Public Information Centre #1. View displays and discuss the study with project staff. Feel free to ask questions and fill out a comment sheet

Transcription

1 Welcome Combined Sewer Overflows Control in the Humber River and Black Creek Sewersheds and Investigation of Flooding in Study Area 6 Class Environmental Assessment Public Information Centre #1 View displays and discuss the study with project staff Feel free to ask questions and fill out a comment sheet 1

2 Purpose of Tonight s Meeting To introduce the problems and study approach To outline potential factors contributing to basement and surface flooding and combined sewer overflows (CSOs) Present possible alternative solutions and criteria for evaluating the alternatives Outline the next steps in the study process Hear from you! Your input is very important 2

3 Purpose of Our Study Identify the causes of basement and/or street flooding (severe ponding on streets during extreme storms) in Basement Flooding Area 6 and make recommendations to reduce the risk of future flooding. Examine CSOs into the Humber River and Black Creek in the Study Area and make recommendations to achieve CSO control as per the City s Wet Weather Flow Management Plan. 3

4 The Study Area is bounded by Highway 401, Highway 400, Humber River and Eglinton Avenue. The Study Area is based on the tributary drainage areas for sanitary and storm sewer systems. The Study Area is serviced by a combination of storm, sanitary and combined sewer systems. Study Area 4

5 Municipal Class Environmental Assessment Process The City must meet the requirements of Ontario s Environmental Assessment (EA) Act for infrastructure projects The EA Act requires the protection, conservation and wise management of the environment while undergoing infrastructure enhancements. The EA process is an opportunity for the public and agencies to provide input. Consultation is facilitated via two Public Information Centres (PIC) We are here PHASE 1 PHASE 2 PHASE 3 PHASE 4 PHASE 5 Problem Or Opportunity Alternative Solutions Incorporate Comments Environmental Study Report Implementation PIC #1 & PIC #2 PIC #3 (TBD) 5

6 Study Approach : The Steps Involved Many steps are involved in the study before solutions can be recommended. This work includes: Collect and review background data on land use, population, soil conditions, sanitary and combined sewer and storm drainage systems, flooding history, and operation/maintenance records; Conduct field surveys to inventory the number of roof leaders disconnected, survey catchbasins, identify low lying areas, and inventory storm and CSO outfalls; Identify preliminary potential causes of basement and surface flooding based on background data review and results of field survey. Develop and receive feedback on alternatives to address the issue of flooding in Basement Flooding Area 6, and address CSO overflows (1 st Public Information Centre) We Are Here Develop computer models to: Analyze the causes of flooding and to predict flows under various weather conditions, and; Assess the quantity of CSOs entering receiving watercourses; Undertake assessment and refinement of alternatives; and, Present preliminary preferred alternatives at 2 nd Public Information Centre. Present recommended design at 3 rd Public Information Centre (TBD, based on project schedule) Finalize the study recommendations based on input from the public and review agencies. 6

7 Combined Sewer Overflows: The Problem A Combined Sewer Overflow (CSO) is a discharge to the environment from a combined sewer system that usually occurs as a result of a precipitation event, when the capacity of the system is exceeded. CSOs contain a mixture of sanitary wastewater (untreated sewage) and stormwater runoff and contains pathogens, suspended solids, nutrients, oil and grease, and other contaminants. CSOs degrade water quality in the receiving water body and can have adverse effects on aquatic life and habitat, recreational uses, and aesthetics. The City is required to meet Ministry of the Environment requirements for CSO control (F-5-5). 7

8 Our Combined Sewer Overflow Findings The Study Area is serviced by a combination of sanitary, combined and storm sewers. There are a number of CSO chamber/ structure locations where sanitary and storm sewers can discharge into the combined sewer system. There are 5 CSO outfalls that allow CSOs to enter the Humber River within the Study Area. Three of these outfalls are located in Basement Flooding Area 6. 8

9 Our Basement Flooding Findings Under normal rainfall events, the storm, sanitary and combined sewer systems operate as designed. However, during extreme storms, the following takes place: Stormwater flow exceeds the storm sewer capacity and overloads the system; Directly connected roof drains, especially flat roofs, contribute significant volumes to the sewer system; Water remains on the surface and flows overland along roads; At low lying areas, water accumulates (ponds) and enters the sanitary sewer system through manhole covers. This causes the sanitary sewers to surcharge and potentially back-up into the basement. 9

10 Our Basement Flooding Findings During these heavy rainfalls, the ground becomes extremely wet and water enters the sanitary system through cracks or broken pipes, cracked maintenance hole walls and loose joints underground. This contributes to backup of the sanitary sewers. Other factors causing sanitary sewer back-up include: Water entering the basement from the surface via window sills and reverse-slope driveways etc. and then through basement floor drains (connected to sanitary); and Downspouts connected to the sanitary system through weeping tiles. 10

