Stormwater Management in Oakville Dodging the Extreme Rainfall Bullet PEO Oakville Chapter March 24, 2016

Transcription

1 Stormwater Management in Oakville Dodging the Extreme Rainfall Bullet PEO Oakville Chapter March 24, 2016

2 Presentation Outline Council s Role and Policy Context Mitigation Efforts and Actions Adaptation Efforts prior to Strategy Climate Change Strategy Development Climate Change Strategy Implementation Stormwater Management Public/private Responsibilities Evolution of Stormwater Management Current Issues and Gaps Stormwater Master Planning Public Outreach A storm is coming

3 Mayor and Council s Role Council s Strategic Goals Member Associations

4 Policy Context Policy Context

5 Policy Context Policy Context Mitigation refers to the promotion of policy, regulatory and project-based measures that contribute to the stabilization or reduction of greenhouse gas concentrations in the atmosphere. Renewable energy programs, energy efficiency frameworks and the substitution of fossil fuels are examples of climate change mitigation measures.

6 Policy Context Adaptation includes any initiatives or actions in response to actual or projected climate change impacts that reduce the effects of climate change on built, natural and social systems. Preparing for climate change adaptation does not negate the need to support and implement mitigation measures, it is just another method of dealing with the climatic change impacts. A formal approach to adaptation was needed.

7 Approach Approach Building Adaptive and Resilient Communities

8 Needed to move from a Reactive to Proactive appraoch. WHY Local Extreme Weather Events

9 Symbol Climatic Change Temperature Observed Degree of Change Canada has seen an increase in annual temperature of 1.3ºC between 1976 and Projected WHY Local Climate Data Oakville can expect to see a further increase of 2.6ºC by Precipitation A 12% increase occurred in the last 50 years. A further increase of 5.1% is projected by High Wind Precipitation, Thunder and Lightning Winter Temperature and Air Quality An average 12 tornadoes are reported to Environment Canada each year in Ontario and 62 nationally. Recent numbers have increased: 23 in 2006, 29 in 2009 and 22 in Tropical Storms: once every 11 years four have occurred from 2003 to Thunderstorms: 30 or more occurred each year from 1971 to The average annual snowfall for the Toronto area is 122cm, distributed over 40.9 days. 16 extreme heat days were experienced from 1971 to Oakville experienced 30 extreme heat days in 2006 alone. Experts project that rising air and water temperatures will contribute more tornado activity. Warmer temperatures and a rise in atmospheric water vapour will cause an increase in thunderstorm activity. The occurrence of freezing rain is expected to increase in the order of 10 to20% on average northern Ontario to expect more than southern Ontario. These numbers could more than triple by 2080.

10 Strategy Development Overview: 23 staff members 15+ departments 80+ plans reviewed 39 impacts / vulnerabilities: 11 high - medium 28 medium - low 300+ actions identified Objectives: 1: Increase town s capacity to protect against and respond to projected climate change impacts. 2: Educate through effective and efficient means of communication. 3: Monitor implementation of adaptation actions and goals to make continuous operational improvements.

11 Impacts on Service Areas

12 Annual Reporting to Council Implementation Staff Education Municipal Risk - Laura Zizzo, Legal issues presentation to Senior management Science - Numerous conferences and webinars Preparedness - seasonal staff training extreme weather, WNV, Lyme Disease, biodiversity, milkweed, spills containment Policy Impact specific teams formed Storm Water Master Plan Phase 2 Energy Conservation and Demand Management Emergency Management Communications Building Code Team Official Plan Review Provided input on existing and proposed climate change legislation

13 Challenges Next Steps and Challenges Keeping the momentum - Continued implementation of strategies objectives, adaptation actions and next steps. Assigning specific timelines for all actions. Next Steps Continue to provide input into the development of federal and provincial climate change strategies. Acquiring and updating climate change data as it relates to specific service areas. Updated Climate Change Strategy for September 2017.

14 Stormwater Management in Oakville

15 Public/Private Responsibilities Item / Asset Lead Recent Initiatives / Practices Sanitary sewer system Town creeks (Bronte, Joshua, etc.) Public storm sewer system (Minor system) Public overland flow routes (Major system) Privately owned storm sewers / channels Lot grading Region of Halton Floodlines regulated by Conservation Halton & Credit Valley Conservation Town undertakes flood control works Town Town roads & easments Region of Halton Region roads Town Town roads & easements Region of Halton region roads Private property owner Private property owner Everything is connected to everything else A Guide to Flooding Prevention & Recovery Town-wide flood study (2008) & follow up studies Stormwater Master Plan Stormwater Master Plan Since 2012, private property owners required to retain qualified professional to certify lot grading/drainage associated with all site alteration permits.

