HERE COMES THE RAIN AGAIN Stormwater Management in a Changing Climate at the City of Toronto

Transcription

1 HERE COMES THE RAIN AGAIN Stormwater Management in a Changing Climate at the City of Toronto Evergreen s Urban Watershed Forum 20 March 2015 Presented by Kurtis Elton Policy & Program Advisor, Toronto Water 1

2 Toronto Water Overview Serves 3.4 million residents and businesses in Toronto, York and Peel City of Toronto: 641 km 2 More than $28.2 billion in infrastructure assets Over 10,800 km of storm, sanitary, and combined sewers We are 100% rate-supported: no reliance on the property tax base 2

3 A Little History 3

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6 Frequency of phrase Frequency of the Phrase stormwater management 6

7 Frequency of phrase Frequency of the Phrase climate change 7

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9 Canadian and U.S. Areas of Concern in the Great Lakes Basin Area of Concern,

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11 Impacts on the Hydrological Cycle 11

12 Sewer System Basics Sanitary sewers Convey wastewater (sewage) to wastewater treatment plants Storm sewers Convey stormwater (e.g., rain, melted snow) to natural watercourses, the lake or to stormwater treatment plants 12

13 Sewer System Basics (cont d) Combined sewers Convey both wastewater and stormwater in the same system to wastewater treatment plants 13

14 Stormwater Exceeds Provincial Water Quality Objectives 14

15 Water Quantity and Erosion Issues Pipes are sized to accommodate peak flow When flow is greater than the design for that system, flooding can occur Erosion occurs mostly as a result of annual flows Photo by 416style, CC BY

16 Wet Weather Flow Master Plan 16

17 Wet Weather Flow Master Plan Goal: reduce and ultimately eliminate the adverse impacts of wet weather flow to protect our environment and improve the ecosystem health of our watersheds Approved by Toronto City Council in year, $1B (2003$) plan 17

18 WWFMP Vision Wet Weather Flow will be managed on a watershed basis in a manner that recognizes rainwater and snowmelt as a resource to be utilized to improve the health of Toronto s watercourses and the near shore zones of Lake Ontario and enhance the natural environment of Toronto s watersheds. 18

19 WWFMP Principles Recognize rainwater and snowmelt as a valuable resource. Manage wet weather flow on a watershed basis using an ecosystem approach. Implement a hierarchy of WWF practices: At-source Conveyance End-of-pipe Inform and educate Toronto s communities about WWF issues and involve the public in developing solutions. 19

20 WWFMP Principles (cont d) 20

21 WWFMP Objectives Water quality Meet or exceed federal, provincial and municipal quality objectives Eliminate toxic substances Improve water quality for body-contact recreation Improve aesthetics Water quantity Preserve and re-establish the natural hydrologic cycle Reduce erosion impacts Eliminate or minimize flooding threats 21

22 Objectives (cont d) Natural areas & wildlife Protect, enhance and restore natural features and functions Achieve healthy aquatic communities Reduce fish contamination Drainage systems Eliminate discharges of sanitary sewage Reduce infiltration and inflow into sanitary sewers Reduce basement flooding 22

23 Source Controls Mandatory Downspout Disconnection Program Low Impact Development Photo by Gabriel Li // StudioGabe, CC BY-NC-ND

24 WWFM Guidelines Practical aid for the preparation, review and approval of Storm Water Management Plans Sets performance objectives for site level SWM consistent with WWFM Policy 24

25 Toronto Green Standard (TGS) The Toronto Green Standard (TGS) is a two-tier set of performance measures with supporting guidelines related to sustainable site and building design for new private and public development The TGS was derived from: Existing Guidelines (e.g., WWFM Guidelines) Targets from existing programs (e.g., Better Buildings) Third party standards (e.g., LEED) 25

26 Conveyance Controls Infiltration/ exfiltration systems Roadside swales 26

27 Green Streets Good for quality, aesthetics and cobenefits Less effective for quantity Some spatial and technical challenges 27

