Final Report

Former CFB Rockcliffe Redevelopment Stormwater Management Existing Conditions &

LID Pilot Project Scoping

Final Report August 2015

Prepared by:

Mississauga – Guelph ‐ Kingston

TABLE OF CONTENTS

3.6 Fluvial Geomorphology ...... 71 1.0 INTRODUCTION ...... 1 3.7 Aquatic Ecology...... 73 2.0 REPORT PURPOSE ...... 2 3.8 Terrestrial Ecology ...... 80 2.1 Report Purpose ...... 2 3.9 Summary of Existing Conditions ...... 90 2.2 Policy Context ...... 7 4.0 MSS STORMWATER STRATEGY ...... 97 2.3 Overview of Existing Land Use ...... 13 4.1 Introduction ...... 98 2.4 Overview of Proposed Land-Use ...... 15 4.2 Conventional SWM System Concept ...... 102 2.5 Geographical Context ...... 17 4.3 Conventional SWM System Phasing ...... 114 2.6 Subwatershed Context ...... 17 5.0 LID DEMONSTRATION PROJECT ...... 115 2.7 Local Climate ...... 17 5.1 Introduction ...... 115 3.0 CHARACTERISATION OF EXISTONG CONDITIONS ...... 19 5.2 LID Demonstration Project Purpose ...... 116 3.1 Geology ...... 19 5.3 Process ...... 116 3.2 Hydrogeology ...... 33 5.4 Chapter Purpose ...... 116 3.3 Surface Water Features ...... 48 5.5 Introduction to LID ...... 117 3.4 Existing Drainage ...... 52 5.6 Summary of LID Lot-Level Controls...... 119 3.5 Hydraulics ...... 58 5.7 Summary of LID Conveyance Controls ...... 123 3.5 Hydrology ...... 60

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5.8 Phasing & Timing ...... 125 5.9 LID Pilot/ Demonstration Project Scope ...... 126 5.10 Suitability of LID Controls by Land-Use ...... 126 5.11 Overview of Proposed LIDs for Implementation ...... 130 5.12 LID Pilot/ Demonstration Project – Phase 1A ...... 146 5.13 Specific Projects ...... 158 5.14 LID Simulations (post Development) ...... 165 5.15 Scaled Conventional SWM Infrastructure Construction ...... 179 5.16 LID Design Guideance ...... 182 5.17 Approvals ...... 185 5.18 Assumption Protocols & Monitoring ...... 187 5.19 Operation & Maintenance ...... 204 5.20 Construction Sequencing ...... 212 5.21 Erosion and Sediment Control (ESC)...... 214 5.22 Policy Considerations ...... 218 5.23 SWM Working Group Summary ...... 221 5.24 Recommendation Summary ...... 223

ATTACHMENT A – Scope of Work ATTACHMENT B – Hydrologic Model (Existing conditions) ATTACHMENT C – Hydrologic Model (Post Development No Control) ATTACHMENT D – Hydrologic Model (Post Development LID Control) ATTACHMENT E – SWM Working Group Presentations

ii Aquafor Beech Ltd. August 2015 – Final Report LIST OF FIGURES Figure 16: The EPA SWMM Model Schematic and Subcatchment Delineation Figure 1: Project Area Delimitation Figure 17: Water Budget Analysis Results for the months of 2013. Figure 2: Land Uses/ Preferred Development Plan Figure 18: Surface Runoff Generated from Western Creek Figure 3: Catchment Delimitations Subwatershed (m3/s) (1996-2013)

Figure 4: Rockcliffe Surficial Geology Figure 19: Surface Runoff Generated from Eastern Creek Subwatershed (m3/s) (1996-2013) Figure 4A: Overburden Materials. Figure 20: Aquatic Habitat Assessment: Western and Eastern Creeks Figure 5: Bedrock Geology Figure 21: Inventory of Existing Trees and Tree Groupings in the Figure 6: Bedrock Depth Contours Study Area Figure 7: Setback Distances Figure 22: Urban Natural Areas Figure 8: Maximum Grade Raise Figure 23: Preliminary Terrestrial Habitat Assessment – Study Area Figure 9: Overburden Potentiometric Contours (DST, 2013)

Figure 10: Shallow Bedrock Potentiometric Contours Figure 24: Butternut Location Plan (Source: DST, 2014)

Figure 10A: In-situ Infiltration Testing Conducted by Aquafor Beech Figure 25: Post Development Conditions Drainage Area Plan – (September 2014) Minor System Connectivity

Figure 11: Surface Water Flow Measurement Locations Figure 26: Post Development Conditions Drainage Area Plan – Major System Connectivity Figure 12: Existing Drainage Conditions Figure 27: Eastern SWM Facility – Layout, Grading and Facility Figure 13: Existing Conditions Drainage Area Plan Attributes

Figure 14: Precipitation Record (mm/hr) from 1996 to 2013 Figure 28: Western SWM Facility – Layout, Grading and Facility Attributes Figure 15: Average Potential Evapotranspiration Values between 1996 and 2013 Figure 29: Park Dry Pond - Plan View and Cross Section A-A

Figure 30: Eastern Dry Pond - Plan View and Cross Section A-A

Figure 31: Central Dry Pond - Plan View and Cross Section A-A

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Figure 32: Southwest Channel – Typical Channel Section Figure 47: Soil Amendment- Typical Detail Default Ratio 3:1

Figure 33: Development Phasing Plan Figure 48: Soil Amendments – Typical Detail Import and Replace

Figure 34: Development Phasing Plan & LID Pilot/ Demonstration Figure 49: Typical Enhanced Swale Detail Area (Phase 1A) Figure 50: Typical Bioswale Detail Figure 34-A: Overall SWM Locations including Recommended LID Lot-level and LID Conveyance Controls Figure 51: Example Permeable Interlocking Concrete Pavement Detail (Reference Only) 34-AFigure 35: Section 1A, Major Collector (26 m) Figure 52: Post-Development Land Use within the Delineated Figure 36: Section 1B, Collector (26 m) Subcatchments

Figure 37: Section 2, Hemlock Core Street (24 m) Figure 53: Water Budget Volumes within the Proposed Development under Different Scenarios Figure 38: Section 3A, Local Road (20 m) Figure 54: Water Budget Volumes within the LID Pilot Area (Phase Figure 39: Section 3B, Local Road (20 m) 1A) under Different Scenarios

Figure 41: Potential LIDs: Collector Road Cross Section 1B (26m Figure 55: Construction Sequencing for Residential Soakaways ROW)

Figure 40: Potential LIDs: Major Collector Road Cross Section 1A (26m ROW)

Figure 42: Potential LIDs: Core Street Road Cross Section 2 (24m ROW)

Figure 43: Potential LIDs: Local Road Cross Section 3A (20m Local ROW)

Figure 44: Potential LIDs: Local Road Cross Section 3B (20m Local ROW)

Figure 45: LID Pilot Project #1- Phase 1A Candidate Development Blocks for LID

Figure 46: Typical Soakaway Detail

iv Aquafor Beech Ltd. August 2015 – Final Report LIST OF TABLES Table 17: Surface Runoff Volumes and Rates at the Outfalls of Western and Eastern Creeks Table 1: Relevant SWM Criteria Table 18: Findings of the Fluvial Geomorphology Assessment (DST, Table 2: Proposed Land Uses September 2013) Table 3: Groundwater Elevation Measurements, 2006 and 2013 Table 19: Aquatic Habitat Assessment Findings- Channel (NAD 83, Zone 18) Characteristics

Table 4: Ranges of Water Levels Measured by DST in 2014 for Table 20: Total Bank Undercuts various Monitor Wells (NAD 83, Zone 18) – (Adapted from DST BH, Table 21: Water Temperature 2014) Table 22: Possible SAR Based on Presence of Potentially Suitable Table 5: Rockcliffe Hydraulic Conductivity Measurements (DST Slug Habitat (Source: DST, 2013) Tests Only) Table 23: Low Impact Development (LID) Suitability Matrix by Land- Table 6: Descriptions and Variability Regarding Infiltration Tests Use

