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HomeMy WebLinkAboutENG 11-20 Report to Executive Committee Report Number: ENG 11-20 Date: December 7, 2020 From: Richard Holborn Director, Engineering Services Subject: Stormwater Management Facilities Asset Management Plan -Final Report July 2020 -File: 1440 Recommendation: 1.That the Stormwater Management Facilities Asset Management Plan, Final Report July 2020, prepared by The Municipal Infrastructure Group Ltd. a T.Y. LIN International Company be received for information; 2.That Council endorse the Stormwater Management Facilities Asset Management Plan to be used by staff as a resource document for identifying and planning maintenance projects for the Stormwater Management Facilities under the jurisdiction of the City of Pickering; 3.That staff be authorized to implement the recommendations within the Stormwater Management Facilities Asset Management Plan, subject to budget and further Council approval for the individual projects; and, 4.That the appropriate officials of the City of Pickering be authorized to take the necessary actions as indicated in this report. Executive Summary: The Stormwater Management Facilities Asset Management Plan Final Report July 2020 (SWMF AMP) (Attachment #1) provides a comprehensive review and inspection of 18 of the 20 existing stormwater management facilities that are owned and operated by the City. The 2 remaining facilities owned by the City were recently constructed/reconstructed, therefore, were excluded from the SWMF AMP review scope. The SWMF AMP will comply with Ontario Regulation 588/17, which requires municipalities to complete asset management plans for its core infrastructure by July 1, 2021. The recommended management plan includes a priority list for facility maintenance (cleanout) projects and recommends a number of reconstruction/retrofit (capital) projects. All maintenance projects and reconstruction/retrofit projects can proceed directly to detailed design and/or construction stages. It is recommended that the SWMF AMP be endorsed by Council as a resource document to be used by staff. Financial Implications: Council endorsement of the SWMF AMP is a commitment, in principal, to implement a maintenance program for the City’s existing stormwater management facilities (SWMFs), in order to meet the level of service required by the Ministry of the Environment, ENG 11-20 December 7, 2020 Subject: Stormwater Management Facilities Asset Management Plan Final Report July 2020 Page 2 Conservation and Parks. The recommended maintenance (cleanout) projects are estimated to have a total cost of approximately $6.1 million, and the recommended reconstruction/retrofit projects are estimated to have a total cost of approximately $2.0 million. The 2020 budget includes an annual contribution of $200,000 .00 to the Stormwater Management Reserve Fund. These funds can be used to help offset the costs identified above. Council will have to consider increasing the annual contribution to match the planned expenditure levels. All projects recommended in the SWMF AMP will need to be included and approved in future capital budgets in order to be implemented. Discussion: The City owns and operates 20 SWMFs with the majority of these facilities being constructed in the 1980’s or 1990’s and in need of major repairs and cleanouts. Currently, the City does not have a comprehensive SWMFs maintenance program or dedicated funding program to ensure that proper maintenance is completed in a timely manner. The Municipal Infrastructure Group Ltd. a T.Y. LIN International Company was retained by the City of Pickering in June 2019 (Resolution #111/19) to prepare the SWMF AMP. The purpose of the SWMF AMP was to assess the current condition of the City’s existing SWMFs and determine a prioritized list of maintenance and reconstruction/retrofit projects to ensure an acceptable level of service is provided. In addition, the SWMF AMP will comply with Ontario Regulation 588/17, which requires municipalities to complete asset management plans for its core infrastructure by July 1, 2021. The SWMF AMP provides a comprehensive review and evaluation of 18 existing SWMFs (12 wet and 6 dry SWMFs). The 2 remaining facilities owned by the City were recently constructed/reconstructed, therefore, they were excluded from the SWMF AMP review scope. The objectives of the SWMF AMP were as follows: assess current physical conditions of the SWMFs through visual inspections; quantify sediment volumes in wet ponds through sediment accumulation surveys and assess the current performance of the SWMFs; determine sediment quality in each facility to recommend disposal methods; complete screening of the vegetation level and sensitive species assessment at each facility to determine vegetation restoration needs and costs associated with environmental requirements for recommended works; update and populate the City’s GIS database with information reviewed and collected through the SWMF AMP process; identify public safety and regulatory policy concerns; identify the potential of retrofitting SWMFs for improved performance under a capital works plan that outlines recommended works, regulatory requirements and estimated costs ; and, ENG 11-20 December 7, 2020 Subject: Stormwater Management Facilities Asset Management Plan Final Report July 2020 Page 3 evaluate the maintenance required at the SWMFs to develop a prioritized list of recommended works in a SWMFs maintenance plan that outlines sediment cleanout needs, recommended repairs, ongoing maintenance requirements and estimated costs. The SWMF AMP provides an overall evaluation of each facility, as well as a short and long term maintenance and capital projects plan, based on SWMF condition assessments, including a cost estimate for required maintenance tasks for each facility. The SWMFs were evaluated to establish a ranking that identifies which SWMFs are most in need of maintenance, and they were also evaluated for their suitability for retrofit/reconstruction to improve their performance and level of service. The recommendations from the SWMFs evaluation included a retrofit of 2 facilities and sediment cleanout at 12 other facilities with priority ranking and cost estimates as follows: Recommended SWMF Reconstruction/Retrofit (Capital) Projects Priority SWMF Name (ID) Estimated Retrofit Cost 1 Lisgoold (C2-08-GC) $716,300.00 2 Rouge (C1-01-ER) 1,287,000.00 Total Estimated Recommended/Retrofit Cost $2,003,300.00 Recommended SWMF Maintenance (Cleanout) Projects Priority SWMF Name (ID) Estimated Cleanout Cost 1 Rouge (C1-01-ER) $838,500.00 2 Lisgoold (C2-08-GC) 313,300.00 3 Autumn (C1-03-PT) 620,100.00 4 Begley Street (R3-02-AB) 315,900.00 5 Chickadee (C1-05-PT) 297,700.00 6 Dixie Estates 2 (C2-02D-PC) 336,700.00 7 Cognac (C2-01-DN) 412,100.00 8 Valley Farm (C2-06-WD) 347,100.00 9 Durham Woods (R3-04-LD) 1,031,400.00 10 Calvington Trail (C1-04-PT) 370,500.00 T11 Bopa (C1-02-PT) 374,400.00 T11 Mattamy (C3-08-UC) 804,700.00 Total Estimated Maintenance (Cleanout) Cost $6,062,400.00 ENG 11-20 December 7, 2020 Subject: Stormwater Management Facilities Asset Management Plan Final Report July 2020 Page 4 The estimated cleanout costs can be used to plan for future capital budgets with an indexing factor to be applied to reflect the change in construction costs. The actual costs for the reconstruction/retrofit projects will be updated through the detailed design process. All projects recommended in the SWMF AMP must be approved in future capital budgets in order to be implemented. The SWMF AMP provides the City with a GIS database that gives staff the ability to quickly access and retrieve information, to promptly respond to inquiries from residents, government agencies and consultants. Also, the database will be used to effectively communicate internally, between departments. The database provides a consistent method to enter new information from new or existing facilities and track inspections and maintenance records. City Staff will update the database regularly based on projects as they are completed and new SWMFs when they are built. During the existing conditions assessment of the SWMFs, there were qu ite a number of encroachments that were found. The most common violations included private structures, such as fences, furniture, retaining walls and plantings placed on City owned lands. Staff are investigating the violations, and will focus first on the encroachments that impact (or potentially impact) the operation and maintenance of the SWMF. The maintenance and capital projects plan recommended in the SWMF AMP will provide multiple benefits to the City, such as; helping to safeguard public health, reducing flooding potential for public and private properties, improving water quality in the receiving creeks and demonstrating due diligence with respect to good asset management principles and practices. Attachments: 1.Stormwater Management Facilities Asset Management Plan Final Report July 2020 2.Stormwater Management Facilities Location Map ENG 11-20 December 7, 2020 Subject: Stormwater Management Facilities Asset Management Plan Final Report July 2020 Page 5 Prepared By: Approved/Endorsed By: Irina Marouchko, P.Eng. Richard Holborn, P.Eng Senior Water Resources Engineer Director, Engineering Services Marilee Gadzovski, M. Sc. (Eng), P.Eng. Division Head, Water Resources & Development Services IM:mjh Recommended for the consideration of Pickering City Council Marisa Carpino, M.A. Interim Chief Administrative Officer Stormwater Management Facilities Asset Management Plan FINAL REPORT ▪ JULY 2020 REPORT PREPARED FOR CITY OF PICKERING ONE THE ESPLANADE PICKERING, ON L1V 6K7 REPORT PREPARED BY THE MUNICIPAL INFRASTRUCTURE GROUP LTD. A T.Y. LIN INTERNATIONAL COMPANY 8800 DUFFERIN STREET, SUITE 200 VAUGHAN, ON L4K 0C5 (905) 738-5700 TMIG PROJECT NUMBER 19163 REPORT PREPARED IN ASSOCIATION WITH GROUNDWATER ENVIRONMENTAL MANAGEMENT SERVICES Attachment #1 to Report #ENG 11-20 CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE i 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX CONTENTS 1 INTRODUCTION AND BACKGROUND............................................ 1 1.1 Overview and Purpose .................................................................. 1 1.2 Background Review ...................................................................... 4 1.2.1 GIS Database ................................................................................ 4 1.2.2 Design Drawings and SWM Reports ............................................. 4 1.2.3 Facility Inspection Records ............................................................ 5 1.2.4 Other Information ........................................................................... 5 2 FACILITY INSPECTIONS AND SURVEYS ....................................... 6 2.1 Visual Inspection ........................................................................... 6 2.2 Sediment Survey ........................................................................... 6 2.2.1 Sediment Volume .......................................................................... 6 2.2.2 Sediment Quality ........................................................................... 6 2.3 Ecology .......................................................................................... 6 3 FACILITY CONDITION ASSESSMENT ............................................ 7 3.1 Physical Condition ........................................................................ 7 3.2 Sediment and TSS Removal Efficiency ....................................... 7 3.2.1 Sediment Volumes ........................................................................ 7 3.2.2 TSS Removal Efficiency ................................................................ 8 3.2.3 Sediment Quality and Disposal Methods ..................................... 10 3.3 Ecological Assessment .............................................................. 11 3.3.1 Vegetation and Wildlife ................................................................ 11 3.3.2 Fish Management ........................................................................ 11 3.4 Facility Condition Summary ....................................................... 11 4 SWM FACILITY DATABASE .......................................................... 30 4.1 Database Fields ........................................................................... 30 4.2 Database Functionality and Limitations .................................... 31 5 FACILITY EVALUATION ................................................................. 36 5.1 Evaluation Criteria ....................................................................... 36 5.1.1 Weighted Scoring ........................................................................ 38 5.1.2 Maintenance Evaluation Criteria Interpretation ........................... 38 5.1.3 Retrofit Opportunity Evaluation .................................................... 43 5.2 Evaluation Results ...................................................................... 46 6 CAPITAL PROJECTS PLAN ........................................................... 47 6.1 Priority No. 1: Lisgoold Pond ..................................................... 47 6.1.1 Issues .......................................................................................... 47 6.1.2 Recommended Works ................................................................. 47 6.1.3 Cost Estimate .............................................................................. 48 6.2 Priority No. 2: Rouge Pond ......................................................... 49 6.2.1 Issues .......................................................................................... 49 6.2.2 Recommended Works ................................................................. 49 6.2.3 Cost Estimate .............................................................................. 50 7 MAINTENANCE PLAN .................................................................... 52 Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE ii TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 7.1 SWMF Cleanout Priority Ranking ............................................... 52 7.2 Cost Estimate ............................................................................... 54 7.3 SWMF Cleanout Schedule and Checklist .................................. 54 7.4 SWMF Inspections ....................................................................... 56 7.4.1 SWMF Inspections and Minor Maintenance ................................ 56 7.4.2 Sediment Accumulation Assessments ........................................ 57 8 SUMMARY ....................................................................................... 58 9 REFERENCES ................................................................................. 61 APPENDICES APPENDIX A FACILITY INSPECTION FORMS APPENDIX B SEDIMENT SURVEYS AND CALCULATIONS APPENDIX C ECOLOGY ASSESSMENTS AND SEDIMENT QUALITY SAMPLING APPENDIX D EVALUATION MATRICES APPENDIX E COST ESTIMATES APPENDIX F SWMF INFORMATION FILES (DIGITAL FILES) CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE iii 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX FIGURES Figure 1-1 SWM Facility Locations ................................................................ 2 Figure 6-1 Lisgoold Pond Recommended Works ....................................... 48 Figure 6-2 Rouge Pond Recommended Works ........................................... 50 TABLES Table 1-1 Existing GIS Attribute Table for SWMFs...................................... 4 Table 3-1 SWMF Sediment Volumes............................................................. 8 Table 3-2 Water Quality Storage Relationships (Table 3.2 of MOE SWM Manual) ................................................................................. 9 Table 3-3 SWMF Sediment Removal Efficiencies ...................................... 10 Table 3-4 SWMF Condition Assessment Summary – Autumn Pond ....... 12 Table 3-5 SWMF Condition Assessment Summary – Begley Street Pond ............................................................................................. 13 Table 3-6 SWMF Condition Assessment Summary – Bopa Pond ............ 14 Table 3-7 SWMF Condition Assessment Summary – Calvington Trail Pond ............................................................................................. 15 Table 3-8 SWMF Condition Assessment Summary – Chickadee Pond ... 16 Table 3-9 SWMF Condition Assessment Summary – Cognac Pond ........ 17 Table 3-10 SWMF Condition Assessment Summary – Dixie Estates Pond 2 ........................................................................................ 18 Table 3-11 SWMF Condition Assessment Summary – Durham Woods Pond ........................................................................................ 19 Table 3-12 SWMF Condition Assessment Summary – Lisgoold Pond ...... 20 Table 3-13 SWMF Condition Assessment Summary – Mattamy Pond ...... 21 Table 3-14 SWMF Condition Assessment Summary – Rouge Pond.......... 22 Table 3-15 SWMF Condition Assessment Summary – Valley Farm Pond ........................................................................................ 23 Table 3-16 SWMF Condition Assessment Summary – Braeburn Pond ..... 24 Table 3-17 SWMF Condition Assessment Summary – Brock Ridge Pond ........................................................................................ 25 Table 3-18 SWMF Condition Assessment Summary – Dixie Estates Pond 1 ........................................................................................ 26 Table 3-19 SWMF Condition Assessment Summary – Steeple Hill Pond ........................................................................................ 27 Table 3-20 SWMF Condition Assessment Summary – Strathmore Crescent Pond ............................................................................. 28 Table 3-21 SWMF Condition Assessment Summary – Pine Ridge High School Pond ................................................................................. 29 Table 4-1 GIS Database for SWMFs (Main Feature) .................................. 32 Table 4-2 GIS Database for SWMFs (Stormwater Management Pond) .... 33 Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE iv TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 4-3 GIS Database for SWMFs (Additional Data) .............................. 33 Table 4-4 GIS Database for SWMFs (Inspection, Operation and Maintenance) ................................................................................ 