because of the increased runoff. The magnitude of changes is expected to be low

because the relative area of modified catchment is much smaller than the total catchment areas of local watersheds. This effect may occur within or outside the restricted activity timing window to protect fish/fish habitat during construction and operations. The net effect would have a long-term duration because the land cover change will remain during operations of the road. However, construction laydowns will be temporary and the extents of change in land cover will be limited through mitigation measures. The effect is expected to occur continuously and the receiving waterbodies have a high resilience to changes of this magnitude. The effect is reversible and the likelihood of occurrence is certain during construction and operations.

• Installation of waterbody crossing structures leading to temporary changes to discharge rates upstream or downstream of waterbody crossings

Construction of waterbody crossing structures would temporarily change discharge rates in the local waterbody. The effect would be negative because stream discharge will increase or decrease in local areas and change from normal flow conditions. The extent of the change would be limited to the LSA and short-term outside the restricted activity timing window for fish/fish habitat (refer to Section 7.4). The magnitude of the change is expected to be low because construction of permanent and temporary waterbody crossing structures will be timed for low-flow conditions to minimize the effect of temporary diversions on stream discharge. The occurrence of the effect would be infrequent and would be more likely to occur after large precipitation events and probable to occur during construction. The receiving waterbodies would be highly resilient to changes with the implementation of mitigation measures, and the effect is reversible.

• Permanent waterbody crossings leading to changes in local hydraulics (flow depth/water level and velocity)

Changes to local hydraulics (flow depth/water level and velocity) at and around constructed waterbody crossings could result in an increase or reduction of local shear stress, erosion, water levels, and sedimentation upstream or downstream of the crossings during the operations phase. The direction of the effect is negative because any change to depth and velocity could result in adverse consequences and the spatial extents would be limited to the waterbody near the crossing and LSA. The magnitude of the change is expected to be low because the waterbody crossings are designed to pass lower bankfull floods without velocity or water level changes and higher peak design floods with limited velocity and water level changes. Design mitigation will be incorporated to crossings that require skewed structures to minimize adverse changes to flow depth/water level and velocity for streams that run parallel to the road for short distances. Erosion will be mitigated through the engineering design of waterbody crossing inlets and outlets.

These effects may occur within or outside the restricted activity timing window to protect fish/fish habitat and are infrequent following large melt or precipitation events. The effects could occur anytime in the long-term while the waterbody crossings are in place. The waterbodies would have a high resilience to these changes and would be reversible after rehabilitation. The likelihood of occurrence is certain.

• Road maintenance resulting in changes to overland runoff drainage patterns

Changes in overland flow paths due to road drainage system maintenance, winter snow clearing, localize road surface repairs, and vegetation control would result in an increased or decreased streamflow or water levels in the local receiving bodies. The spatial extents are limited to the LSA and the direction of the effect is negative because an increase to runoff in areas could result in erosion and sedimentation while a decrease in water recharge could be detrimental to sensitive habitat. The magnitude of the change is expected to be low because of mitigation measures such as waterbody crossings and cross-culverts to maintain existing overland flow paths as much as possible. The effect would continue in the medium-term throughout the operations phase while maintenance activities are ongoing. The timing of changes may be within or outside the restricted activity timing window to protect fish/fish habitat. The effect would be expected to occur continuously and the receiving system would have a high resilience to changes. The change would be reversible after rehabilitation and certain to occur.

7.5.2.2             Change in Surface Water Quality

• Short-term discharges of construction water, wastewater, or wash water

Short-term discharges of construction water, wastewater, or wash water could result in increased chemical constituents and exceedances of water quality guidelines in nearby waterbodies. The spatial extents of the change in water quality would be limited to the receiving waterbody and downstream watershed. The magnitude of the change in quality would decrease over time and distance from the discharge. The direction of the effect is negative because an increase to chemical constituents in streams and waterbodies may adversely affect fish, fish habitats, vegetation, and wetlands.