Table 7: In-situ Infiltration Testing Results (Aquafor Beech, Table 24: Screening Framework for Sources of Runoff, Typical September 2014) Characteristics & Opportunities for Treatment and Use

Table 8: Average Hydraulic Conductivity from In-situ Testing Table 25: Recommended LID within Proposed Road Cross-Sections Table 9: Baseflow Measurements according to ROW Features

Table 10: Summary of Existing Culvert Capacity Table 26: Phase 1A Post Development Characteristics and LID Controlled Table 11: Existing Conditions Drainage Area Characteristics Calculations Table 27: Subsurface Investigation Results within 50 Metres of Proposed SWM Infiltration Facilities Locations Table 12: Existing Conditions Drainage Area Characteristics Table 28: Subcatchment Characteristics under Post-Development Table 13: Existing Conditions Model Results Conditions

Table 14: Subcatchment Characteristics in the Study Area Table 29: Infiltration Parameters for the Soils Encountered in the Study Area Table 15: Infiltration Parameters for the Soils Encountered in the Study Area Table 30: LID Engineered Soil Characteristics (Green-Ampt Model)

Table 16: Water Budget Analysis Results for the Study Area Table 31: Water Budget over Total Area

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Table 32: Water Budget over LID Pilot Area (Phase 1A) Table 50 – Summary of Recommendations and Associated Development Timing Table 33: Surface Runoff Depth (mm) and Volumes (m3) over the Total Developed Area

Table 34: Surface Runoff Depth (mm) and Volumes (m3) over the LID Pilot Area (Phase 1A)

Table 35: LID Design Targets for Former CFB Rockcliffe

Table 36: Correction Factor Divided into Measured Kfs Rates in Layered Soils

Table 37: Level of Certification & Associated Protocols

Table 38: The Advantages and Disadvantages of the Varying Level of Certification

Table 39: Proposed Soakaway Pit Monitoring Program

Table 40: Proposed Bioswale and Enhanced Swale Monitoring Program

Table 41: Proposed Overall System Monitoring Program

Table 42: Proposed Construction Monitoring Program

Table 43: Summary of O&M Approaches for LID Controls

Table 44: Maintenance Program Service Matrix (CWP, July 2008)

Table 45: Summary of Maintenance Requirements for LID Controls

Table 46: LID Vegetation Community Monitoring Program

Table 47: Typical Maintenance Costs by Activity for LID Measures

Table 48: Summary of Erosion Control BMPs and Sediment Control BMPs

Table 49 – SWM Working Group Comments Received to Date vi Aquafor Beech Ltd. August 2015 – Final Report ACCOMPANYING DOCUMENTS/ APPENDICES APPENDIX D- AQUATIC HABITAT ASSESSMENT WESTERN AND EASTERN CREEKS FORMER CFB ROCKCLIFFE (DST, AUGUST The following documents have been used as source and reference 2013) documents for subsequent sections of this report and have been submitted as supporting documents for the Former CFB Rockcliffe CDP. As such, the documents listed below are considered appendices APPENDIX E- PRELIMINARY TERRESTRIAL HABITAT ASSESSMENT FOR PROPOSED STORMWATER PONDS AT THE to this document and are referenced to as such. FORMER CFB ROCKCLIFFE (DST, AUGUST 26, 2013)

APPENDIX F- BUTTERNUT SURVEY FOR PROPOSED APPENDIX A – DST GEOTECHNICAL & HYDROGEOTECHNICAL STORMWATER PONDS AT THE FORMER CFB ROCKCLIFFE (DST, REPORTS AUGUST 26, 2013)

1. COMMUNITY DESIGN PLAN GEOTECHNICAL INVESTIGATION FORMER APPENDIX G - CFB ROCKLIFFE VEGETATION SURVEY – CFB ROCKCLIFFE DEVELOPMENT, OTTAWA, ONTARIO (DST, JUNE ARBORIST REPORT (BAKER, JANUARY 2013) 2014)

2. FORMER CFB ROCKCLIFFE STORMWATER MANAGEMENT PONDS OTTAWA, ONTARIO (DST, JUNE 2014)

3. FORMER CFB ROCKCLIFFE STORM WATER INFILTRATION PONDS OTTAWA, ONTARIO (DST, NOVEMBER 11, 2013)

4. HYDROGEOLOGICAL REPORT STORMWATER MANAGEMENT SUPPORT STUDIES, FORMER CFB ROCKCLIFFE, OTTAWA, ONTARIO (DST, JUNE 2014)

APPENDIX B – FLUVIAL GEOMORPHOLOGY ASSESSMENT – WESTERN AND EASTERN CREEKS, FORMER CFB ROCKCLIFFE (DST, SEPTEMBER 2013)

APPENDIX C– ROCKCLIFFE REDEVELOPMENT AREA - HYDROLOGIC AND HYDRAULIC ANALYSIS OF EXISTING SITE CONDITIONS AND PROPOSED DEVELOPMENT MEMORANDUM (IBI, JUNE 17, 2014)

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INTRODUCTION

Canada Lands Company Ltd. acquired the detailed planning applications and Existing Conditions Reports have been former Canadian Forces Base (CFB) approvals. prepared for other study disciplines under Rockcliffe site from the Department of separate cover. The content of this report National Defense in 2011, with a mandate Canada Lands Company is renewing a is intended to provide an overview of to optimize the financial and community planning and consultation process which existing conditions from the perspective of value of the site. Toward this goal, Canada was conducted between 2005 and 2007. In water resources and stormwater Lands Company in partnership with the 2007, work was ceased on the project due management (SWM) to provide context City of Ottawa and the Algonquins of to ongoing land claim negotiations and direction for the development of the Ontario, is preparing a Community Design between the federal government and the Former CFB Rockcliffe site using Low Plan (CDP) to establish a broad planning Algonquins of Ontario First Nation. In Impact Development (LID) as part of a framework to guide the development of 2010, a Participation Agreement was demonstration project in cooperation with the site. Involvement of the City, the reached between Canada Lands Company the City of Ottawa. surrounding communities, and the and the Algonquins of Ontario, in Algonquins of Ontario as partners in this collaboration with the Government of This report aims to describe the project process is intended to ensure that the CDP Canada. Following acquisition of the site context and the existing environmental and ultimately the redeveloped site meet by Canada Lands Company in 2011, conditions as they relate specifically to and exceed planning policy and best Canada Lands Company reinitiated SWM in addition to providing direction for practices. The CDP will set out the broad planning and design efforts for the former future studies and next steps. framework for those subsequent more CFB Rockcliffe.

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REPORT PURPOSE

demonstration project which is system, minor drainage system, system 2.1 REPORT PURPOSE proposed for the Former CFB outlets), hydraulics, hydrology, fluvial Rockcliffe CDP (Section 5). geomorphology, aquatic and terrestrial This report serves to summarize the ecology as well as an overall summary are following: Existing Conditions presented in Section 3.0. The existing drainage features within the 1. Characterisation of Existing Overview of the Conceptual SWM System study area summarized in Section 3 AND Conditions - to summarize the Concept and Details existing conditions as they relate include study area geology, hydrogeology, specifically to the water resources surface water features, existing drainage As detailed in the Master Servicing Study and stormwater management (major drainage system, minor drainage (MSS) an integrated environmental (SWM) of the Former CFB system, system outlets), hydraulics, assessment and planning process has been Rockcliffe CDP (Section 3). hydrology, fluvial geomorphology, aquatic completed by IBI (2015) under separate and terrestrial ecology relating to water cover. 2. Overview of the Conceptual SWM resources and stormwater management System Concept and Details - per (SWM) of the Former CFB Rockcliffe CDP Section 4.0 of this document provides a the MSS (IBI, 2015) (Section 4). site. summary of the conceptual SWM system systems concepts as detailed within the 3. LID Demonstration Project - to Descriptions and mapping of the area MSS. The summary presented herein is not provide a scope for the Low geology, hydrogeology, surface water intended to be comprehensives, rather to Impact Development (LID) features, existing drainage (major drainage