34 Table 5-1 SWMF Maintenance Assessment Criteria ................................. 37 Table 5-2 SWMF Retrofit Assessment Criteria .......................................... 38 Table 5-3 Maintenance Questions for Performance / Health and Safety Issues ................................................................................ 39 Table 5-4 Maintenance Questions for Operations Considerations .......... 40 Table 5-5 Maintenance Questions for Statutory and Regulatory Requirements ............................................................................... 41 Table 5-6 Maintenance Questions for Environmental Concerns ............. 42 Table 5-7 Maintenance Questions for Community Concerns .................. 42 Table 5-8 Retrofit Questions for Performance / Health and Safety .......... 43 Table 5-9 Retrofit Questions for Operations Considerations ................... 44 Table 5-10 Retrofit Questions for Cost-Benefit Analysis ............................ 44 Table 5-11 Retrofit Questions for Statutory and Regulatory Requirements ............................................................................... 45 Table 5-12 Retrofit Questions for Environmental Issues ............................ 45 Table 5-13 Retrofit Questions for Community Concerns ........................... 46 Table 7-1 SWMF Maintenance Priority ....................................................... 53 Table 7-2 SWMF Cleanout Schedule .......................................................... 55 Table 8-1 Recommended SWMF Retrofits (Capital Works Plan) ............. 58 Table 8-2 SWMF Maintenance Priority (Maintenance Plan) ...................... 59 CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 1 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 1 INTRODUCTION AND BACKGROUND 1.1 Overview and Purpose The Municipal Infrastructure Group Ltd. (TMIG), in association with Groundwater Environmental Management Services Inc. (GEMS), was retained by the City of Pickering to complete a Stormwater Management Facilities Asset Management Plan (SWMF AMP). The SWMF AMP builds upon the City’s existing facility inspection records and database with a comprehensive review and field program to develop practical capital works and maintenance plans to manage the City’s SWMFs. The City of Pickering owns and operates 20 SWM facilities, of which 18 were included in this SWMF AMP. A total of 12 wet facilities six (6) dry ponds were evaluated in this study and included in the capital works and maintenance plans. The two remaining facilities owned by the City (Abbott Crescent Pond and Operations Center Pond) were recently constructed or reconstructed and were therefore excluded from this evaluation. Several of the SWM facilities have deteriorated physical components and performance due to inconsistent maintenance over their lifespan. The City required a review of its SWMFs to plan maintenance and retrofit projects to ensure an acceptable level of service is provided for the foreseeable future. The purpose of the SWMF AMP is to assess the current conditions of the City of Pickering’s SWMFs and determine a prioritized list of capital works and maintenance requirements for the short to medium term (up to 10 years). The objectives of the SWMF AMP are as follows: ■ Assess the current physical conditions of the SWMFs through visual inspections. ■ Quantify sediment volumes in wet ponds through sediment accumulation surveys and assess the current performance of the SWMFs. ■ Determine sediment quality in each pond to recommend disposal methods. ■ Complete screening level vegetation and sensitive species assessments at each pond to determine methods and costs associated with environmental requirements for recommended works. ■ Update and populate the City’s GIS database with information reviewed or collected through the SWMF AMP. ■ Identify public safety and regulatory policy concerns. ■ Identify the potential for retrofitting SWMFs for improved performance under a capital works plan that outlines the recommended works, regulatory requirements and estimated costs. ■ Evaluate the maintenance required at the SWMFs to develop a prioritized list of works requirements in a SWMF maintenance plan that outlines sediment cleanout needs, recommended repairs, ongoing maintenance requirement, regulatory requirements and estimated costs. This SWMF AMP report describes the background review of the City’s SWMFs (Section 1.2), outlines the site inspections completed (Section 2), summarizes current facility conditions and updates to the City’s GIS database (Sections 3 and 4), and describes the facility evaluation and resulting maintenance and capital works plans (Sections 5 through 7). Durham Woods Pond R3-04-LD Begley Street Pond R3-02-AB Steeple Hill Pond R3-01D-PT Autumn Pond C1-03-PT Braeburn Pond C1-06D-PT Calvington Trail Pond C1-04-PT Chickadee Pond C1-05-PT Rouge Pond C1-01-ER Bopa Pond C1-02-PT Cognac Pond C2-01-DN Dixie Estates Pond 1 C2-03-PC Dixie Estates Pond 2 C2-02D-PC Strathmore Crescent Pond C2-05D-WD Lisgoold Pond C2-08-GC Mattamy Pond C3-08-UC Pine Ridge High School C2-04D-WD Valley Farm Pond C2-06-WD Brock Ridge Park C2-07D-WD Highway 4 0 1 Finch Avenue Whites RoadKingst o n R o a dAltona RoadBayly StreetDixie RoadLiverpool RoadBrock RoadRosebank RoadThird Concession Road Valley Farm RoadStrouds Lane Glenanna RoadFairport RoadSheppard Avenue Pickering Parkway Church Street SSpruce Hill RoadSideline 34Clements RoadSquires Beach RoadSandy Beach RoadGlendale DriveOklahoma Drive Aspen Road Notion RoadTwyn Rivers DrivePine Grove AvenueAmberlea RoadAppleview RoadBowler DriveKellino Street Modl in Road Granite C o u r tRougemount DriveHighview Road Woodview AvenueWalnut LaneFawndale RoadOld Forest RoadDunbarton R o a d Dillingham RoadRockwood DriveSalk RoadS o u t h c o t t R o a d Marshcourt DriveDouglas AvenueNew Street Linwood Street Breezy Drive Glenview RoadAlliance RoadRosefield RoadVicki Drive Longbow DriveCommerce Street Ba y l a w n D r i v e Vistula Drive Littleford Street Denmar Road Martins Street Davidson Street Huntsmill DriveDarwin Drive Rossland Road W Fairview AvenueEagleview DriveSilicone Drive Post Drive Lawson Street Sunbird Tr ail Miriam RoadCraighurst Cou r t Cherrywood Avenue Charnwood Court Bonita Avenue Hoover Drive The Espl a n a d e NLydia CrescentAnton SquareBrands Court The Espla n a d e S Falconcrest DriveBurnside DriveBicroft CourtThird Concession RoadRosebank RoadFairport RoadCITY OF PICKERING SWMF ASSET MANAGEMENT PLAN SWMF LOCATIONSDocument Path: G:\Projects\2019\19163 - Pickering - SWMF Asset Management Plan\4. Drawings\GIS\2020-07-24- Figure 1-1.mxdSCALE DATE JULY 2020 ³ 0 0.5 1 1.5 20.25 Kilometers FIGURE NO. 1-1 1 :30,000 PROJECT NO. 19163 ID WATERSHED PT Petticoat CreekAB Armor Business Park (Frenchman's Bay)LD Low Duffins CreekER East Rouge RiverDN Dunbarton CreekPC Pine CreekWD West Duffins CreekED East Duffins CreekGC Ganatsekiagon CreekUC Urfe CreekWV Whitevale Creek Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 4 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 1.2 Background Review A background review of information available from the City was completed prior to the existing conditions assessment and development of the AMP. The available background information for the SWMFs in this AMP included the existing GIS database, 2018 orthophotos, drainage area plans, plan, profile and details drawings of the SWMFs, SWM reports, and SWMF inspection forms from the last several years. Other information available for select SWMFs include digital drawing files and Ministry of the Environment, Conservation and Parks (MECP) Environmental Compliance Approvals (ECAs). Additional details of the background information is provided in the following sections. 1.2.1 GIS Database The City’s existing GIS database includes SWMF information as well as property parcel boundaries, City owned property, storm sewer information (sewers, maintenance holes, outfalls), and ditches. In particular, the existing SWMF shapefile contains the facilities as polygons depicting the pond basin and an attribute table (Table 1-1). Some storm sewers, maintenance holes, and outfalls within the pond blocks are included with their respective layers in the City’s database and represented by polylines and points. Pond blocks are represented within the Parcel layer of the database. Table 1-1 Existing GIS Attribute Table for SWMFs Field GIS Nomenclature Notes Object ID OBJECTID Shape Shape All SWMFs represented by polygons SWMF ID POND_ID Common Name for SWMF Assetname Owner Owner All SWMFs are owned by the City of Pickering Facility type Type Wet or dry Project number Project_Num Unknown project number reference Sort Number Sort_Num TCA ID TCA_ID Polygon shape length Shape_Length Length in meters Polygon shape area Shape_Area Area in meters 1.2.2 Design Drawings and SWM Reports Design drawings were available for each of the SWMFs, which included at least one or more of the following: drainage area plans, SWMF plan, profile and details drawings, landscaping plans, and erosion and sediment control plans. For older SWMFs, digital scans of the drawing in PDF format were available. Select new facilities had digital (PDF) drawing files or AutoCAD files. The available drawings are organized under the SWMF information files (digital files) found in Appendix F. These design drawings and associated SWM reports were reviewed and referenced for their information on SWMF components, control structures, drainage area, and design specifications, which were used to complete the facility condition assessments and determine the recommended works in the capital and maintenance plans. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 5 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 1.2.3 Facility Inspection Records SWMF inspection reports were available for 2012, and 2015 to 2018 for most SWMFs. The inspections were completed by City staff and reported in excel files. The inspections include visual observations of key components at each facility and recommended actions to monitor, clean out or repair concerns. From the City’s inspections, SWMF inspection memos were completed in 2016, 2017 and 2018 that highlighted maintenance concerns requiring action at several SWMFs. These memos were addressed to the City’s operations staff. All previous inspection records are found in the SWMF information files (digital files) found in Appendix F. In general, common issues at the SWMFs included excessive vegetation growth and debris at outlet structures causing blockages, minor damage to fence posts and outlet grates, and beaver activity at select ponds. Many of these issues had not been rectified and were reviewed ahead of TMIG’s facility inspections. 1.2.4 Other Information Other information that was reviewed for this AMP include the following: ■ Environmental Compliance Approvals (ECAs) (formerly known as Certificates of Approval – C of As) were available for: □ Bopa Pond (ECA no. 9557-4ZZS3D) □ Calvington Trail Pond (ECA no. 7347-6LRRBE) □ Durham Woods (ECA no. 7098-5ZKPEP) □ Lisgoold Pond (ECA no. 3-0348-93-006) □ Mattamy (ECA no. 0871-89PR2R) □ Rouge Pond (ECA no. 3-0372-93-006) ■ 2018 City of Pickering Orthophotos ■ Online mapping regarding natural heritage through the Ministry of Natural Resources and Forestry Natural Heritage Areas mapping application. General SWMF asset management and maintenance information from guideline documents and recent studies at other municipalities and conservation authorities were also reviewed to assist with developing this AMP, which included the following: ■ Lake Simcoe Region Conservation Authority’s report on Stormwater Inspection and Record Management Best Practices, and Data Model Design (GHD, 2017). ■ Sustainable Technologies Evaluation Program (STEP) Inspection and Maintenance Guide for SWM Ponds and Constructed Wetlands (TRCA and CH2M, 2016). ■ Ministry of the Environment, Conservation and Parks (MECP) Stormwater Management Planning and Design Manual (MOE, 2003). ■ City of Pickering Stormwater Management Design Guidelines (July 2019). Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 6 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 2 FACILITY INSPECTIONS AND SURVEYS SWMF inspections and surveys were completed in the summer and fall of 2019 by TMIG, GEMS, and GEMS’ Environmental Monitoring and Compliance (EMAC) division. The following sections describe the work that was completed. 2.1 Visual Inspection TMIG completed visual inspections of SWMF components between July 18 and July 31, 2019, at the 12 wet ponds and six (6) dry ponds in this AMP. Follow-up inspections were completed on November 20, 2019 at select facilities. The inspections involved locating components detailed on design drawings to assess their condition and function. Maintenance hole covers containing flow splitting weirs or control structures were opened and visually inspected from ground level where possible. Pond access barriers such as bollards and gates were inspected and general public safety concerns were noted. Incidences of encroachment on City property (within the pond block) were also documented. The inspection results were recorded on a modified version of the City’s pond inspection forms. Photographs were taken of the SWMFs and items of concern. Inspection forms and photographs are provided in the SWMF information files (digital files) found in Appendix F. 2.2 Sediment Survey 2.2.1 Sediment Volume Bathymetric surveys and sediment depth measurements were completed by EMAC between July 23 and August 31, 2019, at the 12 wet ponds. Both traditional survey methods and echosounder survey equipment were used depending on the amount of vegetation, debris, and depth of water impacting the equipment. Results from the sediment volume surveys were summarized in Section 3.2.1 and in Appendix B. 2.2.2 Sediment Quality GEMS completed sediment quality sampling at the 12 wet ponds between July 18 and August 22, 2019. A ponar dredge was used to collect the sediment samples at each sampling location. The number of samples collected at each wet pond varied between one (1) and four (4) depending on the size of the pond and access restrictions. The sediment samples were analyzed at Bureau Veritas in Mississauga, Ontario. The sampling results were compared against criteria in Table 1 of Ontario Regulation 153/04. A leachate test (Toxicity Characteristic Leaching Procedure – TCLP) was also completed and compared against Ontario Regulation 588/00 to determine whether the sediment is considered hazardous (and cannot be disposed in a landfill). Sediment sampling results are summarized in Section 3.2.3 and full methodology, sampling locations and results are found in Appendix C. 2.3 Ecology GEMS completed ecological assessments between July 18 and September 5, 2019 for the 18 wet and dry ponds included in this AMP to identify general vegetation communities in and around the pond, incidental wildlife observations, review adjacent environmental features, and recommend mitigation measures for future pond works. The vegetation assessment was completed in general accordance with standard Ecological Land Classification for Southern Ontario (ELC) protocols. Recommendations on fish management during pond retrofits or cleanouts was also provided. Ecologic assessment findings are summarized in Section 3.2.3 and full results are found in Appendix C. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 7 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 3 FACILITY CONDITION ASSESSMENT The results of the facility inspections and analysis are described in the following sections. A general overview of the assessments is provided in Sections 3.1 to 3.3, while summary tables for individual ponds are found in Section 3.4. 3.1 Physical Condition Visual inspections were completed for each of the 18 wet and dry ponds in this AMP. In general, there were no items of concern that require emergency attention and repair for public safety concerns. However, conditions at several ponds require maintenance to restore the operating functions. In general, the SWMFs had signs that indicated insufficient routine maintenance such as debris cleanup and minor repairs to outlet grates, fences, etc. Common items of concern noted throughout the inspection of the SWMFs are summarized below. Specific notes on each facility are found on inspections forms in Appendix A and summary tables in Section 3.4. ■ Outlet pipes, catchbasins, and hickenbottoms were blocked by debris and vegetation growth in the immediate area. As a result, water levels above design were observed and likely decreased extended detention and active storage volumes. ■ Damage to headwalls such as loose fence posts, missing or damaged fence components, missing or damaged grates. ■ Scour and erosion around inlet and outlet headwalls. ■ Beaver activity was observed at several ponds, which contribute to the debris and blocked outlets. ■ Invasive phragmite growth at several ponds, which in some instances was contributing to blocked outlets. ■ Insufficient signage, fence damage, missing gate locks, and other items related to site security. 3.2 Sediment and TSS Removal Efficiency 3.2.1 Sediment Volumes Sediment volumes were estimated from the sediment surveys for each wet pond. The sediment volumes ranged from 41 m3 to 1030 m3 (Table 3-1). These volumes consider the top of sediment and an assumed bottom of the pond, based on field survey rod probes and echosounder survey results. The sediment volumes were used to further calculate suspended solids (TSS) removal efficiencies and was a key factor to determining the priority of pond cleanout. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 8 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-1 SWMF Sediment Volumes SWMF Name SWMF ID Date of Survey Sediment Volume (m3) Autumn Pond C1-03-PT July 24, 2019 764 Begley Street Pond R3-02-AB August 16, 2019 200 Bopa Pond C1-02-PT July 29, 2019 188 Calvington Trail Pond C1-04-PT July 26, 2019 211 Chickadee Pond C1-05-PT August 22, 2019 155 Cognac Pond C2-01-DN August 9, 2019 441 Dixie Estates Pond 2 C2-02D-PC August 20, 2019 41 Durham Woods Pond R3-04-LD August 1, 2019 1618 Lisgoold Pond C2-08-GC August 22, 2019 119 Mattamy Pond C3-08-UC August 31, 2019 1030 Rouge Pond C1-01-ER August 19, 2019 850 Valley Farm Pond C2-06-WD July 23, 2019 117 (Note 1) 1 The sediment volume surveyed within the pond was 117 m3, however, the total sediment volume surveyed was 293 m3 which accounted for an additional 176 m3 sediment accumulated adjacent to the pond from an external drainage diversion channel. 