The magnitude of the change is expected to be low because limitations and restrictions will be applied to where, when, and how much water can be discharged. The effects would primarily be outside the restricted activity timing window to protect fish/fish habitat during construction (refer to Section 7.4). The duration of the effects will be short-term because discharges will be limited to only occur during construction phase. The effect is expected to occur frequently during construction. The waterbodies have high resilience to this effect because of the mitigation measures and limitations applied to discharges. The likelihood of occurrence is possible because short-term discharges will be required for construction, but concentrations of chemical constituents may be low and not reduce water quality. The net effect is reversible and water quality should return to pre-construction levels shortly after the termination of water discharges, depending on weather and the change of seasons.

• Blasting activities releasing chemical constituents into nearby waterbodies

Blasting activities could release chemicals and sediment into nearby waterbodies through airborne particulate or runoff. As a result, water quality guidelines could be exceeded. The spatial extents would be limited to the waterbodies in close proximity to blasting activities and downstream watersheds. The direction of the effect is negative because there could be an increase to chemical constituents and turbidity in streams and waterbodies resulting in potential adverse effects to fish, fish habitats, vegetation, and wetlands. The magnitude of the changes is expected to be low because the timing of blasting near a watercourse will be constrained to outside the restricted activity timing window and transport of released chemicals will be minimized through erosion and sediment control measures (refer to Section 7.4 of this EAR/IS, Section 5.12 – Blasting Near a Watercourse in Appendix E – Mitigation Measures, and Section 5.16 – Erosion and Sediment Control in Appendix E – Mitigation Measures). The effects would be infrequent and short-term in duration around the timing of blasting activities. The likelihood of occurrence is probable and the effects would be reversible.

• Road maintenance activities leading to the deposition of sediment into waterbodies

Road drainage system maintenance, winter snow clearing, localize road surface repairs, and vegetation control could result in deposition of sediment into nearby waterways and changes to water chemistry. The spatial extents are limited to the LSA and the direction of the effect is negative because there could be an increase to chemical constituents and turbidity in streams and waterbodies resulting in potential adverse effects to fish, fish habitats, vegetation, and wetlands. The effect may occur within or outside the restricted activity timing window to protect fish/fish habitat and would continue in the medium-term throughout the operations phase. The magnitude of the effect is predicted to be low and to occur on a frequent basis. The receiving waterbodies are expected to have a high resilience relative to the magnitude of the effect and the effect is reversible after the completion of operations. The likelihood of occurrence is probable because maintenance activities will be ongoing, although concentrations of chemical constituents may be low and not reduce water quality.

7.5.2.3             Change in Sediment Quality

• Short-term discharges of construction water, wastewater, or wash water runoff

Effect from short-term discharges via runoff from construction water, wastewater, or wash water could increase pollutants entering the waterways and depositing as sediment. Spatial extents will be contingent on the characteristics of transported suspended sediment via runoff but limited to the LSA. Fine suspended sediment has the potential to travel beyond the directly impacted areas. The direction of effect is negative because increased chemical constituents and total suspended solids concentrations may adversely affect fish, fish habitats, vegetation, and wetlands. The magnitude of changes is negligible due to the imposition of restrictions and limitations on the location, timing, and volume of water discharge as runoff. The duration of the effects will be short-term, occurring during construction phase. The likelihood of occurrence is possible because short-term discharges will be necessary for construction, although concentrations of chemical constituents may be low and not reduce sediment quality. The net effect is reversible, and sediment quality should return to pre-construction levels within a year and with the changing seasons, depending on the weather.

• Blasting activities releasing chemical constituents into nearby waterbodies

Blasting activities may result in an increase in chemical constituents and exceedances of sediment quality guidelines. Explosive spills and residues could runoff into surface waterbodies, settling as sediment, impacting fish habitat and sediment quality. Spatial extents would be limited to the active blasting area, determined by the features of the chemical constituents and the settlement of suspended matter. Direction of effect is negative resulting in increase of chemical constituents or suspended solids resulting in potential adverse effects to fish, fish habitat, vegetation, and wetlands; however, sediment deposition would be limited to the proximity to blasting activities and downstream watersheds.