16 Sanitary Sewer System Region

17 Town Creeks Town-wide Flood Study (2008) Core Area Master Plan

18 Flood Mitigation Opportunities Looking at areas of greatest risk for riverine flooding from Town Wide Flood Study Challenge to balance hazard management with ecologically sensitive areas including red side dace habitat Sometimes there are NO EASY FIXES that offer any benefit to reduce flooding Mitigation options that offer reduced flood risk to properties are sometimes CHALLENGING: Approvals require significant technical study and may not be supported by various agencies Land requirements may be necessary Improvements may be major costly undertakings Improvements may rely on participation of other key landowners such at MTO or CNR/Metrolinx

19 Public Storm Sewer System & Overland Flow Routes Major system (street) - Older areas no formal design - Newer areas 100 year design Minor system Generally 2-5 year design in residential areas (both old and new)

20 Evolution of Stormwater Management Progression of standards over decades of development Minimal standards prior to Hurricane Hazel (1954) No ditches No (designed) major system Ditches No (designed) major system Minor (storm) system No (designed) major system 50 year design standard on smaller creek systems (1960s+, Wedgewood Creek, Morrison Creek, etc.) 1981 guidelines on lot grading and drainage control (MEA/Consulting Engineers Ontario) 1982 Oakville Storm Drainage Policies and Criteria Manual

21 Evolution of Stormwater Management 1994 MOE Stormwater Management Practices Planning and Design Manual (updated 2003) Current standard: 5 year minor (pipe) system Major system (streets) designed to convey 100 year event Stormwater management ponds designed for peak flow, water quality and erosion control All (new) riverine systems designed to convey the greater of the Regional Event (Hurricane Hazel) or the 100 year event Consideration of climate change

22 Changes to Surface Runoff Surface runoff increases with urban development due to more hard surfaces (e.g. roofs, roads) and more compacted soils.

23 47% Impervious 22% Imp. Original 67% Imp. Rebuild 64% Impervious m (75.0 ft) 27.9 m (91.5 ft) 12.4 m (40.7 ft) m (75.0 ft) South Oakville North Oakville

24 Design Storms & Recent Events Design storm (years) 1 hour volume (mm) 24 hour volume (mm) Minor/ major systems active? Minor All Minor (ponding) Both Most Both Most Development safe? Both Post Development Hurricane Hazel 212 mm In 12 hours Toronto (2013) 140 mm In 3 hours 4700 homes Burlington (2014) 191 mm In 8 hours 3100 homes Peterborough (2004) 240 mm In 11 hours 2000 properties All

25 Oakville Stormwater Management Legend Dry Ponds Flow Control Chamber Wet Ponds Future Ponds Master Plan Focus Area No formal major system design

26 Typical (good) conditions south of QEW Well defined lot grading and ditch system Low point at creek

27 Typical conditions south of QEW Low spot in road with no creek outlet Sunken driveway with minimal curb

28 Existing Conditions North of QEW Major system (walkway) will route flows safely between residences Low point on road routes flow to stormwater pond

29 Why do a Master Plan? Understand vulnerabilities and risks Understand level of risk Develop possible solutions/mitigation Increase public education and awareness Be well positioned should funding become available Heightened need driven by recent events in neighbouring communities

30 Stormwater Master Plan Similar process to TMP use of historical data to characterize infrastructure and predict future demands Phase 1: Data collection and preliminary infrastructure needs assessment Phase 2: Detailed analytical assessment, final infrastructure needs assessment and implementation plan Phase 3: Funding opportunities

31 Storm sewer Assessment Background data review Phase 1 Zoom camera inspections within core area Results 85% of inspected pipes were in state of good repair (minor pipe system)

32 SW Master Plan Phase 2 Initiated recently (notice of commencement) Analyse using a model for both minor (sewer) and major (overland) systems Identify vulnerabilities Low points in road, public flow through private lands Develop needs assessment Prepare implementation plan

33 Modelling/Simulations

34 Potential Recommendations minor drainage system improvements (e.g. increase size of sewer, add grates) major drainage system improvements (e.g. regrading) Area specific improvements (e.g. add new sewer network as recommended for Maplehurst Drive) Funding requirements for above Policy or design changes/improvements

35 Actions in the Interim Provide more information for residents Distribute informative door hanger to homes in new subdivisions Initiate Active Site Plan improvements Increase public education and awareness

36 Active Process Improvements Underway Addressing on-going intensification south of QEW in recognition of existing drainage concerns including but not limited to West Street, Maplehurst, Coronation Park, Elton Park Initiating new engineering site plan process Scoped site plan process Technical supporting studies Areas of focus: stormwater, forestry, environmental Mitigate existing local drainage issues

37 Path Forward Continue with Phase 2 Public meeting #1 Q Public meeting #2 Q Expected study completion Q Implement new engineering site plan process in 2016 Phase 3, Funding strategy initiate Q (approx. 24 months to complete)

38 QUESTIONS?

39 Community Outreach

40 Community Outreach Multiple: Tactics Climate Change Primer, events, social media, website, television advertisements, gamification Partners town and regional departments and private businesses, resident and community groups Events Fire Prevention Week and Keep Calm and Adapt plus farmer s markets, Energy and Sustainability Fair

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42 Saturday April 30, 2016 Coincides with - Earth Week - Emergency Preparedness Wk - National Safe Building Month - National Safe Boating Week Exhibitors - Regional gov t & Conservation Halton - 7 municipal dept Planning, Building, Parks, Emergency Preparedness - Office of the Fire Marshall - Insurance Bureau of Canada - Emergency Management Ontario - Local utilities exhibitors - local community groups

43 Entertainment Gamification Raffles and Giveaways