3.2.2 TSS Removal Efficiency The TSS removal efficiency at the wet ponds was assessed using design methods outlined in the Stormwater Management Planning and Design Manual (SWM Manual) (MOE, 2003). In particular, Chapter 3 of the SWM Manual provides water quality criteria that are currently used in the design of wet ponds, recognizing that a number of facilities were designed prior to the standards described in the SWM Manual. In particular, a number of facilities were not designed with a permanent pool (including Chickadee Pond, Dixie Estates 2 Pond, Lisgoold Pond, and Rouge Pond). For these facilities, the TSS removal efficiencies were not calculated, except for Rouge Pond, which was assumed to have an average permanent pool depth of 0.15 m that is comparable to a wetland facility. For wet ponds designed with a permanent pool, the as-designed TSS removal efficiency (percentage) was obtained from SWM reports where available. For many ponds that predate the 2003 SWM Manual, the removal efficiency was calculated using the as-designed permanent pool volume (from SWM reports or estimated from design / as-built drawings) and the contributing drainage area / imperviousness. The relationships presented in Table 3.2 of the SWM Manual were interpolated and extrapolated for the wet ponds, noting that extrapolations far beyond the lower and upper values presented in the table were viewed with discretion. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 9 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-2 Water Quality Storage Relationships (Table 3.2 of MOE SWM Manual) In general, the design TSS removal efficiencies of six (6) of the wet ponds were above Normal Protection Levels (70% long-term TSS removal). The remainder includes Cognac Pond (65%) and the five (5) ponds without permanent pools in their design. The current TSS removal efficiencies were calculated using the same method above, but considered the surveyed sediment volume, which was assumed to reduce the permanent pool volume and thus reduce the TSS removal efficiencies. The results of the current TSS removal efficiency calculation help determine the urgency for sediment cleanout at each facility. As a guide, the SWM Manual recommends sediment cleanout of the pond when TSS removal efficiencies are reduced by more than 5%. Overall, the reduction in TSS removal efficiencies at the SWMFs ranged from 1% to 10%, of which, Autumn Pond, Begley Street Pond, Cognac Pond, and Rouge Pond had TSS removal efficiencies reduced by more than 5% from design and are below 80% TSS removal efficiency. Results of the calculations are provided in Table 3-3 and calculations are found in Appendix B. Of note, the Mattamy Pond had a high sediment accumulation volume that is likely attributable to the continued construction activity within its contributing drainage area. However, the pond also included a large permanent pool volume and thus has the capacity to accumulate more sediment before a reduction in Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 10 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX settling efficiency below 80%. A sediment assessment is recommended at the Mattamy Pond once the contributing drainage area has been fully built out. Table 3-3 SWMF Sediment Removal Efficiencies SWMF Name SWMF ID As-designed TSS Removal Efficiency Current TSS Removal Efficiency Autumn Pond C1-03-PT 81% 71% Begley Street Pond R3-02-AB 78% 72% Bopa Pond C1-02-PT 77% 75% Calvington Trail Pond C1-04-PT >90% 87% Chickadee Pond C1-05-PT N/A (not designed with permanent pool) N/A Cognac Pond C2-01-DN 65% 57% Dixie Estates Pond 2 C2-02D-PC N/A (not designed with permanent pool) N/A Durham Woods Pond R3-04-LD 87% 82% Lisgoold Pond C2-08-GC N/A (not designed with permanent pool) N/A Mattamy Pond C3-08-UC 90% 86% Rouge Pond C1-01-ER 62% (not designed with permanent pool, assumed 0.15 m wetland depth) 51% Valley Farm Pond C2-06-WD N/A (not designed with permanent pool) N/A 3.2.3 Sediment Quality and Disposal Methods The TCLP (leachate test) analysis (O. Reg. 558/00) results for samples collected during facility inspections were not considered hazardous and therefore can disposed of in a landfill. The samples were also compared to Table 1 of Ontario Regulation 153/04 for sediment. Table 1 criteria determine the suitability of the sediment for reuse at other locations. Ponds that do not exceed Table 1 criteria, with the exception of Sodium Adsorption Ratio (SAR) and electrical conductivity (EC), are generally candidates for sediment reuse at other locations. However, the presence of phragmites at many of the SWMFs requires the sediment to be disposed at landfill. This is based on the recommended landfill disposal for phragmites, a highly invasive plant species which grows in the sediment and would be removed at the same time. In general, sediment reuse for the relatively small volumes of sediment at the SWMFs do not provide a cost advantage over landfill disposal. The sediment quality sampling completed for the SWMF AMP was to inform the disposal methods for planning cleanouts, for example, to estimate costs and identify any potential challenges with sediment disposal. The testing does not provide sufficient sampling data to proceed with disposal. Additional testing is required under O. Reg. 406/19: On-site and Excess Soil Management and the sediment disposal testing and disposal shall refer to the Rules for Soil Management and Excess Soil Quality Standards (Soil Rules) (MECP, 2019), particularly the sections that refer to stormwater management pond sediment. In general, the CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 11 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX excavation and removal of sediment from SWM ponds will require a sampling and analysis plan with specific requirements for SWM pond sediment with respect to sampling frequencies and test parameters. 3.3 Ecological Assessment 3.3.1 Vegetation and Wildlife The vegetation assessment covered the stormwater management block for each pond and adjacent areas where appropriate, such as the outlet areas. The wet pond blocks generally had cultural thicket-type vegetation communities as well as vegetation consistent with cultural seed mixes that were used at pond construction. Vegetation communities and species noted at each pond were documented in Appendix C. Common amongst several wet ponds is the presence of invasive phragmites (Phragmites australis), which were especially heavy at the Begley Street Pond and Calvington Trail Pond. Butternut trees were identified at the ponds, with one each at Cognac Pond and Valley Farm Pond. The butternut trees will require confirmation and guidance from a butternut health assessor to determine the required protection and/or mitigation requirements of the tree ahead of a sediment cleanout or retrofit project. There was also a presence of milkweed at several ponds which is associated with the observations of Monarch butterflies. While Monarch butterflies are not protected by the Species at Risk Act due to the ranking as special concern, it is recommended that any vegetation removal should ensure the replacement of milkweed within the area to maintain Monarch butterfly habitat. With respect to wildlife, the only Species at Risk observed was Barn Swallow at Calvington Trail Pond, Durham Woods Pond, Mattamy Pond, and Rouge Pond. Sediment cleanout and/or retrofit works are required to take measures to not harm the species or its habitat but adhering to the Migratory Birds Convention Act. Any vegetation removals required within the core breeding bird season (between April 1st and August 31st) will require clearance surveys for active nesting. The removal or disturbance of active nests that contain eggs or young birds is prohibited unless a permit is obtained from the MNRF. If any significant habitat for the barn swallow is altered or destroyed, mitigation measures (such as nest cups or structures) must be put into place once construction works are complete. Other incident wildlife observations that were common amongst the ponds include green frog, great blue heron, red wing blackbird, and dragonfly species. There was also evidence of beaver activity in several ponds that had caused blockages in outlet structures (or has the potential to cause blockages). If beavers persistently interfere with the function of a SWMF, the beaver should be relocated to a more suitable habitat. 3.3.2 Fish Management At many wet ponds, numerous goldfish were observed. Based on the habitat within the pond, it is likely that other species are also present at all ponds. A Fish Relocation Program is recommended prior to sediment cleanout works at each SWMF, to be carried out by a qualified crew, led by an Aquatic/Fisheries Biologist or Technician. The relocation effort should ensure that all fish and aquatic species are released into a suitable habitat after capture. Rescue efforts should be undertaken during the pre-drawdown and the drawdown phase. A License to Collect Fish for Scientific Purposes is required from the Ministry of Natural Resources and Forestry (MNRF) to capture and transport any aquatic wildlife. Fish may also need to be euthanized if deemed necessary by the MNRF. 3.4 Facility Condition Summary The following tables summarize the facility condition assessment for each of the SWMF in this study. The tables highlight major findings with respect to the physical condition of the SWMF, sediment volumes and TSS removal efficiency, sediment quality and disposal methods, and ecological assessment. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 12 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-4 SWMF Condition Assessment Summary – Autumn Pond SWMF ID C1-03-PT SWMF Name Autumn Pond Physical Condition Summary ■ Overgrown vegetation along maintenance access road prevents vehicle access around pond. ■ Poison ivy observed on trail near outlet of the facility. ■ Beaver activity noted in the vicinity. SWMF discharges to ponded area upstream of railway and outlet pipe is partially submerged. ■ Informal trails connecting the pond to Calvington Pond and Altona Forest Trails. ■ No rip-rap surrounding the outlet CSP riser and the filter fabric is exposed. ■ Vegetation growth around outlet structure. ■ The outlet pipe is likely clogged with debris, which has caused an elevated water level and partially submerged inlet. ■ Fence damage at south-east corner of pond site adjacent the railway. Recommendations: Clean out sediment, remove debris around hickenbottom outlet structure, repair riprap material around the outlet CSP riser, and repair damaged fence. Add signage noting the presence of poison ivy. If present, beaver in the area should be relocated to avoid operational issues associated with debris. Pond Sediment Volume: 764 m3 Disposal Method: Landfill TSS Removal Efficiency Current: 71% Design: 81% (estimated from design drawings) Ecological Assessment Summary Species at Risk: None observed Discharge Receiver Habitat: Petticoat Creek tributary with north and south woodlands of unknown significance. Additional Mitigation: n.a. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 13 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-5 SWMF Condition Assessment Summary – Begley Street Pond SWMF ID R3-02-AB SWMF Name Begley Street Pond Physical Condition Summary ■ Maintenance access road requires vegetation clearing for vehicle access. ■ Heavy phragmite growth in pond. ■ Outlet headwall and pipe submerged. ■ Heavy vegetation around outlet area. ■ Overland flow route potentially drains toward townhouses rather than overland flow dispersion swale. ■ Overland flow dispersion swale not well defined. Recommendations: Clean out sediment and clean out vegetation at outlet area. Confirm overland flow route by survey and regrade if necessary. Pond Sediment Volume: 200 m3 Disposal Method: Landfill. Potential for reuse near roadways, subject to geotechnical requirements, however, phragmite removal (during sediment removal) will require landfill disposal. TSS Removal Efficiency Current: 72% Design: 78% (estimated from design drawings) Ecological Assessment Summary Species at Risk: Monarch Butterfly (special concern) Discharge Receiver Habitat: Frenchman’s Bay Coastal Wetland Complex (Provincially Significant Wetland) to the west of the pond. Additional Mitigation: Replacement of milkweed in area to accommodate Monarch butterflies. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 14 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-6 SWMF Condition Assessment Summary – Bopa Pond SWMF ID C1-02-PT SWMF Name Bopa Pond Physical Condition Summary ■ Evidence of beaver activity within the pond. ■ The PVC riser may be partially clogged. ■ CSP riser / protection for PVC outlet pipe not present. ■ Outlet headwall. Recommendations: Clean out sediment, clean out perforated outlet riser and install CSP riser. Relocate beaver from pond if present. Pond Sediment Volume: 188 m3 Disposal Method: Landfill TSS Removal Efficiency Current: 75% Design: 77% Ecological Assessment Summary Species at Risk: None observed Discharge Receiver Habitat: Petticoat Creek tributary with north and south woodlands. Additional Mitigation: n.a. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 15 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-7 SWMF Condition Assessment Summary – Calvington Trail Pond SWMF ID C1-04-PT SWMF Name Calvington Trail Pond Physical Condition Summary ■ Signage not present at pond. ■ Heavy phragmite growth in pond. ■ Encroachment along north edge of pond block (plantings by residents). ■ Evidence of beaver activity in vicinity of the pond. ■ Inlet headwall fence post damaged (loose fence post). ■ Outlet headwall fence damage (missing crossbar) Recommendations: Clean out sediment, repair headwall fencing and install signs. Relocate beaver if present. Pond Sediment Volume: 211 m3 Disposal Method: Landfill. TSS Removal Efficiency Current: 87% Design: >90% Ecological Assessment Summary Species at Risk: Barn Swallow, Monarch Butterfly (special concern) Discharge Receiver Habitat: Petticoat Creek and woodland of unknown significance. Additional Mitigation: Construction adherence to the Migratory Birds Convention Act. Vegetation removals within core breeding bird season, between April 1st and August 31st, will require clearance surveys for active nesting. Removal or disturbance of active nests is prohibited unless permit is obtained. Replacement of milkweed in area to accommodate monarch butterflies. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 16 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-8 SWMF Condition Assessment Summary – Chickadee Pond SWMF ID C1-05-PT SWMF Name Chickadee Pond Physical Condition Summary ■ Heavy vegetation within pond block. ■ No signs at access gate to inlet (northeast access). ■ Steep maintenance access to inlet and outlet areas. ■ Evidence of beaver activity within pond. ■ Outlet hickenbottom submerged and surrounded by vegetation and debris. ■ Outlet likely partially blocked causing elevated water level. ■ Inlet area and pipe submerged. Recommendations: Clean out sediment and vegetation, clean or replace hickenbottom outlet, and install signs at northeast access gate. Relocate beaver if present. Pond Sediment Volume: 155 m3 Disposal Method: Landfill TSS Removal Efficiency Current: N/A Design: N/A (not designed with permanent pool) Ecological Assessment Summary Species at Risk: None observed Discharge Receiver Habitat: Petticoat Creek and woodland of unknown significance Additional Mitigation: n.a. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 17 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-9 SWMF Condition Assessment Summary – Cognac Pond SWMF ID C2-01-DN SWMF Name Cognac Pond Physical Condition Summary ■ Phragmite growth within west side of pond. ■ Fallen tree at east side of pond. ■ Evidence of beaver activity within pond. ■ Scour pool, deteriorated riprap and exposed filter fabric at inlet. ■ Minor erosion along south berm. Recommendations: Clean out sediment, repair inlet area, monitor erosion areas on berm and stabilize if required. Pond Sediment Volume: 441 m3 Disposal Method: Landfill. Potential reuse subject to further sediment sampling. Phragmites require landfill disposal. TSS Removal Efficiency Current: 57% Design: 65% Ecological Assessment Summary Species at Risk: Potential butternut tree, Monarch butterfly (special concern) Discharge Receiver Habitat: Dunbarton Creek and woodland of unknown significance. Additional Mitigation: Butternut health assessment. Replacement of milkweed in area to accommodate Monarch butterflies. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 18 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-10 SWMF Condition Assessment Summary – Dixie Estates Pond 2 SWMF ID C2-02D-PC SWMF Name Dixie Estates Pond 2 Physical Condition Summary ■ Facility water level elevated and inlet pipe partially submerged. ■ Encroachment along west side of pond block from homeowner plantings and yard furnishings. ■ Seepage through berm around inlet headwall. ■ Signs of bank erosion (undercut and slumping) in downstream watercourse. ■ Outlet riprap spillway washed out. Recommendations: Cleanout facility outlet, repair inlet pipe and repair outlet spillway. Pond Sediment Volume: 41 m3 Disposal Method: Landfill TSS Removal Efficiency Current: N/A Design: N/A (not designed with permanent pool) Ecological Assessment Summary Species at Risk: None observed Discharge Receiver Habitat: Pine Creek tributary and woodlands of unknown significance. Additional Mitigation: N/A CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 19 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-11 SWMF Condition Assessment Summary – Durham Woods Pond SWMF ID R3-04-LD SWMF Name Durham Woods Pond Physical Condition Summary ■ View of pond looking east towards access gate. ■ Access gate unlocked and obstructed by brush. ■ Cracks in concrete headwalls at north and south inlets. ■ Cracks in headwall at fence posts at north and south inlets. ■ Erosion gullies along berm. ■ Drainage from adjacent vacant property to the east had causes erosion gullies (approximately 1.5 m wide and 0.5 m deep). Recommendations: Repair headwalls and repair/stabilize erosion rills in berms. Complete maintenance on access gate. Pond Sediment Volume: 1618 m3 Disposal Method: Landfill TSS Removal Efficiency Current: 82% Design: 87% Ecological Assessment Summary Species at Risk: Barn Swallow, monarch butterfly (special concern) Discharge Receiver Habitat: Duffins Creek and Duffins Creek Marsh (Provincially significant wetland) about 500 m downstream of SWMF. Additional Mitigation: Construction adherence to the Migratory Birds Convention Act. Vegetation removals within core breeding bird season, between April 1st and August 31st, will require clearance surveys for active nesting. Removal or disturbance of active nests is prohibited unless permit is obtained. Replacement of milkweed in area to accommodate monarch butterflies. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 20 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-12 SWMF Condition Assessment Summary – Lisgoold Pond SWMF ID C2-08-GC SWMF Name Lisgoold Pond Physical Condition Summary ■ Outlet clogged with debris causing elevated water level. ■ Fallen tree in pond. ■ Degraded channel downstream of west inlet (washed out riprap spillway, knickpoint, eroded side slope). ■ Exposed headwall and degraded riprap at south inlet. Recommendations: Clean out sediment, clean outlet structure, repair inlet channel and repair riprap around south inlet. Pond Sediment Volume: 119 m3 Disposal Method: Landfill TSS Removal Efficiency Current: N/A Design: N/A (not designed with permanent pool) Ecological Assessment Summary Species at Risk: None observed Discharge Receiver Habitat: Ganatsekiagon Creek tributary (occupied or recovery reach for Redside Dace) and woodlands of unknown significance. Additional Mitigation: In-water works/construction may be limited to the fisheries timing window of July 1 to September 15. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 21 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-13 SWMF Condition Assessment Summary – Mattamy Pond SWMF ID C3-08-UC SWMF Name Mattamy Pond Physical Condition Summary ■ Evidence of beaver activity within pond block. ■ Signage at pond for park rules, does not provide warnings for SWMF. ■ Wetland flow spreader. Recommendations: Install signs with SWMF warnings. Relocate beaver if present. Pond Sediment Volume: 1030 m3 Disposal Method: Landfill. Potential reuse subject to further sampling. TSS Removal Efficiency Current: 86% Design: 90% Ecological Assessment Summary Species at Risk: Barn Swallow, Monarch Butterfly (special concern) Discharge Receiver Habitat: Urfe Creek tributary (occupied or recovery reach for Redside Dace), woodlands of unknown significance, and unevaluated wetland. Additional Mitigation: Construction adherence to the Migratory Birds Convention Act. Vegetation removals within core breeding bird season, between April 1st and August 31st, will require clearance surveys for active nesting. Removal or disturbance of active nests is prohibited unless permit is obtained. Replacement of milkweed in area to accommodate monarch butterflies. In-water works/construction may be limited to the fisheries timing window of July 1 to September 15. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 22 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-14 SWMF Condition Assessment Summary – Rouge Pond SWMF ID C1-01-ER SWMF Name Rouge Pond Physical Condition Summary ■ Outlet from quality pond likely blocked resulting in high water level. ■ Evidence of beaver activity in vicinity of pond. ■ Encroachment at along east edge of pond block (landscaping and plantings by residents) ■ Outlet from quality pond likely blocked resulting in high water level. ■ Vegetation surrounding hickenbottom. ■ Inlet grate at quality pond unhinged. Recommendations: Cleanout sediment and cleanout outlet from water quality pond. Repair inlet grate. Relocate beaver if required. Pond Sediment Volume: 850 m3 Disposal Method: Landfill. Potential reuse where site locations meet the Excess Soil Guidelines. TSS Removal Efficiency Current: 51% Design: 62% (assumes 0.15 m average wetland depth) Ecological Assessment Summary Species at Risk: Barn Swallow, Monarch Butterfly (special concern) Discharge Receiver Habitat: Rouge River. Discharge to an Area of Natural and Scientific Interest (ANSI), which consists of woodlands of unknown significance and Provincially Significant Wetland northwest (upstream) of SWMF. Additional Mitigation: Construction adherence to the Migratory Birds Convention Act. Vegetation removals within core breeding bird season, between April 1st and August 31st, will require clearance surveys for active nesting. Removal or disturbance of active nests is prohibited unless permit is obtained. Replacement of milkweed in area to accommodate monarch butterflies. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 23 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-15 SWMF Condition Assessment Summary – Valley Farm Pond SWMF ID C2-06-WD SWMF Name Valley Farm Pond Physical Condition Summary ■ Debris and vegetation surrounding hickenbottom outlet. ■ Heavy vegetation within pond. ■ No signage at the pond. ■ Heavy vegetation around outlet headwall. ■ Water ponded downstream of outlet. ■ Ponded water downstream of outlet at pedestrian trail. ■ Ponded water and sediment accumulated adjacent to the pond berm from an external drainage channel. Recommendations: Clean out sediment, remove debris around hickenbottom outlet and downstream headwall. Install signs. Consider installing culvert and grading trail at outlet channel of pond. Consider removing sediment from adjacent ponded area and restoring the external drainage diversion channel. Pond Sediment Volume: 117 m3 within the pond. An additional sediment volume of 176 m3 was surveyed in the area adjacent to the pond where an external drainage diversion channel is located. The total sediment volume surveyed was 293 m3. Disposal Method: Landfill TSS Removal Efficiency Current: N/A Design: N/A (not designed with permanent pool) Ecological Assessment Summary Species at Risk: Potential butternut tree Discharge Receiver Habitat: West Duffins Creek tributary and woodlands of unknown significance. Additional Mitigation: Butternut health assessment and associated recommendations. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 24 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-16 SWMF Condition Assessment Summary – Braeburn Pond SWMF ID C1-06D-PT SWMF Name Braeburn Pond Physical Condition Summary ■ Basin is manicured lawn. ■ Minor ponding at inlet channel. ■ Downstream end of culverts near outlet with small scour pool. Recommendations: Clear debris to improve drainage at inlet culvert. Repair minor scour pool. Pond Sediment Volume: N/A Disposal Method: N/A TSS Removal Efficiency Current: N/A Design: N/A Ecological Assessment Summary Species at Risk: Monarch butterfly (special concern) Discharge Receiver Habitat: N/A (storm sewer) Additional Mitigation: Replacement of milkweed for Monarch butterflies. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 25 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-17 SWMF Condition Assessment Summary – Brock Ridge Pond SWMF ID C2-07D-WD SWMF Name Brock Ridge Park Physical Condition Summary ■ Outlet pipe is damaged. ■ Spillway and berm have collapsed above outlet pipe. ■ Ponding at inlet channel to pond basin and entrance to parking lot ■ Minor ponding and vehicle ruts in inlet grassed swale. Recommendations: Repair outlet pipe and spillway berm. Regrade inlet channel to reduce ponding. Pond Sediment Volume: N/A Disposal Method: N/A TSS Removal Efficiency Current: N/A Design: N/A Ecological Assessment Summary Species at Risk: Monarch butterfly (special concern) Discharge Receiver Habitat: West Duffins Creek and woodlands of unknown significance. Additional Mitigation: Replacement of milkweed for Monarch butterflies. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 26 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-18 SWMF Condition Assessment Summary – Dixie Estates Pond 1 SWMF ID C2-03-PC SWMF Name Dixie Estates Pond 1 Physical Condition Summary ■ Gravel access road containing control culvert, view looking west. ■ Erosion at edge of gravel road at downstream headwall. ■ Upstream side of control culvert headwall fence damaged (leaning). ■ Debris and vegetation around upstream grate. ■ Debris at downstream DICB (downstream of pond). ■ Erosion around headwall and immediately upstream of DICB. ■ MH at DICB not secured to structure. ■ Pedestrian path downstream of facility eroded by channel flows (public safety hazard). Recommendations: Repair headwall fence damage, clean debris from control culvert. Repair downstream DICB. Pond Sediment Volume: N/A Disposal Method: N/A TSS Removal Efficiency Current: N/A Design: N/A Ecological Assessment Summary Species at Risk: Monarch butterfly (special concern) Discharge Receiver Habitat: N.A. (storm sewer at Maple Ridge Park). Additional Mitigation: Replacement of milkweed for Monarch butterflies. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 27 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-19 SWMF Condition Assessment Summary – Steeple Hill Pond SWMF ID R3-01D-PT SWMF Name Steeple Hill Pond Physical Condition Summary ■ Main basin of pond well vegetated, view looking east. ■ Grate at north inlet pipe damaged. ■ Upstream side of outlet culvert across Kingston Road. Recommendations: Repair north inlet pipe grate. Pond Sediment Volume: N/A Disposal Method: N/A TSS Removal Efficiency Current: N/A Design: N/A Ecological Assessment Summary Species at Risk: Monarch butterfly (special concern) Discharge Receiver Habitat: Petticoat Creek tributary Additional Mitigation: Replacement of milkweed for Monarch butterflies. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 28 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-20 SWMF Condition Assessment Summary – Strathmore Crescent Pond SWMF ID C2-05D-WD SWMF Name Strathmore Crescent Pond Physical Condition Summary ■ Main basin of pond well vegetated. ■ Minor debris at inlet pipe grate. ■ Damaged outlet pipe. ■ Approximately 1 m deep scour pool in creek downstream of outlet pipe. Recommendations: Monitor low flow channel erosion. Potentially modify outlet culvert to reduce scour in receiving creek. Pond Sediment Volume: N/A Disposal Method: N/A TSS Removal Efficiency Current: N/A Design: N/A Ecological Assessment Summary Species at Risk: Monarch butterfly (special concern) Discharge Receiver Habitat: West Duffins Creek and woodland of unknown significance. Additional Mitigation: Replacement of milkweed for Monarch butterflies. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 29 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 3-21 SWMF Condition Assessment Summary – Pine Ridge High School Pond SWMF ID C2-04D-WD SWMF Name Pine Ridge High School Physical Condition Summary ■ Ponded water at inlet. ■ Minor sediment noted in basin of pond. ■ Two (2) outlet pipes located with small scour pool downstream of pipes. Recommendations: Continue monitoring and inspections. Pond Sediment Volume: N/A Disposal Method: N/A TSS Removal Efficiency Current: N/A Design: N/A Ecological Assessment Summary Species at Risk: Monarch butterfly (special concern) Discharge Receiver Habitat: West Duffins Creek and woodland of unknown significance. Additional Mitigation: Replacement of milkweed for Monarch butterflies. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 30 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 4 SWM FACILITY DATABASE The City’s GIS database information on SWMF was updated to include the information reviewed and collected as part of this AMP. The database was also set up in anticipation of future data inputs and information needs. The GIS database update was based on a best practices review of stormwater management inspection and record management completed by Lake Simcoe Region Conservation Authority (LSRCA) (GHD, 2017). The best practices review included surveys and workshops with municipalities within the LSRCA to determine a data model design, which is a description of the rules by which data is defined, organized, queried and updated within a database. The TRCA, Region of Durham and MECP also participated in the workshops for the data model design. 4.1 Database Fields The LSRCA proposed data model included a comprehensive list of fields pertaining to SWM and LID facilities. The attributes pertaining to SWMFs were reviewed and it was determined that the list of fields from the LSRCA data model were generally appropriate for the City’s database, considering future data needs of the City and the information that would be available from new SWM infrastructure. With respect to the SWMFs in this AMP, the data fields were populated to the extent possible using information from available drawings, reports, and the site inspections (Appendix F). The data model proposes four (4) categories of data, all of which can be stored within the attribute tables for the ‘Stormwater Management Ponds” layer of the City’s database. The exceptions are SWM facility features that are represented as a polygon or point within the geodatabase, such as specific control structures within the pond, the pond block or easements. The main categories are as follows: ■ Main Feature – these fields are applicable to all stormwater management infrastructure such as SWM Ponds, LID facilities, and oil-grit separators. Fields include the name, ECA, facility location, etc. (Table 4-1). This data is stored under the SWMF layer of the GIS database. ■ Stormwater Management Pond – these fields pertain specifically to SWM ponds to describe their type and function (Table 4-2). This data is stored under the SWMF layer of the GIS database. ■ Additional Data – the fields are intended to apply to all SWM infrastructure and includes technical specifications and hyperlinks to SWM reports, drawings, etc. (Table 4-3). The data is to be stored with the feature that represents the data, for example, specifications for a control structure is to be stored with a point that represents the structure. ■ Inspection, Operation and Maintenance – the fields include information regarding maintenance and hyperlinks to inspection reports, monitoring reports, operating manuals, etc. (Table 4-4). The database fields listed in the tables above are also marked as ‘mandatory’ or ‘optional’. The intent of the mandatory designation is to define fields that are required for each facility, recognizing that older facilities may not have the complete information available. New/future facilities are expected to have information for most, if not all the mandatory fields. The optional fields generally cover information that will be available from inspections, maintenance and operations of the SWMF, or more detailed information with respect to pond design specifications. It is recommended that fields be filled out with all available information. New/future SWMFs will generally include more information in drawings and reports than older facilities and allow the database to be populated more easily. To that end, from the background and information review to complete this SWMF AMP, all available information that fit the database fields were entered. Note that SWMF features recommended to be stored in the database as point or polygons (such as controls structures) were not entered into the database as these features did not have available survey data or digital as-built drawings to assist. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 31 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 4.2 Database Functionality and Limitations The database defines, organizes, and provides the ability to query data for SWMFs, which allows City staff to access information more quickly and better respond to requests between departments, other government agencies and public requests. The database provides a consistent method to enter new information from new or existing facilities and keep track of inspections and maintenance records. Future SWMFs condition assessments can be completed with less effort with information readily available. The City is also expecting a large number of SWMFs to enter service from new developments and the reliance on City staff ‘knowledge’ of specifications to manage the infrastructure will be less feasible moving forward without tools such as a database. Overall, it allows the City to more effectively manage their SWM infrastructure. The database is most valuable if the information is up-to-date, recognizing that maintaining the database requires regular effort from City staff or retaining a consultant. The database should be reviewed and updated after site inspections and maintenance works at each facility. It is also important to correct misinformation where needed. The recommended frequency of review is annual, to coincide with the recommended minimum SWMF inspection frequency of once per year. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 32 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 4-1 GIS Database for SWMFs (Main Feature) Field GIS Nomenclature How it is represented in GIS How the data is represented in attribute table Recommended Data Collection Definition Common Name FacName Polygon Text Mandatory Common name of works/facility Unique ID – primary key SWMID Polygon Text Mandatory SWM ID ECA/C of A ID ECAID Polygon Text Mandatory ECA / C of A ID ECA/C of A Date ECADate Polygon Date Mandatory Date of authorizing letter ECA/C of A Description ECADesc Polygon Hyperlink Mandatory Hyperlink to authorizing letter Cert. of Completion ID CofCompID Polygon Text Optional Cert. of Completion ID (if applicable) Cert. of Completion Date CofDate Polygon Date Optional Date of authorizing letter Cert. of Completion Description CofDesc Polygon Hyperlink Optional Hyperlink to authorizing letter Facility Location Location Polygon Text Mandatory Intersection/Address Facility Location II Northing Polygon Double Mandatory Coordinates (UTM) (captured at outfall) Facility Location III Easting Polygon Double Mandatory Coordinates (UTM) (captured at outfall) Subdivision Name SubName Polygon Text Optional Subdivision name in which works/facility is located Parcel ID ParcelID Polygon Text Optional Registered plan (M-Plan) parcel ID (if applicable) Municipality MunName Polygon Text Mandatory Municipality name Conservation Authority ConsAuth Polygon Text Mandatory Conservation Authority name Subwatershed Wtrshed Polygon Text Mandatory Subwatershed within Conservation Authority Drainage/Catchme nt Area CatchArea Polygon Double Mandatory Unique ID of drainage/catchment area spatial layer Ownership Owner Polygon Text Mandatory Includes private land name/description Management Mgmt Polygon Text Optional Details/name of management (if applicable) Online/Offline OnOffline Polygon Text Mandatory Online/offline Year Built YrBuilt Polygon Text Mandatory Year facility was constructed Year Assumed YrAssmd Polygon Text Optional Year facility was assumed Year Inspected YrInspect Polygon Text Optional Most recent year works/facility was inspected Year Cleaned YrCleaned Polygon Text Optional Most recent year works/facility was cleaned GIS metadata last date modified GISDate Polygon Date Optional Most recent date GIS data was modified GIS metadata last editor GISStaff Polygon Text Optional Most recent name of GIS editor of data Notes Notes Polygon Text Optional Notes / Important information CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 33 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 4-2 GIS Database for SWMFs (Stormwater Management Pond) Field GIS Nomenclature How it is represented in GIS How the data is represented in the attribute table Recommended Data Collection Definition Multi-Stage Facility MSFac Polygon Text Optional Y/N Facility Draw Down Method FDDMthd Polygon Text Optional Drawdown method within facility Facility Area FacAreaM Polygon Double Optional Area of facility (polygon) Facility Material FacMat Polygon Text Optional Material contained within facility Facility Type FacType Polygon Text Mandatory Wet/Dry/Wetland/Hybrid /Other Facility Function FacFunc Polygon Text Optional Water Quality / Erosion / Quantity Table 4-3 GIS Database for SWMFs (Additional Data) Field GIS Nomenclature How it is represented in GIS How the data is represented in the attribute table Recommended Data Collection Definition Easement Esmt Polygon Text Optional Description of easement Access FacAccess Polygon Text Optional Y/N Access Type Access Typ - Text Optional Driveway, Turnaround, Gate, Lock Facility Fence and Type Fence Type Polyline - Optional Chain link, other Overland Flow Elevation OvFlElev Polygon Double Optional Overland flow elevation Overland Flow Location OvFloc Polygon Text Optional Overland flow location(s) Emergency Spillway By-Pass Elevation EmSpElev Polygon Double Optional Emergency spillway elevation Emergency Spillway By-Pass Location EmSpLoc Polygon Text Optional Emergency spillway location 100 Year Elevation Elev100y Polygon Double Optional 100-year elevation Permanent Pool Elevation PoolElev Polygon Double Optional Permanent pool elevation (as-built) Permanent Pool Volume PoolVol Polygon Double Optional Permanent pool volume (as-built) Sediment Drying Area SDADesc Polygon Text Optional Sediment drying area location description Utilities Nearby UtilDesc Point/Line/ Polygon Text Optional Description of nearby utilities Inlet Pipe size InSize Point Short Integer Optional Inlet pipe size Inlet Pipe type InType Point Text Optional Inlet pipe type Inlet Invert Elevation InvtElev Point Double Optional Inlet invert elevation Outlet Pipe Size OutSize Point Short Integer Optional Outlet pipe size Outlet Pipe Type OutType Point Text Optional Outlet pipe type Outlet Invert Elevation OutElev Point Double Optional Outlet invert elevation Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 34 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Field GIS Nomenclature How it is represented in GIS How the data is represented in the attribute table Recommended Data Collection Definition Submerged Inlet InSubmerg Point Text Optional Y/N Control Structure description CoStDesc Point/ Polygon Text Optional Control structure description Control Structure orifice-type CoStOrif Point/ Polygon Text Optional Plate, pipe, weir, etc. Control Structure Size CoStSize Point/ Polygon Short Integer Optional Control structure size Control Structure Elevation CoStElev Point/ Polygon Double Optional Control structure elevation Control Structure Quantity CoStQuan Point/ Polygon Double Optional Quantity control volume (m3) Control Structure Quality CoStQual Point/ Polygon Double Optional Quality control volume (m3) Safety Features SafeFeat Point/Line/ Polygon Text Optional Lifesaving stations, grading Special Features SpecFeat Point/Line/ Polygon Text Optional Clay liner, underdrain, lined forebay, etc Retrofits RetDesc Point/ Polygon Text Optional Retrofit description Table 4-4 GIS Database for SWMFs (Inspection, Operation and Maintenance) Field GIS Nomenclature How it is represented in GIS How the data is represented in the attribute table Recommended Data Collection Definition Inspector’s Name InspName Polygon – SWM/LID Text Optional Name of inspector(s) Sediment Accumulation Status Date SACDate Polygon – SWM/LID Date Optional Date of sediment volume survey Sediment Accumulation Status Volume (m3) SACVol Polygon – SWM/LID Double Optional Measured volume of sediment Condition FacCond Polygon – SWM/LID Text Optional Overall facility condition Sampling Sampling Polygon – SWM/LID Hyperlink Optional Previous sediment survey records Cleaning Frequency FreqClean Polygon – SWM/LID Text Optional Frequency of cleanouts Inspection Frequency FreqInsp Polygon – SWM/LID Text Optional Frequency of inspections Maintenance Record - Polygon – SWM/LID Hyperlink Optional Link to folder with maintenance records Complaints - Polygon – SWM/LID Hyperlink Optional Link to folder with complaints records SWM reports - Polygon – SWM/LID Hyperlink Optional Link to folder with SWM reports Inspection Reports - Polygon – SWM/LID Hyperlink Optional Link to folder with inspection forms Monitoring Reports - Polygon – SWM/LID Hyperlink Optional Link to folder with monitoring reports CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 35 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Field GIS Nomenclature How it is represented in GIS How the data is represented in the attribute table Recommended Data Collection Definition O & M Manual - Polygon – SWM/LID Hyperlink Optional Link to folder with O & M manual Drawings - Polygon – SWM/LID Hyperlink Optional Link to folder with drawings Surveys - Polygon – SWM/LID Hyperlink Optional Link to folder with surveys Costs - Polygon – SWM/LID Hyperlink Optional Link to folder with costs Site Photos/ Drone Video - Polygon – SWM/LID Hyperlink Optional Link to folder with photos Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 36 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 5 FACILITY EVALUATION The SWMFs were evaluated on specific parameters that are based on the current physical condition and assessed performance, public safety, regulatory compliance, environmental issues and community concerns related to the SWMFs. The results of the evaluation prioritize the SWMFs for the capital projects and maintenance plans. The SWMF evaluation is also intended to provide a consistent method to re-evaluate the SWMFs in later years. 5.1 Evaluation Criteria The SWMFs were evaluated using a set of criteria developed with the City of Pickering to establish a ranking that identifies the SWMFs most in need of maintenance. Separately, the SWMFs were also evaluated for their suitability for retrofit. The SWMFs that were identified as both a high priority for maintenance and highly suitable retrofit candidate were recommended for inclusion in the City’s capital projects plan (Section 6). Of the remaining SWMFs, the facilities requiring cleanout or major maintenance were recommended for placement on the City’s maintenance plan (Section 7). The general criteria and associated weightings for the maintenance and retrofit assessments are outlined in Table 5-1 and Table 5-2, respectively, and are very similar for both assessments. The rubric questions are tailored to identify maintenance priorities or retrofit candidacy. The weighting of the criteria were selected to provide practical differentiation between the SWMFs in the evaluation results. Therefore, the weighting for ‘performance / health and safety’ was (by far) the highest because this category had the greatest variation in scoring and was expected drive the prioritization of the maintenance and retrofit works. However, this does not suggest that certain criteria are more important than others with respect to the overall management of the SWMFs. It is important to note that the retrofit evaluation is to develop retrofit candidacy, however, the capital works plan will consider the result of both the maintenance evaluation and retrofit evaluation to determine which SWMFs are both in need of maintenance and will benefit from a retrofit. The rationale for retrofitting a SWMF can be varied and requires a case-by-case review of the SWMF. The retrofit evaluation rubric serves as a guide to begin the discussion. Both wet ponds and dry ponds were evaluated using the same rubric and ranked through the same evaluation. The wet ponds were expected to score higher (and be higher priority) for maintenance works due to the performance aspects and higher complexity of the facilities providing higher scores. Detailed descriptions of the evaluation criteria and rubric questions are provided in the following sections. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 37 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 5-1 SWMF Maintenance Assessment Criteria Criteria Weight 1. Performance / Health and Safety ■ Sediment accumulation and settling efficiency ■ Condition of SWMF structures and berms ■ Erosion and deposition in receiving watercourse ■ Water quantity (flood) control performance ■ Security and public safety hazards 60 2. Construction Considerations ■ Disposal method for removed sediment ■ Complexity of the permitting, approvals for cleanout or retrofit 15 3. Statutory and Regulatory Requirements ■ Future level of service according to O. Reg. 588/17 ■ Federal and Provincial regulatory requirements (MECP ECAs, TRCA Permitting) ■ Compliance with City policies, by-laws, standards and criteria 10 4. Environmental ■ Environmental benefits/impacts (ecological habitat and sensitive plant and fish communities) 10 5. Community Concerns ■ Community concerns/complaints (aesthetics and safety1) ■ Recreational use in the area (trails or walkways) 5 TOTAL 100 1 Note that public safety is primarily addressed in Criteria 1: Performance / Health and Safety Issues Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 38 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 5-2 SWMF Retrofit Assessment Criteria Criteria Weight 1. Performance / Health and Safety ■ Land area for potential facility expansion ■ Facility structure improvements for performance, functionality or durability ■ Increases in storage volume and associated performance ■ Security and public safety improvements 50 2. Construction Considerations ■ Complexity of the permitting, approvals for cleanout or retrofit 15 3. Cost-Benefit Analysis ■ Cost relative to potential damages related to downstream flooding and erosion ■ Benefitting drainage area ■ Cost effectiveness of the retrofit vs. cleanout 10 4. Statutory and Regulatory Requirements ■ Future level of service according to O. Reg. 588/17 ■ Federal and Provincial regulatory requirements (MECP ECAs, TRCA Permitting) ■ Compliance with City policies, by-laws, standards and criteria 10 5. Environmental ■ Environmental benefits/impacts (ecological habitat and sensitive plant and fish communities) 10 6. Community Concerns ■ Community concerns/complaints (aesthetics and safety1) ■ Recreational use in the area (trails or walkways) 5 TOTAL 100 1 Note that public safety is primarily addressed in Criteria 1: Performance / Health and Safety Issues 5.1.1 Weighted Scoring Each category rubric consists of a number of questions, with a maximum score of 3 per question. The maximum possible total score for a category such as the Performance/ Health and Safety Issues for maintenance is 18 points (6 questions x 3 points). This category in particular is the most important and contained the highest number of questions, therefore it was assigned a value of 60 out of 100. The weighted score for this category is multiplied by the ratio of the actual score and the criteria weighting, as follows: 𝑊𝑐�ℎ𝑖�𝑟𝑐𝑐 𝑆𝑐𝑜𝑟𝑐=∑𝑆𝑐𝑜𝑟𝑐𝑟 × 60 18 For example, if the answers to the six questions in this category total 12 (out of a possible score of 18), the weighted score would be: 12 × 60 18 =40 This approach is used for each SWMF across all of the evaluation criteria categories. 5.1.2 Maintenance Evaluation Criteria Interpretation 5.1.2.1 Performance / Health and Safety Issues The performance / health and safety issues with respect to assessing the maintenance of the SWMFs are scored according to the rubric in Table 5-3. Each of the six (6) rubric questions in the performance / health and safety issues category are discussed below. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 39 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 5-3 Maintenance Questions for Performance / Health and Safety Issues Evaluation Criteria Scoring 0 1 2 3 How severe is sediment accumulation in the SWMF? None or n/a Minor Moderate Severe What is the current TSS removal efficiency of the SWMF? > 80% or n/a 70-80% 60-70% < 60% What is the condition of the SWMF inlet/outlet structures and berms? Good Condition Minor Concerns Moderate Concerns Poor Condition How effective is the erosion control performance of the SWMF? As Designed Slightly Ineffective Moderately Ineffective High Ineffective How effective is the SWMF in achieving quantity control to prevent downstream flooding? As Designed Slightly Ineffective Moderately Ineffective High Ineffective Are there security and public safety hazards associated with the SWMF? None Minor Moderate Severe 1. How severe is sediment accumulation in the SWMF? The accumulation of sediment leads to clogged outlet structures and decreased sediment removal efficiency in the pond. The approach of the MOE SWM Planning and Design Manual (2003) to TSS removal efficiency is to estimate the long-term suspended sediment removal in wet ponds. In this evaluation, the long-term suspended sediment removal was calculated by determining the current permanent pool volume in the pond (design permanent pool volume minus accumulated sediment volume determined by survey). The MOE SWM Planning and Design Manual (2003) recommends that a 5% reduction in removal efficiency is acceptable from a maintenance frequency perspective. Therefore, removal efficiencies within 5% of the original design is considered to be within intended operational range (rating = 0). The remaining scoring is as follows: 5% to 20% below design efficiency is minor severity (rating = 1), 20% to 50% is moderate severity (rating = 2) and greater than 50% is severe (rating = 3). The rating scale is intended to prioritize the ponds with the greatest sediment accumulation, however, ponds with a greater than 5% reduction in removal efficiency should be cleaned out. Dry ponds have a rating of 0 for this question. 2. What is the current TSS removal efficiency of the SWMF? The City’s SWMF have design removal efficiencies ranging from Enhanced (80% long-term suspended sediment removal) to Basic (60% long- term suspended sediment removal) or worse. To maintain at least basic levels of treatment, SWMFs with lower removal efficiencies are prioritized. 3. What is the condition of the SWMF inlet/outlet structures and berms? This criteria is based on a qualitative risk assessment of the outlet structures and berm. For facilities that require immediate repair, it is considered to be in poor condition (rating = 3), repairs that need to be completed in the near future is considered a moderate concern (rating = 2), and if the components have minor signs of damage that need to be monitored, it is considered a minor concern (rating = 1). SWMFs with components in good condition were rated 0. 4. How effective is the erosion control performance of the SWMF? For facilities that provide erosion control, the design erosion control storage is compared with what currently exists on site. Additionally, the amount of sediment observed downstream and signs of erosion at the receiving watercourse are also taken into consideration. The rating for this question was assigned based on a qualitative assessment of whether erosion control is hindered by malfunctioning components (i.e. clogged orifice Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 40 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX controls and high water levels) or if there are observations of the SWMF’s ineffectiveness in providing erosion control. 5. How effective is the SWMF in achieving quantity control to prevent downstream flooding? For facilities that provide quantity control, the design storage and outlet structures are qualitatively assessed for their function. Recorded / anecdotal observations or public complaints of flooding issues are also considered. 6. Are there security and public safety hazards associated with the SWMF? Each facility should adhere to City standards for security and public safety, such as adequate signage, fencing and gates. Additionally, any facility containing hazardous vegetation such as giant hogweed, wild parsnip or poison ivy would require additional signage. SWMFs that were observed with security and public safety hazards had higher scores. 5.1.2.2 Construction Considerations The construction considerations with respect to assessing the maintenance of the SWMFs are scored according to the rubric in Table 5-4. The two (2) rubric questions in this category are discussed below. Table 5-4 Maintenance Questions for Construction Considerations Evaluation Criteria Scoring 0 1 2 3 What is the disposal method for removed sediment? n/a Hazardous Waste Landfill Other Uses How complex is permitting, approval and construction of the recommended maintenance? n/a Major Medium Minor 1. What is the disposal method for removed sediment? The sediment quality sampling completed for the facility conditions assessment provided insight into the potential disposal methods for removed sediment at each wet pond facility. Higher scores are assigned to SWMFs where sediment has a potential for reuse such as off-site fill (score=3). Lower scores are given to facilities where the sediment requires hazardous waste disposal (score=1). Note that the sediment in the majority of wet pond facilities requires landfill disposal (score=2), that is typical for pond cleanouts, based on sediment quality and/or the need to dispose of phragmites with the sediment. 