Aquafor Beech Ltd. August 2015 – Final Report 2 provide context for the development of Overview of LID alternatives would be identified for the LID Demonstration Project. implementation on a trial basis, phase by LID is an innovative state of the art phase. To maintain this flexibility, the LID approach to managing stormwater by first For more detailed information in regards alternatives were evaluated independently and foremost treating runoff to the analysis, modelling, function, by Aquafor Beech. The two independent, (precipitation) at its source, as a resource phasing and infrastructure sizes etc., refer but interrelated, studies include: to be managed and protected rather than to Section 6.0 of the MSS (IBI, 2015). a waste. In this regard, the emphasis in 1. CFB Rockcliffe (MSS) Master LID Demonstration Project managing runoff is to retain/maintain the Servicing Study (IBI, February existing infiltration of water into the The City of Ottawa and CLC have agreed to 2015) – under separate cover. ground by managing runoff through lot pursue a phased stormwater management level (source) and conveyance (street 2. Stormwater Management Existing demonstration project for the former CFB level) measures using what is referred to Conditions & LID Demonstration Rockcliffe using LID Best Management by the Ministry of the Environment (MOE) Project Scoping Document Practices (BMPs). An integral component as a “treatment train” approach to (Aquafor Beech, February, 2015) – of this process is the City of Ottawa and stormwater management. LID measures this document. CLC's desire to advance the Rockcliffe CDP implemented on individual lots, and as a demonstration (or pilot) project for combined with additional LID measures This report should be read in parallel with Low Impact Development (LID). within road rights-of-way (ROW) this MSS document. • CLC`s Goal – is for the Former CFB encourage infiltration and reduce the CFB Rockcliffe (MSS) Master Servicing Rockcliffe development to be a model quantity of runoff reaching local drainage Study (IBI, February 2015) community for LID. features. The MSS has been completed using sound LID Demonstration Process engineering principles in the development • City of Ottawa`s Goal – is to of the preferred stormwater solution implement LID as part of As part of the pursuit of the phased applying conventional stormwater development, monitor, gain stormwater management demonstration practices including, but not limited to, experience, answer key questions project for the former CFB Rockcliffe using piped stormwater infrastructure and and build capacity in a phased and LID, traditional servicing and LID stormwater management facilities. The controlled setting with a willing alternatives were reviewed in parallel as preferred stormwater solution using partner. two independent, but interrelated, conventional stormwater practices has studies. This was done recognizing that LID

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been developed in accordance with · Determine the information drawbacks from the proposed LID regulatory requirements to service the required to design the integrated approaches. In this regard, each phase of proposed development as a stand-alone LID SWM system potential LID implementation system and to accommodate the potential corresponding to the phases of LID practices identified in the second · Determine the information to be development will involve the completion independent study detailed below. collected during the monitoring of six (6) steps: programs Stormwater Management Existing 1. Planning (subject of the LID SWM Conditions & LID Demonstration Project · Review the collected monitoring Demonstration Project Study) 2. Construction Scoping Document (Aquafor Beech, data from each successive phase 3. Monitoring February, 2015) of development 4. Reporting The ‘LID Pilot Project Study’ is intended to · Determine the type and extent of 5. Quantification of benefits permit the implementation, monitoring, the stormwater management 6. Refinement of the LID approach and evaluation of alternative stormwater ‘credits’ to be applied to prior to the subsequent phase of management systems based upon the subsequent phases of LID implementation principles of Low Impact Development development and servicing for (LID). The work program for the LID Steps 5 and 6 (Quantification of benefits water quality, water quantity, Stormwater Pilot Project Study was and Refinement) are critical process erosion and water balance control. developed in consultation with the City of elements, allowing ‘real-world’ results to The credits will be based on the Ottawa and will provide direction for the be communicated to and vetted by City of cumulative collected monitoring implementation of LID controls in parallel Ottawa staff and agencies and data from each successive phase with the conventional storm servicing subsequently translated into direction for of development presented in the MSS. both the refinement of future LID The proposed LID implementation process implementation and refinement of the A SWM Working Group has been formed, for former CFB Rockcliffe was developed conventional storm servicing presented in consisting of key members of the City of using a phased Adaptive Management the MSS. In this manner, it is only the Ottawa, CLC staff, and consultants System (AMS) approach whereby a quantifiable benefits that will influence engaged by CLC. The SWM Working Group science-based methodology is developed stormwater servicing of former CFB will: and applied to understand and quantify Rockcliffe. · Make recommendations the function, potential benefits and

4 Aquafor Beech Ltd. August 2015 – Final Report The LID SWM Pilot Project Study report for redevelopment of former CFB An overall study process is detailed in the should be read in parallel with this MSS Rockcliffe will be flexible and realizes that diagram below. It summarizes the MSS, document as it relates to storm sewer stormwater BMPs, techniques and CDP, LID SWM Demonstration Project servicing. Furthermore, forthcoming approaches will change as the knowledge Study and the proposed LID monitoring reports which quantify the base advances, that future phases and implementation process for former CFB performance of LID practices as it relates associated monitoring will refine the Rockcliffe and uses the AMS approach. to water quality, water balance, volume, findings from the MSS and LID SWM Additional information relating to the LID and peak flows should also be considered Demonstration Project Study and that this demonstration project is presented in and related to the aforementioned two overall stormwater servicing approach is Section 5. independent documents. The not static. implementation of stormwater servicing

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LID Stormwater (SWM) Pilot Exis ting Conditions Reports Project Study and other Technical Studies

Community Master Servicing Public Transportation Study (MSS) and Consultation Study Supporting Studies Reports Planning Interaction Scoping Document Modelling Preliminary Design SWM Working Group Community Design Plan (CDP) Preferred LID Practices (Phase 1-3)

Preferred Municipal

Servicing Alternative LID DCoevnseltoprucmetionnt Phases 1A - 3 3 3 Refine Conventional Refine LID Monitoring Water Stormwater Approach

Infrastructure Wastewater P h as e s 1 A - · Phase 1B D et ai l e d si gn · Phase 2 Quantification Stormwater Reporting · Phase 3 of Benefits

Overall Study Process

6 Aquafor Beech Ltd. August 2015 – Final Report

CONTEXT

means that all local Official Plans are to be provide ecological and hydrological 2.2 POLICY CONTEXT prepared to be consistent with the PPS. functions and processes. Green infrastructure can include components such The following describes the policy The PPS provides policy direction on as natural heritage features and systems, framework governing the study area, matters of provincial interest related to parklands, stormwater management specifically, the Provincial Policy land use planning and development. It sets systems, street trees, urban forests, natural Statement (PPS) and the City of Ottawa the policy foundation for regulating the channels, permeable surfaces, and green Policies. Where relevant, Provincial and use of land. Regional and Municipal OPs roofs. agency policies are highlighted. are to build on this policy foundation with The Provincially Policy Statement (PPS) more detailed policy direction that is In regards to stormwater, Section 1.6.6.7 consistent with the PPS policies. of the PPS states that “Planning for The Provincial Policy Statement (PPS) Stormwater Management shall:” establishes a broad vision for how In regards to Infrastructure and Public communities should grow over time. To Service Facilities, Section 1.6.2 of the PPS a) minimize, or, where possible, ensure that the policies in the PPS are states that Planning authorities should prevent increases in contaminant applied in all communities as a key promote green infrastructure to loads; component of the planning process, the complement and augment infrastructure. b) minimize changes in water Planning Act requires that all decisions balance and erosion; affecting land use planning matters “shall The PPS defines Green Infrastructure as be consistent with” the PPS. This also natural and human-made elements that