28 Green Streets (cont d) Committed to advancing green infrastructure projects Pilot projects ongoing Working with Planning and Transportation to develop green streets guidelines 28

29 End-of-Pipe Controls Earl Bales Stormwater Management Pond 3.2 hectare pond manages stormwater runoff from a 550 ha residential and industrial area Treated stormwater to be used for snow-making for nearby ski hill in winter and to water golf course in summer Awarded 2012 Living City Award for Healthy Rivers and Shorelines Earl Bales Ski Hill Don Valley Golf Club Earl Bales SWM Pond 29 29

30 Don River & Central Waterfront Project Lower Don River - Inner Harbour - Taylor Massey Creek 30

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32 Stream Restoration Natural channel design projects: Improved channel hydraulics, water quality, aquatic and riparian habitat Amenity to local community Humber Creek before restoration Humber Creek after restoration 32

33 Municipal Operations & Practices Outfall monitoring Street sweeping Catchbasin cleaning 33

34 Public Education 34

35 Meanwhile Photo by the Hindrew on Flickr, CC BY-NC-SA

36 Catastrophic Failure: Finch Avenue West at Black Creek August 19,

37 Exposed Trunk Sanitary Sewer

38 4,200+ flooding complaints $600 million+ in damages Photos captured by a City Councillor in her own home! 38

39 Causes of Basement Flooding Sewer systems perform as designed Normal storm conditions During extreme storms: Sanitary sewer system is overloaded Widespread surface flooding, including private property 39

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42 August 19 3:00 pm

43 August 19 3:30 pm

44 August 19 4:10 pm

45 August 19 4:30 pm

46 August 19 4:50 pm

47 August 19 5:10 pm

48 August 19 5:30 pm

49 August 19 5:50 pm

50 August 19 6:10 pm

51 August 19 6:30 pm

52 August 19 7:30 pm

53 Basement Flooding Protection Program Approved by City Council in 2006 Design standards approved: Upgrade sanitary sewer design standard Upgrade storm drainage systems to the New Development standard: 100-year storm Includes committed funding for capacity assessments and construction projects Started with 34 priority study areas 53

54 Infrastructure Upgrades 54

55 Old Sheppard Park Stormwater Tank Located in north Toronto 12,000 m 3 underground stormwater storage tank Completed in 2012 Courtesy: Google Maps 55

56 July 8, 2013 Photo by Anz-I on Flickr, CC BY-NC-ND

57 4,700+ reported basement floodings $850 million+ in insurance claims 450+ watercourse erosion sites 300,000+ properties without power 57

58 What did we learn? Toronto s Basement Flooding Protection Program did not include many of the areas most impacted on July 8, 2013 A fair and equitable solution is needed for the whole City no more storm chasing Public expectations are growing, so solutions need to be delivered faster Photo by Bunton & Peel on Flickr, CC BY-NC-SA

59 Program is City Wide 41 study areas (yellow and blue) cover approximately 39% of the City 26 new studies (pink and green) will cover the rest of the City, to be completed over 12 years 59

60 Acceleration of Capital Works Budget for BFPP in 2010 was ~$20M Budget for BFPP in 2015 is $57M The year Capital Plan for Toronto Water includes an added $548M for Basement Flooding Total of $1.5B over ten years All of this while other WWFMP and SOGR projects continue! 60

61 Supporting Initiatives Basement Flooding Protection Subsidy Program Up to $3,400 per property to install flood protection devices Mandatory Downspout Disconnection Program City-Wide Zoning By-law changes No reverse-slope driveways Maximum lot coverage areas 61

62 More Education and Outreach 62

63 Final Thoughts Scale and complexity are huge Quality and quantity control Shared responsibility Continue adaptive management 63

64 Bold Question What does it mean to build a resilient city, and how can we work together to build it? 64

65 THANK YOU. ANY QUESTIONS? Evergreen s Urban Watershed Forum 20 March 2015 Kurtis Elton Policy & Program Advisor, Toronto Water kelton@toronto.ca (416)