2. How complex is the construction, permitting and approval processes of the recommended maintenance? Each facility was scored on the difficulty, cost and duration of work required to clean out the pond and repair the facility. This also considers the complexity of permitting and approvals. For example, a maintenance recommendation of cleaning out a large amount of sediment, removing and replanting vegetation and repairing an eroded outlet channel with limited site access will be challenging and would receive a lower rating. A straight-forward cleanout with good site access was given a higher rating. 5.1.2.3 Statutory and Regulatory Requirements The statutory and regulatory requirements with respect to assessing the maintenance of the SWMFs are scored according to the rubric in Table 5-5. Each of the three (3) rubric questions in this category are discussed below. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 41 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 5-5 Maintenance Questions for Statutory and Regulatory Requirements Evaluation Criteria Scoring 0 1 2 3 Is the current Level of Service less than the proposed Level of Service (under O. Reg. 588/17)? No n/a n/a Yes Is maintenance required by Federal or Provincial Agencies or the Conservation Authority? No n/a n/a Yes Are the site conditions currently in violation of any City policies or by-laws? No n/a n/a Yes 1. Is the current Level of Service less than the proposed Level of Service under O. Reg. 588/17 Section 6? The question addresses whether the level of service of the SWMF is below the anticipated level of service under O. Reg. 588/17 Section 6 (proposed levels of service). If yes, a rating of 3 was given. Otherwise, the rating for the SWMF was given a rating of 0. The evaluation recognizes that the ‘proposed levels of service’ for stormwater management assets under Section 6 of O. Reg. 588/17 has not been established by the City. To that end, the assumption used in this evaluation is that the current level of service for all SWMFs is equivalent to the proposed level of service. For example, if a SWMF is operating according to its designed performance, it is assumed to be operating at the current and proposed level of service. 2. Is maintenance required by Federal or Provincial Agencies or the Conservation Authority? A key regulatory requirement for SWMFs in operation is the Environmental Compliance Approval (ECA) from the Ministry of Environment, Conservation and Parks (MECP), which typically include a condition for maintaining the facility in good operating condition. Through the ECA and the authority of the MECP through the Water Resources Act (OWRA Section 53), orders can be potentially issued to rectify issues with SWMFs, which would escalate the priority for maintenance or repair. In general, for the evaluation scoring, SWMFs were scored a rating of 0 unless a clear and major violation of the SWMF’s ECA was identified and/or a Provincial Officer’s Order had been issued. 3. Are the site conditions currently in violation of any City policies or by-laws? The most common violation of City by-law applicable to the SWMF is encroachment, which includes private structures (fences, furniture, retaining walls, plantings etc.) on City owned lands. A scoring scale from 0 to 3 was used to rate the severity of City by-law violations, with particular consideration for instances where it has impacts (or potential impacts) to the operation and maintenance of the SWMF. 5.1.2.4 Environmental Concerns The environmental concerns with respect to assessing the maintenance of the SWMFs are scored according to the rubric in Table 5-6. The three (3) rubric questions in this category are discussed below. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 42 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 5-6 Maintenance Questions for Environmental Concerns Evaluation Criteria Scoring 0 1 2 3 What is the current impact of the SWMF on ecological habitat? No Impact or Positive Slightly Negative Moderately Negative Significantly Negative What is the proximity of the SWMF discharge to sensitive plant and fish communities? No sensitive receivers Distant Moderate Near What is the impact of maintenance on ecological habitat? n/a or Negative No Impact Moderately Positive Significantly Positive 1. What is the current impact of the SWMF on ecological habitat? A qualitative assessment was made of the degree of invasive species, presence of Species at Risk, and the temperature and quality of the SWMF’s discharge water. A higher score indicates that the current condition of a SWMF is negatively impacting the adjacent natural heritage system. 2. What is the proximity of the SWMF discharge to sensitive plant and fish communities? The proximity to sensitive habitat, namely Redside Dace contributing watercourses or Provincially significant wetlands, are indicative of the potential benefit of cleaning out a SWMF and are thus given priority (with higher scores). 3. What is the impact of maintenance on ecological habitat? This question evaluates the impact of the maintenance works (cleanout, repairs, component replacements, etc.) on ecological habitat, with particular consideration for sensitive plant and fish communities, and the effectiveness of mitigation measures during the works. 5.1.2.5 Community Concerns The environmental concerns with respect to assessing the maintenance of the SWMFs are scored according to the rubric in Table 5-7. The two (2) rubric questions in this category are discussed below. Table 5-7 Maintenance Questions for Community Concerns Evaluation Criteria Scoring 0 1 2 3 Are there known or potential community concerns with the SWMF? No Minor Moderate Major Are there opportunities to repair or enhance public amenities? No Minor Moderate Major 1. Are there known or potential community concerns with the SWMF? SWMFs that have damaged physical components and signs of environmental degradation that are visible to the public were given a score of 3, while SWMFs that are not accessible to the public were given a score of 0. Documented public complaints for issues such as aesthetics, odours or safety were also considered. 2. Are there opportunities to repair or enhance public amenities? If public amenities such as trails, look out points or park features can be improved during recommended maintenance works, a score of 3 was given. A score of 0 is given if such improvements are not applicable. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 43 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 5.1.3 Retrofit Opportunity Evaluation 5.1.3.1 Performance / Health and Safety The potential gain in performance / health and safety with respect to the potential retrofit of SWMFs are scored according to the rubric in Table 5-8. Each of the four (4) rubric questions in the performance / health and safety category are discussed below. Table 5-8 Retrofit Questions for Performance / Health and Safety Evaluation Criteria Scoring 0 1 2 3 What is the available land area to expand the SWMF? None Minor Moderate High What is the potential to replace inlet or outlet structures for improved performance or functionality? None Minor Moderate High What is the potential gain in storage volume and associated performance? None Minor Moderate High What is the potential to improve public health and safety? None Minor Moderate High 1. What is the available land area to expand the SWMF? The ratio of current SWMF area to available land area for expanding the SWMF was calculated. In general, the SWMFs with most available land area to expand could increase their footprint by 50% or more, and thus were given the highest score. The available land area for expanding a SWMF was measured in GIS, however, it considered a number of factors determined through the review of background information and field observations to assess the suitability for expansion. This includes the extent of the City’s parcel for the SWMF, available topographic information, location of sensitive environment features, and the location of the floodplain. Specific considerations for each SWMF is outlined in the evaluation results (Section 5.2). 2. What is the potential to replace inlet or the outlet control structure for improved performance, functionality or durability? This question evaluates the degree to which the SWMF can be improved by redesigning the inlet or outlet structures without expanding the footprint of the pond. For example, higher scores were assigned to SWMFs that can provide a larger permanent pool by raising the outlet invert (if there is available freeboard to maintain erosion control and quantity control volumes). The question also addresses potential improvements for durability or resilience of the SWMF to deterioration. 3. What is the potential gain in storage volume and associated performance? Similar to Question 2, the degree to which the SWMF can be improved by expanding the permanent pool or active storage volume. This would generally require an expansion of the SWMF’s footprint, or a steepening of s ide slopes. Higher scores were assigned to SWMFs that have the potential to provide significantly more storage volume. 4. What is the potential to improve public health and safety? Potential improvements to public health and safety include measures to restrict access and / or the removal of safety hazards such as steep slopes. The SWMFs were scored according to the impact of health and safety improvements that could be incorporated into a retrofit project. 5.1.3.2 Construction Considerations The construction considerations with respect to the potential retrofit of the SWMFs are scored according to the rubric in Table 5-9. The single (1) rubric question in this category is discussed below. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 44 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 5-9 Retrofit Questions for Construction Considerations Evaluation Criteria Scoring 0 1 2 3 How complex is permitting, approval and construction of the retrofit? n/a Major Medium Minor 1. How complex is the permitting, approval and construction process of the retrofit? Each facility is scored on difficulty, cost and duration of construction required to implement the retrofit and any enhancements to the natural environment. This considers the complexity of permitting and approvals in addition to implementation. For example, completing the works in a site with limited access will be challenging and would receive a lower score, while sites with good access, staging areas and straight- forward permitting would score highest. 5.1.3.3 Cost-Benefit Analysis The cost-benefit analysis with respect to the potential retrofit of the SWMFs are scored according to the rubric in Table 5-10. The three (3) rubric questions in this category are discussed below. Table 5-10 Retrofit Questions for Cost-Benefit Analysis Evaluation Criteria Scoring 0 1 2 3 What is the cost effectiveness of a retrofit relative to potential damages related to downstream flooding and erosion? n/a Low Medium High What is the drainage area to the SWMF? < 5 ha or n/a 5 to 10 ha 10 to 20 ha > 20 ha What is the potential cost efficiency of a retrofit in lieu of a SWMF cleanout? n/a Low Medium High 1. What is the cost effectiveness of a retrofit relative to potential damages related to downstream flooding and erosion? The cost of a potential retrofit was compared to the cost the potential gain in suspended sediment removal, erosion control and peak flow control. Potential retrofits with high costs but provide major gains in performance were scored the highest. Similarly, low cost retrofits with performance gains also had high scores. 2. What is the drainage area to the SWMF? The drainage area to a SWMF is representative of the amount of stormwater runoff and associated pollutant loading that is treated where the larger the drainage area, the greater the benefit to downstream receivers, and thus a higher score. 3. What is the cost efficiency of a retrofit in lieu of a SWMF cleanout? This question compares the cost estimates of a potential retrofit to a SWMF cleanout where only sediment is removed and minor repairs are completed. A higher score is given if there is potential to complete retrofit works without significant costs beyond a regular SWMF cleanout. 5.1.3.4 Statutory and Regulatory Requirements The statutory and regulatory requirements with respect to the potential retrofit of the SWMFs are scored according to the rubric in Table 5-11. Each of the three (3) rubric questions in this category are discussed below. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 45 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 5-11 Retrofit Questions for Statutory and Regulatory Requirements Evaluation Criteria Scoring 0 1 2 3 Will the potential retrofit achieve the proposed Level of Service under O. Reg. 588/17 Section 6? No n/a n/a Yes Is a retrofit required by Federal or Provincial Agencies or the Conservation Authority? No n/a n/a Yes Will a potential retrofit be in violation of any City policies or by-laws? No n/a n/a Yes 1. Will a retrofit achieve the proposed Level of Service under O. Reg. 588/17 Section 6? The question addresses whether the level of service of the SWMF is equivalent to the anticipated level of service under O. Reg. 588/17 Section 6 (proposed levels of service). If yes, a rating of 3 was given. Otherwise, the rating for the SWMF was given a rating of 0. The evaluation recognizes that the ‘proposed levels of service’ for stormwater management assets under Section 6 of O. Reg. 588/17 has not been established by the City. To that end, the assumption used in this evaluation is that the current level of service for all SWMFs is equivalent to the proposed level of service, unless otherwise discussed with the City. For example, if a SWMF is operating according to its designed performance, it is assumed to be operating at the current and proposed level of service. 2. Is a retrofit required by Federal or Provincial Agencies of the Conservation Authority? A key regulatory requirement for SWMFs in operation is the Environmental Compliance Approval (ECA) from the Ministry of Environment, Conservation and Parks (MECP), which typically include a condition for maintaining the facility in good operating condition. To that end, a cleanout and repair of a SWMF would be sufficient to satisfy ECA conditions and thus, there would be limited instances where a retrofit would be required by agencies. 3. Will a retrofit be in violation of any City policies or by-laws? With the potential expansion of a SWMF, the project will need to consider the City’s policies around land use, infrastructure placement, works within or near the natural heritage system, and parks. 5.1.3.5 Environmental Issues The environmental issues with respect to the potential retrofit of the SWMFs are scored according to the rubric in Table 5-12. The two (2) rubric questions in this category are discussed below. Table 5-12 Retrofit Questions for Environmental Issues Evaluation Criteria Scoring 0 1 2 3 What is the impact of the retrofit on ecological habitat and sensitive species? n/a or Negative No Impact Moderately Positive Significantly Positive What is the proximity of the SWMF discharge to sensitive plant and fish communities? No sensitive receivers Distant Moderate Near 1. What is the impact of the retrofit on ecological habitat and sensitive species? This question evaluates the impact of the retrofit on ecological habitat, with particular consideration for sensitive plant and fish communities, and the effectiveness of mitigation measures during the works. Examples of Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 46 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX retrofit components that could provide ecological benefit include bottom draw outlets for lower discharge temperatures to receiving watercourse, reduced sediment loadings in the discharge, and native vegetation plantings. 2. What is the proximity of the SWMF discharge to sensitive plant and fish communities? The proximity to sensitive habitat, namely Redside Dace contributing watercourses or Provincially significant wetlands, are indicative of the potential benefit of retrofitting a SWMF and are thus given higher scores. 5.1.3.6 Community Concerns The community concerns with respect to the potential retrofit of the SWMFs are scored according to the rubric in Table 5-13. The two (2) rubric questions in this category are discussed below. Table 5-13 Retrofit Questions for Community Concerns Evaluation Criteria Scoring 0 1 2 3 Are there potential community concerns? No n/a n/a Yes Are there opportunities to expand or enhance public amenities? No n/a n/a Yes 1. Are there potential community concerns regarding construction of the retrofit? Retrofit projects that are in close proximity to residential areas have the potential to concern local residents during construction, with the increase in noise, vibration, dust and traffic. 2. Are there opportunities to repair or enhance public amenities? If public amenities such as trails, look out points or park features can be improved or implemented as part of the retrofit project, a score of 3 was given. A score of 0 is given if such improvements are not applicable or feasible. 5.2 Evaluation Results The evaluation scores for the SWMF maintenance and retrofit opportunities are provided in Appendix D. The results of both evaluations were reviewed in conjunction to develop the recommended capital projects plan and maintenance plan for the SWMFs. The results indicated that there are generally two groupings of SWMFs where the first group consists of facilities that require cleanout and/or major repairs and a second group consists of ponds that are recommended for ongoing monitoring and routine maintenance instead of a cleanout. The SWMFs that require cleanout and major repairs were further separated and ranked in the recommended capital works plan and maintenance plan with specific recommendations at each facility. Further discussion for these SWMFs is provided in Sections 6 and 7. General monitoring and maintenance recommendations are provided for the remaining ponds, which were determined to be in good operating condition. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 47 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 6 CAPITAL PROJECTS PLAN The SWMF AMP has been prepared to assist with the development of the City’s capital plan. From the facility evaluation, two facilities were identified to have retrofit opportunity due to their advanced state of deterioration and/or the potentially favourable cost-benefit analysis of a retrofit. Each of the identified facilities, Lisgoold Pond and Rouge Pond, have unique factors that justify their recommendation for the capital plan, as described in the follow sections. The recommended works at each facility are intended to provide guidance on the potential improvements at each facility and have not undergone analysis or design to evaluate its feasibility. 6.1 Priority No. 1: Lisgoold Pond 6.1.1 Issues As described in Section 3, the facility inspection noted several areas of deterioration at the Lisgoold Pond (ID C2-08-GC). This included a degraded west inlet channel that receives flow from an 825 mm storm sewer. The riprap lining the channel has eroded along the entire length to the main pond basin. There was some bank erosion and a knickpoint along the channel. The hickenbottom outlet was clogged with debris that prevented the pond from draining to the outlet invert. The water level was elevated to the top of the riser pipe, where there was additional debris partially blocking the top of the riser pipe. There was a large amount of vegetation in the pond, including a fallen tree, and many trees growing on the pond slopes. Accumulated sediment was estimated to be 119 m3 by survey. The Lisgoold Pond was recommended for the capital works plan because the amount of repair is beyond a typical facility cleanout scope. There are also opportunities to implement modifications to the pond design that could provide more resilience to future deterioration and facilitate future maintenance. A review of potential facility performance improvements was also completed. The current facility was designed in the early 1990s as a water quality pond that provided extended detention of the 30 mm storm. The design volume of the 30 mm storm was 1,674 m3 with a provided volume of 2,026 m3 at a depth of 3.8 m (top elevation of 99.8 m) (Paul Wisner & Associates, 1993). The original facility design did not provide a permanent pool or quantity control beyond the 30 mm storm, however, based on the 3:1 side slopes, the narrow pond block and small pond base, there is little opportunity to excavate a larger storage volume at Lisgoold Pond. 6.1.2 Recommended Works The recommended works are related to the restoration of the existing pond design, with improvements to structures to provide greater resilience to future deterioration. There are limited opportunities to provide greater performance for treating runoff. The location of the facility adjacent to the well vegetated creek valley and the small pond block area limits the ability to expand the pond. Thus the recommended works focus on reconstructing deteriorated components of the facility, as follows: ■ Reconstruct west inlet channel with channel armouring and a plunge pool or other energy dissipater downstream of the headwall to mitigate erosion. ■ Repair south inlet spillway and consider implementing more robust energy dissipater downstream of headwall. ■ Replace outlet structure with a reversed slope outlet pipe. Excavate a deep pool at outlet area to implement the outlet, which will prevent clogging and lower the temperature of water discharge to the receiving watercourse, which is an occupied or recovery reach for Redside Dace. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 48 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX There are some challenges to consider in the design and construction of the SWMF retrofit at Lisgoold Pond: ■ The pond discharges to a tributary of Ganatsekiagon Creek, which is an occupied or recovery reach for Redside Dace. This requires construction to adhere to the in-water works timing window of July 1 to September 15. ■ The pond block is small and only has one site entrance for construction. There are limited (if any) areas for staging and the pond berms are in close proximity to residential properties. Figure 6-1 Lisgoold Pond Recommended Works 6.1.3 Cost Estimate A high-level cost estimate for the retrofit was prepared based on the recommended works described in Section 6.1.2. Without a design for the retrofit, the cost estimate provides general categories of items and assigns quantities using conservative measurements of available information (such as sediment volume and pond areas) or assumptions based on past experience with similar projects while considering the constructability challenges of the site. Unit rates are based on TMIG’s recent project experience with SWMF retrofits in Greater Toronto Area municipalities, including the City’s Abbott Crescent Pond Reconstruction project in 2018. Quantities were estimated for earthworks and landscaping. The quantity (volume) of earthworks was conservatively estimated by assuming that the entire area of works/disturbance will have an average earthworks depth of 1 m. The landscape quantity (area) was based on the estimated total area of disturbance that will require replanting. The total estimated cost of the Lisgoold Pond retrofit was $716,300, which includes a cost contingency of 30% that accounts for engineering, landscape architecture, environment consultants, permitting, and Reconstruct west inlet channel Repair south inlet spillway Replace outlet structure with reverse slope pipe CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 49 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX contract administration. This compares to the cost estimate of $313,300 for the cleanout and basic repair of the facility. The cost estimate breakdown is provided in Appendix E. 6.2 Priority No. 2: Rouge Pond 6.2.1 Issues As described in Section 3, the facility inspection noted an elevated water level at the water quality (wet cell) of the facility, likely due to a clogged hickenbottom outlet. The outlet cover was damaged and not accessible for inspection (which may have also contributed to the lack of cleaning). The elevated water level reduces the amount of active storage available at the facility. The sediment volume survey results indicated that estimated accumulated sediment was 850 m3. The high level of sediment also contributes to the reduction in active storage at the facility, since the design of the facility did not include a permanent pool. Conversely, with an informal permanent pool volume due to the clogged outlet, there is likely some suspended solids settling function at the facility in its current condition. Note that the water quantity control cell (dry cell) was found to be in good condition at the time of inspection, however, the function of the water quantity cell was not observed or monitored. Outside of the facility, the overland land flow route from the north was designed as a swale through an easement between two homes on White Pine Crescent. During recent utilities maintenance in the boulevard of White Pine Crescent where the easement is located, the curb and boulevard were reconstructed without a depression (and the addition of a transformer box), which has cut off the overland flow route to the pond from the north. There are two additional considerations from a design perspective in a potential retrofit of the Rouge Pond. First, the inlet for the wet cell discharges into the middle of the basin with the outlet located in one corner. There is a short circuiting of flows from the inlet to outlet and a ‘dead zone’ at the far eastern corner of the wet cell. Lengthening the flow path will provide additional settling effectiveness. Secondly, the facility was designed without a permanent pool in the wet basin, though the size and layout of the facility suggest it will benefit from adding deeper pockets to establish a permanent pool, similar to a wetland SWM facility. Note that the facility was designed in the early 1990s and predates more recent SWM facility design guidelines. 6.2.2 Recommended Works The recommended works include sediment removal from the wet cell. The retrofit will include the addition of modern wetland facility features: ■ The reconfiguration of the inlet pipe and headwall to be further east towards the eastern corner of the basin to increase flow path, recognizing the slope of the inlet storm sewer may limit the extension of the inlet pipe. A berm or silt curtain are also options to lengthen the flow path. ■ Construct a forebay with 1 m depth downstream of the inlet to provide pretreatment. Construct an access ramp to the forebay to facilitate regular sediment removal without disturbing the main wetland cell. ■ Replace outlet structure and excavate a deep pool immediately upstream of the outlet with a reverse sloped pipe to prevent vegetation growth and clogging of the outlet. ■ Excavate the bottom of the pond to create an average permanent pool depth of between 150 mm and 300 mm. Create low flow path and deeper wetland pockets scattered throughout the basin. An average permanent pool depth of 300 mm across the bottom of the wet basin will allow the facility to achieve about 70% TSS removal efficiency (Normal protection). This an improvement over the original design that did not have a permanent pool. ■ Plant appropriate native wetland vegetation. ■ Reconstruct the depressed curb at the north overland flow route to reinstate the drainage path. In addition, it is recommended that the function of the water quantity cell be monitored to determine if modifications or repairs are necessary or feasible during the retrofit of the facility. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 50 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX With respect to the retrofit’s constructability, it has the benefit of having a relatively large pond block area and frontage along Valley Ridge Crescent to facilitate vehicle access and staging. It also has the advantage of a separate dry cell where flows can be diverted during construction in the wet cell, thus simplifying dewatering requirements. A temporary sediment basin can be implemented within the dry basin for sediment control during construction if needed. Figure 6-2 Rouge Pond Recommended Works 6.2.3 Cost Estimate A high-level cost estimate for the retrofit was prepared based on the recommended works described in Section 6.2.2. Without a design for the retrofit, the cost estimate provides general categories of items and assigns quantities using conservative measurements of available information (such as sediment volume and pond areas) or assumptions based on past experience with similar projects while considering the constructability challenges of the site. Unit rates are based on TMIG’s recent project experience with SWMF retrofits in Greater Toronto Area municipalities, including the City’s Abbott Crescent Pond Reconstruction project in 2018. Quantities were estimated for earthworks and landscaping. The quantity (volume) of earthworks was conservatively estimated by assuming that the entire area of works/disturbance will have an average earthworks depth of 1 m. The landscape quantity (area) was based on the estimated total area of disturbance that will require replanting. The estimated cost of the Rouge Pond retrofit was $1,287,000, which includes soft cost contingency of 30% that accounts for engineering, landscape architecture, environment consultants, permitting, and contract administration. This compares to the cost estimate of $838,500 for the cleanout and basic repair of the Create low flow path and deeper wetland pockets Water quality (wet) basin Water quantity (dry) basin Construct forebay and maintenance access for cleanouts Replace hickenbottom outlet with reverse slope pipe and excavate deep pool Reconfigure inlet towards the east side of basin Reconstruct depressed curb for overland flow route CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 51 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX facility. The relatively small increase in cost from a cleanout to a retrofit is a cost-benefit advantage of selecting the Rouge Pond for retrofit. A factor that contributes to this relative small price difference is the cost of landscaping the entire bottom of the pond, which would be required regardless of a retrofit or a cleanout. The cost estimate breakdown is provided in Appendix E. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 52 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 7 MAINTENANCE PLAN The SWMF AMP maintenance plan provides a prioritized list of pond cleanout projects and recommended procedures. From the facility evaluation, ten facilities were identified to require a cleanout to maintain their design performance or mitigate risks associated with deteriorated components. Lisgoold Pond and Rouge Pond were also identified as retrofit candidates as described in Section 6, which not coincidently, are the top two ranked SWMF for the maintenance plan. Those SWMFs have been included in the maintenance plan to illustrate the relative priority for maintenance among all the facilities. The City will ultimately decide what works are to be completed at each facility. General monitoring and maintenance recommendations are provided for the dry ponds, which were determined to be in good overall operating condition and are not ranked in the maintenance plan. 7.1 SWMF Cleanout Priority Ranking The SWMF cleanout priority ranking is summarized in Table 7-1 and includes all the wet ponds evaluated in this SWMF AMP. However, based on the conditions assessment, the top eight (8) facilities in the ranking are considered the priority facilities because of observed performance or operational concerns that require a cleanout or maintenance beyond basic upkeep or monitoring. For the remaining facilities (ranked below no. 8), minor repairs and regular inspections are recommended. In general, these concerns affect the ability of the SWMFs to mitigate runoff impacts, such as decreased storage volumes leading to reduced water quantity and quality control. There are also operational and safety risks associated with deteriorated SWMF components that, if allowed to worsen, may lead to safety concerns or costly repairs in the future. Note that at the time of inspection, there were no observed concerns that required emergency action. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 53 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 7-1 SWMF Maintenance Priority Priority (Score) SWMF Name (ID) Sediment Volume (m3) Key Issues Estimated Cleanout Cost 1 (53.9) Rouge (C1-01-ER) 850 ■ Accumulated sediment volume. ■ Outlet from quality pond likely blocked resulting in elevated water level and reduced active storage. ■ TSS removal efficiency below basic level. ■ Encroachment at along east edge of pond block (landscaping and plantings by residents) $838,500 2 (48.1) Lisgoold (C2-08-GC) 119 ■ Outlet blocked resulting in high water level and reduced active storage. ■ Degraded channel downstream of west inlet (washed out riprap spillway, knickpoint, eroded side slope). $313,300 3 (45.3) Autumn (C1-03-PT) 764 ■ Accumulated sediment volume. ■ The outlet pipe is likely clogged with debris, which has caused an elevated water level and partially submerged inlet. $620,100 4 (42.5) Begley Street (R3-02-AB) 200 ■ Heavy phragmite growth and debris in pond and outlet area. ■ Overland flow route potentially drains toward townhouses rather than overland flow dispersion swale. $315,900 5 (40.3) Chickadee (C1-05-PT) 155 ■ Outlet partially blocked causing elevated water level and reduced active storage. $297,700 6 (38.6) Dixie Estates 2 (C2-02D-PC) 41 ■ Facility water level elevated and inlet pipe partially submerged. ■ Seepage through berm around inlet headwall. ■ Signs of bank erosion (undercut and slumping) in downstream watercourse. ■ Encroachment along west side of pond block (resident plantings and yard furnishings) $336,700 7 (35.3) Cognac (C2-01-DN) 441 ■ Scour pool, deteriorated riprap and exposed filter fabric at inlet. ■ TSS removal efficiency below basic level. $412,100 8 (35.3) Valley Farm (C2-06-WD) 117 ■ Heavy vegetation growth and debris in pond and outlet area. ■ Ponded water and sediment adjacent to facility. $347,100 9 (24.7) Durham Woods (R3-04-LD) 1618 ■ Access gate unlocked and obstructed by brush. ■ Drainage from adjacent vacant property to the east had caused erosion gullies $1,031,400 10 (24.2) Calvington Trail (C1-04-PT) 211 ■ Heavy phragmite growth in pond. ■ Encroachment along north edge of pond block (plantings by residents) $370,500 T11 (23.6) Bopa (C1-02-PT) 188 ■ The PVC riser may be partially clogged. $374,400 T11 (23.6) Mattamy (C3-08-UC) 1030 ■ Evidence of beaver activity within pond block. $804,700 Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 54 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 7.2 Cost Estimate High-level cost estimates for the SWMF cleanouts were prepared for the ranked facilities (Appendix E). Without a design for the cleanout, the cost estimate provides general categories of items and assigns quantities using conservative measurements of available information (such as sediment volume and pond areas) or assumptions based on past experience with similar projects while considering the constructability challenges of the site. Unit rates are based on TMIG’s recent project experience with SWMF retrofits in Greater Toronto Area municipalities, including the City’s Abbott Crescent Pond Reconstruction project in 2018. A review of SWMF cleanout guidelines and cost estimates from Greater Toronto Area municipalities was also completed. In general, the cost of SWMF cleanouts is greatly varied: ■ Pond cleaning costs are generally higher per cubic meter of sediment for smaller sediment volumes. Data collected by the City of Markham suggests that for volumes of sediment under 1,000 m3 (which was the case for most of the SWMFs surveyed), total project costs can vary between $100 per m3 to $900 per m3. The median cost is about $550 per m3, noting that these costs exclude engineering, permitting and contract administration fees. ■ The STEP Inspection and Maintenance Guide for Stormwater Management Ponds and Constructed Wetlands described total project costs for pond cleanouts range from $53 per m3 to $512 per m3 of sediment removed, from a total of 11 projects. Sediment disposal costs alone ranged from $76 to $112 per m3 from five of those projects. SWMF cleanout costs have increased in the last several years, in part, due to the timing for cleanouts. Guidance on mitigation measures from the MNRF notes that most SWMFs support amphibians and reptiles, as such, cleanouts are likely required to be completed during the active season for those species, which is generally