11 Typical Causes of Basement Flooding 11

12 Typical Causes of Basement Flooding Note: typical connections shown, however private drainage systems can be more complex and each one is unique. 12

13 Methods for Reducing Flooding and/or Providing CSO Control Source Controls Source control measures involve managing stormwater where it originates (roofs, roads, driveways), before it enters the City s sewer systems. These measures include: Downspout disconnection Rain barrels Surface flow diversion Sewer rehabilitation Backwater valves, foundation drain disconnection Sanitary manhole sealing Pervious pavements Conveyance Controls Conveyance control measures help to control stormwater as it travels along the drainage system (in pipes or along the road). These measures include: Alternate road cross-sections (grassed ditches / swales) Catchbasin inlet controls Bioretention filters and bioswales Sewer pipe diversion, replacement or twinning Sewer separation in combined sewer areas Overland flow control Increase number of catchbasins Parking lot retrofits End-of-Pipe Controls End-of-pipe control measures control stormwater and CSOs just before it is discharged to a watercourse (stream, river, or lake). These measures include: Surface dry ponds Surface wet ponds or constructed wetlands Underground storage tanks or shafts High-Rate treatment facilities 13

14 Potential Solutions Source Control OPTIONS BEING CONSIDERED IN THE STUDY AREA INCLUDE: SOURCE CONTROLS Sealing Maintenance Downspout Surface Flow Path Pervious Pavement Hole Covers Disconnection Diversion (Controls Flooding & CSOs) (Controls Flooding & CSOs) (Controls Flooding & CSOs) (Controls Flooding & CSOs) Rain Barrels (Controls Flooding & CSOs) 14

15 Potential Solutions Conveyance Controls OPTIONS BEING CONSIDERED IN THE STUDY AREA INCLUDE: Local Bioretention Filters (Reduces CSOs in combined areas) Alternate Road Cross-Sections (Ditches) (Reduces CSOs in combined areas) A vegetated depression and underground trench designed to filter stormwater runoff to remove pollutants and promote infiltration/evapotranspiration Diversion of small overland or piped drainage areas for small storm events Excavation of a trench with specific soil mixture and surface plantings and underdrain within an open area such as a boulevard or park In place of concrete curb and gutter, replace with grassed ditches and a series of culverts which slows surface water down and encourages infiltration/filtration Removal of curb and gutter (if existing) and reconstruction of roadway and boulevard Installation of shallow culvert pipes 15

16 Potential Solutions Conveyance Controls OPTIONS BEING CONSIDERED IN THE STUDY AREA INCLUDE Catchbasin Inlet Controls (Controls Flooding) Public Parking Lot Retrofit for Surface Storage (Controls Flooding) Installation of inlet control devices (ICDs) on catchbasins to limit release into the storm and combined sewer system to control back-up (surcharge) A plastic or metal plate / device installed inside the catchbasin outlet (not visible from surface) Minimal effort and time to install Keeps more water on the surface Installation of ICDs in public parking lots to store stormwater on surface Installation of public roof drain controls to store stormwater on large flat roof areas Retrofit of City-Owned property (where physically possible) 16

17 Potential Solutions Conveyance Controls OPTIONS BEING CONSIDERED IN THE STUDY AREA INCLUDE: Replacement of Existing Storm and/or Sanitary Sewers (Controls Flooding) Increase the size of the sewer pipe by replacing the old sewer with a larger pipe Road excavation within City limits Removal of old sewer and structures (manholes & catchbasins) and disconnection of sewer service line(s) Placement of new sewer, reconnection of sewer service line(s) and restoration of road and boulevard Adding New Sewers (Twinning) (Controls Flooding) Increase the capacity of the sewer system by adding another sewer pipe in addition to the existing pipe Road excavation within City limits Replacement of old structures (manholes & catchbasins) and reconnection of sewer service line(s) if necessary Placement of new sewer, reconnection of sewer service line(s) and restoration of road and boulevard 17

18 Potential Solutions Conveyance Controls OPTIONS BEING CONSIDERED IN THE STUDY AREA INCLUDE: Overland (Major System) Control (Controls Flooding) The diversion of surface drainage away from low lying areas that have no direct outlet, to reduce surface ponding depths Addition of speed bump or curb cut to redirect overland flow to strategic locations Interception of road or boulevard flows with large inlet grate or curb drain to dedicated major system sewer Increase Number of Catchbasins (Controls Flooding) Where the storm sewer has existing capacity, add more catchbasins to capture more flow from the surface Minor street excavation for installation of new catchbasin(s) and connection to storm sewer Curb replacement and road restoration 18