Magnitude of changes is expected to be low due to the low potential of an increase in chemical constituents surpassing sediment quality guidelines. Blasting activities are limited to the construction phase and short durations, with anticipated return to normal chemical concentrations after construction. The timing of blasting will be constrained to outside the restricted activity timing window and transport of released chemicals will be minimized through erosion and sediment control measures (refer to Section 7.4 of this EAR/IS, Section 5.12 – Blasting Near a Watercourse in Appendix E – Mitigation Measures, and Section 5.16 – Erosion and Sediment Control in Appendix E – Mitigation Measures). The effects would be infrequent and short-term in duration around the timing of blasting activities. The likelihood of occurrence is probable, and the effects would be reversible.

• Road maintenance activities leading to the deposition of sediment into waterbodies

Road drainage system maintenance, winter snow clearing, localize road surface repairs, and vegetation control could result in deposition of sediment into nearby waterways. The spatial extents are limited to the LSA and the direction of the effect is negative because there could be an increase to chemical constituents in sediment and waterbodies resulting in potential adverse effects to fish, fish habitats, vegetation, and wetlands. The effect may occur within or outside the restricted activity timing window to protect fish/fish habitat and would continue in the medium-term throughout the operations phase. The magnitude of the effect is predicted to be low and to occur on a frequent basis. The receiving waterbodies are expected to have a high resilience relative to the magnitude of the effect and the effect is reversible after the completion of operations. The likelihood of occurrence is probable because maintenance activities will be ongoing, although concentrations of chemical constituents may be low and not reduce sediment quality.

7.5.3             Summary

A summary of the characterization of predicted net effects is provided in Table 7-16.

Table 7-16:    Summary of Predicted Net Effects on Surface Water Resources VC

Note: Refer to Table 7-15 for definitions of categories for net effect characterization

7.6                   Determination of Significance

Significant effects are those of sufficient magnitude, spatial extent, duration, frequency, irreversibility and likelihood to cause a change in the environment beyond an acceptable standard.

Adverse consequences resulting from changes to water quantity would include:

• Alteration of water flow in the RSA caused by project activities, leading to the inundation of waterbodies or land;
• Disruption to the operational balance of waterbodies, affecting habitats, ecology, and human activities, such as recreation, navigation, and traditional practices that include fishing, hunting, and trapping;
• Loss of fish habitat from connecting waterbodies that are unaccounted for through compensation; and
• Increased erosion and sedimentation to levels above regulatory standards.

Adverse consequences resulting from changes to water quality would include:

• Increased concentration of chemical contaminants that lead to acute or chronic toxicity for aquatic life; and
• Disruption to the operational balance of waterbodies, affecting habitats, ecology, and human activities, such as drinking water and traditional practices that include fishing, hunting, and trapping.

Adverse consequences resulting from changes to sediment quality would include:

• Increased concentration of chemical contaminants that lead to acute or chronic toxicity for aquatic life including benthic invertebrate;
• Increased erosion and sedimentation to levels above regulatory standards;
• Increased suspended sediment in the water column can lead to reduced light penetration, inhibiting photosynthesis and negatively impacting aquatic plants and habitats; and
• The presence of excessive sediment can be challenging to obtain clean drinking water for human consumption.

Several methodologies can be used to determine whether an adverse environmental effect is significant or not significant, as outlined in the Interim Technical Guidance Determining Whether a Designated Project is Likely to Cause Significant Adverse Environmental Effects under the Canadian Environmental Assessment Act (CEA Agency, 2018). A qualitative aggregation method is used for determination of significance based on the sequential interaction among the magnitude, geographic extent, duration, frequency, reversibility, and likelihood of occurrence criteria for effects. The following sequential interactions form the basis for determination of significance of adverse net effects on Surface Water Resources VC:

• A predict net effects is considered not significant if the effect is:
  • Low to moderate in magnitude, local to regional in extent, short-term to permanent in duration, infrequent to continuous occurrence, reversible to irreversible in nature, and unlikely to certain to occur.
• A predict net effects is considered significant if the effect is:
  • Moderate to high in magnitude, regional in extent, long-term to permanent in duration, continuous in occurrence, irreversible in nature, and probable (likely) or certain to occur.