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c) not increase risks to human functions, natural heritage l) ensuring consideration of health and safety and property features and areas, and surface environmental lake capacity, damage; water features including shoreline where applicable; and d) maximize the extent and function areas, which are necessary for the m) ensuring stormwater of vegetative and pervious ecological and hydrological management practices minimize surfaces; and integrity of the watershed; stormwater volumes and e) promote stormwater i) maintaining linkages and related contaminant loads, and maintain management best practices, functions among ground water or increase the extent of including stormwater attenuation features, hydrologic functions, vegetative and pervious surfaces. and re-use, and low impact natural heritage features and development. areas, and surface water features Section 2.2.2 of the PPS (2014) states that: In regards to water resources (Section 2.2) including shoreline areas; Development and site alteration shall be specifically, Section 2.2.1 of the PPS j) implementing necessary restricted in or near sensitive surface (2014) states that: “Planning authorities restrictions on development and water features and sensitive ground water shall protect, improve or restore the site alteration to: features such that these features and their quality and quantity of water by: 1. protect all municipal drinking related hydrologic functions will be water supplies and designated protected, improved or restored. f) using the watershed as the vulnerable areas; and ecologically meaningful scale for 2. protect, improve or restore Mitigative measures and/or alternative integrated and long-term vulnerable surface and ground development approaches may be required planning, which can be a water, sensitive surface water in order to protect, improve or restore foundation for considering features and sensitive ground sensitive surface water features, sensitive cumulative impacts of water features, and their ground water features, and their development; hydrologic functions; hydrologic functions. g) minimizing potential negative k) planning for efficient and City of Ottawa Policies impacts, including cross- sustainable use of water jurisdictional and cross-watershed resources, through practices for The City of Ottawa Official Plan (2003) impacts; water conservation and sustaining contains policies for Maintaining h) identifying water resource water quality; Environmental Integrity (Section 2.4) and systems consisting of ground Environmental Protection (Section 4.7) water features, hydrologic

8 Aquafor Beech Ltd. August 2015 – Final Report which contain relevant policies for the living walls and light coloured building large new development areas for the provision of stormwater management materials following objectives: controls including LID controls. Relevant policies have been summarized below: Section 2.4.2 – Natural Features & · Increasing forest cover across the Functions addresses both natural features city; Section 2.4 - Maintaining Environmental as well as natural functions, including · Maintaining and improving water Integrity ensures the protection and groundwater recharge, provision wildlife quality; enhancement of the quality of the habitat, temperature moderation, and the · Maintaining base flows and environment in the city by: natural cleansing and filtration of surface reducing peak flows in surface water. Section 2 b) ensures protection of water; · Improving air quality and reducing the NHS by Protecting the quality and · Protecting and improving the greenhouse gas emissions; quantity of groundwater. habitat for fish and wildlife in · Identifying and protecting natural stream corridors; features; Section 2.4.4– Groundwater Management · Protecting springs, recharge · Planning on the basis of the ensures the protection, improvement and areas, headwater wetlands and natural systems defined by restoration of quality and quantity of other hydrological areas; watersheds; groundwater. It acknowledges that · Managing resources by using low- · Managing groundwater resources; groundwater contributes to the baseflow maintenance, natural solutions. · Planning for forests and other of streams as well as to the quantity and This section of the City OP is based on greenspaces. quality of potable well-water. design with natural principles.

Section 2.4.5 – Greenspaces Section 2.4.1 Air Quality & Climate Section 4.7.3 – Erosion Prevention & acknowledges that greenspaces come in Change the City will take measures to Protection of Surface Water ensure the many forms including the casually tended adapt to the effects of climate change by: protection of stream corridors and the grass around stormwater management surface water environment, such that the Policy 3d) Reducing the urban heat island ponds. dual purpose of preserving and enhancing effect through landscaping, tree planting, the environmental quality of stream and and encouragement of courtyards and Section 4.7 – Environmental Protection river corridors and their aquatic habitat, as innovative green spaces with permeable ensures that lands be developed in ways well as reducing risks from natural hazards surfaces and trees and of green building that support natural features and associated with watercourse. measures such as the use of green roofs, functions on individual sites and across

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Policy 11 - Under the Development, design and meet relevant federal, environmental management plan and Interference with Wetlands and provincial and agency regulations. require that stormwater site management Alterations to Shorelines and plans be submitted in accordance with the Watercourses Regulation, pursuant to the Policy 15 - Development and site guidance set out in the environmental Conservation Authorities Act of Ontario, alteration will not be permitted in fish management, subwatershed and the approval of the Conservation Authority habitat except in accordance with federal watershed plans. is required for works such as site grading, and provincial requirements. Development the placement of fill, the alteration of applications near or adjacent to water Policy 1 - A stormwater site management existing channels of watercourses, and bodies that provide fish habitat will be plan will be required to support certain construction projects. required to demonstrate that the subdivision and site-plan applications. proposed development will not have a Policy 13 - An erosion and sediment negative impact on fish habitat. Fish Policy 2 - Stormwater site management control plan will be provided that shows habitat is defined as those areas on which plans will be prepared in accordance with how erosion on the site will be minimized fish depend directly or indirectly to carry the guidance set out in a subwatershed or during construction through application of out their life processes. Fish habitat watershed plans (see Section 2.4.3). established standards and procedures. includes spawning grounds, nursery and Generally, stormwater site management Measures to maintain vegetative cover rearing areas, areas that supply food, and plans will include details on subdivision along the slope during and after features that allow migration. In the event management, specific best management construction will be addressed. that a negative impact is unavoidable, the practices for stormwater, erosion and proposal must be reviewed and authorized sediment control, and details for Policy 14 - Natural watercourses should be by the federal Department of Fisheries and enhancement and rehabilitation of natural maintained in their natural condition. Oceans (DFO). features. Where no subwatershed plan or Where an alteration is assessed as being environmental management plan exists, environmentally appropriate and Section 4.7.6 – Stormwater Management the City will review stormwater site consistent with an approved ensures planning in completed on a management plans to ensure that: subwatershed plan, environmental watershed and subwatershed basis n) Flows are not altered in a way management plan or a storm water site pursuant to Section 2.4.3 and confirms that would increase the risk of management plan, watercourse that the City will implement the downstream flooding or channel alterations must follow natural channel recommendations of the relevant erosion in the receiving watershed, subwatershed or watercourse or municipal drain;

10 Aquafor Beech Ltd. August 2015 – Final Report o) Base flow in the watercourse is identified in the document ‘Managing Relevant criteria have been summarized in not reduced; Capacity to Support Intensification and Table 1. p) The quality of water that supports Infill’ contained in Section 6 of the aquatic life and fish habitat is not Infrastructure Master Plan may be Table 1: Relevant SWM Criteria Criteria Source adversely affected; considered. The 5 year flow (or the q) The quality of water that supports 10 year flow from water-based recreational uses is Policy 4 - Where insufficient stormwater arterial roads and not affected; and/or sewer capacity is available to Transitway corridors) is r) Natural habitat linkages that are support the development the proponent conveyed by the storm City of located in or traverse the site are may be required to contribute to the sewers. Storm sewer Ottawa, MOE maintained or enhanced; advancement of any relevant sewer sizing is based on s) Groundwater is not negatively rehabilitation project of the City and/or rational method with an impacted; undertake the rehabilitation of the sewer initial time of concentration of 10 t) Any other impacts on the existing system on the City’s behalf. minutes. infrastructure or natural Inlet control devices environment are addressed in a Provincial, Agency & City of Ottawa (ICDs) are utilized to manner consistent with Stormwater Management control the surcharge in Criteria established standards and the minor system during City of procedures; The design of stormwater management infrequent storm events, Ottawa u) Objectives related to the systems shall be in accordance with the as well as to maximize optimization of wet weather use of available surface relevant Provincial, Agency and City of infrastructure management are ponding. Ottawa standards, per the following realized. Surface ponding on documents: roads and in parking · The MOE Stormwater Management Policy 3 - In areas of intensification the lots is utilized during Planning and Design Manual (March events less frequent City will encourage new development or City of 2003) than the 5 year event redevelopment to incorporate on-site Ottawa · City of Ottawa Sewer Design Guidelines to a maximum depth stormwater management and/or retention (November 2004) and Technical of 0.3 m (includes measures. Where onsite measure cannot Bulletin ISDTB-2012-4 (June 2012) static and dynamic be provided other alternative measures depth).