19 Potential Solutions Conveyance Controls OPTIONS BEING CONSIDERED IN THE STUDY AREA INCLUDE: Sewer Separation in Combined Sewer Areas (Controls Flooding & CSOs) Redirect wastewater to a sanitary sewer and storm water to a storm sewer Road excavation within City limits Removal of old sewer and structures (manholes & catchbasins) and disconnection of sewer service line(s) Placement of a new storm sewer or a new sanitary sewer, reconnection of all sewer services and restoration of road and boulevard 19

20 Potential Solutions End-of-Pipe Controls OPTIONS BEING CONSIDERED IN THE STUDY AREA INCLUDE: Dry Pond (Controls Flooding) Wet Wet Pond/Wetland (Controls Flooding) An engineered surface depression that controls the quantity (and possibly quality) of inflowing stormwater through storage and slow release to the receiving system Typically fills with water during extreme storm events and drains within 24 to 48 hours or less Excavation and shaping of a suitable open space Addition of inlet/outlet structures Restoration and landscaping An engineered pond or wetland with a permanent water surface that controls the quantity and quality of inflowing stormwater through storage and slow release to the receiving system Excavation and shaping of a suitable open space Addition of inlet/outlet structures Restoration and landscaping (aquatic and side-slope) Infrequent maintenance (sediment removal) 20

21 Potential Solutions End-of-Pipe Controls OPTIONS BEING CONSIDERED IN THE STUDY AREA INCLUDE: Underground Storage Tank (Controls Flooding & CSOs) An underground tank or pipe that controls the rate of inflowing combined, sanitary or stormwater through temporary detention and slow release to the receiving sewer, reducing the potential for flooding or a CSO overflow Excavation and construction of tank or pipe, including inlet and outlet structures Infrequent maintenance (monitoring, clean-out) High Rate Treatment (Controls CSOs) A treatment unit that provides equivalent to primary to treatment to CSO discharges Excavation and construction of a new treatment unit Ongoing operations and maintenance of the treatment unit 21

22 Evaluation of Solutions The following criteria are suggested for evaluating each of the options and identifying the recommended solutions: Natural Environment Potential Impact on Terrestrial Systems (Vegetation, Trees, Wildlife) Potential Impact on Aquatic Systems (Aquatic Life and Vegetation, Surface Water, Groundwater) Soil and Geology Socio-Cultural Effect on Urban Greenspace (Parks, Ravines, Open Spaces) Disruption to Existing Community During Construction (Traffic, Noise) Disruption to Existing Community Post Construction (Visual Impact, Odour, Safety) Archaeology and First Nations Technical Feasibility of Control Measure (Available Space, Accessibility, Constructability) Effectiveness in controlling CSOs Effectiveness in controlling basement and/or surface flooding Impact on Upstream and Downstream Infrastructure Operations & Maintenance Requirements Economic Capital Costs Operating & maintenance costs Economic 22

23 Thank You for Attending We welcome your feedback. Please fill out the comment sheet provided. Following this PIC, the study team will review and consider your comments in the evaluation of alternative solutions. The next PIC is expected to be held in Fall 2013 to present the recommended solutions. Contact Information For more information on this study, to provide your comments or to be placed on the project mailing list, please contact: Josie Franch, Public Consultation Unit 55 John Street, Metro Hall, 19th Floor Toronto, ON M5V 3C6 Phone: , Website: 23