7.6.1             Surface Water Quantity

Mitigation measures through engineering design and construction management practices are proposed to minimize the impact of the Project on water quantity. Alteration of water flow in the RSA will be limited by installing water crossings that are sufficiently sized to pass frequent floods and accommodate potential use of navigable waterways. Construction of water crossing structures will be timed during low-flow conditions and outside the restricted activity period to minimize impact on fish habitat and the effect of temporary diversions on stream discharge. Erosion and sediment control measures will be implemented and maintained throughout construction that include, but are not limited to, sediment fences, sedimentation ponds, check dams, and erosion control fabric. The net effects on surface water quantity are of low magnitude and predicted to be not significant.

7.6.2             Surface Water Quality

Local water quality within the LSA may experience increases of potential contaminant of concerns above MOE PWQOs, CCME CEQGs and GCDWQ; however, these changes are expected to be of low magnitude and contained within the boundaries of the LSA. With mitigation and environmental protection measures applied, the net effects on the surface water quality are of low magnitude and predicted to be not significant.

Background concentrations were typically below water quality guidelines for all parameters with the exception of iron, aluminum, and manganese and other temporal outliers. The regular exceedance of manganese was related to the drinking water quality guidelines and the guideline for aquatic life was not exceeded. The drinking water guideline is for treated drinking water and is a more stringent criteria that should just be considered as a guide in the absence of other criteria. The aluminum guideline exceedances were primarily due to pH threshold being lower than 6.5 in field samples and was not highlighted as a significant concern. Exceedances of the iron guideline were the most common; however, the net effects of project activities to iron concentrations are not predicted to be significant.

7.6.3             Sediment Quality

Local sediment quality within Winisk River, Ekwan River, and Attawapiskat River watersheds may experience increases of potential contaminant of concerns above one or more of the CCME PEHH, ISQG and MOE LEL; however, these changes are expected to be of low magnitude and contained within the boundaries of the LSA. With mitigation and environmental protection measures applied, the net effects on the sediment quality are of low magnitude and predicted to be not significant.

7.7                   Cumulative Effects

In addition to assessing the net environmental effects of the Project, the assessment for Surface Water Resources VC also evaluates and assesses the significance of net effects from the Project that overlap temporally and spatially with effects from other past, present and reasonably foreseeable developments (RFDs) and activities (i.e., cumulative effects).

For a valued component that has identified net effects where the magnitude was determined to be higher than negligible, it is necessary to determine if the effects from the Project interact both temporally and spatially with the effects from one or more past, present RFDs or activities, since the combined effects may differ in nature or extent from the effects of individual project activities. Where information is available, the cumulative effects assessment estimates or predicts the contribution of effects from the Project and other human activities on the criteria, in the context of changes to the natural, health, social or economic environments.

For this Surface Water Resources VC assessment, the net effects in Section 7.5 that are characterized as having a likelihood of occurrence of “probable” or “certain” and a “low” to “high” magnitude have been carried forward to the cumulative effects assessment. Net effects with this characterization are most likely to interact with other RFD and activities.

The cumulative effects assessment for the Project is completed at the regional scale (i.e., VC specific RSA). The cumulative effects assessment for each VC is primarily qualitative and describes how the interacting effects of human activities and natural factors are predicted to affect indicators for each VC. The assessment is presented as a reasoned narrative describing the outcomes of cumulative effects for each VC.

The predicted net effects of the Project on the Surface Water Resources VC that are carried forward for the assessment of cumulative effects within the Surface Water Resources RSA include:

• Change in surface water quantity; and
• Change in surface water quality.

Results of the cumulative effects assessment for the Surface Water Resources VC with consideration of RFDs and activities are presented in Section 21.