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Criteria Source Criteria Source The SWM facilities provides guidelines control flow to meet on establishing MOE, existing conditions water quality Conservation levels in receiving targets. Authority creeks for 2, 5, 100 The aquatic/terrestrial year storm events. habitat assessment to SWM facility storage be completed to inform volumes provide an whether temperature City of Enhanced Level of mitigation measures Ottawa Protection, MOE are required for corresponding to a long- outflow from SWM term average removal of facilities. 80% of suspended solids. Where feasible, The fluvial structural and non- City of geomorphological structural BMPs are to Ottawa assessment is to be City of be implemented across completed to inform Ottawa the development. erosion control and A water balance is to baseflow requirements. be completed, City of A sensitivity analysis informed by a Ottawa is to be completed hydrogeological to determine the report. most critical storms. The City of Ottawa provides IDF curves; City of Chicago, AES, and Ottawa, MOE SCS storm distributions; historical storms; and stress test requirements. The MOE Manual

12 Aquafor Beech Ltd. August 2015 – Final Report 2.3 OVERVIEW OF EXISTING component of the Base was, however, to LAND USE be retained for the following five to ten years. The Rockcliffe site has had a long and historic life as a military base, rifle range, In 1996, following the identification by the aerodrome and experimental photography Treasury Board Secretariat (TBS) that CFB station and was home to more than 600 Rockcliffe was a potential “managed land residential dwellings. disposal” candidate, the lands were transferred to the Canada Lands Company The following information was retrieved for redevelopment. through the Canada Lands Company’s archives. The Rockcliffe site long history In 1999, following the completion of an began in 1898, when CFB Rockcliffe was existing conditions analysis by CLC, the originally established by the Department Rockcliffe site had some 599 residential of National Defense (DND). In 1920 the dwelling units in 469 buildings on the Ministry of National Defence Air Board Former CFB Rockcliffe CDP site, with total approved redevelopment of the rifle range a population of 1,510. as an aerodrome and experimental The ownership of the former CFB photography station and expanded the Rockcliffe was officially transferred to CLC land holdings which grew to approximately in 2011. Since the official closure of CFB 183ha (453 acres). At its peak, following Rockcliffe in 2009, all of the buildings and World War II, land holdings totalled more houses on the site have been demolished. than 326ha (800 acres) and approximately Today the total area of the Former CFB 600 housing units were built on the Rockcliffe CDP site is approximately 131ha airbase to accommodate the short-term (Figure 1). needs of returning military personnel.

In 1989, CFB Ottawa North (Rockcliffe) was reduced in size and occupancy, as a result of implementation of the Infrastructure Adjustment Program (IAP). The residential

Aquafor Beech Ltd. August 2015 – Final Report 13 B ATT LE OF BRI TAI N B LVD

M Y N A R S K I P R

A LT A IR

PR

V I A

V E G A

P R

B IS H O P P R

DR AY TO N PR 2.4 OVERVIEW OF Table 2 – Proposed Land Uses PROPOSED LAND-USE Area % of Upon completion the Former CFB Land Uses (ha) Total Rockcliffe CDP site will be a mixed-use The vision statement for the “Former CFB Low-Rise Residential 25.60 19.5% Rockcliffe” as stated in the draft community with integrated: Mid-Rise Residential 3.02 2.3% Community Design Plan (CDP) is the Low-Rise Mixed-Use 3.56 2.7% · Residential, Mid-Rise Mixed-Use 13.17 10.0% following: High-Rise Mixed-Use ** 7.17 5.5% · Retail, Low-Rise Retail** 0.86 0.7% “The redevelopment of the former School 6.77 5.1% Employment 6.33 4.8% Canadian Forces Base (CFB) Rockcliffe will · Employment, be a contemporary mixed-use community. Parks 18.93 14.4% Natural Areas 6.21 4.7% It will be walkable, cycling-supportive, · Open space, and SWM Features 5.31 4.0% transit-oriented and built at a human Important Tree 10.07 7.7% scale. These principles will be realized · Recreational development. Groupings through improved connectivity to the Roads 24.30 18.5% Active transportation and Low Impact Lanes 0.1 0.1% surrounding neighbourhoods, and by Total Estimated Land Development (LID) stormwater 131.4 100% providing access to open space for Uses management will be two of the key everyone. The site will connect to the ** Some Employment and Retail Parcels listed elements in the integration of sustainable on sheet "BLOCKS" are within Mixed-Use history of the Algonquin people. It will development with the natural systems on blocks, and do not count toward the Total celebrate its military heritage. Estimated Land Use Areas and surrounding the site. Redevelopment of the former CFB Rockcliffe will demonstrate urban design Land Use and landscape excellence, innovation in The mixed-use community of the Former sustainability, cultural/social dynamism, CFB Rockcliffe CDP site will contain sixty- and a high quality of life. It will be one (61) development blocks (See Figure forward-looking in its development 2). Table 2 summarizes the proposed land approach by integrating the site’s natural uses as part of the overall plan. ecological functions into the design”

Aquafor Beech Ltd. August 2015 – Final Report 15

16 Aquafor Beech Ltd. August 2015 – Final Report 2.5 GEOGRAPHICAL Within the Ottawa River East Tributary CONTEXT · South and west by the Monfort Subwatershed there are numerous smaller Hospital and the Montfort Woods local catchments as defined by the City of The boundaries of the Former CFB (an environmentally sensitive Ottawa. The largest of which is designated Rockcliffe CDP site (study area) are feature) and the established as Military 1. situated on a plateau overlooking the community of Fairhaven. Ottawa River and Gatineau Hills. Other established neighborhood, namely, The vast majority of the Former CFB Rockcliffe-Manor Park and Rothwell Rockcliffe CDP site is contained within The Former CFB Rockcliffe CDP site (Figure Heights-Beacon Hill lie immediately to the Military 1, with a small portion located 1) which is the subject of the Community west and east respectively. within Military 2 and catchment number Design Plan (CDP) totals some 131 04271 (Figure 3). hectares, divided accordingly: The site can be accessed at three (3) locations: · 125.3 hectares owned by the 2.7 LOCAL CLIMATE · Codds Road from the south Canada Lands Corporation (CLC) The City of Ottawa has a humid · 5.3 hectares owned by the · Hemlock Road from the west continental climate. According to National Research Council (NRC) Environment Canada’s 1981- 2010 Climate

· Douglas Street (through the NRC) Normals for the Ottawa International The site is bordered on the: campus from the east. Airport, the city has a mean annual · North by the Aviation Parkway, temperature of 6.3 °C, with an average Ottawa Rockcliffe Airport and the 2.6 SUBWATERSHED temperature of -10.3 °C in January and 21.0 °C in July. Normal annual Canada Aviation and Space CONTEXT Museum. precipitation is 943 mm, most of which falls as rain. Normal total annual snowfall The Former CFB Rockcliffe CDP site is for the 1981-2010 period is 222 cm. · East by NRC lands which occupies located within the Ottawa River East two parcels of land (approx. 154 Tributary Subwatershed which drains ha) with frontage on Montreal directly to the Ottawa River (Figure 3). At Road and extend south form the present there does not exist a formal Rockcliffe Parkway, across watershed plan, stormwater management Montreal Road, to Ogilvie Road. criteria or targets for this subwatershed.