24 Basement Flooding Area 6 ACADEMY ROAD WALWYN AVENUE ETTRICK CRES CENT HIGHWAY 400 DEERHURST AVENUE DALBEATTIE AVENUE GARY DRIVE UPHILL AVENUE M APLE LEAF DRIVE LANGSIDE AVENUE WENDELL AVENUE QUEENSLEA AVENUE PORTAGE AVENUE RANWOOD DRIVE LAMONT AVENUE WOODWARD AVENUE CHURCH STREET KING STREET PURDY CRESCENT ROBERT STREET STREET CYPRESS QUEENS DRIVE JOHN STREET JOSEPH STREET Elm Trunk Sewer GRATTAN STREET ELM STREET WILLIAM STREET PATIKA AVENUE MACDONALD AVENUE MARSHLYNN AVENUE PINE STREET MERRILL AVENUE HEARNE AVENUE VIMY AVENUE ROSEMOUNT AVENUE SPRINGMOUNT AVENUE WALSH DIXON ROAD AVENUE TOR B ARR IE ROAD CLAYSON ROAD WENDELL AVENUE HIGHWAY GARY DRIVE ROSEMOUNT AVENUE HI G H WAY COLLECTOR 400 HIGHWAY 401 CHURCH STREET 6 WESTON ROAD WILSON AVENUE JANE STREET FALSTAFF AVENUE LAWRENCE AVENUE WEST MAPLE LEAF DRIVE RUSTIC ROAD CULFORD ROAD KEELE STREET JOHN STREET SOUTH STATION STREET WESTON ROAD RALPH STREET BOYD AVENUE LAWRENCE AVENUE WEST PINE STREET GIBSON AVENUE ELLIS AVENUE SPEERS AVENUE WRIGHT AVENUE JANE STREET ROMANWAY CRESCENT T R E T H E W E Y DRIVE THE ISLINGTON AVENUE WESTWAY LA ROSE AVENUE SCARLETT ROAD Humber River Basement Flooding Areas Key Map EMMETT AVENUE EAST DRIVE EGLINTON AVENUE WEST BLACK CREEK DRIVE LAMBTON AVENUE ROCKCLIFFE BOULEVARD Black Creek BELLEVUE CRESCENT H I C KORYTREE ROAD RICHWOOD STREET SAM FRUSTAGLIO DRIVE MARGARET ROSECOURT PLAINFIELD ROAD JOHN BEST AVENUE Potential Remedial Measures Source Controls Roof downspout disconnection where feasible City s Basement Flooding Protection Subsidy Program (backwater valves, disconnected foundation drains with sump pump discharge to surface) Rain barrels Surface flow path diversion away from low areas Sewer maintenance and rehabilitation Seal sanitary manhole covers in low lying/ponding areas Pervious pavement Conveyance Controls Sewer pipe diversion, replacement or twinning Overland control Increase the number of catchbasins Catchbasin inlet controls in select areas Public parking lot retrofit for surface storage Sewer separation in combined sewer areas End-of-Pipe Controls Surface dry ponds Surface wet ponds or constructed wetlands Underground storage tanks or shafts Legend Humber River μ Basement Flooding Areas Watercourses Combined Sewers Sanitary Sewers Storm Sewers Combined Trunk Sewer Sanitary Trunk Sewer Forcemains! C Outfall Reverse Sloped Driveways Roof Downspout Connection Connected to Sewer WILBY CRESCENT VICTORIA AVENUE WEST SYKES AVENUE DENISON ROAD WEST CLOUSTON AVENUE CENTRE ROA D VICTORIA AVENUE EAST LIPPINCOTT STREET WEST ARTHUR STREET MONKLANDS AVENUE EDMUND AVENUE MOUNT DENNIS DRIVE LIPPINCOTT STREET EAST PIONEER AVENUE SIDNEY BELSEY CRESCENT DENISON ROAD EAST Partially Connected to Sewer Meters November 2012

25 Study Area - CSOs KEELE STREET CLAYSON ROAD μ WALSH AVEN UE BEV WILSON AVENUE ERLY HILLS DRIVE HI GHWAY 401 HIGHWAY 401 COLLECTO R FALSTAFF AVENUE Definition CSO - Combined Sewer Overflow WENDELL AVENUE HIGHWAY 400 Combined sewers collect and convey both sanitary and storm flow. GARY DRIVE MAPLE LEAF DRIVE OAK STREET LAWRENCE AVENUE WEST JANE STREET DIXON ROAD ST PHILLIPS R OAD ROYAL YORK ROAD Humber River ROSEMOUNT AVENUE!C!C Elm Trunk Sewer!C!C PINE STREET 6 BLACK CREEK DRIVE BROOKHAVEN DRIVE Black Creek T R E T H EWEY DRIVE!C THE WESTWAY Humber River Trunk Sewer WESTON ROAD E MMET T AVENUE RAY AVENUE INDUS T RY STREET Potential Remedial Measures Source Controls Roof downspout disconnection where feasible Rain barrels Surface flow path diversion away from low areas Sewer maintenance and rehabilitation Seal sanitary manhole covers in low lying/ponding areas Pervious pavement Conveyance Controls Alternate road cross-section (grassed ditches/swales) Bioretention filters and bioswales Sewer separation in combined sewer areas End-of-Pipe Controls Underground storage tanks or shafts High rate treatment facilities Le ge nd!c!p CSO Outfalls CSO Chamber/Structure "P Pumping Station!C Storm Outfalls EA Study Areas Basement Flooding Areas Watercourses Combined Sewers Sanitary Sewers Storm Sewers Combined Trunk Sewer Sanitary Trunk Sewer Forcemains EGLINTON AVENU E W EST EAST DRIVE LAMBTON AVENUE Rockcliffe Trunk Sewer Mt. Dennis Trunk Sewer ALLIANCE AVENUE Black Creek Trunk Sewer ,000 Meters November 2012