7.8                   Prediction Confidence in the Assessment

The level of confidence in the effects assessment for surface water resources is moderate. The uncertainty in the prediction confidence is primarily associated with limited data availability for stream discharges and sparse climate data relative to the size of the LSA and RSA. There is also a high degree of uncertainty linked with climate change predictions in the long-term. Proven mitigation methods will be used to increase the level of confidence while conservative design approaches and professional judgement were used to account for higher uncertainty in-stream discharges.

Effects on water quantity are assessed based on runoff characterization at all identified waterbody crossings. Peak discharge estimates at the waterbody crossing locations were calculated using three methods discussed in Section 7.2 and in Appendix F – NEEC Report. The MIFM was selected as the most appropriate based on the limited availability of data in the project study areas. Climate change poses a high uncertainty to future peak discharges during the lifespan of the Project. Conservative assumptions were made adjusting peak discharges to account for climate change, and it is likely that environmental effects of the Project on water quantity are less than predicted. Potential effects on water quantity are addressed through standard and site-specific mitigation measures as discussed in Section 7.4.

Effects on water quality are predicted to be of low magnitude resulting from short-term discharges, blasting activities, and erosion and sedimentation. Water quality sample data were collected from major crossings and will be used in conjunction with an environmental monitoring plan to compare water quality conditions post-construction and during operations. The moderate confidence level is attributed to the complexity inherent in predicting the magnitude of effects, considering the dynamic nature of surface runoff patterns and potential influences on water quality. The Project does not include the release or diversion of any substantial water sources and mitigation measures are planned for accidental release of chemicals.

Effects on sediment quality are predicted to be of low magnitude resulting from long-term alterations to land cover (roadway surface), soil disturbance, blasting activities, stockpile material handling, road traffic, and general erosion and sedimentation. Sediment quality sample baseline data were collected at select locations along the major crossings and will be used in conjunction with an environmental monitoring plan to compare sediment quality conditions post- construction and during operations. The moderate confidence level is influenced by the inherent challenge in precisely

predicting the magnitude of effects, given the complexity of long-term alterations to land cover and potential influences on sediment quality. The Project does not involve the release or diversion of any substantial water sources that would lead to considerable surface runoff and erosion of sediments. Surface runoff is mostly caused by intermittent and seasonal precipitation as well as the melting of snow. Mitigation measures are designed to prevent erosion and sedimentation.

7.9                   Predicted Future Condition of the Environment if the Project Does Not Proceed

The Project lies within un-surveyed/un-developed Ontario Crown lands and Webequie First Nation Reserve lands. There are existing mineral exploration activities (particularly near the east end of the proposed WSR) and it is predicted/assumed that there will be other proposed future mining developments in the area, which is referred to as the Ring of Fire area. Therefore, it is likely that other road construction projects would occur to support the current and future mining activities in the Ring of Fire area if this Project would not proceed.

Future road construction projects are anticipated to have similar effects on surface water resources. Without construction of the proposed WSR, the anticipated future state of surface water resources is expected to remain largely consistent with the existing conditions described in Section 7.2. However, it is important to note that surface water resources may undergo changes over time due to the impacts of climate change.

7.10           Follow-Up and Monitoring

The purposes of the follow-up and monitoring programs are to:

• Verify environmental effects predictions made during the EA/IA for the Project;
• Provide data with which to evaluate the effectiveness of mitigation measures and modify or enhance these measures, where necessary;
• Provide data with which to implement adaptive management measures for improving future environmental protection activities;
• Document additional measures of adaptive measures to improve future environmental protection activities; and
• Document compliance with required conditions as stipulated in permits, approvals, licenses and/or authorizations.

The recommended monitoring program related to Surface Water Resources VC are described as follows:

• Qualified environmental inspector(s) should be appointed to guide implementation, monitor, and report on the effectiveness of the construction procedures and mitigation measures.
• Surface water quality and sediment quality should be monitored, documented, and reported according to terms and conditions of the approved water taking permit (e.g., PTTW or EASR) and others permits, if applicable.