Aquafor Beech Ltd. August 2015 – Final Report 17

CHARACTERISATION OF EXITING CONDITIONS

· Bedrock is grey flat-lying limestone, quartz, feldspar, carbonate and generally unweathered except for the amphiboles from source bedrock 3.1 GEOLOGY upper 1 metre; (Scott, 2003);

The following section provides an · The basal overburden consists of · Post Champlain Sea deposits consist overview of the geology of the Former CFB discontinuous remnants of till, of stratified sand with some silt, Rockcliffe CDP site and further describes composed of sand (average 67%), silt formed on fluvial terraces and in the surficial geology and bedrock geology. (average 26%) and clay (average 7%) channels cut in marine clay, including Figure 4 - Surficial Geology is reproduced with some gravel, olive to brown in former sand bars and spits (Gadd, in from St. Onge (2009), supplemented with colour (Kettles and Shiltz, in Fulton Fulton, 1987); the DST logs and surface plans. 1987); · The area marked “Landslide” on Surficial Geology · Much of the area is covered by Figure 4 is a historic landslide scar The geology of the area is summarized as Champlain Sea marine deposits of mapped by the Geological Survey of follows, the Former CFB Rockcliffe CDP clay, silty clay and silt, commonly Canada (Klugman and Chung, 1976)i. area from oldest to youngest (see Fulton, calcareous and occasionally overlain There was also a major landslide on 1987) and Figure 4 (from St. Onge, 2009): by a thin veneer of sand. Most of the April 3, 1967, involving some 30,000 clay is, in fact, not clay minerals but cubic yards of clay at CFB Rockcliffe clay-sized (<2 µm) rock flour of that slipped into the Ottawa River

Aquafor Beech Ltd. August 2015 – Final Report 19

(Mitchell, 1970). This event occurred · Elsewhere on the site, overburden Rockcliffe CDP site and the Rockcliffe when early snow cover in autumn thicknesses are up to 10 metres Parkway comprises marine sediments prevented frost penetration. A major (Belanger, 2008). (clay/silt, sand) and fill material, with an snow melt (about 20 inches) was overburden thickness of greater than 10m. Site Stratigraphy accompanied and followed by heavy Overburden Units rainfall. The level clay terrace of CFB The Former CFB Rockcliffe CDP site Rockcliffe slid into the Ottawa River. contains variable thicknesses and types of The following generally describes the Geotechnical investigations in 2006, overburden materials overlying the overburden soil units at the Former CFB 2013 and 2014 by DST drilled a series bedrock. A shallow overburden soil Rockcliffe CDP site. of boreholes within this “Landslide” condition (defined as less than 2 m of area. Boreholes BH9 and BH12 from overburden thickness overlying bedrock) Surficial Material and Topsoil - Grass and the 2006 report, boreholes BH13-10 exists in several areas, covering other organic material with roots and BH13-11 from the 2013 approximately 17% of the site. In other extending about 10 cm below grade is geotechnical investigation and areas of the site the overburden thickness present over much of the site, with topsoil boreholes BH14-39 and BH14-38 ranges from greater than 2m to about extending up to about 20 cm in depth. completed in 2014, do not indicate 10m. Asphalt, with a thickness of about 10 cm, weak native materials from the is present on existing roads and driveways. geotechnical point of view. Both the The native overburden comprises clay to steepness and height of slopes are silt marine deposits over the Southern half Fill Material - Fill material consisting of important factors influencing of the site, silty to sandy till plain in parts silty sand, sand and gravel or clay is known stability. of the Western and Northern portions of to be present in various areas of the site. the site, and sand/silt alluvial sediments During previous field investigations by · The area marked “Pa” on Figure 4 is forming parts of the Western portion of DST, fill was identified at many formerly characterized by shallow overburden the site (Figure 4). Various fill materials development areas of the site, with fill (thickness less than 2 metres) over are present from previous anthropogenic thickness ranging from approximately 0.5 Paleozoic limestone bedrock activities at the Former CFB Rockcliffe CDP to 4.3 m (DST, 2006). Localized fill (Bélanger 2008), that covers site. thickness greater than the observed values approximately 17% of the site; and, may exist. Fill material was also observed The generalized surface geology of the in several boreholes North of the site, at NCC-owned land between the Former CFB the bottom of the escarpment. There the

20 Aquafor Beech Ltd. August 2015 – Final Report fill, approximately 1 to 4 m thick, consists asphalt surface treatment underlain by formations, including East View Formation of compacted grey to orange coloured silt granular sand and gravel which is again to Upper Lindsay Formation are often with sand and gravel. Concrete and underlain by silt or clay layer followed by referred to as the Ottawa Group and asphalt materials were encountered within bedrock. The generalized stratigraphy for middle to upper Ordovician in age the fill the west side of the site consists of a thin (Belanger, 1998). layer of topsoil underlain by silty clay and Clay - Grey-coloured silty clay is the sand and gravel layers followed by During previous field investigations by DST dominant natural overburden type in the possible bedrock. Figure 4A identifies the (see Appendix A), boreholes drilled into central and Southern portion of the general location of the site overburden the bedrock at the Rockcliffe property Former CFB Rockcliffe CDP site. The clay materials including clay and silt/sand; clay typically encountered horizontally- layer extends from near surface to a depth and sand/silt/gravel regimes. bedded, grey crystalline to fossiliferous of more than 6 m in the south and thins limestone with minor narrow shale Bedrock Geology out to the northeast and north where it bedding, interpreted to be of the Ottawa Group. Minor narrow silt-fine sandstone overlies silty till deposits at depths of 1 to The Former CFB Rockcliffe CDP site beds were encountered within the 2 m. Grey-coloured clay to silty clay with location is underlain by bedrock from the limestone unit in one borehole (BHMW 12, minor silt, sand and gravel was upper Ordovician Formations, mainly East 2004). The bedrock surface is generally un- encountered in the NCC land north of the View Formation and Ottawa Formation weathered, or has a narrow weathering escarpment. (Urban Geology of Canadian Cities, GAC zone, less than one metre thick and Special Paper 42) (Figure 5). Rocks types in occasionally limonite-stained. The Till - The Northern and Eastern portion of the East View Formation include shale, Northeastern portion of the Former CFB the site is generally underlain by till limestone, dolostone and siltstone. Rock Rockcliffe CDP site contains blocky material consisting of grey-coloured types in the Ottawa Formation include (jointed) limestone in the upper 5 m of compact silt, sand and minor gravel. limestone with some shaley partings and bedrock, and fault gouge was observed at Where encountered during previous some sandstone in the basal part. drilling, the till is 1 to 3 m thick, underlying depths of about 2.5 m and/or 4.5 m in several metres of fill material. Williams (1991) subdivided the Ottawa several boreholes in the northeast of the Formation defined by Wilson (1946) into property. Figure 6 illustrates the bedrock General Summary of Overburden Units several formations such as Shadow Lake, contours of the Former CFB Rockcliffe CDP In summary, the generalized stratigraphy Gull River, Bobcaygeon, Verulam and site as determined by subsurface for the east side of the site consists of Lower Lindsay Formations. The investigations.

Aquafor Beech Ltd. August 2015 – Final Report 21 Figure 4

Figure 5 - Bedrock Geology

24 Aquafor Beech Ltd. August 2015 – Final Report SITE BOUNDARIES

MINOR CONTOUR (2 m Interval)

MAJOR CONTOUR (10 m Interval)

BOREHOLE (DST 2014)

BOREHOLE (DST 2013)

TESTPIT (DST 2013)

BOREHOLE MONITORING WELL (DST 2013)

BOREHOLE (DST 2006)

TESTPIT (DST 2006)

BOREHOLE MONITORING WELL (DST 2006)

BOREHOLE MONITORING WELL (DST 2004)