from April 15 to September 30 (MNRF, 2016). With that, tendering for SWMF cleanout projects compete with larger scale construction projects for contractor services during the core construction season. This is in contrast to previous practice where SWMFs were commonly cleaned out during the winter, during slower construction activity at costs that were more favourable to the municipality. The cost estimate for the SWMF cleanouts included the following assumptions: ■ The unit cost of the sediment cleanout was assumed to be $300 per m3 of sediment, which is conservative due to the low total volumes of sediment at all of the City’s facilities (most SWMFs less than 1,000 m3, with many under 500 m3). ■ Unit costs for earthworks ($20 per m3), landscaping ($30 per m2), and other components such as outlet structures were estimated based on past project experience. The quantities (volume) for earthworks was based on an average 0.5 m depth of grading across the permanent pool area. The quantities for landscaping is based on an estimated disturbed area that requires replanting. ■ General construction costs (mobilization and demobilization, traffic control, erosion and sediment control, dewatering, topographic survey and other miscellaneous items) were estimated as a lump sump of $100,000 for each SWMF. ■ Soft costs and contingency (engineering, landscape architecture, environmental, permitting and contract administration) was estimated as 30% of construction cost. 7.3 SWMF Cleanout Schedule and Checklist The SWMF cleanout schedule and checklist (Table 7-2) outline the major steps required for a cleanout project and considered the requirements of the SWMFs reviewed in this AMP. Note that the STEP Inspection and Maintenance Guide for Stormwater Management Ponds and Constructed Wetlands includes more detailed guidance on specific tasks outlined on this checklist, or other items that were not anticipated to be required of the City’s SWMFs. Preparation for SWMF cleanouts should be initiated the year prior to the scheduled works, recognizing that specific construction timing windows are likely required and considering the time required for permitting. In CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 55 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX TMIG’s recommended schedule, the cleanout projects are to be initiated in August of the year prior to the cleanout and begin with retaining the engineering consultant who will prepare the design and tender package for the project. Table 7-2 SWMF Cleanout Schedule Date Task Description Lead August (of year prior to cleanout) Obtain Consultants Obtain engineering consultant (lead consultant) and subconsultants for surveying, environmental, and others as required. City of Pickering September to October (of year prior to cleanout) Site Inspection Site inspection to confirm facility condition and determine required works or repairs during sediment cleanout. Engineering Consultant Ecology and Tree Survey Complete ecology and tree surveys for all SWMFs that require environmental mitigation and tree removals. Environmental Consultant Bathymetric Survey A detailed survey is required to obtain an accurate volume of sediment that has been accumulated. Surveyor Sediment Sampling Collect sediment samples and submit for laboratory analysis. Results should be presented in a report. Environmental Consultant November (of year prior to cleanout) Sediment Disposal and Removal Method Based on the sediment quality, determine how to dispose and/ or if it can be reused. Analyze the sediment sample collected and provide a report on the results. Engineering Consultant Dewatering Plan Determine dewatering plan. Engineering Consultant Engineering Drawings Prepare engineering drawings for the cleanout, including erosion and sediment control plan. Engineering Consultant December (of year prior to cleanout) Initiate Tender Package Preparation Begin preparing tender package which includes drawings, cost and tender documents. Engineering Consultant January Authorization under Endangered Species Act If potential species at risk (SAR) are on site, the MECP should be contacted to determine the presence of these at risk species and direction on mitigation or avoidance strategies. Wet ponds that have potential SAR include: ■ Begley Street (monarch butterfly) ■ Calvington Trail (Barn Swallow, Monarch Butterfly) ■ Cognac (Butternut Tree, Monarch Butterfly) ■ Durham Woods (Barn Swallow, Monarch Butterfly) ■ Lisgoold (Redside Dace) ■ Mattamy (Redside Dace, Barn Swallow, Monarch Butterfly) ■ Rouge (Barn Swallow, Monarch Butterfly) ■ Valley Farm (Butternut Tree) Environmental Consultant DFO Screening / Fisheries Act Authorization Conduct DFO Screening by complying with the fish habitat protection provisions of the Fisheries Act and incorporating measures that will avoid the death of fish and any disruptions to their habitat due to the cleanout work. Environmental Consultant Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 56 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Date Task Description Lead January (continued) Development Interference with Wetlands and Alterations to Shorelines and Watercourse Permit or Routine Infrastructure Works Permit Required from TRCA if the SWMF is located within a Regulated Area or is an online facility. If none of these conditions apply, a permission for Routine Infrastructure Works (RIW) can be obtained, subject to qualification criteria. Consultation with the TRCA is recommended. ■ Facilities that may require a permit: Autumn Pond, Begley Street Pond, Bopa Pond, Chickadee Pond, Dixie Estates Pond 2, Lisgoold Pond, Mattamy Pond, Rouge Pond, Valley Farm Pond ■ Facilities that may qualify for permission for RIW: Calvington Trail Pond, Cognac Pond, and Durham Woods Engineering Consultant Licence to Collect Fish for Scientific Purposes Issued under O.Reg. 664/98 for the collection, handling and deposition of fish, which may be required as a result of dewatering of SWMF. Environmental Consultant Wildlife Scientific Collector’s Authorization Issued under the Fish and Wildlife Conservation Act for any collection, handling and deposition of protected wildlife species Environmental Consultant February Finalize and Release Tender Release Tender for contractors to bid on. City of Pickering March Award Tender Award a contractor with tender. City of Pickering Prior to Construction By-Law Permits Any by-law permits required (i.e. any permits required as a result of the trees being removed, dust and/ or noise being created) Engineering Consultant or Contractor Dewatering Permits Any required MECP Permit to Take Water or EASR registration for construction dewatering. Engineering Consultant or Contractor April to September Construction Complete cleanout works within the construction timing window specific to each facility, as determined through the permitting and approvals for the cleanout. City of Pickering and Engineering Consultant (Contract Administrator) 7.4 SWMF Inspections 7.4.1 SWMF Inspections and Minor Maintenance Regular inspection and corrective actions for deficiencies at the City’s SWMFs are recommended. The SWMF cleanout priority ranking recognizes that the cleanouts cannot be completed all at once, therefore, a number of facilities will not receive major maintenance work for several years. Thus it is important to complete regular inspections of the facilities and complete minor corrective actions where possible. The SWMF inspections completed for this AMP noted some relatively minor action items that could be completed by City staff without retaining a contractor, such as: ■ Unclogging of hickenbottom outlets pipes that are plugged by vegetation. This also includes removal of vegetation in the vicinity of the outlet structures. This is one of the most common observations amongst the City’s SWMFs. Completing this work will lower elevated water levels and restore active storage volumes at many of the SWMFs. ■ Repairing or replacing damaged outfall grates to maintain safety measures at the SWMF. CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 57 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX ■Repairing or replacing damaged chain link fencing around headwalls or facility perimeters to maintain safety measures at the SWMF. ■Ensure that adequate signage is present at all SWMFs. A complete list of action items for each facility is found on the SWMF inspection forms (Appendix A). The recommended minimum inspection frequency at each SWMF is once per year under dry weather conditions and a rainfall event inspection once per year. Note that the STEP Inspection and Maintenance Guide for Stormwater Management Ponds and Constructed Wetlands recommends inspections of major components four times a year, and increasing the inspection frequency would be beneficial for components that are showing signs of deterioration. The rainfall event inspection is intended to observe the SWMF function immediately after a large (>25 mm) rainfall event that cannot be inspected during dry weather conditions. This includes the operation of orifice and other flow controls, drawdown times, flow split manholes, water levels and storage volumes, spillways, among other items. Inspection forms and other records shall be retained within the City’s electronic filing system and GIS database. 7.4.2 Sediment Accumulation Assessments Sediment accumulation and removal efficiency assessments are recommended every three to five years to establish an accumulation rate for each SWMF. Once the sediment accumulation rate is known for each SWMF, sediment volumes can be estimated and the frequency of sediment surveys can be decreased, assuming that the contributing drainage areas do not change. SWMF cleanout frequency for each facility can also be established. Section 3 outlines the methods and specifications of the SWMFs designed with permanent pools and describes the calculation for sediment removal efficiency. Assessing sediment accumulation will require surveying the sediment. Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 58 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 8 SUMMARY The City of Pickering owns and operates 20 SWM facilities, of which 18 were included in this SWMF AMP. A total of 12 wet facilities six (6) dry ponds were evaluated and included in the capital works and maintenance plans to ensure an acceptable level of service is provided for the foreseeable future. The purpose of the SWMF AMP is to assess the current conditions of the City of Pickering’s SWMFs and determine a prioritized list of capital works and maintenance requirements for the short to medium term (up to 10 years). A background information review, facility inspections, sediment surveys, and conditions assessments were completed. Available data was also consolidated into a database to be incorporated to the City’s GIS database and recommendations for future data and upkeep of the information was provided. The facility conditions assessment provided data and performance analysis to evaluate the SWMFs through criteria, where the scoring was used to prioritize sediment cleanout and retrofit projects. The recommendations from the evaluation included the retrofit of two facilities (Table 8-1) and sediment cleanout at the remaining facilities, with priority for the top 8 in the ranking (Table 8-2). Table 8-1 Recommended SWMF Retrofits (Capital Works Plan) Priority SWMF Name (ID) Proposed Retrofit Works and Rationale Estimated Retrofit Cost 1 Lisgoold (C2-08-GC) ■ Reconstruct west inlet channel with channel armouring and a plunge pool or other energy dissipater downstream of the headwall to mitigate erosion. ■ Repair south inlet spillway and consider implementing more robust energy dissipater downstream of headwall. ■ Replace outlet structure with a reversed slope outlet pipe. Excavate a deep pool at outlet area to implement the outlet, to prevent clogging and lower the temperature of water discharge to the receiving watercourse, which is an occupied or recovery reach for Redside Dace. $716,300 2 Rouge (C1-01-ER) ■ The reconfiguration of the inlet pipe and headwall to be further east towards the eastern corner of the basin to increase flow path, recognizing the slope of the inlet storm sewer may limit the extension of the inlet pipe. A berm or silt curtain are also options to lengthen the flow path. ■ Construct a forebay with 1 m depth downstream of the inlet to provide pretreatment. Construct an access ramp to the forebay to facilitate regular sediment removal without disturbing the main wetland cell. ■ Replace outlet structure and excavate a deep pool immediately upstream of the outlet with a reverse sloped pipe to prevent vegetation growth and clogging of the outlet. ■ Excavate the bottom of the pond to create an average permanent pool depth of between 150 mm and 300 mm. Create low flow path and deeper wetland pockets scattered throughout the basin. An average permanent pool depth of 300 mm across the bottom of the wet basin will allow the wetland facility to achieve about 70% TSS removal efficiency (Normal protection). This an improvement over the original design that did not have a permanent pool. ■ Plant appropriate native wetland vegetation. ■ Reconstruct the depressed curb at the north overland flow route to reinstate the drainage path. $1,287,000 CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 59 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX Table 8-2 SWMF Maintenance Priority (Maintenance Plan) Priority SWMF Name (ID) Sediment Volume (m3) Key Issues Estimated Cleanout Cost 1 Rouge (C1-01-ER) 850 ■ Accumulated sediment volume. ■ Outlet from quality pond likely blocked resulting in elevated water level and reduced active storage. ■ TSS removal efficiency below basic level. ■ Encroachment at along east edge of pond block (landscaping and plantings by residents) $838,500 2 Lisgoold (C2-08-GC) 119 ■ Outlet blocked resulting in high water level and reduced active storage. ■ Degraded channel downstream of west inlet (washed out riprap spillway, knickpoint, eroded side slope). $313,300 3 Autumn (C1-03-PT) 764 ■ Accumulated sediment volume. ■ The outlet pipe is likely clogged with debris, which has caused an elevated water level and partially submerged inlet. $620,100 4 Begley Street (R3-02-AB) 200 ■ Heavy phragmite growth and debris in pond and outlet area. ■ Overland flow route potentially drains toward townhouses rather than overland flow dispersion swale. $315,900 5 Chickadee (C1-05-PT) 155 ■ Outlet partially blocked causing elevated water level and reduced active storage. $297,700 6 Dixie Estates 2 (C2-02D-PC) 41 ■ Facility water level elevated and inlet pipe partially submerged. ■ Seepage through berm around inlet headwall. ■ Signs of bank erosion (undercut and slumping) in downstream watercourse. ■ Encroachment along west side of pond block (resident plantings and yard furnishings) $336,700 7 Cognac (C2-01-DN) 441 ■ Scour pool, deteriorated riprap and exposed filter fabric at inlet. ■ TSS removal efficiency below basic level. $412,100 8 Valley Farm (C2-06-WD) 117 ■ Heavy vegetation growth and debris in pond and outlet area. ■ Ponded water and sediment adjacent to facility. $347,100 9 Durham Woods (R3-04-LD) 1618 ■ Access gate unlocked and obstructed by brush. ■ Drainage from adjacent vacant property to the east had caused erosion gullies $1,031,400 10 Calvington Trail (C1-04-PT) 211 ■ Heavy phragmite growth in pond. ■ Encroachment along north edge of pond block (plantings by residents) $370,500 T11 Bopa (C1-02-PT) 188 ■ The PVC riser may be partially clogged. $374,400 T11 Mattamy (C3-08-UC) 1030 ■ Evidence of beaver activity within pond block. $804,700 Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 CITY OF PICKERING PAGE 60 TMIG PROJECT NUMBER 19163 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX We trust that is SWMF AMP report meets the current needs of the City at this time. Please feel free to contact the undersigned should you have any questions. Sincerely, THE MUNICIPAL INFRASTRUCTURE GROUP LTD. A T.Y. LIN INTERNATIONAL COMPANY Tony Dang, P.Eng. Steve Hollingworth, P.Eng. Water Resources Engineer Director of Stormwater Management tdang@tmig.ca shollingworth@tmig.ca CITY OF PICKERING Stormwater Management Facilities Asset Management Plan FINAL REPORT • JULY 2020 TMIG PROJECT NUMBER 19163 PAGE 61 2020-07-09 - 19163 - CITY OF PICKERING SWMF AMP.DOCX 9 REFERENCES GHD (2017). ‘Stormwater Inspection and Record Management Best Practices, Data Model Design, and Comprehensive Report’. Prepared for the Lake Simcoe Region Conservation Authority. February 2017. Ontario Ministry of the Environment, Conservation and Parks (MECP) (2019). ‘Rules for Soil Management and Excess Soil Quality Standards’. Queen’s Printer for Ontario. Ontario Ministry of the Environment (MOE) (2003). ‘Stormwater Management Planning and Design Manual.’ Queen’s Printer for Ontario. Ontario Ministry of Natural Resources and Forestry (MNRF) (2016). ‘Stormwater Management Pond Clean- out Best Management Practices.’ Paul Wisner & Associates. (1993). ‘Addendum to the Storm Water Management Strategy Report for the Lisgoold Residential Development.’ Letter Report to Ministry of Natural Resources. March 23, 1993. Toronto and Region Conservation (TRCA) and CH2M Hill Canada Ltd. (CH2M) (2016). ‘Inspection and Maintenance Guide for Stormwater Management Ponds and Constructed Wetlands.’ 2016 (revised April 2018). / Ta u nton Road 0 0 = � 0 L ____ ___::[?:__ ___ ---1f------,---T_h_i 7 r d_C_o_n_c_e_s_s_io_n_R_o_a_d __ 1 IIL-------,-�T�h�i r�d�C�o�n c'.:e::s�s�io�n'..'....'.:R�o�a�d'.......,'----------, ;- ""' M Q) C: Q) :E II) 0 (J � Twyn Riv, rs Drive 0 1 ½ • ;1 • � \f • • Fi I I J • Shepp r d Aven u e "C lt1 &. .ll: C: lt1 .c Q) II) &. Granite court / Toy�ale R oad � D ... C: :::l 0 E Q) Cl :::l (;) 0 • t:: 0 e­"iij u. "E f----�,-� _._______,­ :::l f--�-,----L�c:)-ID ...._-+-----+---+--+-+--+�-0 ..c: II) ... rn- � I--�--� Frenchman's Bay Lake Ontario -c­it! &. e[ .. Q) > ::i JJ e-1----� 0 c.�-� .. � ::i Thi r d Con c ession Road • • "C lt1 ,------'----, &. �+-___[�,---�e-ltl u. >, .!!! • �� "C lt1 L------,&_-,-� .ll: • (.) e ID >< ro -�<( ..... 0 C 5 � • 0 �ayly Str eet = Clem ents R oad M ontgo m e ry Pa rk Ro d "C lt1 &. ..c: (.) lt1 Q) ID 0 Kelli no Str eet 0 I) • II) ... � ... II) ..c: � :::l ..c: (.J B , ly Str eet W >< ro -�<( ..... 0 C 5 � C) -�6/­P1CKER1NG ENGINEERING SERVICES DEPARTMENT a Legend e SWM Facility 1 :15,000 Attachment #2 to Report #ENG 11-20