• Continue surface water sampling on a seasonal basis (e.g., spring, summer and fall) and sediment sampling on an annual basis at representative water body crossings. The monitoring and sampling programs will span pre-, during and post-construction periods (e.g., three years after construction is complete).

For more details on proposed water quality monitoring programs, refer to Section 5.22 (Water Quality Monitoring) in Appendix E – Mitigation Measures. Additional details on the proposed follow-up and monitoring for the Project are described in Section 22 of this EAR/IS, Follow-up and Compliance Monitoring Programs.

7.11           References

Canadian Council of Ministers of the Environment (CCME). 1999. Canadian Sediment Quality Guidelines for the Protection of Aquatic Life. Available at: https://ccme.ca/en/res/protocol-for-the-derivation-of-canadian-sediment- quality-guidelines-for-the-protection-of-aquatic-life-en.pdf

Canadian Council of Ministers of the Environment (CCME). 1999. Canadian Soil Quality Guidelines for the Protection of Environmental and Human Health. Available at: https://support.esdat.net/Environmental%20Standards/canada/soil/rev_soil_summary_tbl_7.0_e.pdf

Canadian Council of Ministers of the Environment (CCME). 2004. Canadian Water Quality Guidelines (CWQG) for the Protection of Aquatic Life: Phosphorus: Canadian Guidance Framework for the Management of Freshwater Systems. Winnipeg. 6 pp.

Canadian Council of Ministers of the Environment (CCME). 2023. Canadian Environmental Quality Guidelines.

Available at: https://ccme.ca/en/current-activities/canadian-environmental-quality-guidelines.

Canadian Environmental Assessment (CEA) Agency. 2018. Interim Technical Guidance Determining Whether a Designated Project is Likely to Cause Significant Adverse Environmental Effects under the Canadian Environmental Assessment Act. Available at: https://www.canada.ca/en/impact-assessment- agency/services/policy-guidance/determining-project-cause-significant-environmental-effects-ceaa2012.html

Impact Assessment Agency of Canada (IAAC). 2020. Webequie Supply Road Project Tailored Impact Statement Guidelines.

Ministry of the Environment, Conservation and Park (MECP), 2008. Guidelines for Identifying, Assessing And Managing Contaminated Sediments in Ontario: An Integrated Approach. Available at: https://www.publications.gov.on.ca/guidelines-for-identifying-assessing-and-managing-contaminated-  sediments-in-ontario-an-integrated-approach-may-2008

MECP. 2019. Ring of Fire Environmental Monitoring Program. Preliminary Report. Report Updated October 2019. MNP LLP. 2023. Weenusk First Nation Existing Conditions Report – Webequie Supply Road Project. Prepared for

Weenusk First Nation.

Noront Resources Ltd. (Noront EA). 2013. A Federal/Provincial Environmental Impact Statement/Environmental Assessment Report.

Ontario Ministry of Environment (MOE). 2011. Soil, ground water and sediment standards for use under Part XV.1 of the Environmental Protection Act. Available at: https://www.ontario.ca/page/soil-ground-water-and-sediment- standards-use-under-part-xv1-environmental-protection-act

Ontario Ministry of Environment and Energy (MOEE). 1994. Water Management: Policies, Guidelines, Provincial Water Quality Objectives of the Ministry of the Environment and Energy. Standards Development Branch.

Ontario Ministry of Natural Resources (MNR). 1990. Environmental Guidelines for Access Roads and Water Crossings. 64 pp. Available at: https://www.ontario.ca/page/environmental-guidelines-access-roads-and-water-crossings.

Ontario Ministry of Natural Resources (MNR). 2019. Ontario Flow Assessment Tool. Available at: https://www.lioapplications.lrc.gov.on.ca/OFAT/index.html?viewer=OFAT.OFAT&locale=en-ca.

Ontario Ministry of Transportation (MTO). 1997. MTO Drainage Management Manual – Part 3. Downsview, ON. Webequie First Nation. 2019a. Webequie First Nation On-reserve Land Use Plan.

Webequie First Nation. 2019b. Webequie First Nation Community Based Land Use Plan. Draft Version 4.3.