General Topography Soil Quality Nutrient levels for the site are generally The underlying silt/clay soils cover large low, which means that certain shrubs and The general topography of the Former CFB portions of the site. These soils are perennials may show deficiencies, and Rockcliffe CDP site is a gently downward composed mainly of silt rather than clay, that plant selections may become slope northwards towards the Rockcliffe and can make excellent planting soils as a important at the individual level. The escarpment which runs east-west along result. This is evident in the rapid growth higher levels of organic matter and CEC the northern boundary of the site. The of trees on the site. across the site will help balance these slope of the site increases to become deficiencies. However, the use of steep at the escarpment. The elevation The pH of these soils is quite acidic fertilizers to compensate for low nutrient across the site ranges from about 70 to 90 (elevated above 7.5) in many areas levels is not recommended within or m above sea level (asl). The base of the because of the large amount of calcium adjacent to proposed SWM controls. escarpment descends to approximately 55 they contain as a result of past m asl at the Rockcliffe Parkway, and about construction and underlying limestone Maintaining Topsoil Quality 45 m asl at the Ottawa River. rock edges. This will require the planting Finally, the presence of brown to grey of species which can tolerate elevated pH coloured topsoil should be useful as The majority of the Former CFB Rockcliffe levels, and excludes many native plant planting soil. Areas of development will CDP site was previously graded to level the types. likely require the removal and stock pile of land for development during its time as a existing topsoil followed by reapplication military base. The cation-exchange capacity (CEC) of the post development for vegetated and turf soils is very good. This is evident by the areas. Overburden Thickness high fertility of soils and the resulting good Geotechnical reports (Appendix A) suggest existing plant growth. CEC is a key soil To be a functioning, healthy soil it must that sufficient overburden thickness exists parameter in regards to water quality have adequate pore space (i.e. porosity) to across the Rockcliffe site to provide performance of soils, specifically heavy allow for the transport and storage of air adequate rooting depth for plant material metal capture and retention. Therefore, and water (TRCA, 2012). When soil is and general site drainage (Note: not additional water quality performance of compacted, porosity decreases and bulk referring to LID controls) with the infiltration facilities can be expected to density (dry mass divided by volume) exception of the northwest corner of the increase as infiltrated water passes increases, which affects the soil’s ability to site which is characterized as having a thin through native soils. infiltrate and store water, limits diversity overburden layer (Figure 6). of soil organisms and nutrient uptake by vegetation, and impedes root growth.

26 Aquafor Beech Ltd. August 2015 – Final Report Generally, once bulk density exceeds 1.7 use on natural heritage restoration temporarily establishing groundcover grams per cubic centimetre (g/cm3), roots sites. Remaining plant material and vegetation composed of non-invasive are no longer able to penetrate through leaf litter should be processed and species (see OIPC, 2011 for list of the soil (Morris and Lowery, 1988). used as an organic material source for suitable groundcovers) either by Likewise, compacted soils have lower composting operations. application of seeded compost or oxygen transfer, higher extreme summer seeded biodegradable mats. To help temperatures, less nutrient retention, and · Information regarding pre- keep topsoil stockpiles contained, less mycorrhyizal fungi compared to construction topsoil depth (i.e. soil mounds should be completely uncompacted soils (Bethenfalvay and horizon A) over the construction site surrounded by erosion and sediment Linderman, 1992). should be used to guide the depth to control fencing or compost filter socks. which topsoil is stripped to minimize For the purposes of the Former CFB incorporation of subsoil in stockpiles. · Where space limitations necessitate Rockcliffe CDP site, general environmental higher mounds, topsoil stockpile stewardship practices for earthwork and · All soils stripped during the first pass mound height should not exceed three soil management recommended by the of equipment (if applicable) should be (3) metres where feasible (AASHTO, American Association of State Highway placed into topsoil stockpiles at 2011). Stockpiling topsoil will result in and Transportation Officials (AASHTO) locations designated on the Grading the disruption and partial loss of Center for Environmental Excellence and Erosion and Sediment Control beneficial soil organisms, and if should be considered (AASHTO, 2011). Plans. stockpiled in mounds over 1.3 metres Regarding stockpiling and preserving in height over a length of time greater topsoil the following best practices should · When stockpiling topsoil, mound soil than six (6) months, may result in total be implemented (TRCA, 2012 adapted no higher than 1.3 metres (4 feet) high loss of soil organisms. When from AASHTO, 2011): for less than one (1) year and reapplying stockpiled topsoil from preferably less than six (6) months mounds of 1.3 metres in height or less, · Plant material and leaf litter generated (AASHTO, 2011), where feasible. Cover the top 30 centimetres of the mound by clearing the construction site of with tarps or woven geotextile should be mixed with the remainder of vegetation should be stockpiled material to prevent soil erosion and the stockpile to help distribute living separately from site topsoil. Large contamination by weeds during soil organisms throughout the topsoil woody material (branches or trunks of storage. Alternatively, topsoil material (AASHTO, 2011). Topsoil 30 centimetres diameter or greater stockpiles can be stabilized by stockpiled in mounds greater than 1.3 should be separated and set aside for

Aquafor Beech Ltd. August 2015 – Final Report 27

metres in height for longer than six (6) based on an assessment of the slope 2. Borehole/monitoring well location months should be amended with conditions. BHMW15 overburden (soil)/bedrock compost to re-establish healthy soil (OB/BR): an upper shallow clay layer structure and help restore soil For the purpose of this study, a (~2.8m thick) underlain by limestone organism populations; preliminary opinion with respect to stable bedrock. The overburden at the toe of the slope setback distance as it relates to slope is found to be variable comprising a Soil Re-use within Infiltration Controls development limits has been provided. gravel layer (> 6.1m) at borehole location Although soils at the Former CFB The work is based on a limited visual BH3 and silt, sand, gravel underlain by clay Rockcliffe CDP site are currently draining observation and review of limited (> 21.0m) at borehole location BH4. well it is not recommended that these subsurface geology at the Former CFB soils be reused in the manufacturing of Rockcliffe CDP site. 3. Borehole/monitoring well location infiltration media (i.e. bioretention/ BHMW10 OB/BR: an upper shallow Based on the preliminary geotechnical bioswale media) due to the relatively high compact to dense sand fill layer and native investigation and limited subsurface proportion of fines (silts and clays). sand layer (~4.4m thick) underlain by boreholes, the generalized geology at the limestone bedrock. The overburden at the North Escarpment area (from East to toe of the slope comprises silt and clay Development Setbacks/ Slope Stability West) is found to be variable and consists layers (> 11.4m) at borehole location BH1. of the following: From the DST report (Appendix A) entitled 4. Borehole/monitoring well location Community Designs Plan Geotechnical BHMW8: an upper clay layer (~7.0m thick) Investigation Former CFB Rockcliffe 1. Borehole/monitoring well location underlain by limestone bedrock. The toe Development (June, 2014) the following BHMW20: an upper shallow silty sand area has not been investigated at this has been summarized in regards to layer (~1.5m thick) underlain by limestone location. development setbacks and slope stability. bedrock. The overburden at the toe of the slope is found to be variable comprising a 5. Boreholes BH13-12, BH13-13, BH13-14 The footprint of the future building sand layer (~3.7m) at borehole location and BH13-15: layer of sand and clay up to structures must be set a safe distance BH5 and silt, gravel and clay (~4.6m) at 12.2m depth, no refusal was encountered. from the crest of the North Escarpment borehole/monitoring well location and the North Boundary of Blocks 4, 6, 27 BHMW6. Considering these geotechnical factors, and 31. Safe setback distances should be the presence of silty clay, sand silt and till, determined during the final investigation and observed bedrock conditions, a

28 Aquafor Beech Ltd. August 2015 – Final Report preliminary stable slope allowance of 3 to of Ottawa document titled, “Slope Stability Results of the analysis and the respective 4 times the height of bank is Guidelines for Development Applications”. impacts are summarized below: recommended for overburden slopes and 1 x time the height of bank is Grade Raise Impact on Development recommended for the underlying bedrock. The predicted settlements as a result of A geotechnical assessment has been The erosion allowance for the subject the grade raise will impact on the completed by DST with the report entitled slope considering the subsurface soil performance of residential and low raise Community Design Plan Geotechnical materials encountered range from 5 to development to be built on the site, Investigation for Former CFB Rockcliffe 10m for the overburden soil and up to however the relative differential Development (June 2014) – Appendix A 10m for the weathered bedrock. Thus the settlement within a single structure or (1). setback distances (stable slope allowance group of structure will be minimal if grade raise plan is uniform across the individual plus erosion allowance) for the subject site An assessment for the anticipated grade building area. Should a different grade would range from 75 to 100 metres raise scenarios was completed in order to raise plan/scenario be developed with measured landward from the toe of the support the next step in the planning very specific locations or areas of grade slope (See Figure 7, reproduced from process. The investigation included site raise, site specific settlement analysis Appendix A - Figure 10). To assess more characterization through a field and should be performed to confirm that the accurately the setback distance further laboratory program, the assessment of angular distortion and total settlement are geotechnical investigation and slope ground settlement under several grade within the tolerances. stability analyses including an assessment raise scenarios (1.0, 1.5 and 2.0m grade of seismic effects (based on site raise), an assessment of impacts on Impacts on Streets classification of the site specific various aspects of the development and a Settlement as a result of the grade raise characteristics) will be required to confirm review of available alternative solutions. will affect streets including sidewalks and this preliminary assessment. The slopes curbs. Low speed limit roads, are generally should be monitored for any signs of The investigation assessed the Former CFB quite tolerant to settlement and instability. Should reduction of the setback Rockcliffe CDP site. It should be noted that settlement predictions indicate that be required, a site specific slope stability this preliminary assessment was not differential settlement is not expected to assessment should be carried out. completed however to assess settlement exceed the 1:100 angular distortion of individual structures, buried utilities suggested as a reasonable criteria. Any future slope stability analyses should and other facilities for final design be undertaken in accordance with the City purposes.

Aquafor Beech Ltd. August 2015 – Final Report 29

Impacts on Buried Services Selection of construction methods and carried out almost immediately after Given that the sewers and watermains will sequencing will also need a consideration grade raise is complete. be buried within the streets, the street of settlement. These can either exacerbate settlement will also be reflected as or reduce settlements. In the event Two (2) methods available for reducing deflections in the pipes. Settlement settlements and angular distortions impacts from grade raises are: predictions indicate that differential exceed the tolerable limits due to site · Load reduction method using settlement is not expected to exceed the specific conditions, the following section lightweight fill 1:100 angular distortion suggested as outlines the approach and solutions to · Ground improvement methods: reasonable criteria for pipes. This complete a feasible grade raise. · Application of preload tolerance should be confirmed by the · Hydraulic modification designers, who should also check that a Grade Raise Solutions · Electrokinetic stabilization 1:100 change in sewer slope will not The main geotechnical risk to the · Chemical modification adversely affect its gravity flow proposed grade raise for the site is related · Inclusion

performance. Service connections are not to consolidation settlement with respect Maximum Allowable Grade Raise expected to be a problem if the buildings to the design criteria to even small changes in fill loads. If a grade raise thicker are designed to settle less than 25 mm Based on the results of the settlement than the recommended 1.0 m or non- under foundation loads alone. analyses for the three (3) different grade uniform grade raise thickness is required raise thicknesses, in order to limit Other Impacts some methods can be applied to minimize potential subsurface settlement after site Settlement as a result of the grade raise the impacts on the developments. development, it is recommended that will also affect ancillary features on lots. grade raises be restricted to a maximum of These include fences, driveways, pools, There are various ways solutions available 2 m through the north and central parts of decks, sidewalks, etc. The impact will which minimize post construction total the site where bedrock overburden is depend on individual design details and and differential settlement within shallowest. In other areas of the site that tolerances. Overall, the impact will involve manageable magnitudes and a reasonable contain clay layers on top of the site settlement in the 11 to 693 mm range, and time frame. While some methods are bedrock, grade raises of 1 m are if grades are to be maintained over the simple with limited effectiveness, others recommended (Figure 8). The details of design life the initial grades will need to be are complex and more effective. In general the approach to establishing these grade over-built to accommodate the more effective methods are more costly raises are included in the above settlement. but buy time required for settlement duration so that development can be referenced DST reports.

30 Aquafor Beech Ltd. August 2015 – Final Report 0 50 100 200 400m consulting engineers 2150 THURSTON DRIVE, SUITE 203 OTTAWA, ONTARIO, K1G 5T9 TEL (613) 748-1415 FAX (613) 748-1356 www.dstgroup.com

NOTES: 1. THIS DRAWING SHALL BE READ IN CONJUNCTION WITH THE ASSOCIATED TECHNICAL REPORT. 2. DO NOT SCALE DRAWING.

1

8

.

0

LEGEND:

1

8

. 0

18.0 Toe of Slope

18.0 75 m Setback

18.0 100 m Setback

18.0 18.0 18.0

18.0

2

6

.

0

2 6 . 0

18.0 26 .0

18.0

2 6 . 0

1 8 . 0

18.0 18.0 18.0

1 8 . 0

1 8 0 MAR. 27, 2014 Original M.W.B. .4

1 8 . 0 REV DATE ISSUE APPROVAL PROJECT TITLE

1 8 . 0 Geotechnical Investigation Former CFB Rockcliffe Ottawa, Ontario

DRAWING TITLE SETBACK DISTANCES NORTH ESCARPMENT

DESIGNED BY SCALE B.V. As Shown DRAWN BY DATE M.L. MARCH 2014 APPROVED BY PROJECT NO.: M.W.B OE-OT-015358 Base map and survey drawing provided by BrookMcIlroy/MMM GROUP Figure 10 0

TP13-06

BH13-10 50

BH13-11 100

BH9 200

TP4 18.0

BH13-08 18.0

400m 18.0

TP13-05 26.0

TP13-07

18.0

BH13-12 18.0

TP13-08 BH13-07 BH13-09 18.0 TP13-15

18.0 TP13-16 18.4 BH13-13

26.0

TP13-17

BHMW24 26.0

18.0 20.0 BHMW15

BH4 TP13-04

BH13-14 18.0 BHMW15 TP13-03

TP13-09 26.0

20.0 18.0 BHMW14 TP13-11 TP5

BHMW13 18.0 BHMW22

TP13-18

26.0 18.0

BH13-02 60.0

BHMW9 TP13-19

BH13-01 BH13-15 CODD'S ROAD CODD'S 26.0

18.0 BHMW23 CODD'S ROAD CODD'S TP13-10 BHMW12

BHMW21 TP13-20

20.0

MAIN STREET TP13-21 18.0 BHMW18 TP13-12 TP13-25 BHMW20 BH13-03 TP13-22 BHMW11 BHMW19

TP3 TP13-24 26.0 18.0 BHMW16 18.0 TP13-23 BHMW8

BHMW17 BHMW7

TP2

18.0 TP13-13 BHMW10 15.0 BHMW6 18.0 18.0 18.0 18.0 BHMW26 BH13-06

26.0 18.0

BH8 18.0

BHMW25 18.0

18.0 18.0 BH13-05 BHMW5 18.0 18.0 18.0

BH13-04

TP13-01

TP13-02

BHMW3 BHMW1 18.0 BH13-16

TP1

BHMW4

18.0 BHMW2

26.0

TP13-14 DRAWN BY DESIGNED BY DRAWING TITLE PROJECT TITLE APPROVED BY .THIS DRAWING SHALL BE READ IN CONJUNCTION 1. .DO NOT SCALE DRAWING. 2. LEGEND: NOTES: REV WITH THE ASSOCIATED TECHNICAL REPORT. 0 TEL (613) 748-1415 FAX 748-1356 Geotechnical Investigation consulting engineers 2150 THURSTON DRIVE, SUITE 203 GRADE RAISE AREAS MAY. 20, 2014 M.L. B.V. G.T. Former CFB Rockcliffe MAP OF MAXIMUM OTTAWA, ONTARIO, K1G 5T9 DATE Ottawa, Ontario MAXIMUM GRADE RAISE AREA (2 m) MAXIMUM GRADE RAISE AREA (1 m) www.dstgroup.com PROJECT NO.: DATE SCALE ISSUE Original OE-OT-015358 MAY 2014 As Shown APPROVAL G.T.